Stream video with GridFSBucketAdapter (implements byte-range requests) (#6028)

* Stream video with GridFSBucketAdapter (implements byte-range requests)

Closes: https://github.com/parse-community/parse-server/issues/5834

Similar to https://github.com/parse-community/parse-server/pull/2437

I ran into this issue while trying to view a mov file in safari from the dashboard.

* Rename getFileStream to handleFileStream

src/Adapters/Files/GridFSBucketAdapter.js

@@ -59,7 +59,7 @@ export class GridFSBucketAdapter extends FilesAdapter {
 
   async deleteFile(filename: string) {
     const bucket = await this._getBucket();
-    const documents = await bucket.find({ filename: filename }).toArray();
+    const documents = await bucket.find({ filename }).toArray();
     if (documents.length === 0) {
       throw new Error('FileNotFound');
     }
@@ -71,7 +71,8 @@ export class GridFSBucketAdapter extends FilesAdapter {
   }
 
   async getFileData(filename: string) {
-    const stream = await this.getDownloadStream(filename);
+    const bucket = await this._getBucket();
+    const stream = bucket.openDownloadStreamByName(filename);
     stream.read();
     return new Promise((resolve, reject) => {
       const chunks = [];
@@ -97,9 +98,39 @@ export class GridFSBucketAdapter extends FilesAdapter {
     );
   }
 
-  async getDownloadStream(filename: string) {
+  async handleFileStream(filename: string, req, res, contentType) {
     const bucket = await this._getBucket();
-    return bucket.openDownloadStreamByName(filename);
+    const files = await bucket.find({ filename }).toArray();
+    if (files.length === 0) {
+      throw new Error('FileNotFound');
+    }
+    const parts = req
+      .get('Range')
+      .replace(/bytes=/, '')
+      .split('-');
+    const partialstart = parts[0];
+    const partialend = parts[1];
+
+    const start = parseInt(partialstart, 10);
+    const end = partialend ? parseInt(partialend, 10) : files[0].length - 1;
+
+    res.writeHead(206, {
+      'Accept-Ranges': 'bytes',
+      'Content-Length': end - start + 1,
+      'Content-Range': 'bytes ' + start + '-' + end + '/' + files[0].length,
+      'Content-Type': contentType,
+    });
+    const stream = bucket.openDownloadStreamByName(filename);
+    stream.start(start);
+    stream.on('data', chunk => {
+      res.write(chunk);
+    });
+    stream.on('error', () => {
+      res.sendStatus(404);
+    });
+    stream.on('end', () => {
+      res.end();
+    });
   }
 
   handleShutdown() {

src/Adapters/Files/GridStoreAdapter.js

@@ -94,13 +94,14 @@ export class GridStoreAdapter extends FilesAdapter {
     );
   }
 
-  getFileStream(filename: string) {
-    return this._connect().then(database => {
+  async handleFileStream(filename: string, req, res, contentType) {
+    const stream = await this._connect().then(database => {
       return GridStore.exist(database, filename).then(() => {
         const gridStore = new GridStore(database, filename, 'r');
         return gridStore.open();
       });
     });
+    handleRangeRequest(stream, req, res, contentType);
   }
 
   handleShutdown() {
@@ -111,4 +112,73 @@ export class GridStoreAdapter extends FilesAdapter {
   }
 }
 
+// handleRangeRequest is licensed under Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
+// Author: LEROIB at weightingformypizza (https://weightingformypizza.wordpress.com/2015/06/24/stream-html5-media-content-like-video-audio-from-mongodb-using-express-and-gridstore/).
+function handleRangeRequest(stream, req, res, contentType) {
+  const buffer_size = 1024 * 1024; //1024Kb
+  // Range request, partial stream the file
+  const parts = req
+    .get('Range')
+    .replace(/bytes=/, '')
+    .split('-');
+  let [start, end] = parts;
+  const notEnded = !end && end !== 0;
+  const notStarted = !start && start !== 0;
+  // No end provided, we want all bytes
+  if (notEnded) {
+    end = stream.length - 1;
+  }
+  // No start provided, we're reading backwards
+  if (notStarted) {
+    start = stream.length - end;
+    end = start + end - 1;
+  }
+
+  // Data exceeds the buffer_size, cap
+  if (end - start >= buffer_size) {
+    end = start + buffer_size - 1;
+  }
+
+  const contentLength = end - start + 1;
+
+  res.writeHead(206, {
+    'Content-Range': 'bytes ' + start + '-' + end + '/' + stream.length,
+    'Accept-Ranges': 'bytes',
+    'Content-Length': contentLength,
+    'Content-Type': contentType,
+  });
+
+  stream.seek(start, function() {
+    // Get gridFile stream
+    const gridFileStream = stream.stream(true);
+    let bufferAvail = 0;
+    let remainingBytesToWrite = contentLength;
+    let totalBytesWritten = 0;
+    // Write to response
+    gridFileStream.on('data', function(data) {
+      bufferAvail += data.length;
+      if (bufferAvail > 0) {
+        // slice returns the same buffer if overflowing
+        // safe to call in any case
+        const buffer = data.slice(0, remainingBytesToWrite);
+        // Write the buffer
+        res.write(buffer);
+        // Increment total
+        totalBytesWritten += buffer.length;
+        // Decrement remaining
+        remainingBytesToWrite -= data.length;
+        // Decrement the available buffer
+        bufferAvail -= buffer.length;
+      }
+      // In case of small slices, all values will be good at that point
+      // we've written enough, end...
+      if (totalBytesWritten >= contentLength) {
+        stream.close();
+        res.end();
+        this.destroy();
+      }
+    });
+  });
+}
+
 export default GridStoreAdapter;

