Directly

Apply Directly to the Django.

---

About

Directly is a simplified ExtDirect implementation for Django apps using an ExtJS frontend.
My goal with this project was to make ExtDirect as easy as possible to use with Django, with the least amount of editing required.

The idea is fairly simple, so let's keep this module simple!

• Write a function in python
• Call it in JavaScript as if it was a JavaScript function

If you're new to Django/ExtJS development and want to get into ExtDirect as fast as possible, this might be perfect for you.

Developed with:

• Python 2.7.6
• Django 1.6.5
• ExtJS 4.2

Additionally tested with:

• Django 1.7
• ExtJS 5.0 (See notes at the end for possible issues)

Files to edit

ExtDirect is supposed to be an interface between your server and your ExtJS app.
That's why I want to stay out of views or settings. All redirecting is done through the urls.py.
Obviously you'd need to write your python functions to call and the ExtJS part that calls them. But other than that, there is no special treatment for your existing Django project required.

If you're new to ExtDirect and/or Django, read below. Otherwise scroll to the bottom of this file for a short summary.

---

Using Directly in 4 steps

======= 1: Create your backend functions =======

Create a new python file in your app folder to write your functions into.
In this example I will be creating a collections of functions to log the user in, out and retrieve their username.
I'll just call it users.py.

In Directly we separate our namespaces by classes.
The UserAuth class will be the one to call if I need to log in or out.
The UserStuff class will be responsible for additional goodies, like getting the user's username.

# file: django_project/app/users.py

class UserAuth():
    @staticmethod
    def log_in(request, username, password):
        status = login(username, password)
        return status
    
    @staticmethod
    def log_out(request):
        return logout(request.user)

class UserStuff():
    @staticmethod
    def get_username(request):
        return request.user.username

All methods need the @staticmethod decoration, since they're standalone functions. We will not be using the classes in the 'traditional' way.
Also, you get the HttpRequest like you usually do in your views, so your methods need at least one parameter, which will be the request, conveniently, also called request.
Just imagine the functions login() and logout() actually exist and do log the user in and out.

---

======= 2: Decorate your methods to expose them =======

Import Directly to your users.py
All you really need is in the Ext class: from Directly import Ext

Decorate your classes with Ext.cls and methods with Ext.method.
This way, only the methods you want to be exposed to ExtJS will be exposed.
All classes and methods without decoration will be ignored when creating the API, so you won't be able to access them from ExtJS.
Here's the code from above with decorations.

# file: django_project/app/users.py

from Directly import Ext

@Ext.cls
class UserAuth():
    @staticmethod
    @Ext.method
    def log_in(request, username, password):
        status = login(username, password)
        return status
    
    @staticmethod
    @Ext.method
    def log_out(request):
        return logout(request.user)

@Ext.cls
class UserStuff():
    @staticmethod
    @Ext.method
    def get_username(request):
        return request.user.username

Please note that @Ext.method goes below @staticmethod.

---

======= 3: Get the API =======

In your main urls.py, redirect whatever you want to be the access point to your API to Ext.getApi().

# file: django_project/app/urls.py

from Directly import Ext
from app import users

urlpatterns = patterns('',
    # ... Other patterns
    url(r'^userAPI.js', Ext.getApi(namespace='SuperApp', apis=[users], url='/user')),
)

The API will now be accessible at yourdomain/userAPI.js.
It doesn't have to be a .js extension, since it's not really a file behind it, but it seems to make more sense. ;)

Arguments:

• namespace: The name at which you can call your classes. Defaults to Directly
• apis: Your module(s) (files), cointainung your classes. It can be either a single one, or a list/tuple of modules.
• url: The url where all ExtDirect calls using your API will be sent to.

Import the js in your html template.

...
<head>
    <script type="text/javascript" src="userAPI.js"></script>
</head>
...

---

======= 4: Catch your calls =======

You can already use your functions, but they will throw a 404 error, because Django doesn't know how to deal with a request to the provided url.

Add another line to the urls.py and redirect the url you've chosen above to Ext.rpc().

# file: django_project/app/urls.py

from Directly import Ext
from app import users

urlpatterns = patterns('',
    # ... Other patterns
    url(r'^userAPI.js', Ext.getApi(namespace='SuperApp', apis=[users], url='/user')),
    
    url(r'^user', Ext.rpc(apis=[users])),
)

Arguments:

• apis: Again, a list of modules with your classes.
  It doesn't have to be the same as the ones in Ext.getApi, so you can split your API and process different methods on different URLs.

---

That's it.

Now, to log in with this example in ExtJS, you can use the API like it's a JS function.
You need Ext.direct.* imported manually, if you're working with Architect.
For more information on where to replace your Ajax-calls with ExtDirect, check the sencha examples.

Use them like Namespace.Class.method(*arguments*, callback_function).

// Some JS or chrome-console
SuperApp.UserAuth.log_in('admin', 'password123', function(val) {
    if(val === true) {
        console.log("You are now logged in!");
    }
});
SuperApp.UserStuff.get_username(function(val) {
    console.log("Logged in as " + val);
});

---

What else?

Ext.rpc currently takes two optional arguments:

• debug: True/False/Function - Prints every RPC object to console if True, or calls a function providing the RPC object as an argument. Defaults to False.
• exempt: True/False - Does not decorate with csrf_exempt if False. You need to handle it yourself if you want to use it. Defaults to True for simplicity.

ExtJS 5.x with Sencha Architect 3.1 now defaults to using the microloader. If you're using the microloader, it might try to load your API before loading the app.js, resulting in Ext being undefined when calling Ext.direct.Manager[...]. Possible workarounds:

Disable microloader and manifest in app.json:

{
[...]
    "output": {
        "microloader": {
            "enable": false
        },
        "manifest": {
            "enable": false
        }
    }
[...]
}

This way the old-skool single-file app is generated and you're free to include your generated API after that.

Generate non-executed / non-Ext API code and run it yourself:

I've added an additional optional keyword to getApi: form
It takes a string keyword:

• 'json': Generates pure JSON representation of your API.
• 'var': Generates Namespace.REMOTING_API variable containing your API.
• Anything else will result in the regular self-executing Ext-code.
  Both of the above need to be added using Ext.direct.Manager.addProvider(apiObj) inside your app. I suggest using the launch listener:

launch: function() {
    Ext.create('Project.view.Viewport');
    if(Project.REMOTING_API !== undefined) {
        if(Project.REMOTING_API instanceof Array) {
            Ext.each(Project.REMOTING_API, function(api) {
                Ext.direct.Manager.addProvider(api);
            });
        }
    }
}

It's less intuitive and I don't like it tbh. It's against my hopes to keep the module as simple as possible, but it works.

---

Short summary for experienced users

(or if you can't be bothered reading 180 readme-lines...)

Write Classes with static methods and decorate them using Ext.cls and Ext.method to expose them to the API:

# file: project/app/direct.py
from Directly import Ext

@Ext.cls
class A():
    @staticmethod
    @Ext.method
    def b(request):
        return True

At least one argument is required for the request.

Forward a request to the api to Ext.getApi, include it in your template and handle the url by forwarding it to Ext.rpc. Both need a list of modules with your python classes.

# file: project/app/urls.py
from Directly import Ext
from app import direct
    # ...
    url(r'^api.js', Ext.getApi(namespace='ExtNamespace', apis=[direct], url='/direct/something')),
    url(r'^direct/something', Ext.rpc(apis=[direct])),

Use it

// console
ExtNamespace.A.b(function(ret) {
    console.log(ret);
});

Dun.