ee-templates

#EE-Templates
Templating integration for Nunjucks (Middleware)

##Middleware
The middleware can be hooked into the application stack and will append a render(status, headers, data, callback) method
to the original http response (or any kind of response which adheres to the interface defined for response in ee-webserver).
The renderer method contains a renderer resolved based on the accept headers, which renders the passed content into an
appropriate representation for the http protocol (properly supperted at the moment: text/html or application/json).

##Renderers
Currently there are only two supported renderers: HTML and JSON. The environments (nunjucks) are application specific
and need to be passed to the middleware.

###HTMLRenderer
The HTMLRenderer is a wrapper for nunjucks. It creates a new environment based on the domain of the request and loads
the template which has to be set on the request (in our case resolved by the rewriting middleware).

###DefaultRenderer
The DefaultRenderer uses JSON.stringify and converts the passed data to a string.

##Templating Extensions
The templating extensions originally provided by this package were moved to their own packages ee-soa-extension-api and
ee-soa-extension-locale. Since environments now are passed into the middleware, the dependency is removed and extensions
are directly attached by the running application.

##Todo

- Add a better loader which allows loading the templates asynchronously
- Improve handling of the mapping between the accept header and the renderer.

##Media Types
Further readings

- Internet Media Types
- RFC 2616
- MDN: Content-Negotiation

##Changelog

$3

- the render method of the response now directly writes the data back to the original response
- the renderers now directly write their assigned content type to the response
- the renderers directly create server errors if the rendering created an error
- therefore the API has slightly changed from render(data, callback) to render(status, headers, data, callback)