ewgi examples

[filippo pacini]

As dmitrii has mentioned we have created a project on github to
collect some ewgi examples:
http://github.com/filippo/ewgi_examples/tree/master

For now we have:
- the usual hello world :-)
- HELLO WORLD a middleware example that trasform a response body to uppercase
- an example of streaming file
- a ewgi_deflate middleware component which might be the base for
serving gzipped content if the client supports it

Others will come.

cheers,
--
Filippo Pacini

[Dmitrii Dimandt]

I'll try to contribute whenever I can as well.

Actually, you could also include an example on how to create chainable middleware.

See http://bit.ly/beepbeep_mw

If you have

get_chain(Modules) ->

    F = fun(Ctx) ->

        beepbeep_mw:stack(Ctx, Modules)

    end,

    F.

and each middleware module is implemented as follows:

-module(middleware_module)

run(Ctx, App) ->

    Ctx1 = modify_request(Ctx),  %% optional

    Ctx2 = App(Ctx1),

    Ctx3 = modify_response(Ctx2), %% optional

    Ctx.

%% or

%% run(Ctx, App, AdditionalModuleOptions)

Then you can invoke

F = get_chain([

    middleware_component1,

    middleware_component2

    {middleware_component3, [with, options]}

]),

F(EwgiContext).

And let the middleware chain take care of itself :)

So, to turn hello_world and uppercase into such a chain:

-module(ewgi_hello).

run(Ctx, _App) ->

    ResponseHeaders = [{"Content-type", "text/plain"}],

    Response = {ewgi_response, {200, "OK"}, ResponseHeaders,

                [<<"Hello world!">>], undefined},

    {ewgi_context, Request, Response}. 

    %% actually the last line should be App(Ctx)

    %% if this is the last middleware in chain

    %% Ctx will be returned

====================

-module(ewgi_to_upper).

run(Ctx, App) ->

    Ctx1 = App(Ctx),

    Body = ewgi_api:response_message_body(Ctx),

    Body1 = [string:to_upper(erlang:binary_to_list(B)) || B <- Body],

    ewgi_api:response_message_body(Body1, Ctx1).

=====================

-module(ewgi_examples_web).

dispatch("/HELLO", Ctx) ->

    F = get_chain([ewgi_to_upper, ewgi_hello]),

    F(Ctx);

Such a chain allows for a more flexible manipulation of requests and responses than F(G(H(...X(Ctx)))) which only operates on responses

    

[Filippo Pacini]

Thanks Dmitrii,
I'll add the chain example too.