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::: cowboy_loop_handler
The `cowboy_loop_handler` behaviour defines the interface used
by HTTP handlers that do not send a response directly, instead
requiring a receive loop to process Erlang messages.
This interface is best fit for long-polling types of requests.
The `init/3` callback will always be called, followed by zero
or more calls to `info/3`. The `terminate/3` callback will
always be called last.
:: Types
None.
:: Callbacks
: init({TransportName, ProtocolName}, Req, Opts)
-> {loop, Req, State}
| {loop, Req, State, hibernate}
| {loop, Req, State, Timeout}
| {loop, Req, State, Timeout, hibernate}
| {shutdown, Req, State}
Types:
* TransportName = tcp | ssl | atom()
* ProtocolName = http | atom()
* Req = cowboy_req:req()
* Opts = any()
* State = any()
* Timeout = timeout()
Initialize the state for this request.
This callback will typically be used to register this process
to an event manager or a message queue in order to receive
the messages the handler wants to process.
The receive loop will run for a duration of up to `Timeout`
milliseconds after it last received data from the socket,
at which point it will stop and send a `204 No Content` reply.
By default this value is set to `infinity`. It is recommended
to either set this value or ensure by any other mechanism
that the handler will be closed after a certain period of
inactivity.
The `hibernate` option will hibernate the process until it
starts receiving messages.
The `shutdown` return value can be used to skip the receive
loop entirely.
: info(Info, Req, State) -> {ok, Req, State} | {loop, Req, State}
| {loop, Req, State, hibernate}
Types:
* Info = any()
* Req = cowboy_req:req()
* State = any()
Handle the Erlang message received.
This function will be called every time an Erlang message
has been received. The message can be any Erlang term.
The `ok` return value can be used to stop the receive loop,
typically because a response has been sent.
The `hibernate` option will hibernate the process until
it receives another message.
: terminate(Reason, Req, State) -> ok
Types:
* Reason = {normal, shutdown} | {normal, timeout} | {error, closed} | {error, overflow} | {error, atom()}
* Req = cowboy_req:req()
* State = any()
Perform any necessary cleanup of the state.
This callback will typically unregister from any event manager
or message queue it registered to in `init/3`.
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.
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