Dynamic Call Center with C# and ASP.NET MVC

In this tutorial we will show how to automate the routing of calls from customers to your support agents. In this example customers would select a product, then be connected to a specialist for that product. If no one is available our customer's number will be saved so that our agent can call them back.

This is what the application does at a high level

Configure a workspace using the Twilio TaskRouter REST API.
Listen for incoming calls and let the user select a product with the dial pad.
Create a Task with the selected product and let TaskRouter handle it.
Store missed calls so agents can return the call to customers.
Redirect users to a voice mail when no one answers the call.
Allow agents to change their status (Available/Offline) via SMS.

Configure the Workspace

In order to instruct TaskRouter to handle the Tasks, we need to configure a Workspace. We can do this in the TaskRouter Console or programmatically using the TaskRouter REST API.

In this ASP.NET MVC application this step will be executed in the Application_Start event every time you run the app.

A Workspace is the container element for any TaskRouter application. The elements are:

Tasks - Represents a customer trying to contact an agent
Workers - The agents responsible for handling Tasks
Task Queues - Holds Tasks to be consumed by a set of Workers
Workflows - Responsible for placing Tasks into Task Queues
Activities - Possible states of a Worker. Eg: idle, offline, busy

We'll use a TaskRouterClient provided in the twilio-csharp helper library to create and configure the workspace.

Create, Setup and Configure the Workspace

TaskRouter.Web/App_Start/WorkspaceConfig.cs

1using System;
2using System.Collections.Generic;
3using System.Linq;
4using System.Web.Helpers;
5using TaskRouter.Web.Infrastructure;
6using Twilio;
7using Twilio.Rest.Taskrouter.V1;
8using Twilio.Rest.Taskrouter.V1.Workspace;
9
10namespace TaskRouter.Web
11{
12    public class WorkspaceConfig
13    {
14        private readonly Config _config;
15
16        private const string VoiceQueue = "VoiceQueue";
17        private const string SmsQueue = "SMSQueue";
18        private const string AllQueue = "AllQueue";
19
20        public static void RegisterWorkspace()
21        {
22            new WorkspaceConfig().Register();
23        }
24
25        public WorkspaceConfig():this(new Config())
26        {
27        }
28
29        public WorkspaceConfig(Config config)
30        {
31            TwilioClient.Init(config.AccountSID, config.AuthToken);
32            _config = config;
33
34        }
35
36        public WorkspaceConfig(Type workspaceResource):this()
37        {
38        }
39
40        public virtual ActivityResource GetActivityByFriendlyName(string workspaceSid, string friendlyName)
41        {
42            return ActivityResource.Read(workspaceSid, friendlyName).First();
43        }
44
45        public virtual ActivityResource CreateActivityWithFriendlyName(string workspaceSid, string friendlyName)
46        {
47            return ActivityResource.Create(workspaceSid, friendlyName);
48        }
49
50        public virtual WorkspaceResource GetWorkspaceByFriendlyName(string friendlyName)
51        {
52            return WorkspaceResource.Read(friendlyName).FirstOrDefault();
53        }
54
55        public virtual WorkspaceResource CreateWorkspace(string friendlyName, Uri eventCallbackUrl)
56        {
57            return WorkspaceResource.Create(friendlyName, eventCallbackUrl);
58        }
59
60        public virtual bool DeleteWorkspace(string workspaceSid)
61        {
62            return WorkspaceResource.Delete(workspaceSid);
63        }
64
65        public virtual WorkerResource CreateWorker(string workspaceSid, string bob, string activitySid, string attributes)
66        {
67            return WorkerResource.Create(workspaceSid, bob, activitySid, attributes);
68        }
69
70        public void Register()
71        {
72            var workspace = DeleteAndCreateWorkspace(
73                "Twilio Workspace", new Uri(new Uri(_config.HostUrl), "/callback/events").AbsoluteUri);
74            var workspaceSid = workspace.Sid;
75
76            var assignmentActivity = GetActivityByFriendlyName(workspaceSid, "Unavailable");
77            var idleActivity = GetActivityByFriendlyName(workspaceSid, "Available");
78            var reservationActivity = CreateActivityWithFriendlyName(workspaceSid, "Reserved");
79            var offlineActivity = GetActivityByFriendlyName(workspaceSid, "Offline");
80
81            var workers = CreateWorkers(workspaceSid, idleActivity);
82            var taskQueues = CreateTaskQueues(workspaceSid, assignmentActivity, reservationActivity);
83            var workflow = CreateWorkflow(workspaceSid, taskQueues);
84
85            Singleton.Instance.WorkspaceSid = workspaceSid;
86            Singleton.Instance.WorkflowSid = workflow.Sid;
87            Singleton.Instance.Workers = workers;
88            Singleton.Instance.PostWorkActivitySid = idleActivity.Sid;
89            Singleton.Instance.IdleActivitySid = idleActivity.Sid;
90            Singleton.Instance.OfflineActivitySid = offlineActivity.Sid;
91        }
92
93        public virtual WorkspaceResource DeleteAndCreateWorkspace(string friendlyName, string eventCallbackUrl) {
94            var workspace = GetWorkspaceByFriendlyName(friendlyName);
95            if (workspace != null)
96            {
97                DeleteWorkspace(workspace.Sid);
98            }
99
100            return CreateWorkspace(friendlyName, new Uri(eventCallbackUrl));
101        }
102
103        private IDictionary<string, string> CreateWorkers(string workspaceSid, ActivityResource activity)
104        {
105            var attributesForBob = new
106            {
107                products = new List<object>()
108                {
109                    "ProgrammableSMS"
110                },
111                contact_uri = _config.AgentForProgrammableSMS
112            };
113
114            var bobWorker = CreateWorker(workspaceSid, "Bob", activity.Sid, Json.Encode(attributesForBob));
115
116            var attributesForAlice = new
117            {
118                products = new List<object>()
119                {
120                    "ProgrammableVoice"
121                },
122                contact_uri = _config.AgentForProgrammableVoice
123            };
124
125            var alice = CreateWorker(workspaceSid, "Alice", activity.Sid, Json.Encode(attributesForAlice));
126
127            return new Dictionary<string, string>
128            {
129                { _config.AgentForProgrammableSMS, bobWorker.Sid },
130                { _config.AgentForProgrammableVoice, alice.Sid },
131            };
132        }
133
134        public virtual TaskQueueResource CreateTaskQueue(
135            string workspaceSid, string friendlyName,
136            string assignmentActivitySid, string reservationActivitySid, string targetWorkers)
137        {
138            var queue = TaskQueueResource.Create(
139                workspaceSid,
140                friendlyName: friendlyName,
141                assignmentActivitySid: assignmentActivitySid,
142                reservationActivitySid: reservationActivitySid
143            );
144
145            TaskQueueResource.Update(
146                workspaceSid,
147                queue.Sid,
148                friendlyName,
149                targetWorkers,
150                assignmentActivitySid,
151                reservationActivitySid,
152                1);
153
154            return queue;
155        }
156
157        private IDictionary<string, TaskQueueResource> CreateTaskQueues(
158            string workspaceSid, ActivityResource assignmentActivity, ActivityResource reservationActivity)
159        {
160
161            var voiceQueue = CreateTaskQueue(
162                workspaceSid, "Voice",
163                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableVoice'");
164
165            var smsQueue = CreateTaskQueue(
166                workspaceSid, "SMS",
167                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableSMS'");
168
169            var allQueue = CreateTaskQueue(
170                workspaceSid, "All",
171                assignmentActivity.Sid, reservationActivity.Sid, "1 == 1");
172
173            return new Dictionary<string, TaskQueueResource> {
174                { VoiceQueue, voiceQueue },
175                { SmsQueue, smsQueue },
176                { AllQueue, allQueue }
177            };
178        }
179
180        public virtual WorkflowResource CreateWorkflow(string workspaceSid, IDictionary<string, TaskQueueResource> taskQueues)
181        {
182            var voiceQueue = taskQueues[VoiceQueue];
183            var smsQueue = taskQueues[SmsQueue];
184            var allQueue = taskQueues[AllQueue];
185
186            var voiceFilter = new {
187                friendlyName = "Voice",
188                expression = "selected_product==\"ProgrammableVoice\"",
189                targets = new List<object>() {
190                    new { queue = voiceQueue.Sid, Priority = "5", Timeout = "30" },
191                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
192                }
193            };
194
195            var smsFilter = new {
196                friendlyName = "SMS",
197                expression = "selected_product==\"ProgrammableSMS\"",
198                targets = new List<object>() {
199                    new { queue = smsQueue.Sid, Priority = "5", Timeout = "30" },
200                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
201                }
202            };
203
204            var workflowConfiguration = new
205            {
206                task_routing = new
207                {
208                    filters = new List<object>()
209                    {
210                        voiceFilter,
211                        smsFilter
212                    },
213                    default_filter = new
214                    {
215                        queue = allQueue.Sid,
216                        expression = "1==1",
217                        priority = "1",
218                        timeout = "30"
219                    }
220                }
221            };
222
223            // Call REST API
224            return WorkflowResource.Create(
225                workspaceSid,
226                "Tech Support",
227                Json.Encode(workflowConfiguration),
228                new Uri($"{_config.HostUrl}/callback/assignment"),
229                new Uri($"{_config.HostUrl}/callback/assignment"),
230                15);
231        }
232    }
233}

