From 849fab7227a2fd1ff5fa4d603ba89037e1c462b4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= Date: Tue, 26 May 2020 09:54:54 +0200 Subject: Cowboy 2.8.0 --- docs/en/cowboy/2.8/manual/cowboy_loop/index.html | 212 +++++++++++++++++++++++ 1 file changed, 212 insertions(+) create mode 100644 docs/en/cowboy/2.8/manual/cowboy_loop/index.html (limited to 'docs/en/cowboy/2.8/manual/cowboy_loop/index.html') diff --git a/docs/en/cowboy/2.8/manual/cowboy_loop/index.html b/docs/en/cowboy/2.8/manual/cowboy_loop/index.html new file mode 100644 index 00000000..190d3005 --- /dev/null +++ b/docs/en/cowboy/2.8/manual/cowboy_loop/index.html @@ -0,0 +1,212 @@ + + + + + + + + + + Nine Nines: cowboy_loop(3) + + + + + + + + + + + + + + +
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cowboy_loop(3)

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Name

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cowboy_loop - Loop handlers

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Description

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The module cowboy_loop defines a callback interface for long running HTTP connections.

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You should switch to this behavior for long polling, server-sent events and similar long-running requests.

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There are generally two usage patterns:

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  • Loop until receiving a specific message, then send a response and stop execution (for example long polling); +
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  • Or initiate a response in init/2 and stream the body in info/3 as necessary (for example server-sent events). +
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Callbacks

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Loop handlers implement the following interface:

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init(Req, State)
+    -> {cowboy_loop, Req, State}
+     | {cowboy_loop, Req, State, hibernate}
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+info(Info, Req, State)
+    -> {ok, Req, State}
+     | {ok, Req, State, hibernate}
+     | {stop, Req, State}
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+terminate(Reason, Req, State) -> ok  %% optional
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+Req    :: cowboy_req:req()
+State  :: any()
+Info   :: any()
+Reason :: stop
+        | {crash, error | exit | throw, any()}
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The init/2 callback is common to all handlers. To switch to the loop behavior, it must return cowboy_loop as the first element of the tuple.

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The info/3 callback will be called for every Erlang message received. It may choose to continue the receive loop or stop it.

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The optional terminate/3 callback will ultimately be called with the reason for the termination of the handler. Cowboy will terminate the process right after this. There is no need to perform any cleanup in this callback.

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The following terminate reasons are defined for loop handlers:

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stop
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The handler requested to close the connection by returning a stop tuple.

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{crash, Class, Reason}
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A crash occurred in the handler. Class and Reason can be used to obtain more information about the crash.

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Changelog

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  • 2.0: Loop handlers no longer need to handle overflow/timeouts. +
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  • 1.0: Behavior introduced. +
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See also

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cowboy(7), cowboy_handler(3)

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+ Cowboy + 2.8 + Function Reference + +

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Navigation

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Version select

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Like my work? Donate!

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Donate to Loïc Hoguin because his work on Cowboy, Ranch, Gun and Erlang.mk is fantastic:

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Recurring payment options are also available via GitHub Sponsors. These funds are used to cover the recurring expenses like food, dedicated servers or domain names.

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