View Source nova_basic_handler (nova v0.10.1)

Summary

Functions

Handler for JSON. It takes two different return objects

Handler for regular views. This will render a template with given variables. If not another view is specified in options a view that corresponds to the controller will be rendered. The first element of the returned tuple could be either ok or view - they are identical in their functionality.

Handles redirects. This will return a 302-status code with a location given by the user. Something like {redirect, "/login"} will send a 302 with location set to "/login"

Handler for returning http status codes. There's three different ways one can return status code. The most basic case is {status, Status} where Status is the code that should be returned.

Handler for regular views and uses the ok-handler. For more info see handle_ok/3.
Handles upgrading to websocket

Handles basic websocket operations. This is a special handler in regards to arguments. Handlers for websocket only takes two arguments; What the controller returned and the state. And the handler should return what cowboy expects.

Types

-type erlydtl_vars() :: map() | [{Key :: atom() | binary() | string(), Value :: any()}].

Functions

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handle_json(_, Callback, Req)

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-spec handle_json({json, JSON :: map()} |
            {json, StatusCode :: integer(), Headers :: map(), JSON :: map()},
            Callback :: function(),
            Req :: cowboy_req:req()) ->
               {ok, State :: cowboy_req:req()}.

Handler for JSON. It takes two different return objects:

{json, JSON :: map()} returns the JSON encoded to the user. If the operation was a POST the HTTP-status code will be 201, otherwise 200.

{json, StatusCode :: integer(), Headers :: map(), JSON :: map()} Same operation as the above except you can set custom status code and custom headers.
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handle_ok(_, Callback, Req)

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-spec handle_ok({ok, Variables :: erlydtl_vars()} | {ok, Variables :: erlydtl_vars(), Options :: map()},
          Callback :: function(),
          Req :: cowboy_req:req()) ->
             {ok, cowboy_req:req()}.

Handler for regular views. This will render a template with given variables. If not another view is specified in options a view that corresponds to the controller will be rendered. The first element of the returned tuple could be either ok or view - they are identical in their functionality.

-module(my_first_controller). -compile(export_all).

my_function(_Req) -> {ok, []}.

The example above will then render the view named 'app_main.dtl'

Options can be specified as follows:

- view - Specifies if another view should be rendered instead of default one

- headers - Custom headers
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handle_redirect(_, Callback, Req)

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-spec handle_redirect({redirect, Route :: list() | binary()},
                Callback :: function(),
                Req :: cowboy_req:req()) ->
                   {ok, Req :: cowboy_req:req()}.
Handles redirects. This will return a 302-status code with a location given by the user. Something like {redirect, "/login"} will send a 302 with location set to "/login"
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handle_sendfile(_, Callback, Req)

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-spec handle_sendfile({sendfile,
                 StatusCode :: integer(),
                 Headers :: map(),
                 {Offset :: integer(), Length :: integer(), Path :: list()},
                 Mime :: binary()},
                Callback :: function(),
                Req) ->
                   {ok, Req}
                   when Req :: cowboy_req:req().
Handles sendfile.
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handle_status(_, Callback, Req)

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-spec handle_status({status, StatusCode :: integer()} |
              {status, StatusCode :: integer(), ExtraHeaders :: map()} |
              {status, StatusCode :: integer(), ExtraHeaders :: map(), Body :: binary() | map()},
              Callback :: function(),
              Req :: cowboy_req:req()) ->
                 {ok, Req :: cowboy_req:req()}.

Handler for returning http status codes. There's three different ways one can return status code. The most basic case is {status, Status} where Status is the code that should be returned.

If there's a need for additional headers to be sent along with the http code one can specify a third argument that is a map with header-fields.

One can also send in a body as a fourth argument in the tuple. It can either be a binary or a map. If it's a map it will be considered a JSON-structure and encoded.
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handle_view(_, Callback, Req)

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Handler for regular views and uses the ok-handler. For more info see handle_ok/3.
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handle_websocket(_, Callback, Req)

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-spec handle_websocket({websocket, ControllerData :: any()},
                 Callback :: function(),
                 Req :: cowboy_req:req()) ->
                    {ok, Req :: cowboy_req:req()}.
Handles upgrading to websocket

Handles basic websocket operations. This is a special handler in regards to arguments. Handlers for websocket only takes two arguments; What the controller returned and the state. And the handler should return what cowboy expects.

Example of a valid return value is {reply, Frame, State}