Programmable SMS Quickstart for C# with .NET Core

With just a few lines of code, your .NET Core application can send and receive text messages with Twilio Programmable SMS.

This C# SMS Quickstart will teach you how to do this using our Communications REST API and the Twilio helper library for .NET Core.

このクイックスタートでは、下記のことを学んでいきます:

1. Twilioにサインアップして、SMS機能を持ったはじめてのTwilio電話番号を入手する
2. メッセージを送受信できるように開発環境をセットアップする
3. 最初のSMSを送信する
4. テキストメッセージを受信する
5. 受信メッセージに対してSMSで返信する

ビデオを見ながらの入門がお好みですか？ YouTube上のC# SMSクイックスタートビデオ（英語）をご覧ください。

Twilioにサインアップし電話番号を入手する

Before you can send an SMS from C#, you'll need to sign up for a Twilio account or sign into your existing account and purchase an SMS-capable phone number.

Now that you have a Twilio account and a programmable phone number, you can start writing some code! To make things even easier, we'll install Twilio's official helper for .NET Core applications.

Install .NET Core

You can check if you already have .NET Core installed on your machine by opening up a command prompt or terminal and running the following command:

dotnet --version

You should see something like 2.1.3. If you receive an error message, you can download .NET Core from Microsoft and install it.

Create a new project and add the Twilio NuGet package

Run these commands to create a new .NET project and install the Twilio NuGet package:

mkdir TwilioSend
cd TwilioSend
dotnet new console
dotnet add package Twilio

Send an outbound SMS message with C#

Now that we have .NET Core and the Twilio .NET NuGet package installed, we can send an outbound text message from the Twilio phone number we just purchased with a single API request. Open the file in your new project called Program.cs and type or paste in this code sample, replacing the template code that's already there.

メッセージの送信前に、このファイルを少々編集する必要があります:

プレースホルダーのクレデンシャル値を置き換える

Swap the placeholder values for accountSid and authToken with your personal Twilio credentials. Go to https://www.twilio.com/console and log in. On this page, you’ll find your unique Account SID and Auth Token, which you’ll need any time you send messages through the Twilio Client like this. You can reveal your auth token by clicking on the 'view' link:

Program.csを編集し、accountSidおよびauthTokenに対応する値をご使用の一意な値に置き換えます。

Replace the "from" phone number

数分前に購入した、SMS機能対応の電話番号を覚えていますか？ どうぞ、既存のfrom番号をご自身の番号に置き換えてください。 また、E.164形式が使用されていることも確認します。

[+][country code][phone number including area code]

「To」電話番号を置き換える

Replace the to phone number with your mobile phone number. This can be any phone number that can receive text messages, but it’s a good idea to test with your own phone, so you can see the magic happen! As above, you should use E.164 formatting for this value.

Save your changes and run this code:

dotnet run

一丁上がり！ ほどなくして、Twilio電話番号から携帯電話にSMSが受信されるはずです。

Are your customers in the U.S. or Canada? You can also send them MMS messages by adding just one line of code. Check out this sending MMS tutorial to see how it's done.

Receive and reply to inbound SMS messages with ASP.NET Core

When your Twilio number receives an incoming message, Twilio will send an HTTP request to a server you control. This callback mechanism is known as a webhook. When Twilio sends your application a request, it expects a response in the TwiML XML format telling it how to respond to the message. Let's see how we would build this in C# using ASP.NET Core.

Create a new ASP.NET Core project

Run these commands to create a new ASP.NET Core project and install the Twilio NuGet package:

mkdir TwilioReceive
cd TwilioReceive
dotnet new mvc
dotnet add package Twilio.AspNet.Core

Create a new controller

Controllersという名前のディレクトリーで、SmsController.csという新規コントローラーを作成し、下記のコードを使用して受信メッセージを処理できるサーバーを作成します。

You now need to make your application accessible over the internet. While you can do that in any number of ways, we recommend a tool that provides an externally accessible URL called ngrok. We'll show you how to set that up next so your app can receive messages.

Allow Twilio to talk to your ASP.NET Core application with ngrok

We’ve just built a small ASP.NET Core application to receive incoming messages. Before it will work, we need to make sure that Twilio can reach your application.

ほとんどのTwilioのサービスはWebhookを使用して皆さんのアプリケーションと通信を行います。たとえばTwilioがSMSを受信すると、メッセージの処理方法の指示を得ようと、皆さんのアプリケーションのURLにアクセスを行います。

When you’re working on your ASP.NET Core application in your development environment, your app is only reachable by other programs on your computer, so Twilio won’t be able to talk to it. We need to solve this problem by making your application accessible over the internet.

While there are a lot of ways to do this, like deploying your application to Azure or AWS, you'll probably want a less laborious way to test your Twilio application. For a lightweight way to make your app available on the internet, we recommend a tool called ngrok. Ngrok listens on the same port that your local web server is running on and provides a unique URL on the ngrok.io domain, forwarding incoming requests to your local development environment. It works something like this:

If you haven't done so already, download and install ngrok. For more info on ngrok, including some great tips and tricks, check out this in-depth blog post.

Change your application's launch settings

Once you have ngrok downloaded, you need to make one small change to the Properties/launchSettings.json file. Find the line that has:

"applicationUrl": "https://localhost:5001;http://localhost:5000",

And change it to:

"applicationUrl": "http://localhost:5000",

This change is needed because ngrok will create a secure tunnel for you but will not work with the self-signed certificate that ASP.NET Core provides.

Start your ASP.NET Core application

Start your application by running:

dotnet run

You should see Now listening on: http://localhost:5000. You can try opening http://localhost:5000/sms in the browser and see the TwiML response we will be sending to Twilio. As we discussed, however, Twilio can't find your localhost, so we need one more step.

Start the ngrok tunnel

Now, start up ngrok on port 5000:

ngrok http 5000

You should see something like the following:

これで、外部からアクセスできるURLを用意できました。

WebhookのURLを設定する

Twilioにどこを参照して良いか知らせるため、メッセージの受信時にTwilio電話番号にWebhook URLを呼び出すよう構成することが必要です。

1. jp.twilio.comにログインし、Console上の電話番号ページに移動します
   
2. SMS機能対応の電話番号をクリックします。
3. メッセージの送受信セクションを見つけます。 「構成内容 (CONFIGURE WITH) 」は、既定である「Webhook/TwiML」にしておく必要があります。
4. In the “A MESSAGE COMES IN” section, select "Webhook" and paste in your URL: in this quickstart step above, it would be: https://354f5b25.ngrok.io/sms - be sure to add /sms at the end, as this is the route to your SmsController class.

変更点を保存すれば、準備万端です！

アプリケーションをテストする

Make sure your project is running and your ngrok tunnel is running. If you restarted ngrok, you will have to update your webhook in the console to use the right URL.

With both of those servers running, we’re ready for the fun part - testing our new ASP.NET Core SMS application!

Send an SMS from your mobile phone to your Twilio phone number that's configured with this webhook. You should see an HTTP request in your ngrok console. Your ASP.NET Core app will process the text message, and you’ll get your response back as an SMS.

関連トピック

C#および.NETを使用したSMSおよびMMSの送受信の基本について理解できたところで、下記の資料について調べてみるのも良いかもしれません。

• REST API documentation
• TwiMLリファレンス・ドキュメント
• C#用の完全なサンプルアプリケーションを含むチュートリアル
• Twilioの着信リクエストを検証してC# / ASP.NETアプリケーションを安全にする

楽しいプログラミングを！