Now let's look in more detail at all the steps, starting with the creation of the workspace itself.

Create a Workspace

Before creating a workspace, we need to delete any others with the same friendlyName as the one we are trying to create. In order to create a workspace we need to provide a friendlyName and a eventCallbackUrl where a requests will be made every time an event is triggered in our workspace.

Create Workspace

TaskRouter.Web/App_Start/WorkspaceConfig.cs

1using System;
2using System.Collections.Generic;
3using System.Linq;
4using System.Web.Helpers;
5using TaskRouter.Web.Infrastructure;
6using Twilio;
7using Twilio.Rest.Taskrouter.V1;
8using Twilio.Rest.Taskrouter.V1.Workspace;
9
10namespace TaskRouter.Web
11{
12    public class WorkspaceConfig
13    {
14        private readonly Config _config;
15
16        private const string VoiceQueue = "VoiceQueue";
17        private const string SmsQueue = "SMSQueue";
18        private const string AllQueue = "AllQueue";
19
20        public static void RegisterWorkspace()
21        {
22            new WorkspaceConfig().Register();
23        }
24
25        public WorkspaceConfig():this(new Config())
26        {
27        }
28
29        public WorkspaceConfig(Config config)
30        {
31            TwilioClient.Init(config.AccountSID, config.AuthToken);
32            _config = config;
33
34        }
35
36        public WorkspaceConfig(Type workspaceResource):this()
37        {
38        }
39
40        public virtual ActivityResource GetActivityByFriendlyName(string workspaceSid, string friendlyName)
41        {
42            return ActivityResource.Read(workspaceSid, friendlyName).First();
43        }
44
45        public virtual ActivityResource CreateActivityWithFriendlyName(string workspaceSid, string friendlyName)
46        {
47            return ActivityResource.Create(workspaceSid, friendlyName);
48        }
49
50        public virtual WorkspaceResource GetWorkspaceByFriendlyName(string friendlyName)
51        {
52            return WorkspaceResource.Read(friendlyName).FirstOrDefault();
53        }
54
55        public virtual WorkspaceResource CreateWorkspace(string friendlyName, Uri eventCallbackUrl)
56        {
57            return WorkspaceResource.Create(friendlyName, eventCallbackUrl);
58        }
59
60        public virtual bool DeleteWorkspace(string workspaceSid)
61        {
62            return WorkspaceResource.Delete(workspaceSid);
63        }
64
65        public virtual WorkerResource CreateWorker(string workspaceSid, string bob, string activitySid, string attributes)
66        {
67            return WorkerResource.Create(workspaceSid, bob, activitySid, attributes);
68        }
69
70        public void Register()
71        {
72            var workspace = DeleteAndCreateWorkspace(
73                "Twilio Workspace", new Uri(new Uri(_config.HostUrl), "/callback/events").AbsoluteUri);
74            var workspaceSid = workspace.Sid;
75
76            var assignmentActivity = GetActivityByFriendlyName(workspaceSid, "Unavailable");
77            var idleActivity = GetActivityByFriendlyName(workspaceSid, "Available");
78            var reservationActivity = CreateActivityWithFriendlyName(workspaceSid, "Reserved");
79            var offlineActivity = GetActivityByFriendlyName(workspaceSid, "Offline");
80
81            var workers = CreateWorkers(workspaceSid, idleActivity);
82            var taskQueues = CreateTaskQueues(workspaceSid, assignmentActivity, reservationActivity);
83            var workflow = CreateWorkflow(workspaceSid, taskQueues);
84
85            Singleton.Instance.WorkspaceSid = workspaceSid;
86            Singleton.Instance.WorkflowSid = workflow.Sid;
87            Singleton.Instance.Workers = workers;
88            Singleton.Instance.PostWorkActivitySid = idleActivity.Sid;
89            Singleton.Instance.IdleActivitySid = idleActivity.Sid;
90            Singleton.Instance.OfflineActivitySid = offlineActivity.Sid;
91        }
92
93        public virtual WorkspaceResource DeleteAndCreateWorkspace(string friendlyName, string eventCallbackUrl) {
94            var workspace = GetWorkspaceByFriendlyName(friendlyName);
95            if (workspace != null)
96            {
97                DeleteWorkspace(workspace.Sid);
98            }
99
100            return CreateWorkspace(friendlyName, new Uri(eventCallbackUrl));
101        }
102
103        private IDictionary<string, string> CreateWorkers(string workspaceSid, ActivityResource activity)
104        {
105            var attributesForBob = new
106            {
107                products = new List<object>()
108                {
109                    "ProgrammableSMS"
110                },
111                contact_uri = _config.AgentForProgrammableSMS
112            };
113
114            var bobWorker = CreateWorker(workspaceSid, "Bob", activity.Sid, Json.Encode(attributesForBob));
115
116            var attributesForAlice = new
117            {
118                products = new List<object>()
119                {
120                    "ProgrammableVoice"
121                },
122                contact_uri = _config.AgentForProgrammableVoice
123            };
124
125            var alice = CreateWorker(workspaceSid, "Alice", activity.Sid, Json.Encode(attributesForAlice));
126
127            return new Dictionary<string, string>
128            {
129                { _config.AgentForProgrammableSMS, bobWorker.Sid },
130                { _config.AgentForProgrammableVoice, alice.Sid },
131            };
132        }
133
134        public virtual TaskQueueResource CreateTaskQueue(
135            string workspaceSid, string friendlyName,
136            string assignmentActivitySid, string reservationActivitySid, string targetWorkers)
137        {
138            var queue = TaskQueueResource.Create(
139                workspaceSid,
140                friendlyName: friendlyName,
141                assignmentActivitySid: assignmentActivitySid,
142                reservationActivitySid: reservationActivitySid
143            );
144
145            TaskQueueResource.Update(
146                workspaceSid,
147                queue.Sid,
148                friendlyName,
149                targetWorkers,
150                assignmentActivitySid,
151                reservationActivitySid,
152                1);
153
154            return queue;
155        }
156
157        private IDictionary<string, TaskQueueResource> CreateTaskQueues(
158            string workspaceSid, ActivityResource assignmentActivity, ActivityResource reservationActivity)
159        {
160
161            var voiceQueue = CreateTaskQueue(
162                workspaceSid, "Voice",
163                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableVoice'");
164
165            var smsQueue = CreateTaskQueue(
166                workspaceSid, "SMS",
167                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableSMS'");
168
169            var allQueue = CreateTaskQueue(
170                workspaceSid, "All",
171                assignmentActivity.Sid, reservationActivity.Sid, "1 == 1");
172
173            return new Dictionary<string, TaskQueueResource> {
174                { VoiceQueue, voiceQueue },
175                { SmsQueue, smsQueue },
176                { AllQueue, allQueue }
177            };
178        }
179
180        public virtual WorkflowResource CreateWorkflow(string workspaceSid, IDictionary<string, TaskQueueResource> taskQueues)
181        {
182            var voiceQueue = taskQueues[VoiceQueue];
183            var smsQueue = taskQueues[SmsQueue];
184            var allQueue = taskQueues[AllQueue];
185
186            var voiceFilter = new {
187                friendlyName = "Voice",
188                expression = "selected_product==\"ProgrammableVoice\"",
189                targets = new List<object>() {
190                    new { queue = voiceQueue.Sid, Priority = "5", Timeout = "30" },
191                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
192                }
193            };
194
195            var smsFilter = new {
196                friendlyName = "SMS",
197                expression = "selected_product==\"ProgrammableSMS\"",
198                targets = new List<object>() {
199                    new { queue = smsQueue.Sid, Priority = "5", Timeout = "30" },
200                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
201                }
202            };
203
204            var workflowConfiguration = new
205            {
206                task_routing = new
207                {
208                    filters = new List<object>()
209                    {
210                        voiceFilter,
211                        smsFilter
212                    },
213                    default_filter = new
214                    {
215                        queue = allQueue.Sid,
216                        expression = "1==1",
217                        priority = "1",
218                        timeout = "30"
219                    }
220                }
221            };
222
223            // Call REST API
224            return WorkflowResource.Create(
225                workspaceSid,
226                "Tech Support",
227                Json.Encode(workflowConfiguration),
228                new Uri($"{_config.HostUrl}/callback/assignment"),
229                new Uri($"{_config.HostUrl}/callback/assignment"),
230                15);
231        }
232    }
233}

