This guide assumes you have already set up your web application to receive incoming phone calls. If you still need to complete this step, check out this guide. It should walk you through the process of buying a Twilio number and configuring your app to receive incoming calls.
The <Gather> TwiML verb allows us to collect input from the user during a phone call. Gathering user input through the keypad is a core mechanism of Interactive Voice Response (IVR) systems where users can press "1" to connect to one menu of options and press "2" to reach another. These prompts can be accompanied by voice prompts to the caller, using the TwiML <Say> and <Play> verbs. In this example, we will prompt the user to enter a number to connect to a certain department within our little IVR system.
If the user doesn't enter any input after a configurable timeout, Twilio will continue processing the TwiML in the document to determine what should happen next in the call. When the end of the document is reached, Twilio will hang up the call. In the above example, we use the <Redirect> verb to have Twilio request the same URL again, repeating the prompt for the user
If a user were to enter input with the example above, the user would hear the same prompt over and over again regardless of what button you pressed. By default, if the user does enter input in the <Gather>, Twilio will send another HTTP request to the current webhook URL with a POST parameter containing the Digits entered by the user. In the sample above, we weren't handling this input at all. Let's update that logic to also process user input if it is present.
アプリケーション中にまったく別の呼び出し先を設けて、ユーザー入力を処理したいこともあるでしょう。 <Gather>動詞の"action"属性を使えばこれが可能です。 サンプルを書き換え、ユーザー入力の処理を受け持つ第2の呼び出し先を追加してみましょう。