src/telegram: Add TelegramBot#getFileStream()

References:

  * FR: https://github.com/yagop/node-telegram-bot-api/issues/442

CHANGELOG.md

@@ -12,6 +12,8 @@ Added:
   * (#440) *TelegramBot#setChatStickerSet*, *TelegramBot#deleteChatStickerSet* (by @kamikazechaser)
 1. Support Bot API v3.5:
   * Support `provider_data` parameter in *TelegramBot#sendInvoice* (by @GochoMugo)
+1. Add methods:
+  * *TelegramBot#getFileStream* (#442) (by @GochoMugo, requested-by @Xaqron)
 1. Add options to *TelegramBot#stopPolling()* (by @GochoMugo)
 1. Add `metadata` argument in `message` event (and
    friends e.g. `text`, `audio`, etc.) (#409) (by @jlsjonas, @GochoMugo)

doc/api.md

@@ -61,6 +61,7 @@ TelegramBot
         * [.sendContact(chatId, phoneNumber, firstName, [options])](#TelegramBot+sendContact) ⇒ <code>Promise</code>
         * [.getFile(fileId, [options])](#TelegramBot+getFile) ⇒ <code>Promise</code>
         * [.getFileLink(fileId, [options])](#TelegramBot+getFileLink) ⇒ <code>Promise</code>
+        * [.getFileStream(fileId, [options])](#TelegramBot+getFileStream) ⇒ <code>stream.Readable</code>
         * [.downloadFile(fileId, downloadDir, [options])](#TelegramBot+downloadFile) ⇒ <code>Promise</code>
         * [.onText(regexp, callback)](#TelegramBot+onText)
         * [.removeTextListener(regexp)](#TelegramBot+removeTextListener) ⇒ <code>Object</code>
@@ -841,6 +842,22 @@ which returns just path to file on remote server (you will have to manually buil
 | fileId | <code>String</code> | File identifier to get info about |
 | [options] | <code>Object</code> | Additional Telegram query options |
 
+<a name="TelegramBot+getFileStream"></a>
+
+### telegramBot.getFileStream(fileId, [options]) ⇒ <code>stream.Readable</code>
+Return a readable stream for file.
+
+This method is a sugar extension of the [getFileLink](#TelegramBot+getFileLink) method,
+which returns the full URI to the file on remote server.
+
+**Kind**: instance method of <code>[TelegramBot](#TelegramBot)</code>  
+**Returns**: <code>stream.Readable</code> - stream  
+
+| Param | Type | Description |
+| --- | --- | --- |
+| fileId | <code>String</code> | File identifier to get info about |
+| [options] | <code>Object</code> | Additional Telegram query options |
+
 <a name="TelegramBot+downloadFile"></a>
 
 ### telegramBot.downloadFile(fileId, downloadDir, [options]) ⇒ <code>Promise</code>

package.json

@@ -53,6 +53,7 @@
     "babel-plugin-transform-strict-mode": "^6.6.5",
     "babel-preset-es2015": "^6.6.0",
     "babel-register": "^6.7.2",
+    "concat-stream": "^1.6.0",
     "contributor": "^0.1.25",
     "eslint": "^2.13.1",
     "eslint-config-airbnb": "^6.2.0",

src/telegram.js

@@ -1322,6 +1322,28 @@ class TelegramBot extends EventEmitter {
       .then(resp => `${this.options.baseApiUrl}/file/bot${this.token}/${resp.file_path}`);
   }
 
+  /**
+   * Return a readable stream for file.
+   *
+   * This method is a sugar extension of the [getFileLink](#TelegramBot+getFileLink) method,
+   * which returns the full URI to the file on remote server.
+   *
+   * @param  {String} fileId File identifier to get info about
+   * @param  {Object} [options] Additional Telegram query options
+   * @return {stream.Readable} stream
+   */
+  getFileStream(fileId, form = {}) {
+    const fileStream = new stream.PassThrough();
+    this.getFileLink(fileId, form)
+      .then((fileURI) => {
+        pump(streamedRequest({ uri: fileURI }), fileStream);
+      })
+      .catch((error) => {
+        fileStream.emit('error', error);
+      });
+    return fileStream;
+  }
+
   /**
    * Downloads file in the specified folder.
    * This is just a sugar for (getFile)[#getfilefiled] method

test/telegram.js

@@ -5,9 +5,11 @@ const assert = require('assert');
 const fs = require('fs');
 const os = require('os');
 const path = require('path');
+const stream = require('stream');
 const is = require('is');
 const utils = require('./utils');
 const isCI = require('is-ci');
+const concat = require('concat-stream');
 
 // Allows self-signed certificates to be used in our tests
 process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
@@ -41,6 +43,7 @@ const ip = '216.58.210.174'; // Google IP ¯\_(ツ)_/¯
 const cert = `${__dirname}/../examples/crt.pem`;
 const lat = 47.5351072;
 const long = -52.7508537;
+const FILE_PATH = `${__dirname}/data/photo.gif`;
 let FILE_ID;
 let GAME_CHAT_ID;
 let GAME_MSG_ID;
@@ -101,7 +104,7 @@ describe('TelegramBot', function telegramSuite() {
     utils.handleRatelimit(bot, 'sendPhoto', this);
     utils.handleRatelimit(bot, 'sendMessage', this);
     utils.handleRatelimit(bot, 'sendGame', this);
-    return bot.sendPhoto(USERID, `${__dirname}/data/photo.gif`).then(resp => {
+    return bot.sendPhoto(USERID, FILE_PATH).then(resp => {
       FILE_ID = resp.photo[0].file_id;
       return bot.sendMessage(USERID, 'chat');
     }).then(resp => {
@@ -1162,6 +1165,21 @@ describe('TelegramBot', function telegramSuite() {
     });
   });
 
+  describe('#getFileStream', function getFileStreamSuite() {
+    this.timeout(timeout);
+    before(function before() {
+      // utils.handleRatelimit(bot, 'getFileStream', this);
+    });
+    it('should get a file stream', function test(done) {
+      const fileStream = bot.getFileStream(FILE_ID);
+      assert.ok(fileStream instanceof stream.Readable);
+      fileStream.pipe(concat(function readFile(buffer) {
+        buffer.equals(fs.readFileSync(FILE_PATH)); // sync :(
+        return done();
+      }));
+    });
+  });
+
   describe('#downloadFile', function downloadFileSuite() {
     const downloadPath = os.tmpdir();
     this.timeout(timeout);
@@ -1362,9 +1380,9 @@ describe('TelegramBot', function telegramSuite() {
       });
     });
     it('should allow stream.path that can not be parsed', function test() {
-      const stream = fs.createReadStream(`${__dirname}/data/photo.gif`);
+      const fileStream = fs.createReadStream(`${__dirname}/data/photo.gif`);
-      stream.path = '/?id=123'; // for example, 'http://example.com/?id=666'
+      fileStream.path = '/?id=123'; // for example, 'http://example.com/?id=666'
-      return bot.sendPhoto(USERID, stream);
+      return bot.sendPhoto(USERID, fileStream);
     });
   });