From 5cb08c35580023b91091c93f9a1f9198e35055c2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= Date: Tue, 3 Oct 2017 15:50:36 +0200 Subject: Fix some links and add Ranch 1.4 docs They were mistakenly labeled as 1.3. Sorry! --- docs/en/ranch/1.4/guide/protocols/index.html | 261 +++++++++++++++++++++++++++ 1 file changed, 261 insertions(+) create mode 100644 docs/en/ranch/1.4/guide/protocols/index.html (limited to 'docs/en/ranch/1.4/guide/protocols/index.html') diff --git a/docs/en/ranch/1.4/guide/protocols/index.html b/docs/en/ranch/1.4/guide/protocols/index.html new file mode 100644 index 00000000..eef4ca91 --- /dev/null +++ b/docs/en/ranch/1.4/guide/protocols/index.html @@ -0,0 +1,261 @@ + + + + + + + + + + + + Nine Nines: Protocols + + + + + + + + + + + + + + +
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Protocols

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A protocol handler starts a connection process and defines the +protocol logic executed in this process.

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+

Writing a protocol handler

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+

All protocol handlers must implement the ranch_protocol behavior +which defines a single callback, start_link/4. This callback is +responsible for spawning a new process for handling the connection. +It receives four arguments: the name of the listener, the socket, the +transport handler being used and the protocol options defined in +the call to ranch:start_listener/5. This callback must +return {ok, Pid}, with Pid the pid of the new process.

+

The newly started process can then freely initialize itself. However, +it must call ranch:accept_ack/1 before doing any socket operation. +This will ensure the connection process is the owner of the socket. +It expects the listener’s name as argument.

+
+
Acknowledge accepting the socket
+
+
ok = ranch:accept_ack(Ref).
+

If your protocol code requires specific socket options, you should +set them while initializing your connection process, after +calling ranch:accept_ack/1. You can use Transport:setopts/2 +for that purpose.

+

Following is the complete protocol code for the example found +in examples/tcp_echo/.

+
+
Protocol module that echoes everything it receives
+
+
-module(echo_protocol).
+-behaviour(ranch_protocol).
+
+-export([start_link/4]).
+-export([init/4]).
+
+start_link(Ref, Socket, Transport, Opts) ->
+        Pid = spawn_link(?MODULE, init, [Ref, Socket, Transport, Opts]),
+        {ok, Pid}.
+
+init(Ref, Socket, Transport, _Opts = []) ->
+        ok = ranch:accept_ack(Ref),
+        loop(Socket, Transport).
+
+loop(Socket, Transport) ->
+        case Transport:recv(Socket, 0, 5000) of
+                {ok, Data} ->
+                        Transport:send(Socket, Data),
+                        loop(Socket, Transport);
+                _ ->
+                        ok = Transport:close(Socket)
+        end.
+
+
+
+

Using gen_server

+
+

Special processes like the ones that use the gen_server or gen_fsm +behaviours have the particularity of having their start_link call not +return until the init function returns. This is problematic, because +you won’t be able to call ranch:accept_ack/1 from the init callback +as this would cause a deadlock to happen.

+

Use the gen_server:enter_loop/3 function. It allows you to start your process +normally (although it must be started with proc_lib like all special +processes), then perform any needed operations before falling back into +the normal gen_server execution loop.

+
+
Use a gen_server for protocol handling
+
+
-module(my_protocol).
+-behaviour(gen_server).
+-behaviour(ranch_protocol).
+
+-export([start_link/4]).
+-export([init/1]).
+%% Exports of other gen_server callbacks here.
+
+start_link(Ref, Socket, Transport, Opts) ->
+        {ok, proc_lib:spawn_link(?MODULE, init, [{Ref, Socket, Transport, Opts}])}.
+
+init({Ref, Socket, Transport, _Opts = []}) ->
+        %% Perform any required state initialization here.
+        ok = ranch:accept_ack(Ref),
+        ok = Transport:setopts(Socket, [{active, once}]),
+        gen_server:enter_loop(?MODULE, [], {state, Socket, Transport}).
+
+%% Other gen_server callbacks here.
+

Check the tcp_reverse example for a complete example.

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+ + + + + + + + + + + + + + + +
+ +
+ + +

+ Ranch + 1.4 + + User Guide +

+ + + +

Navigation

+ +

Version select

+ + +
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+ + + + + + + + + -- cgit v1.2.3