.. _resource-tree: The *Kapow!* Resource Tree ========================== This is the model that *Kapow!* uses to expose the internals of the user request being serviced. We use this tree to get access to any data that comes in the request, as well as to compose the response. We access the resource tree easily with the ``kapow set`` and ``kapow get`` subcommands. Overview -------- .. code-block:: none / │ ├─ request │ ├──── method Used HTTP Method (GET, POST) │ ├──── host Host part of the URL │ ├──── path Complete URL path (URL-unquoted) │ ├──── matches │ │ └──── Previously matched URL path parts │ ├──── params │ │ └──── URL parameters (after the "?" symbol) │ ├──── headers │ │ └──── HTTP request headers │ ├──── cookies │ │ └──── HTTP request cookie │ ├──── form │ │ └──── Value of the form field with name │ ├──── files │ │ └──── │ │ └──── filename Original file name of the file uploaded in the form field │ │ └──── content The contents of the file uploaded in the form field │ └──── body HTTP request body │ └─ response ├──── status HTTP status code ├──── headers │ └──── HTTP response headers ├──── cookies │ └──── HTTP request cookie └──── body Response body Resources --------- ``/request/method`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The HTTP method of the incoming request. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl -X POST http://kapow.example:8080 then, when handling the request: .. code-block:: console $ kapow get /request/method POST ``/request/host`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~ The ``Host`` header as defined in the HTTP/1.1 spec of the incoming request. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl http://kapow.example:8080 then, when handling the request: .. code-block:: console $ kapow get /request/host kapow.example ``/request/path`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the path substring of the URL. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl http://kapow.example:8080/foo/bar?qux=1 then, when handling the request: .. code-block:: console $ kapow get /request/path /foo/bar ``/request/matches/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the part of the URL captured by the pattern ``name``. Sample Usage ^^^^^^^^^^^^ For a route defined like this: .. code-block:: console $ kapow route add /foo/{mymatch}/bar if the user runs: .. code-block:: console $ curl http://kapow.example:8080/foo/1234/bar then, when handling the request: .. code-block:: console $ kapow get /request/matches/mymatch 1234 ``/request/params/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the URL parameter ``name`` .. note:: In the reference implementation only the first parameter's value can be accessed in the case of multiple values coming in the request. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl http://kapow.example:8080/foo?myparam=bar then, when handling the request: .. code-block:: console $ kapow get /request/params/myparam myparam ``/request/headers/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the HTTP header ``name`` of the incoming request. .. note:: In the reference implementation only the first header's value can be accessed in the case of multiple values coming in the request. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl -H X-My-Header=Bar http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/headers/X-My-Header Bar ``/request/cookies/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the HTTP cookie ``name`` of the incoming request. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl --cookie MYCOOKIE=Bar http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/cookies/MYCOOKIE Bar ``/request/form/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the field ``name`` of the incoming request. .. note:: In the reference implementation there are some caveats: * Only the first form field's value can be accessed in the case of multiple values coming in the request. * In order to get access to the form data a correct 'Content-Type' header must be present in the request ('application/x-www-form-urlencoded' or 'multipart/form-data') Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl -F -d myfield=foo http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/form/myfield foo ``/request/files//filename`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the name of the file uploaded through the incoming request. .. note:: In the reference implementation to get access to the multipart data a correct Content-Type header must be present in the request (multipart/form-data or multipart/mixed). Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl -F 'myfile=@filename.txt' http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/files/myfile/filename filename.txt ``/request/files//content`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contents of the file that is being uploaded in the incoming request. .. note:: In the reference implementation to get access to the multipart data a correct Content-Type header must be present in the request (multipart/form-data or multipart/mixed). Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl -F 'myfile=@filename.txt' http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/files/myfile/content ...filename.txt contents... ``/request/body`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~ Raw contents of the incoming request HTTP body. Sample Usage ^^^^^^^^^^^^ If the user runs: .. code-block:: console $ curl --data-raw foobar http://kapow.example:8080/ then, when handling the request: .. code-block:: console $ kapow get /request/body foobar ``/response/status`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the status code given in the user response. .. note:: In the reference implementation there are some caveats: * The status code value must be between 100 and 999. * There is no way of writing reason phrase in the status line of the response. Sample Usage ^^^^^^^^^^^^ If during the request handling: .. code-block:: console $ kapow set /response/status 418 then the response will have the status code ``418 I am a Teapot``. ``/response/headers/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the header ``name`` in the user response. .. note:: At this moment header values are only appended, there is no way of reset the values once set. Sample Usage ^^^^^^^^^^^^ If during the request handling: .. code-block:: console $ kapow set /response/headers/X-My-Header Foo then the response will contain an HTTP header named ``X-My-Header`` with value ``Foo``. ``/response/cookies/`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the cookie ``name`` that will be set to the user response. Sample Usage ^^^^^^^^^^^^ If during the request handling: .. code-block:: console $ kapow set /response/cookies/MYCOOKIE Foo then the response will set the cookie ``MYCOOKIE`` to the user in following requests. ``/response/body`` Resource ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains the value of the response HTTP body. Sample Usage ^^^^^^^^^^^^ If during the request handling: .. code-block:: console $ kapow set /response/body foobar then the response will contain ``foobar`` in the body.