Breaking Morepath Changes

By Martijn Faassen
2014-01-22
Tags:
planetpython,
python,
morepath

I'm slowly heading to a first release of the Morepath web framework, but right now I can still change anything without breaking any significant code. So I took the opportunity to do so.

What's Morepath? Morepath is your friendly neighborhood web framework with superpowers. Read more here.

These changes are in fact less big than some refactorings I do to Morepath frequently, but they break the public API of Morepath, so they're big in that sense.

These are the changes:

The @app.model directive was renamed to @app.path, as I realized the directive is describing a path more than a model. Here's what it looks like now:
```
@app.path(model=Document, path='documents/{id}')
def get_document(id):
    return query_document(id)
```
The name is justified as such: just like the view directive describes a view, the path directive describes a path. Paths and views are related to each other by model class. The word model was rather overused in Morepath anyway.
The @app.view directive decorates a function that's a view. It used to get request, model parameters. I've changed this to self, request, reversing the order. This to make it clearer to people that a view is really much like a method, and to free up the word model some more. Here's what it looks like:
```
@app.view(model=Document)
def document_default(self, request):
    return "Hello document: %s" % self.id
```
self is not a reserved word in Python, so I figured this was a good place to use it, even though document_default really is a function, not a method. But since it's a generic function it's like a method anyway.

The lookup of the view is still done giving request a greater weight than model, like in Pyramid. That's mostly an implementation detail in Morepath. In Pyramid this matters a lot more, but in Morepath there really isn't anything done yet with different request classes.
The @app.root directive is now gone. It wasn't pulling its weight anymore, as it had become just an alias for @app.path with a path parameter of "/". This is what it looks like now:
```
@app.path(model=Root, path='/')
def get_root():
    return the_root
```

(by the way, if the docs on the Morepath website don't update for you, do a shift reload. I'm not sure how long it takes for the cache to expire.)

Want to talk to me about Morepath? Leave a comment here, drop me an email, use the Morepath issue tracker or join the #morepath IRC channel on freenode. Hope to hear from you!