Support Metadata in GridFSAdapter

* Useful for testing in the JS SDK
* Adds new endpoint to be used with `Parse.File.getData`
* Allows file adapters to return tags as well as future data.

Author: dplewis

spec/GridFSBucketStorageAdapter.spec.js

@@ -4,6 +4,7 @@ const GridFSBucketAdapter = require('../lib/Adapters/Files/GridFSBucketAdapter')
   .GridFSBucketAdapter;
 const { randomString } = require('../lib/cryptoUtils');
 const databaseURI = 'mongodb://localhost:27017/parse';
+const request = require('../lib/request');
 
 async function expectMissingFile(gfsAdapter, name) {
   try {
@@ -33,6 +34,57 @@ describe_only_db('mongo')('GridFSBucket and GridStore interop', () => {
     expect(gfsResult.toString('utf8')).toBe(originalString);
   });
 
+  it('should save metadata', async () => {
+    const gfsAdapter = new GridFSBucketAdapter(databaseURI);
+    const originalString = 'abcdefghi';
+    const metadata = { hello: 'world' };
+    await gfsAdapter.createFile('myFileName', originalString, null, {
+      metadata,
+    });
+    const gfsResult = await gfsAdapter.getFileData('myFileName');
+    expect(gfsResult.toString('utf8')).toBe(originalString);
+    let gfsMetadata = await gfsAdapter.getMetadata('myFileName');
+    expect(gfsMetadata.metadata).toEqual(metadata);
+
+    // Empty json for file not found
+    gfsMetadata = await gfsAdapter.getMetadata('myUnknownFile');
+    expect(gfsMetadata).toEqual({});
+  });
+
+  it('should save metadata with file', async () => {
+    const gfsAdapter = new GridFSBucketAdapter(databaseURI);
+    await reconfigureServer({ filesAdapter: gfsAdapter });
+    const str = 'Hello World!';
+    const data = [];
+    for (let i = 0; i < str.length; i++) {
+      data.push(str.charCodeAt(i));
+    }
+    const metadata = { foo: 'bar' };
+    const file = new Parse.File('hello.txt', data, 'text/plain');
+    file.addMetadata('foo', 'bar');
+    await file.save();
+    let fileData = await gfsAdapter.getMetadata(file.name());
+    expect(fileData.metadata).toEqual(metadata);
+
+    // Can only add metadata on create
+    file.addMetadata('hello', 'world');
+    await file.save();
+    fileData = await gfsAdapter.getMetadata(file.name());
+    expect(fileData.metadata).toEqual(metadata);
+
+    const headers = {
+      'X-Parse-Application-Id': 'test',
+      'X-Parse-REST-API-Key': 'rest',
+    };
+    const response = await request({
+      method: 'GET',
+      headers,
+      url: `http://localhost:8378/1/files/test/metadata/${file.name()}`,
+    });
+    fileData = response.data;
+    expect(fileData.metadata).toEqual(metadata);
+  });
+
   it('properly fetches a large file from GridFS', async () => {
     const gfsAdapter = new GridFSBucketAdapter(databaseURI);
     const twoMegabytesFile = randomString(2048 * 1024);

src/Adapters/Files/FilesAdapter.js

@@ -61,6 +61,14 @@ export class FilesAdapter {
    */
   getFileData(filename: string): Promise<any> {}
 
+  /** Responsible for retrieving metadata and tags
+   *
+   * @param {string} filename - the filename to retrieve metadata
+   *
+   * @return {Promise} a promise that should pass with metadata
+   */
+  getMetadata(filename: string): Promise<any> {}
+
   /** Returns an absolute URL where the file can be accessed
    *
    * @param {Config} config - server configuration

src/Adapters/Files/GridFSBucketAdapter.js

@@ -32,7 +32,7 @@ export class GridFSBucketAdapter extends FilesAdapter {
       this._connectionPromise = MongoClient.connect(
         this._databaseURI,
         this._mongoOptions
-      ).then(client => {
+      ).then((client) => {
         this._client = client;
         return client.db(client.s.options.dbName);
       });
@@ -41,14 +41,16 @@ export class GridFSBucketAdapter extends FilesAdapter {
   }
 
   _getBucket() {
-    return this._connect().then(database => new GridFSBucket(database));
+    return this._connect().then((database) => new GridFSBucket(database));
   }
 
   // For a given config object, filename, and data, store a file
   // Returns a promise
-  async createFile(filename: string, data) {
+  async createFile(filename: string, data, contentType, options = {}) {
     const bucket = await this._getBucket();
-    const stream = await bucket.openUploadStream(filename);
+    const stream = await bucket.openUploadStream(filename, {
+      metadata: options.metadata,
+    });
     await stream.write(data);
     stream.end();
     return new Promise((resolve, reject) => {
@@ -64,7 +66,7 @@ export class GridFSBucketAdapter extends FilesAdapter {
       throw new Error('FileNotFound');
     }
     return Promise.all(
-      documents.map(doc => {
+      documents.map((doc) => {
         return bucket.delete(doc._id);
       })
     );
@@ -76,13 +78,13 @@ export class GridFSBucketAdapter extends FilesAdapter {
     stream.read();
     return new Promise((resolve, reject) => {
       const chunks = [];
-      stream.on('data', data => {
+      stream.on('data', (data) => {
         chunks.push(data);
       });
       stream.on('end', () => {
         resolve(Buffer.concat(chunks));
       });
-      stream.on('error', err => {
+      stream.on('error', (err) => {
         reject(err);
       });
     });
@@ -98,6 +100,16 @@ export class GridFSBucketAdapter extends FilesAdapter {
     );
   }
 
