Stream video with GridStoreAdapter (implements byte-range requests) (#2437)

* Stream video with GridStoreAdapter

* fixing nits. Removing test(Range not accepted as header)

* nit

* Changed names. Added function to check if stream-requirements is fulfilled.

src/Adapters/Files/GridStoreAdapter.js

@@ -66,6 +66,15 @@ export class GridStoreAdapter extends FilesAdapter {
   getFileLocation(config, filename) {
     return (config.mount + '/files/' + config.applicationId + '/' + encodeURIComponent(filename));
   }
+
+  getFileStream(filename: string) {
+    return this._connect().then(database => {
+      return GridStore.exist(database, filename).then(() => {
+        let gridStore = new GridStore(database, filename, 'r');
+        return gridStore.open();
+      });
+    });
+  }
 }
 
 export default GridStoreAdapter;

src/Controllers/FilesController.js

@@ -82,6 +82,10 @@ export class FilesController extends AdaptableController {
   expectedAdapterType() {
     return FilesAdapter;
   }
+
+  getFileStream(config, filename) {
+    return this.adapter.getFileStream(filename);
+   }
 }
 
 export default FilesController;

src/Routers/FilesRouter.js

@@ -36,17 +36,27 @@ export class FilesRouter {
     const config = new Config(req.params.appId);
     const filesController = config.filesController;
     const filename = req.params.filename;
-    filesController.getFileData(config, filename).then((data) => {
-      res.status(200);
-      var contentType = mime.lookup(filename);
-      res.set('Content-Type', contentType);
-      res.set('Content-Length', data.length);
-      res.end(data);
-    }).catch((err) => {
-      res.status(404);
-      res.set('Content-Type', 'text/plain');
-      res.end('File not found.');
-    });
+    const contentType = mime.lookup(filename);
+    if (isFileStreamable(req, filesController)) {
+      filesController.getFileStream(config, filename).then((stream) => {
+        handleFileStream(stream, req, res, contentType);
+      }).catch((err) => {
+        res.status(404);
+        res.set('Content-Type', 'text/plain');
+        res.end('File not found.');
+      });
+    } else {
+      filesController.getFileData(config, filename).then((data) => {
+        res.status(200);
+        res.set('Content-Type', contentType);
+        res.set('Content-Length', data.length);
+        res.end(data);
+      }).catch((err) => {
+        res.status(404);
+        res.set('Content-Type', 'text/plain');
+        res.end('File not found.');
+      });
+    }
   }
 
   createHandler(req, res, next) {
@@ -94,3 +104,97 @@ export class FilesRouter {
     });
   }
 }
+
+function isFileStreamable(req, filesController){
+  if (req.get['Range']) {
+    if (!(typeof filesController.adapter.getFileStream === 'function')) {
+      return false;
+    }
+    if (typeof filesController.adapter.constructor.name !== 'undefined') {
+      if (filesController.adapter.constructor.name == 'GridStoreAdapter') {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+// 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) {
+  var buffer_size = 1024 * 1024;//1024Kb
+  // Range request, partiall stream the file
+  var parts = req.get["Range"].replace(/bytes=/, "").split("-");
+  var partialstart = parts[0];
+  var partialend = parts[1];
+  var start = partialstart ? parseInt(partialstart, 10) : 0;
+  var end = partialend ? parseInt(partialend, 10) : stream.length - 1;
+  var chunksize = (end - start) + 1;
+
+  if (chunksize == 1) {
+    start = 0;
+    partialend = false;
+  }
+
+  if (!partialend) {
+    if (((stream.length-1) - start) < (buffer_size)) {
+        end = stream.length - 1;
+    }else{
+      end = start + (buffer_size);
+    }
+    chunksize = (end - start) + 1;
+  }
+
+  if (start == 0 && end == 2) {
+    chunksize = 1;
+  }
+
+  res.writeHead(206, {
+    'Content-Range': 'bytes ' + start + '-' + end + '/' + stream.length,
+    'Accept-Ranges': 'bytes',
+    'Content-Length': chunksize,
+    'Content-Type': contentType,
+  });
+
+  stream.seek(start, function () {
+    // get gridFile stream
+    var gridFileStream = stream.stream(true);
+    var ended = false;
+    var bufferIdx = 0;
+    var bufferAvail = 0;
+    var range = (end - start) + 1;
+    var totalbyteswanted = (end - start) + 1;
+    var totalbyteswritten = 0;
+    // write to response
+    gridFileStream.on('data', function (buff) {
+      bufferAvail += buff.length;
+      //Ok check if we have enough to cover our range
+      if (bufferAvail < range) {
+        //Not enough bytes to satisfy our full range
+        if (bufferAvail > 0) {
+          //Write full buffer
+          res.write(buff);
+          totalbyteswritten += buff.length;
+          range -= buff.length;
+          bufferIdx += buff.length;
+          bufferAvail -= buff.length;
+        }
+      } else {
+        //Enough bytes to satisfy our full range!
+        if (bufferAvail > 0) {
+          const buffer = buff.slice(0,range);
+          res.write(buffer);
+          totalbyteswritten += buffer.length;
+          bufferIdx += range;
+          bufferAvail -= range;
+        }
+      }
+      if (totalbyteswritten >= totalbyteswanted) {
+        //totalbytes = 0;
+        stream.close();
+        res.end();
+        this.destroy();
+      }
+    });
+  });
+}