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88 lines
2 KiB
Text
88 lines
2 KiB
Text
= cowboy_req:match_cookies(3)
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== Name
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cowboy_req:match_cookies - Match cookies against constraints
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== Description
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[source,erlang]
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----
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match_cookies(Fields :: cowboy:fields(), Req :: cowboy_req:req())
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-> #{atom() => any()}
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----
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Parse the cookies and match specific values against
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constraints.
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Cowboy will only return the cookie values specified in the
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fields list, and ignore all others. Fields can be either
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the name of the cookie requested; the name along with a
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list of constraints; or the name, a list of constraints
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and a default value in case the cookie is missing.
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This function will crash if the cookie is missing and no
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default value is provided. This function will also crash
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if a constraint fails.
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The name of the cookie must be provided as an atom. The
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key of the returned map will be that atom. The value may
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be converted through the use of constraints, making this
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function able to extract, validate and convert values all
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in one step.
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== Arguments
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Fields::
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Cookies to retrieve.
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+
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See link:man:cowboy(3)[cowboy(3)] for a complete description.
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Req::
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The Req object.
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== Return value
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Desired values are returned as a map. The key is the atom
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that was given in the list of fields, and the value is the
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optionally converted value after applying constraints.
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The map contains the same keys that were given in the fields.
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An exception is triggered when the match fails.
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== Changelog
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* *2.0*: Function introduced.
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== Examples
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.Match fields
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[source,erlang]
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----
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%% ID and Lang are binaries.
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#{id := ID, lang := Lang}
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= cowboy_req:match_cookies([id, lang], Req).
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----
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.Match fields and apply constraints
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[source,erlang]
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----
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%% ID is an integer and Lang a non-empty binary.
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#{id := ID, lang := Lang}
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= cowboy_req:match_cookies([{id, int}, {lang, nonempty}], Req).
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----
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.Match fields with default values
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[source,erlang]
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----
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#{lang := Lang}
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= cowboy_req:match_cookies([{lang, [], <<"en-US">>}], Req).
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----
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== See also
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link:man:cowboy_req(3)[cowboy_req(3)],
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link:man:cowboy_req:parse_cookies(3)[cowboy_req:parse_cookies(3)]
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