src/Controllers/FilesController.js

@@ -92,8 +92,8 @@ export class FilesController extends AdaptableController {
     return FilesAdapter;
   }
 
-  getFileStream(config, filename) {
-    return this.adapter.getFileStream(filename);
+  handleFileStream(config, filename, req, res, contentType) {
+    return this.adapter.handleFileStream(filename, req, res, contentType);
   }
 }
 

src/Routers/FilesRouter.js

@@ -45,10 +45,7 @@ export class FilesRouter {
     const contentType = mime.getType(filename);
     if (isFileStreamable(req, filesController)) {
       filesController
-        .getFileStream(config, filename)
-        .then(stream => {
-          handleFileStream(stream, req, res, contentType);
-        })
+        .handleFileStream(config, filename, req, res, contentType)
         .catch(() => {
           res.status(404);
           res.set('Content-Type', 'text/plain');
@@ -142,80 +139,6 @@ export class FilesRouter {
 function isFileStreamable(req, filesController) {
   return (
     req.get('Range') &&
-    typeof filesController.adapter.getFileStream === 'function'
+    typeof filesController.adapter.handleFileStream === 'function'
   );
 }
-
-function getRange(req) {
-  const parts = req
-    .get('Range')
-    .replace(/bytes=/, '')
-    .split('-');
-  return { start: parseInt(parts[0], 10), end: parseInt(parts[1], 10) };
-}
-
-// handleFileStream is licenced under Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
-// Author: LEROIB at weightingformypizza (https://weightingformypizza.wordpress.com/2015/06/24/stream-html5-media-content-like-video-audio-from-mongodb-using-express-and-gridstore/).
-function handleFileStream(stream, req, res, contentType) {
-  const buffer_size = 1024 * 1024; //1024Kb
-  // Range request, partiall stream the file
-  let { start, end } = getRange(req);
-
-  const notEnded = !end && end !== 0;
-  const notStarted = !start && start !== 0;
-  // No end provided, we want all bytes
-  if (notEnded) {
-    end = stream.length - 1;
-  }
-  // No start provided, we're reading backwards
-  if (notStarted) {
-    start = stream.length - end;
-    end = start + end - 1;
-  }
-
-  // Data exceeds the buffer_size, cap
-  if (end - start >= buffer_size) {
-    end = start + buffer_size - 1;
-  }
-
-  const contentLength = end - start + 1;
-
-  res.writeHead(206, {
-    'Content-Range': 'bytes ' + start + '-' + end + '/' + stream.length,
-    'Accept-Ranges': 'bytes',
-    'Content-Length': contentLength,
-    'Content-Type': contentType,
-  });
-
-  stream.seek(start, function() {
-    // get gridFile stream
-    const gridFileStream = stream.stream(true);
-    let bufferAvail = 0;
-    let remainingBytesToWrite = contentLength;
-    let totalBytesWritten = 0;
-    // write to response
-    gridFileStream.on('data', function(data) {
-      bufferAvail += data.length;
-      if (bufferAvail > 0) {
-        // slice returns the same buffer if overflowing
-        // safe to call in any case
-        const buffer = data.slice(0, remainingBytesToWrite);
-        // write the buffer
-        res.write(buffer);
-        // increment total
-        totalBytesWritten += buffer.length;
-        // decrement remaining
-        remainingBytesToWrite -= data.length;
-        // decrement the avaialbe buffer
-        bufferAvail -= buffer.length;
-      }
-      // in case of small slices, all values will be good at that point
-      // we've written enough, end...
-      if (totalBytesWritten >= contentLength) {
-        stream.close();
-        res.end();
-        this.destroy();
-      }
-    });
-  });
-}