We have a brand new workspace, now we need workers. Let's create them on the next step.

Create the Workers

We'll create two workers: Bob and Alice. They each have two attributes: contact_uri a phone number and products, a list of products each worker is specialized in. We also need to specify an activity.Sid and a name for each worker. The selected activity will define the status of the worker.

A set of default activities is created with your workspace. We use the Idle activity to make a worker available for incoming calls.

Create Workers

TaskRouter.Web/App_Start/WorkspaceConfig.cs

1using System;
2using System.Collections.Generic;
3using System.Linq;
4using System.Web.Helpers;
5using TaskRouter.Web.Infrastructure;
6using Twilio;
7using Twilio.Rest.Taskrouter.V1;
8using Twilio.Rest.Taskrouter.V1.Workspace;
9
10namespace TaskRouter.Web
11{
12    public class WorkspaceConfig
13    {
14        private readonly Config _config;
15
16        private const string VoiceQueue = "VoiceQueue";
17        private const string SmsQueue = "SMSQueue";
18        private const string AllQueue = "AllQueue";
19
20        public static void RegisterWorkspace()
21        {
22            new WorkspaceConfig().Register();
23        }
24
25        public WorkspaceConfig():this(new Config())
26        {
27        }
28
29        public WorkspaceConfig(Config config)
30        {
31            TwilioClient.Init(config.AccountSID, config.AuthToken);
32            _config = config;
33
34        }
35
36        public WorkspaceConfig(Type workspaceResource):this()
37        {
38        }
39
40        public virtual ActivityResource GetActivityByFriendlyName(string workspaceSid, string friendlyName)
41        {
42            return ActivityResource.Read(workspaceSid, friendlyName).First();
43        }
44
45        public virtual ActivityResource CreateActivityWithFriendlyName(string workspaceSid, string friendlyName)
46        {
47            return ActivityResource.Create(workspaceSid, friendlyName);
48        }
49
50        public virtual WorkspaceResource GetWorkspaceByFriendlyName(string friendlyName)
51        {
52            return WorkspaceResource.Read(friendlyName).FirstOrDefault();
53        }
54
55        public virtual WorkspaceResource CreateWorkspace(string friendlyName, Uri eventCallbackUrl)
56        {
57            return WorkspaceResource.Create(friendlyName, eventCallbackUrl);
58        }
59
60        public virtual bool DeleteWorkspace(string workspaceSid)
61        {
62            return WorkspaceResource.Delete(workspaceSid);
63        }
64
65        public virtual WorkerResource CreateWorker(string workspaceSid, string bob, string activitySid, string attributes)
66        {
67            return WorkerResource.Create(workspaceSid, bob, activitySid, attributes);
68        }
69
70        public void Register()
71        {
72            var workspace = DeleteAndCreateWorkspace(
73                "Twilio Workspace", new Uri(new Uri(_config.HostUrl), "/callback/events").AbsoluteUri);
74            var workspaceSid = workspace.Sid;
75
76            var assignmentActivity = GetActivityByFriendlyName(workspaceSid, "Unavailable");
77            var idleActivity = GetActivityByFriendlyName(workspaceSid, "Available");
78            var reservationActivity = CreateActivityWithFriendlyName(workspaceSid, "Reserved");
79            var offlineActivity = GetActivityByFriendlyName(workspaceSid, "Offline");
80
81            var workers = CreateWorkers(workspaceSid, idleActivity);
82            var taskQueues = CreateTaskQueues(workspaceSid, assignmentActivity, reservationActivity);
83            var workflow = CreateWorkflow(workspaceSid, taskQueues);
84
85            Singleton.Instance.WorkspaceSid = workspaceSid;
86            Singleton.Instance.WorkflowSid = workflow.Sid;
87            Singleton.Instance.Workers = workers;
88            Singleton.Instance.PostWorkActivitySid = idleActivity.Sid;
89            Singleton.Instance.IdleActivitySid = idleActivity.Sid;
90            Singleton.Instance.OfflineActivitySid = offlineActivity.Sid;
91        }
92
93        public virtual WorkspaceResource DeleteAndCreateWorkspace(string friendlyName, string eventCallbackUrl) {
94            var workspace = GetWorkspaceByFriendlyName(friendlyName);
95            if (workspace != null)
96            {
97                DeleteWorkspace(workspace.Sid);
98            }
99
100            return CreateWorkspace(friendlyName, new Uri(eventCallbackUrl));
101        }
102
103        private IDictionary<string, string> CreateWorkers(string workspaceSid, ActivityResource activity)
104        {
105            var attributesForBob = new
106            {
107                products = new List<object>()
108                {
109                    "ProgrammableSMS"
110                },
111                contact_uri = _config.AgentForProgrammableSMS
112            };
113
114            var bobWorker = CreateWorker(workspaceSid, "Bob", activity.Sid, Json.Encode(attributesForBob));
115
116            var attributesForAlice = new
117            {
118                products = new List<object>()
119                {
120                    "ProgrammableVoice"
121                },
122                contact_uri = _config.AgentForProgrammableVoice
123            };
124
125            var alice = CreateWorker(workspaceSid, "Alice", activity.Sid, Json.Encode(attributesForAlice));
126
127            return new Dictionary<string, string>
128            {
129                { _config.AgentForProgrammableSMS, bobWorker.Sid },
130                { _config.AgentForProgrammableVoice, alice.Sid },
131            };
132        }
133
134        public virtual TaskQueueResource CreateTaskQueue(
135            string workspaceSid, string friendlyName,
136            string assignmentActivitySid, string reservationActivitySid, string targetWorkers)
137        {
138            var queue = TaskQueueResource.Create(
139                workspaceSid,
140                friendlyName: friendlyName,
141                assignmentActivitySid: assignmentActivitySid,
142                reservationActivitySid: reservationActivitySid
143            );
144
145            TaskQueueResource.Update(
146                workspaceSid,
147                queue.Sid,
148                friendlyName,
149                targetWorkers,
150                assignmentActivitySid,
151                reservationActivitySid,
152                1);
153
154            return queue;
155        }
156
157        private IDictionary<string, TaskQueueResource> CreateTaskQueues(
158            string workspaceSid, ActivityResource assignmentActivity, ActivityResource reservationActivity)
159        {
160
161            var voiceQueue = CreateTaskQueue(
162                workspaceSid, "Voice",
163                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableVoice'");
164
165            var smsQueue = CreateTaskQueue(
166                workspaceSid, "SMS",
167                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableSMS'");
168
169            var allQueue = CreateTaskQueue(
170                workspaceSid, "All",
171                assignmentActivity.Sid, reservationActivity.Sid, "1 == 1");
172
173            return new Dictionary<string, TaskQueueResource> {
174                { VoiceQueue, voiceQueue },
175                { SmsQueue, smsQueue },
176                { AllQueue, allQueue }
177            };
178        }
179
180        public virtual WorkflowResource CreateWorkflow(string workspaceSid, IDictionary<string, TaskQueueResource> taskQueues)
181        {
182            var voiceQueue = taskQueues[VoiceQueue];
183            var smsQueue = taskQueues[SmsQueue];
184            var allQueue = taskQueues[AllQueue];
185
186            var voiceFilter = new {
187                friendlyName = "Voice",
188                expression = "selected_product==\"ProgrammableVoice\"",
189                targets = new List<object>() {
190                    new { queue = voiceQueue.Sid, Priority = "5", Timeout = "30" },
191                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
192                }
193            };
194
195            var smsFilter = new {
196                friendlyName = "SMS",
197                expression = "selected_product==\"ProgrammableSMS\"",
198                targets = new List<object>() {
199                    new { queue = smsQueue.Sid, Priority = "5", Timeout = "30" },
200                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
201                }
202            };
203
204            var workflowConfiguration = new
205            {
206                task_routing = new
207                {
208                    filters = new List<object>()
209                    {
210                        voiceFilter,
211                        smsFilter
212                    },
213                    default_filter = new
214                    {
215                        queue = allQueue.Sid,
216                        expression = "1==1",
217                        priority = "1",
218                        timeout = "30"
219                    }
220                }
221            };
222
223            // Call REST API
224            return WorkflowResource.Create(
225                workspaceSid,
226                "Tech Support",
227                Json.Encode(workflowConfiguration),
228                new Uri($"{_config.HostUrl}/callback/assignment"),
229                new Uri($"{_config.HostUrl}/callback/assignment"),
230                15);
231        }
232    }
233}

