use actual file size in dl progress. detect cancelled stream

app/api.js

@@ -74,7 +74,7 @@ export async function metadata(id, keychain) {
     const data = await result.response.json();
     const meta = await keychain.decryptMetadata(b64ToArray(data.metadata));
     return {
-      size: data.size,
+      size: meta.size,
       ttl: data.ttl,
       iv: meta.iv,
       name: meta.name,

app/keychain.js

@@ -172,6 +172,7 @@ export default class Keychain {
         JSON.stringify({
           iv: arrayToB64(this.iv),
           name: metadata.name,
+          size: metadata.size,
           type: metadata.type || 'application/octet-stream'
         })
       )

app/serviceWorker.js

@@ -14,8 +14,7 @@ self.addEventListener('activate', event => {
   self.clients.claim();
 });
 
-async function decryptStream(request) {
+async function decryptStream(id) {
-  const id = request.url.split('/')[5];
   try {
     const file = map.get(id);
     const keychain = new Keychain(file.key, file.nonce);
@@ -27,20 +26,29 @@ async function decryptStream(request) {
 
     const body = await file.download.result;
 
-    const readStream = transformStream(body, {
+    const decrypted = keychain.decryptStream(body);
-      transform: (chunk, controller) => {
+    const readStream = transformStream(
-        file.progress += chunk.length;
+      decrypted,
-        controller.enqueue(chunk);
+      {
+        transform(chunk, controller) {
+          file.progress += chunk.length;
+          controller.enqueue(chunk);
+        }
+      },
+      function oncancel() {
+        // NOTE: cancel doesn't currently fire on chrome
+        // https://bugs.chromium.org/p/chromium/issues/detail?id=638494
+        file.download.cancel();
+        map.delete(id);
       }
-    });
+    );
-    const decrypted = keychain.decryptStream(readStream);
 
     const headers = {
       'Content-Disposition': contentDisposition(file.filename),
       'Content-Type': file.type,
       'Content-Length': file.size
     };
-    return new Response(decrypted, { headers });
+    return new Response(readStream, { headers });
   } catch (e) {
     if (noSave) {
       return new Response(null, { status: e.message });
@@ -48,16 +56,14 @@ async function decryptStream(request) {
 
     const redirectRes = await fetch(`/download/${id}`);
     return new Response(redirectRes.body, { status: 302 });
-  } finally {
-    // TODO: need to clean up, but not break progress
-    // map.delete(id)
   }
 }
 
 self.onfetch = event => {
-  const req = event.request.clone();
+  const req = event.request;
   if (req.url.includes('/api/download')) {
-    event.respondWith(decryptStream(req));
+    const id = req.url.split('/')[5];
+    event.respondWith(decryptStream(id));
   }
 };
 
@@ -73,8 +79,7 @@ self.onmessage = event => {
       url: event.data.url,
       type: event.data.type,
       size: event.data.size,
-      progress: 0,
+      progress: 0
-      cancelled: false
     };
     map.set(event.data.id, info);
 
@@ -82,19 +87,20 @@ self.onmessage = event => {
   } else if (event.data.request === 'progress') {
     const file = map.get(event.data.id);
     if (!file) {
-      event.ports[0].postMessage({ progress: 0 });
-    } else if (file.cancelled) {
       event.ports[0].postMessage({ error: 'cancelled' });
     } else {
+      if (file.progress === file.size) {
+        map.delete(event.data.id);
+      }
       event.ports[0].postMessage({ progress: file.progress });
     }
   } else if (event.data.request === 'cancel') {
     const file = map.get(event.data.id);
     if (file) {
-      file.cancelled = true;
       if (file.download) {
         file.download.cancel();
       }
+      map.delete(event.data.id);
     }
     event.ports[0].postMessage('download cancelled');
   }

app/streams.js

@@ -1,6 +1,6 @@
 /* global ReadableStream TransformStream */
 
-export function transformStream(readable, transformer) {
+export function transformStream(readable, transformer, oncancel) {
   if (typeof TransformStream === 'function') {
     return readable.pipeThrough(new TransformStream(transformer));
   }
@@ -30,8 +30,11 @@ export function transformStream(readable, transformer) {
         await transformer.transform(data.value, wrappedController);
       }
     },
-    cancel() {
+    cancel(reason) {
-      readable.cancel();
+      readable.cancel(reason);
+      if (oncancel) {
+        oncancel(reason);
+      }
     }
   });
 }

server/routes/metadata.js

@@ -4,12 +4,10 @@ module.exports = async function(req, res) {
   const id = req.params.id;
   const meta = req.meta;
   try {
-    const size = await storage.length(id);
     const ttl = await storage.ttl(id);
     res.send({
       metadata: meta.metadata,
       finalDownload: meta.dl + 1 === meta.dlimit,
-      size,
       ttl
     });
   } catch (e) {

test/backend/metadata-tests.js

@@ -30,16 +30,15 @@ describe('/api/metadata', function() {
     storage.length.reset();
   });
 
-  it('calls storage.[ttl|length] with the id parameter', async function() {
+  it('calls storage.ttl with the id parameter', async function() {
     const req = request('x');
     const res = response();
     await metadataRoute(req, res);
     sinon.assert.calledWith(storage.ttl, 'x');
-    sinon.assert.calledWith(storage.length, 'x');
   });
 
   it('sends a 404 on failure', async function() {
-    storage.length.returns(Promise.reject(new Error()));
+    storage.ttl.returns(Promise.reject(new Error()));
     const res = response();
     await metadataRoute(request('x'), res);
     sinon.assert.calledWith(res.sendStatus, 404);
@@ -47,7 +46,6 @@ describe('/api/metadata', function() {
 
   it('returns a json object', async function() {
     storage.ttl.returns(Promise.resolve(123));
-    storage.length.returns(Promise.resolve(987));
     const meta = {
       dlimit: 1,
       dl: 0,
@@ -58,7 +56,6 @@ describe('/api/metadata', function() {
     sinon.assert.calledWithMatch(res.send, {
       metadata: 'foo',
       finalDownload: true,
-      size: 987,
       ttl: 123
     });
   });