Show only save file dialog when clicking public file link

For #390

src/browser/components/MattermostView.jsx

@@ -64,9 +64,14 @@ const MattermostView = React.createClass({
         ipcRenderer.send('confirm-protocol', destURL.protocol, e.url);
         return;
       }
+
       if (currentURL.host === destURL.host) {
-        // New window should disable nodeIntergration.
+        if (destURL.path.match(/^\/api\/v[3-4]\/public\/files\//)) {
-        window.open(e.url, 'Mattermost', 'nodeIntegration=no, show=yes');
+          ipcRenderer.send('download-url', e.url);
+        } else {
+          // New window should disable nodeIntergration.
+          window.open(e.url, 'Mattermost', 'nodeIntegration=no, show=yes');
+        }
       } else {
         // if the link is external, use default browser.
         shell.openExternal(e.url);

src/main.js

@@ -61,6 +61,7 @@ var certificateStore = require('./main/certificateStore').load(path.resolve(app.
 const {createMainWindow} = require('./main/mainWindow');
 const appMenu = require('./main/menus/app');
 const trayMenu = require('./main/menus/tray');
+const downloadURL = require('./main/downloadURL');
 const allowProtocolDialog = require('./main/allowProtocolDialog');
 
 const assetsDir = path.resolve(app.getAppPath(), 'assets');
@@ -323,6 +324,14 @@ app.on('login', (event, webContents, request, authInfo, callback) => {
 
 allowProtocolDialog.init(mainWindow);
 
+ipcMain.on('download-url', (event, URL) => {
+  downloadURL(mainWindow, URL, (err) => {
+    if (err) {
+      console.log(err);
+    }
+  });
+});
+
 // This method will be called when Electron has finished
 // initialization and is ready to create browser windows.
 app.on('ready', () => {

src/main/downloadURL.js

@@ -0,0 +1,52 @@
+const fs = require('fs');
+const path = require('path');
+const zlib = require('zlib');
+const electron = require('electron');
+const {app, dialog} = electron;
+
+function downloadURL(browserWindow, URL, callback) {
+  const {net} = electron;
+  const request = net.request(URL);
+  request.setHeader('Accept-Encoding', 'gzip,deflate');
+  request.on('response', (response) => {
+    const file = getAttachmentName(response.headers);
+    const dialogOptions = {
+      defaultPath: path.join(app.getPath('downloads'), file)
+    };
+    dialog.showSaveDialog(browserWindow, dialogOptions, (filename) => {
+      if (filename) {
+        saveResponseBody(response, filename, callback);
+      }
+    });
+  }).on('error', callback);
+  request.end();
+}
+
+function getAttachmentName(headers) {
+  if (headers['content-disposition']) {
+    const contentDisposition = headers['content-disposition'][0];
+    const matched = contentDisposition.match(/filename="(.*)"/);
+    if (matched) {
+      return path.basename(matched[1]);
+    }
+  }
+  return '';
+}
+
+function saveResponseBody(response, filename, callback) {
+  const output = fs.createWriteStream(filename);
+  output.on('close', callback).on('error', callback);
+  switch (response.headers['content-encoding']) {
+  case 'gzip':
+    response.pipe(zlib.createGunzip()).pipe(output).on('error', callback);
+    break;
+  case 'deflate':
+    response.pipe(zlib.createInflate()).pipe(output).on('error', callback);
+    break;
+  default:
+    response.pipe(output).on('error', callback);
+    break;
+  }
+}
+
+module.exports = downloadURL;