After creating our workers, let's set up the Task Queues.

Create the Task Queues

Next, we set up the Task Queues. Each with a friendlyName and a targetWorkers, which is an expression to match Workers. Our Task Queues are:

SMS - Will target Workers specialized in Programmable SMS, such as Bob, using the expression "products HAS \"ProgrammableSMS\"".
Voice - Will do the same for Programmable Voice Workers, such as Alice, using the expression "products HAS \"ProgrammableVoice\"".

Create Task Queues

TaskRouter.Web/App_Start/WorkspaceConfig.cs

1using System;
2using System.Collections.Generic;
3using System.Linq;
4using System.Web.Helpers;
5using TaskRouter.Web.Infrastructure;
6using Twilio;
7using Twilio.Rest.Taskrouter.V1;
8using Twilio.Rest.Taskrouter.V1.Workspace;
9
10namespace TaskRouter.Web
11{
12    public class WorkspaceConfig
13    {
14        private readonly Config _config;
15
16        private const string VoiceQueue = "VoiceQueue";
17        private const string SmsQueue = "SMSQueue";
18        private const string AllQueue = "AllQueue";
19
20        public static void RegisterWorkspace()
21        {
22            new WorkspaceConfig().Register();
23        }
24
25        public WorkspaceConfig():this(new Config())
26        {
27        }
28
29        public WorkspaceConfig(Config config)
30        {
31            TwilioClient.Init(config.AccountSID, config.AuthToken);
32            _config = config;
33
34        }
35
36        public WorkspaceConfig(Type workspaceResource):this()
37        {
38        }
39
40        public virtual ActivityResource GetActivityByFriendlyName(string workspaceSid, string friendlyName)
41        {
42            return ActivityResource.Read(workspaceSid, friendlyName).First();
43        }
44
45        public virtual ActivityResource CreateActivityWithFriendlyName(string workspaceSid, string friendlyName)
46        {
47            return ActivityResource.Create(workspaceSid, friendlyName);
48        }
49
50        public virtual WorkspaceResource GetWorkspaceByFriendlyName(string friendlyName)
51        {
52            return WorkspaceResource.Read(friendlyName).FirstOrDefault();
53        }
54
55        public virtual WorkspaceResource CreateWorkspace(string friendlyName, Uri eventCallbackUrl)
56        {
57            return WorkspaceResource.Create(friendlyName, eventCallbackUrl);
58        }
59
60        public virtual bool DeleteWorkspace(string workspaceSid)
61        {
62            return WorkspaceResource.Delete(workspaceSid);
63        }
64
65        public virtual WorkerResource CreateWorker(string workspaceSid, string bob, string activitySid, string attributes)
66        {
67            return WorkerResource.Create(workspaceSid, bob, activitySid, attributes);
68        }
69
70        public void Register()
71        {
72            var workspace = DeleteAndCreateWorkspace(
73                "Twilio Workspace", new Uri(new Uri(_config.HostUrl), "/callback/events").AbsoluteUri);
74            var workspaceSid = workspace.Sid;
75
76            var assignmentActivity = GetActivityByFriendlyName(workspaceSid, "Unavailable");
77            var idleActivity = GetActivityByFriendlyName(workspaceSid, "Available");
78            var reservationActivity = CreateActivityWithFriendlyName(workspaceSid, "Reserved");
79            var offlineActivity = GetActivityByFriendlyName(workspaceSid, "Offline");
80
81            var workers = CreateWorkers(workspaceSid, idleActivity);
82            var taskQueues = CreateTaskQueues(workspaceSid, assignmentActivity, reservationActivity);
83            var workflow = CreateWorkflow(workspaceSid, taskQueues);
84
85            Singleton.Instance.WorkspaceSid = workspaceSid;
86            Singleton.Instance.WorkflowSid = workflow.Sid;
87            Singleton.Instance.Workers = workers;
88            Singleton.Instance.PostWorkActivitySid = idleActivity.Sid;
89            Singleton.Instance.IdleActivitySid = idleActivity.Sid;
90            Singleton.Instance.OfflineActivitySid = offlineActivity.Sid;
91        }
92
93        public virtual WorkspaceResource DeleteAndCreateWorkspace(string friendlyName, string eventCallbackUrl) {
94            var workspace = GetWorkspaceByFriendlyName(friendlyName);
95            if (workspace != null)
96            {
97                DeleteWorkspace(workspace.Sid);
98            }
99
100            return CreateWorkspace(friendlyName, new Uri(eventCallbackUrl));
101        }
102
103        private IDictionary<string, string> CreateWorkers(string workspaceSid, ActivityResource activity)
104        {
105            var attributesForBob = new
106            {
107                products = new List<object>()
108                {
109                    "ProgrammableSMS"
110                },
111                contact_uri = _config.AgentForProgrammableSMS
112            };
113
114            var bobWorker = CreateWorker(workspaceSid, "Bob", activity.Sid, Json.Encode(attributesForBob));
115
116            var attributesForAlice = new
117            {
118                products = new List<object>()
119                {
120                    "ProgrammableVoice"
121                },
122                contact_uri = _config.AgentForProgrammableVoice
123            };
124
