Make sure srcserver requests are proxied to the srcserver

Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>

obs_proxy/server.py

@@ -549,8 +549,27 @@ async def worker_build(worker_id: str = None):
 
 
 def proxied_uri():
+    """
+    Construct a URI of the backend's resource corresponding to the proxy's URI
+
+    >>> config.backend.repserver_uri = "http://repserver:1234"
+    >>> config.backend.srcserver_uri = "http://srcserver:5678"
+    >>> async def test_app_context(uri):
+    ...     async with app.test_request_context(uri, method="GET"):
+    ...         return proxied_uri()
+    >>> asyncio.run(test_app_context('/repserver/worker:0/badpackagebinaryversionlist'))
+    'http://repserver:1234/badpackagebinaryversionlist'
+    >>> asyncio.run(test_app_context('/srcserver/worker:0/badpackagebinaryversionlist'))
+    'http://srcserver:5678/badpackagebinaryversionlist'
+    >>> asyncio.run(test_app_context('/repserver/worker:1/build/project/repository/arch/package'))
+    'http://repserver:1234/build/project/repository/arch/package'
+    >>> asyncio.run(test_app_context('/srcserver/worker:1/source/project/package'))
+    'http://srcserver:5678/source/project/package'
+    """
     path = request.path.split(request.root_path, 1)[1] if request.root_path else request.path
-    return config.backend.repserver_uri + '/' + '/'.join(path.split('/')[3:])
+    _, backend, worker_id, *args = path.split('/')
+    backend_uri = config.backend.repserver_uri if backend == "repserver" else config.backend.srcserver_uri
+    return backend_uri + '/' + '/'.join(path.split('/')[3:])
 
 
 @app.route('/repserver/<path:worker_id>/badpackagebinaryversionlist')