Provide a pipeline API

[aesteve]

What is a pipeline ?

It's a way to transform resources either at runtime (dev environment) or at startup or at build time (and then the framework doesn't care).

We could offer a pipeline API which would associate a resource to its built equivalent and map it to one single path. And then would transform it or not dependeing on the context.

Example

If we're on a dev environment :

When the user asks for assets/*.css, look for web/styles/*.scss, then send invoke my transform function and return the result.

If we're on a production environment :

Look for every file in web/styles/*.scss, if you fin their equivalent into dist/styles/*.css then it's OK, serve directly those files when assets/*.css is asked. If some are missing, please invoke my transformation function and save the result.

Pretty complicated to explain, not that easy to implement, but very useful.

[aesteve]

So the pipeline interface could look like this :

public interface Pipeline {
    public String rawPattern();
    public String distDir();
    public String transformName(String originalName);
    public Buffer transform(Buffer originalContent);
}

In case of sass files for instance :

public class SassPipeline implements Pipeline {
    public String rawPattern() {
        return "web/raw/styles/*.scss";
    }

    public String distDir() {
        return "web/dist/styles":
    }

    public String transformName(String originalName) {
        return originalName.replace(".scss", ".css");
    } 

    public Buffer transform(Buffer originalContent) {
       // invoke sass compiler
       return ...
    }
}