125            var alice = CreateWorker(workspaceSid, "Alice", activity.Sid, Json.Encode(attributesForAlice));
126
127            return new Dictionary<string, string>
128            {
129                { _config.AgentForProgrammableSMS, bobWorker.Sid },
130                { _config.AgentForProgrammableVoice, alice.Sid },
131            };
132        }
133
134        public virtual TaskQueueResource CreateTaskQueue(
135            string workspaceSid, string friendlyName,
136            string assignmentActivitySid, string reservationActivitySid, string targetWorkers)
137        {
138            var queue = TaskQueueResource.Create(
139                workspaceSid,
140                friendlyName: friendlyName,
141                assignmentActivitySid: assignmentActivitySid,
142                reservationActivitySid: reservationActivitySid
143            );
144
145            TaskQueueResource.Update(
146                workspaceSid,
147                queue.Sid,
148                friendlyName,
149                targetWorkers,
150                assignmentActivitySid,
151                reservationActivitySid,
152                1);
153
154            return queue;
155        }
156
157        private IDictionary<string, TaskQueueResource> CreateTaskQueues(
158            string workspaceSid, ActivityResource assignmentActivity, ActivityResource reservationActivity)
159        {
160
161            var voiceQueue = CreateTaskQueue(
162                workspaceSid, "Voice",
163                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableVoice'");
164
165            var smsQueue = CreateTaskQueue(
166                workspaceSid, "SMS",
167                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableSMS'");
168
169            var allQueue = CreateTaskQueue(
170                workspaceSid, "All",
171                assignmentActivity.Sid, reservationActivity.Sid, "1 == 1");
172
173            return new Dictionary<string, TaskQueueResource> {
174                { VoiceQueue, voiceQueue },
175                { SmsQueue, smsQueue },
176                { AllQueue, allQueue }
177            };
178        }
179
180        public virtual WorkflowResource CreateWorkflow(string workspaceSid, IDictionary<string, TaskQueueResource> taskQueues)
181        {
182            var voiceQueue = taskQueues[VoiceQueue];
183            var smsQueue = taskQueues[SmsQueue];
184            var allQueue = taskQueues[AllQueue];
185
186            var voiceFilter = new {
187                friendlyName = "Voice",
188                expression = "selected_product==\"ProgrammableVoice\"",
189                targets = new List<object>() {
190                    new { queue = voiceQueue.Sid, Priority = "5", Timeout = "30" },
191                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
192                }
193            };
194
195            var smsFilter = new {
196                friendlyName = "SMS",
197                expression = "selected_product==\"ProgrammableSMS\"",
198                targets = new List<object>() {
199                    new { queue = smsQueue.Sid, Priority = "5", Timeout = "30" },
200                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
201                }
202            };
203
204            var workflowConfiguration = new
205            {
206                task_routing = new
207                {
208                    filters = new List<object>()
209                    {
210                        voiceFilter,
211                        smsFilter
212                    },
213                    default_filter = new
214                    {
215                        queue = allQueue.Sid,
216                        expression = "1==1",
217                        priority = "1",
218                        timeout = "30"
219                    }
220                }
221            };
222
223            // Call REST API
224            return WorkflowResource.Create(
225                workspaceSid,
226                "Tech Support",
227                Json.Encode(workflowConfiguration),
228                new Uri($"{_config.HostUrl}/callback/assignment"),
229                new Uri($"{_config.HostUrl}/callback/assignment"),
230                15);
231        }
232    }
233}

We have a Workspace, Workers and Task Queues... what's left? A Workflow. Let's see how to create one next!

Create a Workflow

Finally, we create the Workflow using the following parameters:

friendlyName as the name of a Workflow.
assignmentCallbackUrl and fallbackAssignmentCallbackUrl as the public URL where a request will be made when this Workflow assigns a Task to a Worker. We will learn how to implement it on the next steps.
Timeout as the maximum time we want to wait until a Worker is available for handling a Task.
workflowConfiguration which is a set of rules for placing Tasks into Task Queues. The routing configuration will take a Task's attribute and match this with Task Queues. This application's Workflow rules are defined as:
- "selected_product==\ "ProgrammableSMS\"" expression for SMS Task Queue. This expression will match any Task with ProgrammableSMS as the selected_product attribute.
- "selected_product==\ "ProgrammableVoice\"" expression for Voice Task Queue.