+  async getMetadata(filename) {
+    const bucket = await this._getBucket();
+    const files = await bucket.find({ filename }).toArray();
+    if (files.length === 0) {
+      return {};
+    }
+    const { metadata } = files[0];
+    return { metadata };
+  }
+
   async handleFileStream(filename: string, req, res, contentType) {
     const bucket = await this._getBucket();
     const files = await bucket.find({ filename }).toArray();
@@ -122,7 +134,7 @@ export class GridFSBucketAdapter extends FilesAdapter {
     });
     const stream = bucket.openDownloadStreamByName(filename);
     stream.start(start);
-    stream.on('data', chunk => {
+    stream.on('data', (chunk) => {
       res.write(chunk);
     });
     stream.on('error', () => {

src/Controllers/FilesController.js

@@ -45,14 +45,21 @@ export class FilesController extends AdaptableController {
     return this.adapter.deleteFile(filename);
   }
 
+  getMetadata(filename) {
+    if (typeof this.adapter.getMetadata === 'function') {
+      return this.adapter.getMetadata(filename);
+    }
+    return Promise.resolve({});
+  }
+
   /**
    * Find file references in REST-format object and adds the url key
    * with the current mount point and app id.
    * Object may be a single object or list of REST-format objects.
    */
   expandFilesInObject(config, object) {
     if (object instanceof Array) {
-      object.map(obj => this.expandFilesInObject(config, obj));
+      object.map((obj) => this.expandFilesInObject(config, obj));
       return;
     }
     if (typeof object !== 'object') {

src/Routers/FilesRouter.js

@@ -10,14 +10,16 @@ const http = require('http');
 
 const downloadFileFromURI = (uri) => {
   return new Promise((res, rej) => {
-    http.get(uri, (response) => {
-      response.setDefaultEncoding('base64');
-      let body = `data:${response.headers['content-type']};base64,`;
-      response.on('data', data => body += data);
-      response.on('end', () => res(body));
-    }).on('error', (e) => {
-      rej(`Error downloading file from ${uri}: ${e.message}`);
-    });
+    http
+      .get(uri, (response) => {
+        response.setDefaultEncoding('base64');
+        let body = `data:${response.headers['content-type']};base64,`;
+        response.on('data', (data) => (body += data));
+        response.on('end', () => res(body));
+      })
+      .on('error', (e) => {
+        rej(`Error downloading file from ${uri}: ${e.message}`);
+      });
   });
 };
 
@@ -38,14 +40,15 @@ const errorMessageFromError = (e) => {
     return e.message;
   }
   return undefined;
-}
+};
 
 export class FilesRouter {
   expressRouter({ maxUploadSize = '20Mb' } = {}) {
     var router = express.Router();
     router.get('/files/:appId/:filename', this.getHandler);
+    router.get('/files/:appId/metadata/:filename', this.metadataHandler);
 
-    router.post('/files', function(req, res, next) {
+    router.post('/files', function (req, res, next) {
       next(
         new Parse.Error(Parse.Error.INVALID_FILE_NAME, 'Filename not provided.')
       );
@@ -88,7 +91,7 @@ export class FilesRouter {
     } else {
       filesController
         .getFileData(config, filename)
-        .then(data => {
+        .then((data) => {
           res.status(200);
           res.set('Content-Type', contentType);
           res.set('Content-Length', data.length);
@@ -135,7 +138,7 @@ export class FilesRouter {
         fileObject,
         config,
         req.auth
-      )
+      );
       let saveResult;
       // if a new ParseFile is returned check if it's an already saved file
       if (triggerResult instanceof Parse.File) {
@@ -187,16 +190,12 @@ export class FilesRouter {
       res.status(201);
       res.set('Location', saveResult.url);
       res.json(saveResult);
-
     } catch (e) {
       logger.error('Error creating a file: ', e);
-      const errorMessage = errorMessageFromError(e) || `Could not store file: ${fileObject.file._name}.`;
-      next(
-        new Parse.Error(
-          Parse.Error.FILE_SAVE_ERROR,
-          errorMessage
-        )
-      );
+      const errorMessage =
+        errorMessageFromError(e) ||
+        `Could not store file: ${fileObject.file._name}.`;
+      next(new Parse.Error(Parse.Error.FILE_SAVE_ERROR, errorMessage));
     }
   }
 
@@ -207,7 +206,7 @@ export class FilesRouter {
       // run beforeDeleteFile trigger
       const file = new Parse.File(filename);
       file._url = filesController.adapter.getFileLocation(req.config, filename);
-      const fileObject = { file, fileSize: null }
+      const fileObject = { file, fileSize: null };
       await triggers.maybeRunFileTrigger(
         triggers.Types.beforeDeleteFile,
         fileObject,
@@ -229,12 +228,21 @@ export class FilesRouter {
     } catch (e) {
       logger.error('Error deleting a file: ', e);
       const errorMessage = errorMessageFromError(e) || `Could not delete file.`;
-      next(
-        new Parse.Error(
-          Parse.Error.FILE_DELETE_ERROR,
-          errorMessage
-        )
-      );
+      next(new Parse.Error(Parse.Error.FILE_DELETE_ERROR, errorMessage));
+    }
+  }
+
+  async metadataHandler(req, res) {
+    const config = Config.get(req.params.appId);
+    const { filesController } = config;
+    const { filename } = req.params;
+    try {
+      const data = await filesController.getMetadata(filename);
+      res.status(200);
+      res.json(data);
+    } catch (e) {
+      res.status(200);
+      res.json({});
     }
   }
 }