1 files changed, 87 insertions, 1 deletions
diff --git a/doc/src/manual/cowboy_handler.ezdoc b/doc/src/manual/cowboy_handler.ezdoc
index 0495f28..b440b60 100644
--- a/doc/src/manual/cowboy_handler.ezdoc
+++ b/doc/src/manual/cowboy_handler.ezdoc
@@ -15,10 +15,96 @@ Environment output:
 
 * result = ok
 
+This module also defines the `cowboy_handler` behaviour that
+defines the basic interface for handlers. All Cowboy handlers
+implement at least the `init/2` callback, and may implement
+the `terminate/3` callback optionally.
+
 :: Types
 
 None.
 
+:: Terminate reasons
+
+The following values may be received as the terminate reason
+in the optional `terminate/3` callback. Different handler types
+may define additional terminate reasons.
+
+: normal
+
+The connection was closed normally.
+
+: {crash, Class, Reason}
+
+A crash occurred in the handler. `Class` and `Reason` can be
+used to obtain more information about the crash. The function
+`erlang:get_stacktrace/0` can also be called to obtain the
+stacktrace of the process when the crash occurred.
+
+:: Callbacks
+
+: init(Req, Opts)
+	-> {ok, Req, State}
+	| {Module, Req, State}
+	| {Module, Req, State, hibernate}
+	| {Module, Req, State, Timeout}
+	| {Module, Req, State, Timeout, hibernate}
+
+Types:
+
+* Req = cowboy_req:req()
+* Opts = any()
+* State = any()
+* Module = module()
+* Timeout = timeout()
+
+Process the request.
+
+This function can be used to switch to an alternate handler
+type by returning the name of the module to be used, along
+with a few options.
+
+For basic handlers this is the function where the response
+should be sent. If no response is sent, Cowboy will ensure
+that a `204 No Content` response is sent.
+
+A crash in this callback will result in `terminate/3` being
+called if it is defined, with the `State` argument set to
+the value of `Opts` originally given to the `init/2` callback.
+
+: terminate(Reason, Req, State) -> ok
+
+Types:
+
+* Reason = any()
+* Req = cowboy_req:req()
+* State = any()
+
+Perform any necessary cleanup of the state.
+
+This callback should release any resource currently in use,
+clear any active timer and reset the process to its original
+state, as it might be reused for future requests sent on the
+same connection. Typical plain HTTP handlers rarely need to
+use it.
+
+A crash in this callback or an invalid return value will
+result in the closing of the connection and the termination
+of the process.
+
 :: Exports
 
-None.
+: terminate(Reason, Req, State, Handler) -> ok
+
+Types:
+
+* Reason = any()
+* Req = cowboy_req:req()
+* State = any()
+* Handler = module()
+
+Call the optional `terminate/3` callback if it exists.
+
+This function should always be called at the end of the execution
+of a handler, to give it a chance to clean up or perform
+miscellaneous operations.