Create a Workflow

TaskRouter.Web/App_Start/WorkspaceConfig.cs

1using System;
2using System.Collections.Generic;
3using System.Linq;
4using System.Web.Helpers;
5using TaskRouter.Web.Infrastructure;
6using Twilio;
7using Twilio.Rest.Taskrouter.V1;
8using Twilio.Rest.Taskrouter.V1.Workspace;
9
10namespace TaskRouter.Web
11{
12    public class WorkspaceConfig
13    {
14        private readonly Config _config;
15
16        private const string VoiceQueue = "VoiceQueue";
17        private const string SmsQueue = "SMSQueue";
18        private const string AllQueue = "AllQueue";
19
20        public static void RegisterWorkspace()
21        {
22            new WorkspaceConfig().Register();
23        }
24
25        public WorkspaceConfig():this(new Config())
26        {
27        }
28
29        public WorkspaceConfig(Config config)
30        {
31            TwilioClient.Init(config.AccountSID, config.AuthToken);
32            _config = config;
33
34        }
35
36        public WorkspaceConfig(Type workspaceResource):this()
37        {
38        }
39
40        public virtual ActivityResource GetActivityByFriendlyName(string workspaceSid, string friendlyName)
41        {
42            return ActivityResource.Read(workspaceSid, friendlyName).First();
43        }
44
45        public virtual ActivityResource CreateActivityWithFriendlyName(string workspaceSid, string friendlyName)
46        {
47            return ActivityResource.Create(workspaceSid, friendlyName);
48        }
49
50        public virtual WorkspaceResource GetWorkspaceByFriendlyName(string friendlyName)
51        {
52            return WorkspaceResource.Read(friendlyName).FirstOrDefault();
53        }
54
55        public virtual WorkspaceResource CreateWorkspace(string friendlyName, Uri eventCallbackUrl)
56        {
57            return WorkspaceResource.Create(friendlyName, eventCallbackUrl);
58        }
59
60        public virtual bool DeleteWorkspace(string workspaceSid)
61        {
62            return WorkspaceResource.Delete(workspaceSid);
63        }
64
65        public virtual WorkerResource CreateWorker(string workspaceSid, string bob, string activitySid, string attributes)
66        {
67            return WorkerResource.Create(workspaceSid, bob, activitySid, attributes);
68        }
69
70        public void Register()
71        {
72            var workspace = DeleteAndCreateWorkspace(
73                "Twilio Workspace", new Uri(new Uri(_config.HostUrl), "/callback/events").AbsoluteUri);
74            var workspaceSid = workspace.Sid;
75
76            var assignmentActivity = GetActivityByFriendlyName(workspaceSid, "Unavailable");
77            var idleActivity = GetActivityByFriendlyName(workspaceSid, "Available");
78            var reservationActivity = CreateActivityWithFriendlyName(workspaceSid, "Reserved");
79            var offlineActivity = GetActivityByFriendlyName(workspaceSid, "Offline");
80
81            var workers = CreateWorkers(workspaceSid, idleActivity);
82            var taskQueues = CreateTaskQueues(workspaceSid, assignmentActivity, reservationActivity);
83            var workflow = CreateWorkflow(workspaceSid, taskQueues);
84
85            Singleton.Instance.WorkspaceSid = workspaceSid;
86            Singleton.Instance.WorkflowSid = workflow.Sid;
87            Singleton.Instance.Workers = workers;
88            Singleton.Instance.PostWorkActivitySid = idleActivity.Sid;
89            Singleton.Instance.IdleActivitySid = idleActivity.Sid;
90            Singleton.Instance.OfflineActivitySid = offlineActivity.Sid;
91        }
92
93        public virtual WorkspaceResource DeleteAndCreateWorkspace(string friendlyName, string eventCallbackUrl) {
94            var workspace = GetWorkspaceByFriendlyName(friendlyName);
95            if (workspace != null)
96            {
97                DeleteWorkspace(workspace.Sid);
98            }
99
100            return CreateWorkspace(friendlyName, new Uri(eventCallbackUrl));
101        }
102
103        private IDictionary<string, string> CreateWorkers(string workspaceSid, ActivityResource activity)
104        {
105            var attributesForBob = new
106            {
107                products = new List<object>()
108                {
109                    "ProgrammableSMS"
110                },
111                contact_uri = _config.AgentForProgrammableSMS
112            };
113
114            var bobWorker = CreateWorker(workspaceSid, "Bob", activity.Sid, Json.Encode(attributesForBob));
115
116            var attributesForAlice = new
117            {
118                products = new List<object>()
119                {
120                    "ProgrammableVoice"
121                },
122                contact_uri = _config.AgentForProgrammableVoice
123            };
124
125            var alice = CreateWorker(workspaceSid, "Alice", activity.Sid, Json.Encode(attributesForAlice));
126
127            return new Dictionary<string, string>
128            {
129                { _config.AgentForProgrammableSMS, bobWorker.Sid },
130                { _config.AgentForProgrammableVoice, alice.Sid },
131            };
132        }
133
134        public virtual TaskQueueResource CreateTaskQueue(
135            string workspaceSid, string friendlyName,
136            string assignmentActivitySid, string reservationActivitySid, string targetWorkers)
137        {
138            var queue = TaskQueueResource.Create(
139                workspaceSid,
140                friendlyName: friendlyName,
141                assignmentActivitySid: assignmentActivitySid,
142                reservationActivitySid: reservationActivitySid
143            );
144
145            TaskQueueResource.Update(
146                workspaceSid,
147                queue.Sid,
148                friendlyName,
149                targetWorkers,
150                assignmentActivitySid,
151                reservationActivitySid,
152                1);
153
154            return queue;
155        }
156
157        private IDictionary<string, TaskQueueResource> CreateTaskQueues(
158            string workspaceSid, ActivityResource assignmentActivity, ActivityResource reservationActivity)
159        {
160
161            var voiceQueue = CreateTaskQueue(
162                workspaceSid, "Voice",
163                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableVoice'");
164
165            var smsQueue = CreateTaskQueue(
166                workspaceSid, "SMS",
167                assignmentActivity.Sid, reservationActivity.Sid, "products HAS 'ProgrammableSMS'");
168
169            var allQueue = CreateTaskQueue(
170                workspaceSid, "All",
171                assignmentActivity.Sid, reservationActivity.Sid, "1 == 1");
172
173            return new Dictionary<string, TaskQueueResource> {
174                { VoiceQueue, voiceQueue },
175                { SmsQueue, smsQueue },
176                { AllQueue, allQueue }
177            };
178        }
179
180        public virtual WorkflowResource CreateWorkflow(string workspaceSid, IDictionary<string, TaskQueueResource> taskQueues)
181        {
182            var voiceQueue = taskQueues[VoiceQueue];
183            var smsQueue = taskQueues[SmsQueue];
184            var allQueue = taskQueues[AllQueue];
185
186            var voiceFilter = new {
187                friendlyName = "Voice",
188                expression = "selected_product==\"ProgrammableVoice\"",
189                targets = new List<object>() {
190                    new { queue = voiceQueue.Sid, Priority = "5", Timeout = "30" },
191                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
192                }
193            };
194
195            var smsFilter = new {
196                friendlyName = "SMS",
197                expression = "selected_product==\"ProgrammableSMS\"",
198                targets = new List<object>() {
199                    new { queue = smsQueue.Sid, Priority = "5", Timeout = "30" },
200                    new { queue = allQueue.Sid, Expression = "1==1", Priority = "1", Timeout = "30" }
201                }
202            };
203
204            var workflowConfiguration = new
205            {
206                task_routing = new
207                {
208                    filters = new List<object>()
209                    {
210                        voiceFilter,
211                        smsFilter
212                    },
213                    default_filter = new
214                    {
215                        queue = allQueue.Sid,
216                        expression = "1==1",
217                        priority = "1",
218                        timeout = "30"
219                    }
220                }
221            };
222
223            // Call REST API
224            return WorkflowResource.Create(
225                workspaceSid,
226                "Tech Support",
227                Json.Encode(workflowConfiguration),
228                new Uri($"{_config.HostUrl}/callback/assignment"),
229                new Uri($"{_config.HostUrl}/callback/assignment"),
230                15);
231        }
232    }
233}

Our workspace is completely setup. Now it's time to see how we use it to route calls.

Handle Twilio's Request

Right after receiving a call, Twilio will send a request to the URL specified on the number's configuration.

The endpoint will then process the request and generate a TwiML response. We'll use the Say verb to give the user product alternatives, and a key they can press in order to select one. The Gather verb allows us to capture the user's key press.

