Networking¶

WebClient and HttpWebRequest work as in Silverlight 3. The runtime sends the requests through the console's HTTP stack (XHttp); in xenia-edge that's the host's WinHTTP, so 127.0.0.1 is the PC running the emulator.

var client = new WebClient();
client.DownloadStringCompleted += delegate(object sender, DownloadStringCompletedEventArgs e)
{
    if (e.Error != null) { ShowError(e.Error); return; }
    Show(XDocument.Parse(e.Result));
};
client.DownloadStringAsync(new Uri("http://127.0.0.1:8360/api/catalog"));

WebClient completion events arrive on the UI thread. samples\Common\ServerClient.cs wraps GET and POST.

• Cross-domain policy: as with any Silverlight app, a server on another host must allow access with /clientaccesspolicy.xml or /crossdomain.xml. The test server serves both.
• Data formats: the platform has no JSON serializer. Use XML with System.Xml.Linq, as the samples do, or ship a JSON library compiled for Silverlight 3.
• Images: BitmapImage takes a URI or a stream; WebClient.OpenReadAsync gets the bytes if you want to cache them (see PosterCache in samples\apps\CatalogBrowser).
• Xbox additions to HttpWebRequest: IsAuthCall, LimitDownloadBufferSize and AllowLocalConnections are passed to the native stack. The last two can't be set once the request has been sent.

Listening for connections¶

Silverlight's Socket only connects out; it has no Bind, Listen or Accept. An app that serves something, such as a file server, calls the console's Winsock directly: xam exports it as NetDll_* functions, each taking the caller (1 for a title) first.

Function	Ordinal
NetDll_WSAStartup, NetDll_XNetStartup	1, 0x33
NetDll_socket, NetDll_closesocket, NetDll_shutdown	3, 4, 5
NetDll_setsockopt, NetDll_getsockname	7, 9
NetDll_bind, NetDll_listen, NetDll_accept	0xB, 0xD, 0xE
NetDll_recv, NetDll_send, NetDll_WSAGetLastError	0x12, 0x16, 0x1B

Declare them with DllImport by ordinal (see Native code) and pass addresses as pinned buffers. They block, so run each socket on a thread of its own.

• Mark every socket as plain TCP. A title's sockets use the console's encrypted protocol by default, which only other consoles speak: a PC's connections go unanswered. setsockopt(socket, SOL_SOCKET, 0x5801, &one, 4) marks a socket as plain, which the console allows for titles with the "insecure sockets" privilege. The Plex host the default profile packages has it. Check the result; xenia-edge accepts any option, so a wrong one only shows on a console.
• In xenia-edge, title TCP goes through its emulated System Link network unless it runs with --systemlink_transport=off; only then does a listening socket open on the PC. Ports below 1024 move up by 10000, so port 21 is 10021 on the PC.

Xbox LIVE and XAuth¶

Requests to partner services were authenticated with XAuth tokens from Xbox LIVE (Microsoft.Xbox.Security.XAuth: call XAuthService.Start, then use XAuthTokenRequest; each request object can be used once). There's no Xbox LIVE to get tokens from, so anything behind XAuth fails. That includes sign-in for many of the shipped apps, Marketplace and social network tokens. Plain HTTP and HTTPS to your own servers work.

The test server¶

samples\TestServer\server.py serves what the samples need:

Endpoint
GET /api/hello, GET /api/time, POST /api/echo	HelloXbox
GET /api/catalog, GET /images/<id>.png	CatalogBrowser: an XML catalog of made-up shows and generated posters
GET /api/media, GET /media/<file>	MediaPlayer: the files in samples\TestServer\media, with byte ranges

It prints every request, so you can see what an app asks for.