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-::: Using cookies
-
-Cookies are a mechanism allowing applications to maintain
-state on top of the stateless HTTP protocol.
-
-Cowboy provides facilities for handling cookies. It is highly
-recommended to use them instead of writing your own, as the
-implementation of cookies can vary greatly between clients.
-
-Cookies are stored client-side and sent with every subsequent
-request that matches the domain and path for which they were
-stored, including requests for static files. For this reason
-they can incur a cost which must be taken in consideration.
-
-Also consider that, regardless of the options used, cookies
-are not to be trusted. They may be read and modified by any
-program on the user's computer, but also by proxies. You
-should always validate cookie values before using them. Do
-not store any sensitive information in cookies either.
-
-When explicitly setting the domain, the cookie will be sent
-for the domain and all subdomains from that domain. Otherwise
-the current domain will be used. The same is true for the
-path.
-
-When the server sets cookies, they will only be available
-for requests that are sent after the client receives the
-response.
-
-Cookies are sent in HTTP headers, therefore they must have
-text values. It is your responsibility to encode any other
-data type. Also note that cookie names are de facto case
-sensitive.
-
-Cookies can be set for the client session (which generally
-means until the browser is closed), or it can be set for
-a number of seconds. Once it expires, or when the server
-says the cookie must exist for up to 0 seconds, the cookie
-is deleted by the client. To avoid this while the user
-is browsing your site, you should set the cookie for
-every request, essentially resetting the expiration time.
-
-Cookies can be restricted to secure channels. This typically
-means that such a cookie will only be sent over HTTPS,
-and that it will only be available by client-side scripts
-that run from HTTPS webpages.
-
-Finally, cookies can be restricted to HTTP and HTTPS requests,
-essentially disabling their access from client-side scripts.
-
-:: Setting cookies
-
-By default, cookies you set are defined for the session.
-
-``` erlang
-SessionID = generate_session_id(),
-Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [], Req).
-```
-
-You can also make them expire at a specific point in the
-future.
-
-``` erlang
-SessionID = generate_session_id(),
-Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
- {max_age, 3600}
-], Req).
-```
-
-You can delete cookies that have already been set. The value
-is ignored.
-
-``` erlang
-Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, <<>>, [
- {max_age, 0}
-], Req).
-```
-
-You can restrict them to a specific domain and path.
-For example, the following cookie will be set for the domain
-`my.example.org` and all its subdomains, but only on the path
-`/account` and all its subdirectories.
-
-``` erlang
-Req2 = cowboy_req:set_resp_cookie(<<"inaccount">>, <<"1">>, [
- {domain, "my.example.org"},
- {path, "/account"}
-], Req).
-```
-
-You can restrict the cookie to secure channels, typically HTTPS.
-
-``` erlang
-SessionID = generate_session_id(),
-Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
- {secure, true}
-], Req).
-```
-
-You can restrict the cookie to client-server communication
-only. Such a cookie will not be available to client-side scripts.
-
-``` erlang
-SessionID = generate_session_id(),
-Req2 = cowboy_req:set_resp_cookie(<<"sessionid">>, SessionID, [
- {http_only, true}
-], Req).
-```
-
-Cookies may also be set client-side, for example using
-Javascript.
-
-:: Reading cookies
-
-As we said, the client sends cookies with every request.
-But unlike the server, the client only sends the cookie
-name and value.
-
-Cowboy provides two different ways to read cookies. You
-can either parse them as a list of key/value pairs, or
-match them into a map, optionally applying constraints
-to the values or providing a default if they are missing.
-
-You can parse the cookies and then use standard library
-functions to access individual values.
-
-``` erlang
-Cookies = cowboy_req:parse_cookies(Req),
-{_, Lang} = lists:keyfind(<<"lang">>, 1, Cookies).
-```
-
-You can match the cookies into a map.
-
-``` erlang
-#{id := ID, lang := Lang} = cowboy_req:match_cookies([id, lang], Req).
-```
-
-You can use constraints to validate the values while matching
-them. The following snippet will crash if the `id` cookie is
-not an integer number or if the `lang` cookie is empty. Additionally
-the `id` cookie value will be converted to an integer term, saving
-you a conversion step.
-
-``` erlang
-CookiesMap = cowboy_req:match_cookies([{id, int}, {lang, nonempty}], Req).
-```
-
-Note that if two cookies share the same name, then the map value
-will be a list of the two cookie values.
-
-Read more about ^constraints^.
-
-A default value can be provided. The default will be used
-if the `lang` cookie is not found. It will not be used if
-the cookie is found but has an empty value.
-
-``` erlang
-#{lang := Lang} = cowboy_req:match_cookies([{lang, [], <<"en-US">>}], Req).
-```
-
-If no default is provided and the value is missing, the
-query string is deemed invalid and the process will crash.