Handling Twilio's Requests

TaskRouter.Web/Controllers/CallController.cs

1using System.Web.Mvc;
2using TaskRouter.Web.Infrastructure;
3using TaskRouter.Web.Models;
4using TaskRouter.Web.Services;
5using Twilio.AspNet.Mvc;
6using Twilio.TwiML;
7
8namespace TaskRouter.Web.Controllers
9{
10    public class CallController : TwilioController
11    {
12        private readonly IMissedCallsService _service;
13
14        public CallController()
15        {
16            _service = new MissedCallsService(new TaskRouterDbContext());
17        }
18
19        public CallController(IMissedCallsService service)
20        {
21            _service = service;
22        }
23
24        [HttpPost]
25        public ActionResult Incoming()
26        {
27            var response = new VoiceResponse();
28            var gather = new Gather(numDigits: 1, action: "/call/enqueue", method: "POST");
29            gather.Say("For Programmable SMS, press one. For Voice, press any other key.");
30            response.Gather(gather);
31
32            return TwiML(response);
33        }
34
35        [HttpPost]
36        public ActionResult Enqueue(string digits)
37        {
38            var selectedProduct = digits == "1" ? "ProgrammableSMS" : "ProgrammableVoice";
39            var response = new VoiceResponse();
40
41            response.Enqueue(
42                selectedProduct,
43                workflowSid: Singleton.Instance.WorkflowSid);
44
45            return TwiML(response);
46        }
47
48
49    }
50}

We just asked the caller to choose a product, next we will use their choice to create the appropriate Task.

Create a Task

This is the endpoint set as the action URL on the Gather verb on the previous step. A request is made to this endpoint when the user presses a key during the call. This request has a Digits parameter that holds the pressed keys. A Task will be created based on the pressed digit with the selected_product as an attribute. The Workflow will take this Task's attributes and match them with the configured expressions in order to find a Task Queue for this Task, so an appropriate available Worker can be assigned to handle it.

We use the Enqueue verb with a WorkflowSid attribute to integrate with TaskRouter. Then the voice call will be put on hold while TaskRouter tries to find an available Worker to handle this Task.

Create a Task

TaskRouter.Web/Controllers/CallController.cs

1using System.Web.Mvc;
2using TaskRouter.Web.Infrastructure;
3using TaskRouter.Web.Models;
4using TaskRouter.Web.Services;
5using Twilio.AspNet.Mvc;
6using Twilio.TwiML;
7
8namespace TaskRouter.Web.Controllers
9{
10    public class CallController : TwilioController
11    {
12        private readonly IMissedCallsService _service;
13
14        public CallController()
15        {
16            _service = new MissedCallsService(new TaskRouterDbContext());
17        }
18
19        public CallController(IMissedCallsService service)
20        {
21            _service = service;
22        }
23
24        [HttpPost]
25        public ActionResult Incoming()
26        {
27            var response = new VoiceResponse();
28            var gather = new Gather(numDigits: 1, action: "/call/enqueue", method: "POST");
29            gather.Say("For Programmable SMS, press one. For Voice, press any other key.");
30            response.Gather(gather);
31
32            return TwiML(response);
33        }
34
35        [HttpPost]
36        public ActionResult Enqueue(string digits)
37        {
38            var selectedProduct = digits == "1" ? "ProgrammableSMS" : "ProgrammableVoice";
39            var response = new VoiceResponse();
40
41            response.Enqueue(
42                selectedProduct,
43                workflowSid: Singleton.Instance.WorkflowSid);
44
45            return TwiML(response);
46        }
47
48
49    }
50}

After sending a Task to Twilio, let's see how we tell TaskRouter which Worker to use to execute that task.

Assign a Worker

When TaskRouter selects a Worker, it does the following:

The Task's Assignment Status is set to 'reserved'.
A Reservation instance is generated, linking the Task to the selected Worker.
At the same time the Reservation is created, a POST request is made to the Workflow's AssignmentCallbackURL, which was configured using the WorkspaceConfig class when the application is initialized. This request includes the full details of the Task, the selected Worker, and the Reservation.

Handling this Assignment Callback is a key component of building a TaskRouter application as we can instruct how the Worker will handle a Task. We could send a text, email, push notifications or make a call.

Since we created this Task during a voice call with an Enqueue verb, let's instruct TaskRouter to dequeue the call and dial a Worker. If we do not specify a to parameter with a phone number, TaskRouter will pick the Worker's contact_uri attribute.

We also send a post_work_activity_sid which will tell TaskRouter which Activity to assign this worker after the call ends.

Assign a Worker

TaskRouter.Web/Controllers/CallbackController.cs

1using Newtonsoft.Json;
2using System;
3using System.Linq;
4using System.Threading.Tasks;
5using System.Web.Mvc;
6using TaskRouter.Web.Infrastructure;
7using TaskRouter.Web.Models;
8using TaskRouter.Web.Services;
9using Twilio;
10using Twilio.AspNet.Mvc;
11using Twilio.Rest.Api.V2010.Account;
12using Twilio.Types;
13
14namespace TaskRouter.Web.Controllers
15{
16    public class CallbackController : TwilioController
17    {
18        private readonly IMissedCallsService _service;
19
20        public CallbackController()
21        {
22            _service = new MissedCallsService(new TaskRouterDbContext());
23
24            if (Config.ENV != "test")
25            {
26                TwilioClient.Init(Config.AccountSID, Config.AuthToken);
27            }
28        }
29
30        public CallbackController(IMissedCallsService service)
31        {
32            _service = service;
33        }
34
35        [HttpPost]
36        public ActionResult Assignment()
37        {
38            var response = new
39            {
40                instruction = "dequeue",
41                post_work_activity_sid = Singleton.Instance.PostWorkActivitySid
42            };
43
44            return new JsonResult() { Data = response };
45        }
46
47        [HttpPost]
48        public async Task<ActionResult> Events(
49            string eventType, string taskAttributes, string workerSid, string workerActivityName, string workerAttributes)
50        {
51            if (IsEventTimeoutOrCanceled(eventType))
52            {
53                await CreateMissedCallAndRedirectToVoiceMail(taskAttributes);
54            }
55
56            if (HasWorkerChangedToOffline(eventType, workerActivityName))
57            {
58                SendMessageToWorker(workerSid, workerAttributes);
59            }
60
61            return new EmptyResult();
62        }
63
64
65        private bool IsEventTimeoutOrCanceled(string eventType)
66        {
67            var desiredEvents = new string[] { "workflow.timeout", "task.canceled" };
68            return desiredEvents.Any(e => e == eventType);
69        }
70
71        private bool HasWorkerChangedToOffline(string eventType, string workerActivityName)
72        {
73            return eventType == "worker.activity.update" && workerActivityName == "Offline";
74        }
75
76        private async Task CreateMissedCallAndRedirectToVoiceMail(string taskAttributes)
77        {
78            dynamic attributes = JsonConvert.DeserializeObject(taskAttributes);
79            var missedCall = new MissedCall
80            {
81                PhoneNumber = attributes.from,
82                Product = attributes.selected_product,
83                CreatedAt = DateTime.Now
84            };
85
86            await _service.CreateAsync(missedCall);
87            string voiceSid = attributes.call_sid;
88            VoiceMail(voiceSid);
89        }
90
91        private void SendMessageToWorker(string workerSid, string workerAttributes)
92        {
93            const string message = "You went offline. To make yourself available reply with \"on\"";
94
95            dynamic attributes = JsonConvert.DeserializeObject(workerAttributes);
96            string workerPhoneNumber = attributes.contact_uri;
97
98            MessageResource.Create(
99                to: new PhoneNumber(Config.TwilioNumber),
100                from: new PhoneNumber(workerPhoneNumber),
101                body: message
102            );
103        }
104
105        private void VoiceMail(string callSid)
106        {
107            var msg = "Sorry, All agents are busy. Please leave a message. We will call you as soon as possible";
108            var routeUrl = "http://twimlets.com/voicemail?Email=" + Config.VoiceMail + "&Message=" + Url.Encode(msg);
109            CallResource.Update(callSid, url: new Uri(routeUrl));
110        }
111    }
112}

Now that our Tasks are routed properly, let's deal with missed calls in the next step.

