Bug 52929 - No 'Access-Control-Allow-Origin'
Summary: No 'Access-Control-Allow-Origin'
Alias: None
Product: Forms
Classification: Xamarin
Component: Android ()
Version: 2.3.4
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: Jimmy [MSFT]
Depends on:
Reported: 2017-03-01 14:07 UTC by Shay
Modified: 2017-03-14 18:04 UTC (History)
3 users (show)

Tags: android, webview
Is this bug a regression?: ---
Last known good build:

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Description Shay 2017-03-01 14:07:04 UTC
I am trying to load a local web page on Xamarin Forms using WebView.
The specific web page is trying to access server data using jQuery.
I am getting the following error (running on an Android device):

[chromium] [INFO:CONSOLE(0)] "XMLHttpRequest cannot load https://XXX. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.", source: file:///android_asset/ (0)

Shouldn't WebView allow such queries?
On iOS everything works fine.


=== Xamarin Studio Business ===

Version 6.2 (build 1821)
Installation UUID: 07360e74-2c80-443b-94a1-6221c776bc97
	Mono 4.8.0 (mono-4.8.0-branch/e4a3cf3) (64-bit)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 408000495

=== NuGet ===


=== Xamarin.Profiler ===

Version: 1.2.0
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

=== Apple Developer Tools ===

Xcode 8.2.1 (11766.1)
Build 8C1002

=== Xamarin.iOS ===

Version: (Xamarin Business)
Hash: 35d1ccd
Branch: cycle9
Build date: 2017-02-16 17:40:00-0500

=== Xamarin.Mac ===

Version: (Xamarin Business)

=== Xamarin Inspector ===

Hash: cdc01b9
Branch: 1.1-release
Build date: Wed, 22 Feb 2017 23:24:11 GMT

=== Xamarin.Android ===

Version: (Xamarin Business)
Android SDK: /Users/shayo/Library/Android/sdk
	Supported Android versions:
		4.0.3 (API level 15)
		4.4   (API level 19)
		5.0   (API level 21)
		5.1   (API level 22)
		6.0   (API level 23)
		7.0   (API level 24)
		7.1   (API level 25)

SDK Tools Version: 25.2.5
SDK Platform Tools Version: 25.0.3
SDK Build Tools Version: 25.0.1

Java SDK: /usr
java version "1.8.0_112"
Java(TM) SE Runtime Environment (build 1.8.0_112-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.112-b16, mixed mode)

Android Designer EPL code available here:

=== Xamarin Android Player ===

Version: 0.6.5
Location: /Applications/Xamarin Android Player.app

=== Build Information ===

Release ID: 602001821
Git revision: d41b6e51f3fa46a1943f2e31a778d28a7c73d069
Build date: 2017-02-17 15:18:19-05
Xamarin addins: 1363a8d943bab7700c93a97474060b6734aa7f94
Build lane: monodevelop-lion-cycle9

=== Operating System ===

Mac OS X 10.12.2
Darwin Shays-MacBook-Pro.local 16.3.0 Darwin Kernel Version 16.3.0
    Thu Nov 17 20:23:58 PST 2016
    root:xnu-3789.31.2~1/RELEASE_X86_64 x86_64
Comment 1 Jimmy [MSFT] 2017-03-01 16:11:28 UTC
Thank you for filing this report! You might be able to resolve this by using a custom WebView renderer to set setAllowUniversalAccessFromFileURLs[1] to true. Let me know if this helps!
[1] https://developer.android.com/reference/android/webkit/WebSettings.html#setAllowUniversalAccessFromFileURLs(boolean)
Comment 2 Shay 2017-03-01 16:44:13 UTC
Dear Jimmy,

Can you please post a full solution?
Thank you,

Comment 3 Jimmy [MSFT] 2017-03-01 17:33:30 UTC
I haven't tested this with a full app, but you can try a custom renderer like this: https://gist.github.com/jimmgarrido/b3a1bd8fc130435b53f62cb5736368a9
Comment 4 Shay 2017-03-02 04:25:55 UTC
Thanks Jimmy. It works. You can close this ticket. Please consider adding this as the default behavior (seems like this is the case for WebView in iOS).
Comment 5 Shay 2017-03-09 01:23:33 UTC
Minor comment. This only works if the server adds to the page the header 
'Access-Control-Allow-Origin', '*'
Is there a way to fix this for pages that I am not hosting?
Comment 6 Jimmy [MSFT] 2017-03-14 18:04:54 UTC
Glad to hear it is working now! Regarding the header question, unfortunately that does not appear to be possible unless you have access to the server: https://www.html5rocks.com/en/tutorials/cors/