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Diffstat (limited to 'guide/req.md')
| -rw-r--r-- | guide/req.md | 53 |
1 files changed, 49 insertions, 4 deletions
diff --git a/guide/req.md b/guide/req.md index 70873ec..503ad65 100644 --- a/guide/req.md +++ b/guide/req.md @@ -15,14 +15,59 @@ while others will not. For example, obtaining request headers can be repeated safely. Obtaining the request body can only be done once, as it is read directly from the socket. -All calls to the `cowboy_req` module will return an updated -request object. You MUST use the new request object instead -of the old one for all subsequent operations. +With few exceptions, all calls to the `cowboy_req` module +will return an updated request object. You MUST use the new +request object instead of the old one for all subsequent +operations. Request ------- -@todo Describe. +Cowboy allows you to retrieve a lot of information about +the request. All these calls return a `{Value, Req}` tuple, +with `Value` the requested value and `Req` the updated +request object. + +The following access functions are defined in `cowboy_req`: + + * `method/1`: the request method (`<<"GET">>`, `<<"POST">>`...) + * `version/1`: the HTTP version (`{1,0}` or `{1,1}`) + * `peer/1`: the peer address and port number + * `peer_addr/1`: the peer address guessed using the request headers + * `host/1`: the hostname requested + * `host_info/1`: the result of the `[...]` match on the host + * `port/1`: the port number used for the connection + * `path/1`: the path requested + * `path_info/1`: the result of the `[...]` match on the path + * `qs/1`: the entire query string unmodified + * `qs_val/{2,3}`: the value for the requested query string key + * `qs_vals/1`: all key/values found in the query string + * `fragment/1`: the fragment part of the URL (e.g. `#nav-links`) + * `host_url/1`: the requested URL without the path, qs and fragment + * `url/1`: the requested URL + * `binding/{2,3}`: the value for the requested binding found during routing + * `bindings/1`: all key/values found during routing + * `header/{2,3}`: the value for the requested header name + * `headers/1`: all headers name/value + * `cookie/{2,3}`: the value for the requested cookie name + * `cookies/1`: all cookies name/value + * `meta/{2,3}`: the meta information for the requested key + +All the functions above that can take two or three arguments +take an optional third argument for the default value if +none is found. Otherwise it will return `undefined`. + +In addition, Cowboy allows you to parse headers using the +`parse_header/{2,3}` function, which takes a header name +as lowercase binary, the request object, and an optional +default value. It returns `{ok, ParsedValue, Req}` if it +could be parsed, `{undefined, RawValue, Req}` if Cowboy +doesn't know this header, and `{error, badarg}` if Cowboy +encountered an error while trying to parse it. + +Finally, Cowboy allows you to set request meta information +using the `set_meta/3` function, which takes a name, a value +and the request object and returns the latter modified. Request body ------------ |