Add route to download app backups

src/apps.js

@@ -56,6 +56,7 @@ exports = module.exports = {
     backup,
     listBackups,
     updateBackup,
+    getBackupDownloadStream,
 
     getTask,
     getLogPaths,
@@ -175,9 +176,11 @@ const appstore = require('./appstore.js'),
     shell = require('./shell.js'),
     spawn = require('child_process').spawn,
     split = require('split'),
+    storage = require('./storage.js'),
     superagent = require('superagent'),
     system = require('./system.js'),
     tasks = require('./tasks.js'),
+    tgz = require('./backupformat/tgz.js'),
     TransformStream = require('stream').Transform,
     users = require('./users.js'),
     util = require('util'),
@@ -2617,6 +2620,25 @@ async function updateBackup(app, backupId, data) {
     await backups.update(backupId, data);
 }
 
+async function getBackupDownloadStream(app, backupId) {
+    assert.strictEqual(typeof app, 'object');
+    assert.strictEqual(typeof backupId, 'string');
+
+    const backup = await backups.get(backupId);
+    if (!backup) throw new BoxError(BoxError.NOT_FOUND, 'Backup not found');
+    if (backup.identifier !== app.id) throw new BoxError(BoxError.NOT_FOUND, 'Backup not found'); // some other app's backup
+    if (backup.format !== 'tgz') throw new BoxError(BoxError.BAD_STATE, 'only tgz backups can be downloaded');
+
+    const backupConfig = await settings.getBackupConfig();
+
+    return new Promise((resolve, reject) => {
+        storage.api(backupConfig.provider).download(backupConfig, tgz.getBackupFilePath(backupConfig, backup.remotePath), function (error, sourceStream) {
+            if (error) return reject(error);
+            resolve(sourceStream);
+        });
+    });
+}
+
 async function restoreInstalledApps(options, auditSource) {
     assert.strictEqual(typeof options, 'object');
     assert.strictEqual(typeof auditSource, 'object');

src/routes/apps.js

@@ -56,6 +56,7 @@ exports = module.exports = {
     downloadFile,
 
     updateBackup,
+    downloadBackup,
 
     getLimits,
     getGraphs,
@@ -852,6 +853,17 @@ async function updateBackup(req, res, next) {
     next(new HttpSuccess(200, {}));
 }
 
+async function downloadBackup(req, res, next) {
+    assert.strictEqual(typeof req.app, 'object');
+    assert.strictEqual(typeof req.params.backupId, 'string');
+
+    const [error, result] = await safe(apps.getBackupDownloadStream(req.app, req.params.backupId));
+    if (error) return next(BoxError.toHttpError(error));
+
+    res.attachment(`${req.params.backupId}.tgz`);
+    result.pipe(res);
+}
+
 async function uploadFile(req, res, next) {
     assert.strictEqual(typeof req.app, 'object');
 

src/server.js

@@ -242,6 +242,7 @@ function initializeExpressSync() {
     router.post('/api/v1/apps/:id/backup',                       json, token, routes.apps.load, authorizeOperator, routes.apps.backup);
     router.get ('/api/v1/apps/:id/backups',                            token, routes.apps.load, authorizeOperator, routes.apps.listBackups);
     router.post('/api/v1/apps/:id/backups/:backupId',            json, token, routes.apps.load, authorizeOperator, routes.apps.updateBackup);
+    router.get ('/api/v1/apps/:id/backups/:backupId/download',         token, routes.apps.load, authorizeOperator, routes.apps.downloadBackup);
     router.post('/api/v1/apps/:id/start',                        json, token, routes.apps.load, authorizeOperator, routes.apps.start);
     router.post('/api/v1/apps/:id/stop',                         json, token, routes.apps.load, authorizeOperator, routes.apps.stop);
     router.post('/api/v1/apps/:id/restart',                      json, token, routes.apps.load, authorizeOperator, routes.apps.restart);