Sinch.Functions.Runtime 0.3.12

Sinch.Functions.Runtime

Development runtime for Sinch Functions - build serverless communication workflows with ease.

Getting Started

The easiest way to get started is using the Sinch CLI:

# Install the CLI
npm install -g @sinch/cli

# Create a new function (interactive)
sinch functions init

The interactive prompt will guide you through:

1. Selecting a runtime (Node.js, C#, etc.)
2. Choosing a template (simple-voice-ivr recommended for first project)
3. Setting up your project

Then start the local development server:

sinch functions dev

Your function is now running locally with hot reload!

Deploy to Production

When you're ready to deploy:

sinch functions deploy

Your function will be built and deployed to the Sinch Functions platform.

Features

Voice API

• SinchVoiceController - Base controller for voice callbacks (ICE, PIE, ACE, DICE)
• SVAML Builders - Fluent API for building voice responses (IceSvamletBuilder, PieSvamletBuilder)
• Menu Utilities - IVR menu builders (MenuFactory.CreateMenu())
• Voice Helpers - TTS, audio playback, and call control utilities
• Webhook Validation - HMAC signature validation for Voice API callbacks

Conversation API

• SinchConversationController - Base controller for omnichannel messaging (SMS, WhatsApp, Messenger, Viber)
• Message Builders - Static helpers and fluent builder for messages
• Extension Methods - Easy access to inbound message properties
• Multi-Channel Support - Automatic SMS_SENDER handling, channel-specific configurations
• Webhook Routing - Automatic routing to typed handlers

Infrastructure

• FunctionContext - Pre-configured SDK clients, caching, logging
• Local Development - In-memory caching, tunnel support for local debugging
• SDK Integration - Pre-configured Sinch SDK clients for Voice and Conversation APIs

Voice IVR Example

using SinchFunctions.Utils;

public class FunctionController : SinchVoiceController
{
    public FunctionController(FunctionContext context, IConfiguration configuration, ILogger<FunctionController> logger)
        : base(context, configuration, logger) { }

    public override async Task<IActionResult> Ice([FromBody] IceCallbackModel callbackData)
    {
        // Create a voice menu
        var menu = MenuFactory.CreateMenu()
            .Prompt("Welcome to Sinch! Press 1 for sales, 2 for support.")
            .Option("1", "return(sales)")
            .Option("2", "return(support)")
            .Build();

        // Return SVAML response
        return Ok(new IceSvamletBuilder()
            .Action.RunMenu(menu)
            .Build());
    }

    public override async Task<IActionResult> Pie([FromBody] PieCallbackModel callbackData)
    {
        var selection = callbackData.MenuResult?.Value;

        return selection switch
        {
            "sales" => Ok(new PieSvamletBuilder().Action.ConnectPstn("+15551234567").Build()),
            "support" => Ok(new PieSvamletBuilder().Action.ConnectPstn("+15559876543").Build()),
            _ => Ok(new PieSvamletBuilder().Action.Hangup().Build())
        };
    }
}

Conversation API Chatbot Example

using Sinch.Conversation.Hooks;
using SinchFunctions.Utils;

public class FunctionController : SinchConversationController
{
    public FunctionController(FunctionContext context, IConfiguration config, ILogger<FunctionController> logger)
        : base(context, config, logger) { }

    public override async Task<IActionResult> MessageInbound(MessageInboundEvent inbound)
    {
        // Use extension methods for easy property access
        var text = inbound.GetText();
        var channel = inbound.GetChannel();
        var contactId = inbound.GetContactId();

        if (string.IsNullOrEmpty(text))
        {
            Logger.LogDebug("Ignoring non-text message from {ContactId}", contactId);
            return Ok();
        }

        Logger.LogInformation("Message from {ContactId} via {Channel}: {Text}", contactId, channel, text);

        // Reply using helper method (auto-sets SMS_SENDER from config for SMS)
        await Context.Conversation!.Messages.Send(Reply(inbound, "Thanks for your message!"));

        return Ok(new { status = "ok" });
    }

    public override Task<IActionResult> MessageDelivery(MessageDeliveryReceiptEvent callback)
    {
        var status = callback.MessageDeliveryReport?.Status?.Value;
        Logger.LogInformation("Delivery status: {Status}", status);
        return Task.FromResult<IActionResult>(Ok());
    }
}

Conversation API Extension Methods

// Easy access to inbound message properties
var text = inbound.GetText();           // Message text content
var channel = inbound.GetChannel();     // SMS, WHATSAPP, MESSENGER, etc.
var identity = inbound.GetIdentity();   // Sender's channel identity (phone/PSID)
var contactId = inbound.GetContactId(); // Sinch contact ID
var to = inbound.GetTo();               // Number the message was sent TO

// Check message types
if (inbound.IsTextMessage()) { /* handle text */ }
if (inbound.IsMediaMessage()) { /* handle media */ }
if (inbound.IsPostback()) { /* handle button click */ }

Conversation API Message Builders

// Simple reply - uses channel from inbound message
await Context.Conversation!.Messages.Send(Reply(inbound, "Hello!"));

// Static helper for SMS
var msg = ConversationMessage.CreateSms(appId, "+15551234567", "Hello!", smsSender);
await Context.Conversation!.Messages.Send(msg);

// Static helper for WhatsApp
var msg = ConversationMessage.CreateWhatsApp(appId, "+15551234567", "Hello!");
await Context.Conversation!.Messages.Send(msg);

// Fluent builder for complex cases
var msg = CreateMessage(inbound)
    .Text("Custom reply")
    .Build();
await Context.Conversation!.Messages.Send(msg);

Conversation API Webhook Events

Conversation API Configuration

Request Limits

A body larger than the limit is rejected with 413 before your handler runs.

The platform router in front of a deployed function enforces the same 10 MB cap, so a body that your handler accepts locally is not rejected in transit once deployed. Exactly 10485760 bytes is accepted; one byte more returns 413.

Logs retain the first 64 KB of a request or response body, appending …[truncated — N bytes total] when the body was longer. Only text formats are retained — JSON, XML, plain text and form data. Anything else, including uploads, images, audio, video, PDFs and archives, is not logged at all. Your function still receives every body in full.

Documentation

• Sinch Functions Documentation
• Sinch Voice API
• Sinch Conversation API
• SVAML Reference

License

MIT License - see LICENSE file for details