Collect Missed Calls

This endpoint will be called after each TaskRouter Event is triggered. In our application, we are trying to collect missed calls, so we would like to handle the workflow.timeout event. This event is triggered when the Task waits more than the limit set on Workflow Configuration-- or rather when no worker is available.

Here we use TwilioRestClient to route this call to a Voicemail Twimlet. Twimlets are tiny web applications for voice. This one will generate a TwiML response using Say verb and record a message using Record verb. The recorded message will then be transcribed and sent to the email address configured.

Note that we are also listening for task.canceled. This is triggered when the customer hangs up before being assigned to an agent, therefore canceling the task. Capturing this event allows us to collect the information from the customers that hang up before the Workflow times out.

Collect Missed Calls

TaskRouter.Web/Controllers/CallbackController.cs

1using Newtonsoft.Json;
2using System;
3using System.Linq;
4using System.Threading.Tasks;
5using System.Web.Mvc;
6using TaskRouter.Web.Infrastructure;
7using TaskRouter.Web.Models;
8using TaskRouter.Web.Services;
9using Twilio;
10using Twilio.AspNet.Mvc;
11using Twilio.Rest.Api.V2010.Account;
12using Twilio.Types;
13
14namespace TaskRouter.Web.Controllers
15{
16    public class CallbackController : TwilioController
17    {
18        private readonly IMissedCallsService _service;
19
20        public CallbackController()
21        {
22            _service = new MissedCallsService(new TaskRouterDbContext());
23
24            if (Config.ENV != "test")
25            {
26                TwilioClient.Init(Config.AccountSID, Config.AuthToken);
27            }
28        }
29
30        public CallbackController(IMissedCallsService service)
31        {
32            _service = service;
33        }
34
35        [HttpPost]
36        public ActionResult Assignment()
37        {
38            var response = new
39            {
40                instruction = "dequeue",
41                post_work_activity_sid = Singleton.Instance.PostWorkActivitySid
42            };
43
44            return new JsonResult() { Data = response };
45        }
46
47        [HttpPost]
48        public async Task<ActionResult> Events(
49            string eventType, string taskAttributes, string workerSid, string workerActivityName, string workerAttributes)
50        {
51            if (IsEventTimeoutOrCanceled(eventType))
52            {
53                await CreateMissedCallAndRedirectToVoiceMail(taskAttributes);
54            }
55
56            if (HasWorkerChangedToOffline(eventType, workerActivityName))
57            {
58                SendMessageToWorker(workerSid, workerAttributes);
59            }
60
61            return new EmptyResult();
62        }
63
64
65        private bool IsEventTimeoutOrCanceled(string eventType)
66        {
67            var desiredEvents = new string[] { "workflow.timeout", "task.canceled" };
68            return desiredEvents.Any(e => e == eventType);
69        }
70
71        private bool HasWorkerChangedToOffline(string eventType, string workerActivityName)
72        {
73            return eventType == "worker.activity.update" && workerActivityName == "Offline";
74        }
75
76        private async Task CreateMissedCallAndRedirectToVoiceMail(string taskAttributes)
77        {
78            dynamic attributes = JsonConvert.DeserializeObject(taskAttributes);
79            var missedCall = new MissedCall
80            {
81                PhoneNumber = attributes.from,
82                Product = attributes.selected_product,
83                CreatedAt = DateTime.Now
84            };
85
86            await _service.CreateAsync(missedCall);
87            string voiceSid = attributes.call_sid;
88            VoiceMail(voiceSid);
89        }
90
91        private void SendMessageToWorker(string workerSid, string workerAttributes)
92        {
93            const string message = "You went offline. To make yourself available reply with \"on\"";
94
95            dynamic attributes = JsonConvert.DeserializeObject(workerAttributes);
96            string workerPhoneNumber = attributes.contact_uri;
97
98            MessageResource.Create(
99                to: new PhoneNumber(Config.TwilioNumber),
100                from: new PhoneNumber(workerPhoneNumber),
101                body: message
102            );
103        }
104
105        private void VoiceMail(string callSid)
106        {
107            var msg = "Sorry, All agents are busy. Please leave a message. We will call you as soon as possible";
108            var routeUrl = "http://twimlets.com/voicemail?Email=" + Config.VoiceMail + "&Message=" + Url.Encode(msg);
109            CallResource.Update(callSid, url: new Uri(routeUrl));
110        }
111    }
112}

Most of the features of our application are implemented. The last piece is allowing the Workers to change their availability status. Let's see how to do that next.

Change a Worker's Activity

We have created this endpoint, so a worker can send an SMS message to the support line with the command "On" or "Off" to change their availability status.

This is important as a worker's activity will change to Offline when they miss a call. When this happens, they receive an SMS letting them know that their activity has changed, and that they can reply with the On command to make themselves available for incoming calls again.

Changing a Worker's Activity

TaskRouter.Web/Controllers/MessageController.cs

1using System;
2using System.Web.Mvc;
3using TaskRouter.Web.Infrastructure;
4using Twilio;
5using Twilio.AspNet.Mvc;
6using Twilio.Rest.Taskrouter.V1.Workspace;
7using Twilio.TwiML;
8
9namespace TaskRouter.Web.Controllers
10{
11    public class MessageController : TwilioController
12    {
13        private const string On = "on";
14        private const string Off = "off";
15
16        public MessageController()
17        {
18            if (Config.ENV != "test")
19            {
20                TwilioClient.Init(Config.AccountSID, Config.AuthToken);
21            }
22        }
23
24        public virtual WorkerResource FetchWorker(string workspaceSid, string workerSid)
25        {
26            return WorkerResource.Fetch(workspaceSid, workerSid);
27        }
28
29        public virtual WorkerResource UpdateWorker(string pathWorkspaceSid, string pathSid, string activitySid = null,
30            string attributes = null, string friendlyName = null)
31        {
32            return WorkerResource.Update(pathWorkspaceSid, pathSid, activitySid, attributes, friendlyName);
33        }
34
35        [HttpPost]
36        public ActionResult Incoming(string from, string body)
37        {
38            var workspaceSid = Singleton.Instance.WorkspaceSid;
39            var workerSid = Singleton.Instance.Workers[from];
40            var idleActivitySid = Singleton.Instance.IdleActivitySid;
41            var offlineActivitySid = Singleton.Instance.OfflineActivitySid;
42            var message = "Unrecognized command, reply with \"on\" to activate your worker or \"off\" otherwise";
43
44            var worker = FetchWorker(workspaceSid, workerSid);
45
46            if (body.Equals(On, StringComparison.InvariantCultureIgnoreCase))
47            {
48                UpdateWorker(workspaceSid, workerSid, idleActivitySid, worker.Attributes, worker.FriendlyName);
49                message = "Your worker is online";
50            }
51
52            if (body.Equals(Off, StringComparison.InvariantCultureIgnoreCase))
53            {
54                UpdateWorker(workspaceSid, workerSid, offlineActivitySid, worker.Attributes, worker.FriendlyName);
55                message = "Your worker is offline";
56            }
57
58            return TwiML(new MessagingResponse().Message(message));
59        }
60    }
61}

Congratulations! You finished this tutorial. As you can see, using Twilio's TaskRouter is quite simple.

Where to Next?

If you're a .NET developer working with Twilio, you might also enjoy these tutorials:

Voice JavaScript SDK Quickstart

Learn how to use Twilio Voice SDK to make browser-to-phone and browser-to-browser calls with ease.

ETA-Notifications

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