Class: MtaJson::Wrapper

Inherits:
Object
  • Object
show all
Defined in:
lib/mta_json/wrapper.rb

Overview

wraps calls to .mta-urls in a MTA-specific format. The main difference is:

  • the request body needs to have the surrounding [ ] removed (which technically represents a JSON-Array)

  • the response body needs [ ] added (again, a JSON-Array) which consists of:

    • body of the response

    • headers

MTA technically allows multiple parameters, but that doesn’t really suit rails’ named parameters (param).

Constant Summary collapse

CONTENT_TYPE =

env

'CONTENT_TYPE'.freeze
BODY = 
'rack.input'.freeze
FORM_INPUT = 
'rack.request.form_input'.freeze
FORM_HASH = 
'rack.request.form_hash'.freeze
SESSION = 
'rack.session'.freeze
METHOD = 
'REQUEST_METHOD'.freeze
POST = 
'POST'.freeze
PATH_INFO = 
'PATH_INFO'.freeze
IP = 
'REMOTE_ADDR'.freeze
CSRF_TOKEN = 
'X-CSRF-Token'.freeze
CONTENT_LENGTH =

HTTP-Response-Headers

'Content-Length'.freeze
ALLOWED_METHODS =

Allowed Methods to be set by MTA

%w(GET)
ALLOWED_METHODS_PRIVATE = 
%w(POST PUT DELETE)

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Wrapper

Returns a new instance of Wrapper.



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# File 'lib/mta_json/wrapper.rb', line 29

def initialize app
  @app = app
end

Instance Method Details

#call(env) ⇒ Object

callRemote on the MTA-side may have [0, 1 or 2] parameter(s):

  • if no parameters, params is empty within rails

  • first parameter - as a table - fills the params hash which is accessible in controllers (etc) i.e.

    callRemote("http://localhost/auth.mta", function, { name = 'a', password = 'b' })

    makes the following parameters available in the called controller

    params[:name] = 'a'
params[:password] = 'b'

  • second parameter - as a table - options on how the request is handled. See update_options for details, for example { ‘method’ = ‘GET’ } allows GET-Requests, while usually callRemote does only POST-Requests.

This is unlike the PHP-SDK, which may have multiple parameters and allows access via numbers

$input = mta::getInput();
$name = $input[0];
$password = $input[1];

Rails has named parameters, so there’s no explicit support for them numbers.

callRemote for MTA should always call files ending with .mta, for example:

  • /auth => /auth.mta

This will call the related JSON-Methods, i.e.

respond_to do |format|
  format.html { ... } # certainly not this
  format.json { render :json => @object } # this gets called!
end

There is no support for elements and/or resources (yet?).



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# File 'lib/mta_json/wrapper.rb', line 60

def call env
  path = env[PATH_INFO]
  if path.end_with?('.mta') and (body = env[BODY].read).length != 0 and env[METHOD] == POST
    # replace ".mta" with ".json"
    env[PATH_INFO] = path[0..-5] + '.json'

    json = JSON.parse body
    raise Exception, "Number of JSON elements > 2: actual #{json.size}" if json.size > 2

    # optional options!
    update_options env, json[1].with_indifferent_access if json.size >= 2

    verify_request_method env

    # any parameters given? otherwise we don't really care for any params
    update_params env, json[0] if json.size >= 1 and json[0] != 0 # 0 is nil in terms of callRemote. JSON has 'null' though!

    # add some CSRF info... maybe.
    add_csrf_info env

    # call the other middlewares
    status, headers, response = @app.call(env)

    # alter only successful status codes to be more mta-ish
    if (200..299).include?(status)
      # mta /can/ handle multiple parameters as response.
      # We do not want and/or need this, but merely wrap the response body in square brackets as to return a single element
      # If render :json => @obj is used in the controller, this should make exactly @obj available in MTA.
      response = to_response(response, headers)

      # overwrite the length if already set
      if headers['Content-Length']
        headers['Content-Length'] = response.length
      end
    end

    return [status, headers, response]
  else
    # normal call, nevermind that whole mta business
    @app.call(env)
  end
end