aboutsummaryrefslogtreecommitdiffstats
path: root/doc/src/guide/loop_handlers.asciidoc
diff options
context:
space:
mode:
authorLoïc Hoguin <[email protected]>2017-02-18 18:26:20 +0100
committerLoïc Hoguin <[email protected]>2017-02-18 18:26:20 +0100
commita45813c60f0f983a24ea29d491b37f0590fdd087 (patch)
treec7e741ac4a684b365e70f7ff73d0c4b6e34232a7 /doc/src/guide/loop_handlers.asciidoc
parent80f8cda7ff8fe6a575b4c2eaedd8451acf4fcef3 (diff)
downloadcowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.tar.gz
cowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.tar.bz2
cowboy-a45813c60f0f983a24ea29d491b37f0590fdd087.zip
Allow passing options to sub protocols
Before this commit we had an issue where configuring a Websocket connection was simply not possible without doing magic, adding callbacks or extra return values. The init/2 function only allowed setting hibernate and timeout options. After this commit, when switching to a different type of handler you can either return {module, Req, State} or {module, Req, State, Opts} where Opts is any value (as far as the sub protocol interface is concerned) and is ultimately checked by the custom handlers. A large protocol like Websocket would accept only a map there, with many different options, while a small interface like loop handlers would allow passing hibernate and nothing else. For Websocket, hibernate must be set from the websocket_init/1 callback, because init/2 executes in a separate process. Sub protocols now have two callbacks: one with the Opts value, one without. The loop handler code was largely reworked and simplified. It does not need to manage a timeout or read from the socket anymore, it's the job of the protocol code. A lot of unnecessary stuff was therefore removed. Websocket compression must now be enabled from the handler options instead of per listener. This means that a project can have two separate Websocket handlers with different options. Compression is still disabled by default, and the idle_timeout value was changed from inifnity to 60000 (60 seconds), as that's safer and is also a good value for mobile devices.
Diffstat (limited to 'doc/src/guide/loop_handlers.asciidoc')
-rw-r--r--doc/src/guide/loop_handlers.asciidoc27
1 files changed, 3 insertions, 24 deletions
diff --git a/doc/src/guide/loop_handlers.asciidoc b/doc/src/guide/loop_handlers.asciidoc
index 2c82c53..dbee927 100644
--- a/doc/src/guide/loop_handlers.asciidoc
+++ b/doc/src/guide/loop_handlers.asciidoc
@@ -34,7 +34,7 @@ loop handler behavior. This tuple may optionally contain
a timeout value and/or the atom `hibernate` to make the
process enter hibernation until a message is received.
-This snippet enables the loop handler.
+This snippet enables the loop handler:
[source,erlang]
----
@@ -42,14 +42,12 @@ init(Req, State) ->
{cowboy_loop, Req, State}.
----
-However it is largely recommended that you set a timeout
-value. The next example sets a timeout value of 30s and
-also makes the process hibernate.
+This also makes the process hibernate:
[source,erlang]
----
init(Req, State) ->
- {cowboy_loop, Req, State, 30000, hibernate}.
+ {cowboy_loop, Req, State, hibernate}.
----
=== Receive loop
@@ -123,25 +121,6 @@ a subsequent request.
Please refer to the xref:handlers[Handlers chapter]
for general instructions about cleaning up.
-=== Timeout
-
-Note that this feature currently does not work. It will be
-brought back in a future 2.0 pre-release.
-
-By default Cowboy will not attempt to close the connection
-if there is no activity from the client. This is not always
-desirable, which is why you can set a timeout. Cowboy will
-close the connection if no data was received from the client
-after the configured time. The timeout only needs to be set
-once and can't be modified afterwards.
-
-Because the request may have had a body, or may be followed
-by another request, Cowboy is forced to buffer all data it
-receives. This data may grow to become too large though,
-so there is a configurable limit for it. The default buffer
-size is of 5000 bytes, but it may be changed by setting the
-`loop_max_buffer` middleware environment value.
-
=== Hibernate
To save memory, you may hibernate the process in between