From f28416fbaf72b74bcf682e4b5486a3cd0bcef5fb Mon Sep 17 00:00:00 2001
From: GochoMugo <mugo@forfuture.co.ke>
Date: Fri, 8 Dec 2017 19:37:12 +0300
Subject: [PATCH] src/telegram: Implement downloadFile() in terms of
 getFileStream()

---
 doc/api.md      |  4 +++-
 src/telegram.js | 33 +++++++++++++++++++--------------
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/doc/api.md b/doc/api.md
index 28a0fd0..a8e7a8f 100644
--- a/doc/api.md
+++ b/doc/api.md
@@ -867,7 +867,9 @@ which returns the full URI to the file on remote server.
 
 ### telegramBot.downloadFile(fileId, downloadDir, [options]) ⇒ <code>Promise</code>
 Downloads file in the specified folder.
-This is just a sugar for (getFile)[#getfilefiled] method
+
+This method is a sugar extension of the [getFileStream](#TelegramBot+getFileStream) method,
+which returns a readable file stream.
 
 **Kind**: instance method of <code>[TelegramBot](#TelegramBot)</code>  
 **Returns**: <code>Promise</code> - promise Promise, which will have *filePath* of downloaded file in resolve callback  
diff --git a/src/telegram.js b/src/telegram.js
index a1be259..7c6b2e7 100644
--- a/src/telegram.js
+++ b/src/telegram.js
@@ -1355,7 +1355,9 @@ class TelegramBot extends EventEmitter {
 
   /**
    * Downloads file in the specified folder.
-   * This is just a sugar for (getFile)[#getfilefiled] method
+   *
+   * This method is a sugar extension of the [getFileStream](#TelegramBot+getFileStream) method,
+   * which returns a readable file stream.
    *
    * @param  {String} fileId  File identifier to get info about
    * @param  {String} downloadDir Absolute path to the folder in which file will be saved
@@ -1363,20 +1365,23 @@ class TelegramBot extends EventEmitter {
    * @return {Promise} promise Promise, which will have *filePath* of downloaded file in resolve callback
    */
   downloadFile(fileId, downloadDir, form = {}) {
-    return this
-      .getFileLink(fileId, form)
-      .then(fileURI => {
-        const fileName = fileURI.slice(fileURI.lastIndexOf('/') + 1);
-        // TODO: Ensure fileName doesn't contains slashes
-        const filePath = path.join(downloadDir, fileName);
-
-        // properly handles errors and closes all streams
-        return Promise
-          .fromCallback(next => {
-            pump(streamedRequest({ uri: fileURI }), fs.createWriteStream(filePath), next);
-          })
-          .return(filePath);
+    let resolve;
+    let reject;
+    const promise = new Promise((a, b) => {
+      resolve = a;
+      reject = b;
+    });
+    const fileStream = this.getFileStream(fileId, form);
+    fileStream.on('info', (info) => {
+      const fileName = info.uri.slice(info.uri.lastIndexOf('/') + 1);
+      // TODO: Ensure fileName doesn't contains slashes
+      const filePath = path.join(downloadDir, fileName);
+      pump(fileStream, fs.createWriteStream(filePath), (error) => {
+        if (error) { return reject(error); }
+        return resolve(filePath);
       });
+    });
+    return promise;
   }
 
   /**