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author | Loïc Hoguin <[email protected]> | 2016-01-14 13:35:25 +0100 |
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committer | Loïc Hoguin <[email protected]> | 2016-01-14 13:37:20 +0100 |
commit | 4023e7f4e429179fd9c2cce4487c33646c6bd327 (patch) | |
tree | 3c4e26d1b5592958e35297c82ad3069bdb642594 /doc/src/guide/middlewares.ezdoc | |
parent | b7d666cfc746f55b0a72ef8d37f703885099daf7 (diff) | |
download | cowboy-4023e7f4e429179fd9c2cce4487c33646c6bd327.tar.gz cowboy-4023e7f4e429179fd9c2cce4487c33646c6bd327.tar.bz2 cowboy-4023e7f4e429179fd9c2cce4487c33646c6bd327.zip |
Convert the documentation to Asciidoc
A few small revisions were made, and Erlang.mk has been updated.
Diffstat (limited to 'doc/src/guide/middlewares.ezdoc')
-rw-r--r-- | doc/src/guide/middlewares.ezdoc | 68 |
1 files changed, 0 insertions, 68 deletions
diff --git a/doc/src/guide/middlewares.ezdoc b/doc/src/guide/middlewares.ezdoc deleted file mode 100644 index 8b047d7..0000000 --- a/doc/src/guide/middlewares.ezdoc +++ /dev/null @@ -1,68 +0,0 @@ -::: Middlewares - -Cowboy delegates the request processing to middleware components. -By default, two middlewares are defined, for the routing and handling -of the request, as is detailed in most of this guide. - -Middlewares give you complete control over how requests are to be -processed. You can add your own middlewares to the mix or completely -change the chain of middlewares as needed. - -Cowboy will execute all middlewares in the given order, unless one -of them decides to stop processing. - -:: Usage - -Middlewares only need to implement a single callback: `execute/2`. -It is defined in the `cowboy_middleware` behavior. - -This callback has two arguments. The first is the `Req` object. -The second is the environment. - -Middlewares can return one of three different values: - -* `{ok, Req, Env}` to continue the request processing -* `{suspend, Module, Function, Args}` to hibernate -* `{stop, Req}` to stop processing and move on to the next request - -Of note is that when hibernating, processing will resume on the given -MFA, discarding all previous stacktrace. Make sure you keep the `Req` -and `Env` in the arguments of this MFA for later use. - -If an error happens during middleware processing, Cowboy will not try -to send an error back to the socket, the process will just crash. It -is up to the middleware to make sure that a reply is sent if something -goes wrong. - -:: Configuration - -The middleware environment is defined as the `env` protocol option. -In the previous chapters we saw it briefly when we needed to pass -the routing information. It is a list of tuples with the first -element being an atom and the second any Erlang term. - -Two values in the environment are reserved: - -* `listener` contains the name of the listener -* `result` contains the result of the processing - -The `listener` value is always defined. The `result` value can be -set by any middleware. If set to anything other than `ok`, Cowboy -will not process any subsequent requests on this connection. - -The middlewares that come with Cowboy may define or require other -environment values to perform. - -You can update the environment by calling the `cowboy:set_env/3` -convenience function, adding or replacing a value in the environment. - -:: Routing middleware - -The routing middleware requires the `dispatch` value. If routing -succeeds, it will put the handler name and options in the `handler` -and `handler_opts` values of the environment, respectively. - -:: Handler middleware - -The handler middleware requires the `handler` and `handler_opts` -values. It puts the result of the request handling into `result`. |