Support Metadata in GridFSAdapter (#6660)

* 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.

* fix tests

* Make getMetadata optional

* Revert "fix tests"

This reverts commit 7706da13c688027483974e854b5b24321fb070cd.

* improve coverage

spec/FilesController.spec.js

@@ -8,6 +8,7 @@ const GridStoreAdapter = require('../lib/Adapters/Files/GridStoreAdapter')
   .GridStoreAdapter;
 const Config = require('../lib/Config');
 const FilesController = require('../lib/Controllers/FilesController').default;
+const databaseURI = 'mongodb://localhost:27017/parse';
 
 const mockAdapter = {
   createFile: () => {
@@ -23,13 +24,13 @@ const mockAdapter = {
 
 // Small additional tests to improve overall coverage
 describe('FilesController', () => {
-  it('should properly expand objects', done => {
+  it('should properly expand objects', (done) => {
     const config = Config.get(Parse.applicationId);
     const gridStoreAdapter = new GridFSBucketAdapter(
       'mongodb://localhost:27017/parse'
     );
     const filesController = new FilesController(gridStoreAdapter);
-    const result = filesController.expandFilesInObject(config, function() {});
+    const result = filesController.expandFilesInObject(config, function () {});
 
     expect(result).toBeUndefined();
 
@@ -47,7 +48,7 @@ describe('FilesController', () => {
     done();
   });
 
-  it('should create a server log on failure', done => {
+  it('should create a server log on failure', (done) => {
     const logController = new LoggerController(new WinstonLoggerAdapter());
 
     reconfigureServer({ filesAdapter: mockAdapter })
@@ -56,22 +57,20 @@ describe('FilesController', () => {
         () => done.fail('should not succeed'),
         () => setImmediate(() => Promise.resolve('done'))
       )
-      .then(() => new Promise(resolve => setTimeout(resolve, 200)))
+      .then(() => new Promise((resolve) => setTimeout(resolve, 200)))
       .then(() =>
         logController.getLogs({ from: Date.now() - 1000, size: 1000 })
       )
-      .then(logs => {
+      .then((logs) => {
         // we get two logs here: 1. the source of the failure to save the file
         // and 2 the message that will be sent back to the client.
 
         const log1 = logs.find(
-          x => x.message === 'Error creating a file: it failed with xyz'
+          (x) => x.message === 'Error creating a file: it failed with xyz'
         );
         expect(log1.level).toBe('error');
 
-        const log2 = logs.find(
-          x => x.message === 'it failed with xyz'
-        );
+        const log2 = logs.find((x) => x.message === 'it failed with xyz');
         expect(log2.level).toBe('error');
         expect(log2.code).toBe(130);
 
@@ -79,7 +78,7 @@ describe('FilesController', () => {
       });
   });
 
-  it('should create a parse error when a string is returned', done => {
+  it('should create a parse error when a string is returned', (done) => {
     const mock2 = mockAdapter;
     mock2.validateFilename = () => {
       return 'Bad file! No biscuit!';
@@ -92,7 +91,7 @@ describe('FilesController', () => {
     done();
   });
 
-  it('should add a unique hash to the file name when the preserveFileName option is false', done => {
+  it('should add a unique hash to the file name when the preserveFileName option is false', (done) => {
     const config = Config.get(Parse.applicationId);
     const gridStoreAdapter = new GridFSBucketAdapter(
       'mongodb://localhost:27017/parse'
@@ -115,7 +114,7 @@ describe('FilesController', () => {
     done();
   });
 
-  it('should not add a unique hash to the file name when the preserveFileName option is true', done => {
+  it('should not add a unique hash to the file name when the preserveFileName option is true', (done) => {
     const config = Config.get(Parse.applicationId);
     const gridStoreAdapter = new GridFSBucketAdapter(
       'mongodb://localhost:27017/parse'
@@ -137,7 +136,16 @@ describe('FilesController', () => {
     done();
   });
 
-  it('should reject slashes in file names', done => {
+  it('should handle adapter without getMetadata', async () => {
+    const gridStoreAdapter = new GridFSBucketAdapter(databaseURI);
+    gridStoreAdapter.getMetadata = null;
+    const filesController = new FilesController(gridStoreAdapter);
+
+    const result = await filesController.getMetadata();
+    expect(result).toEqual({});
+  });
+
+  it('should reject slashes in file names', (done) => {
     const gridStoreAdapter = new GridFSBucketAdapter(
       'mongodb://localhost:27017/parse'
     );
@@ -146,7 +154,7 @@ describe('FilesController', () => {
     done();
   });
 
-  it('should also reject slashes in file names', done => {
+  it('should also reject slashes in file names', (done) => {
     const gridStoreAdapter = new GridStoreAdapter(
       'mongodb://localhost:27017/parse'
     );