Renderer

The Renderer interface in the Controller API allows you to define a custom mechanism for rendering a ViewModel to the response of an HTTP GET request.

The ViewModel is passed from the Loader, which is executed directly before the Renderer in the request lifecycle.

The generic constraint T is the ViewModel, and should match the type constraint also given to the Loader interface. It may be helpful to type assert against the following interface when implementing custom renderers:

Built-in Renderers

You don't always have to implement a custom Renderer!

torque comes with built-in renderers for JSON and HTML, and many more custom renderers can be found in the plugins section.

HTML

The torque framework was designed with server-side rendering (SSR) in mind. The built-in HTML renderer uses the tmpl package to make it easy to render complex hypermedia applications with Go.

torque uses tylermmorton/tmpl to compile and render HTML templates using Go's template syntax. It offers all the features of html/template plus template nesting and fragments, runtime analysis, static typing for templates, and more.

To take advantage of the built-in renderer, your ViewModel type must implement the TemplateProvider interface from the tmpl package.

The following is an example of a ViewModel that implements the TemplateProvider interface. For a detailed breakdown of the template workflow, see the Template documentation.

JSON

By default, if no Renderer is implemented on a Controller, and the ViewModel does not provide any HTML template, torque will render the ViewModel as JSON. This is useful for APIs or single-page applications (SPAs) that use JavaScript to render the frontend.

torque does mind the request's Accept header and will always respond with JSON if the header is set to application/json, even when the Controller implements some other custom Renderer.