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tests/wpt/web-platform-tests/tools/wptserve/docs/introduction.rst

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+Introduction
+============
+
+wptserve has been designed with the specific goal of making a server
+that is suitable for writing tests for the web platform. This means
+that it cannot use common abstractions over HTTP such as WSGI, since
+these assume that the goal is to generate a well-formed HTTP
+response. Testcases, however, often require precise control of the
+exact bytes sent over the wire and their timing. The full list of
+design goals for the server are:
+
+* Suitable to run on individual test machines and over the public internet.
+
+* Support plain TCP and SSL servers.
+
+* Serve static files with the minimum of configuration.
+
+* Allow headers to be overwritten on a per-file and per-directory
+  basis.
+
+* Full customisation of headers sent (e.g. altering or omitting
+  "mandatory" headers).
+
+* Simple per-client state.
+
+* Complex logic in tests, up to precise control over the individual
+  bytes sent and the timing of sending them.
+
+Request Handling
+----------------
+
+At the high level, the design of the server is based around similar
+concepts to those found in common web frameworks like Django, Pyramid
+or Flask. In particular the lifecycle of a typical request will be
+familiar to users of these systems. Incoming requests are parsed and a
+:doc:`Request <request>` object is constructed. This object is passed
+to a :ref:`Router <router.Interface>` instance, which is
+responsible for mapping the request method and path to a handler
+function. This handler is passed two arguments; the request object and
+a :doc:`Response <response>` object. In cases where only simple
+responses are required, the handler function may fill in the
+properties of the response object and the server will take care of
+constructing the response. However each Response also contains a
+:ref:`ResponseWriter <response.Interface>` which can be
+used to directly control the TCP socket.
+
+By default there are several built-in handler functions that provide a
+higher level API than direct manipulation of the Response
+object. These are documented in :doc:`handlers`.
+
+