Bug 1784880 - Support range requests on blob URLs in fetch/XMLHttpRequest; r=dlrobertson,necko-reviewers,jesup

Differential Revision: https://phabricator.services.mozilla.com/D184281

dom/xhr/XMLHttpRequestMainThread.cpp

@@ -811,6 +811,28 @@ bool XMLHttpRequestMainThread::IsDeniedCrossSiteCORSRequest() {
   return false;
 }
 
+Maybe<nsBaseChannel::ContentRange>
+XMLHttpRequestMainThread::GetRequestedContentRange() const {
+  MOZ_ASSERT(mChannel);
+  if (!IsBlobURI(mRequestURL)) {
+    return mozilla::Nothing();
+  }
+  nsBaseChannel* baseChan = static_cast<nsBaseChannel*>(mChannel.get());
+  if (!baseChan) {
+    return mozilla::Nothing();
+  }
+  return baseChan->GetContentRange();
+}
+
+void XMLHttpRequestMainThread::GetContentRangeHeader(nsACString& out) const {
+  Maybe<nsBaseChannel::ContentRange> range = GetRequestedContentRange();
+  if (range.isSome()) {
+    range->AsHeader(out);
+  } else {
+    out.SetIsVoid(true);
+  }
+}
+
 void XMLHttpRequestMainThread::GetResponseURL(nsAString& aUrl) {
   aUrl.Truncate();
 
@@ -867,8 +889,8 @@ uint32_t XMLHttpRequestMainThread::GetStatus(ErrorResult& aRv) {
 
   nsCOMPtr<nsIHttpChannel> httpChannel = GetCurrentHttpChannel();
   if (!httpChannel) {
-    // Pretend like we got a 200 response, since our load was successful
-    return 200;
+    // Pretend like we got a 200/206 response, since our load was successful
+    return GetRequestedContentRange().isSome() ? 206 : 200;
   }
 
   uint32_t status;
@@ -1175,6 +1197,17 @@ void XMLHttpRequestMainThread::GetAllResponseHeaders(
       aResponseHeaders.AppendLiteral("\r\n");
     }
   }
+
+  // Should set a Content-Range header for blob scheme.
+  // From https://fetch.spec.whatwg.org/#scheme-fetch 3.blob.9.20:
+  // "Set response’s header list to «(`Content-Length`, serializedSlicedLength),
+  //  (`Content-Type`, type), (`Content-Range`, contentRange)»."
+  GetContentRangeHeader(value);
+  if (!value.IsVoid()) {
+    aResponseHeaders.AppendLiteral("Content-Range: ");
+    aResponseHeaders.Append(value);
+    aResponseHeaders.AppendLiteral("\r\n");
+  }
 }
 
 void XMLHttpRequestMainThread::GetResponseHeader(const nsACString& header,
@@ -1229,6 +1262,11 @@ void XMLHttpRequestMainThread::GetResponseHeader(const nsACString& header,
       }
     }
 
+    // Content Range:
+    else if (header.LowerCaseEqualsASCII("content-range")) {
+      GetContentRangeHeader(_retval);
+    }
+
     return;
   }
 
@@ -1865,6 +1903,13 @@ XMLHttpRequestMainThread::OnStartRequest(nsIRequest* request) {
     return NS_OK;
   }
 
+  // If we were asked for a bad range on a blob URL, but we're async,
+  // we should throw now in order to fire an error progress event.
+  if (GetRequestedContentRange().isNothing() &&
+      mAuthorRequestHeaders.Has("range")) {
+    return NS_ERROR_NET_PARTIAL_TRANSFER;
+  }
+
   nsCOMPtr<nsIChannel> channel(do_QueryInterface(request));
   NS_ENSURE_TRUE(channel, NS_ERROR_UNEXPECTED);
 
@@ -1905,11 +1950,13 @@ XMLHttpRequestMainThread::OnStartRequest(nsIRequest* request) {
     channel->SetContentType(NS_ConvertUTF16toUTF8(mOverrideMimeType));
   }
 
-  // Fallback to 'application/octet-stream'
-  nsAutoCString type;
-  channel->GetContentType(type);
-  if (type.IsEmpty() || type.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
-    channel->SetContentType(nsLiteralCString(APPLICATION_OCTET_STREAM));
+  // Fallback to 'application/octet-stream' (leaving data URLs alone)
+  if (!IsBlobURI(mRequestURL)) {
+    nsAutoCString type;
+    channel->GetContentType(type);
+    if (type.IsEmpty() || type.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
+      channel->SetContentType(nsLiteralCString(APPLICATION_OCTET_STREAM));
+    }
   }
 
   DetectCharset();
@@ -2665,6 +2712,21 @@ nsresult XMLHttpRequestMainThread::InitiateFetch(
     }
   }
 
+  // Should set a Content-Range header for blob scheme, and also slice the
+  // blob appropriately, so we process the Range header here for later use.
+  if (IsBlobURI(mRequestURL)) {
+    nsAutoCString range;
+    mAuthorRequestHeaders.Get("range", range);
+    if (!range.IsVoid()) {
+      rv = NS_SetChannelContentRangeForBlobURI(mChannel, mRequestURL, range);
+      if (mFlagSynchronous && NS_FAILED(rv)) {
+        // We later fire an error progress event for non-sync
+        mState = XMLHttpRequest_Binding::DONE;
+        return NS_ERROR_DOM_NETWORK_ERR;
+      }
+    }
+  }
+
   // Due to the chrome-only XHR.channel API, we need a hacky way to set the
   // SEC_COOKIES_INCLUDE *after* the channel has been has been created, since
   // .withCredentials can be called after open() is called.
@@ -2813,6 +2875,11 @@ already_AddRefed<PreloaderBase> XMLHttpRequestMainThread::FindPreload() {
 void XMLHttpRequestMainThread::EnsureChannelContentType() {
   MOZ_ASSERT(mChannel);
 
+  // We don't mess with the content type of a blob URL.
+  if (IsBlobURI(mRequestURL)) {
+    return;
+  }
+
   // Since we expect XML data, set the type hint accordingly
   // if the channel doesn't know any content type.
   // This means that we always try to parse local files as XML