jquery.pyproxy

The goal of jquery.pyproxy is to help integration of Ajax calls with JQuery in Python powered sites. The main idea is to use jquery syntax inside your Python call to update the page the users are seeing. This way, you do not have to return complex data to the Javascript client that will have to decrypt them.

IMPORTANT: the product is not yet finalized and might not work in every situations.

Installing

Add jquery.pyproxy to your buildout eggs and run the buildout, if you do not use buildout, you can easy_install jquery.pyproxy (or do as you usually do with other products).

In Plone, go to the quickinstaller and install jquery.pyproxy. That's all, happy Plone users can now skip to 'Simple example'.

In Django, you should also add django-appmedia to you buildout eggs and appmedia to the list of installed apps. Run buildout, then run bin/django symlinkmedia. Now in your templates, add:

<script type="text/javascript" src="{{MEDIA_URL}}/pyproxy/jquery.pyproxy.min.js"></script>

If you want to have a spinner automatically shown when a request is done, you can also add in your header:

<script type="text/javascript" src="{{MEDIA_URL}}/pyproxy/jquery.pyproxy.spinner.min.js"></script>
<link rel="stylesheet" href="{{MEDIA_URL}}/pyproxy/jquery.pyproxy.spinner.css" type="text/css" media="screen">

You need to have a pyproxy_spinner.gif image available at the root of the site. If not (or if your media files are hosted on a different subdomain), you should declare a javascrit variable called pyproxy_spinner_location that points to the URL of the file. The declaration should be done before including the jquery.pyproxy.spinner.js file.

If you do not want to use app_media, you can download the javascript library from github (https://github.com/vincent-psarga/jquery.pyproxy/blob/master/jquery/pyproxy/media/jquery.pyproxy.min.js - please ensure to match the egg version and js version) and install it to your media folder. You can then include it to your templates.

Simple example

A simple example should be easier to explain the idea behind jquery.pyproxy. You do not want user to have to reload the full page when submitting a comment to your blog, so you will use an Ajax call. Here's how you do this with jquery.pyproxy.

First, you create a view that will manage the information sent by the user (here with django, but the principle is the same with Plone):

from jquery.pyproxy.jq_django import JQueryProxy, jquery

# The @jquery decorator handles the transformation of your results
# into JSON so we can decode it on client side.

@jquery
def ajax_add_comment(request):
    # The JQuery proxy object helps us to manipulate the page the user sees.
    jq = JQueryProxy()
    # The data/form sent with Ajax just apear like a classical POST form.
    form = request.POST

    #we do some validation of the form.
    ...

    if errors:
        # We display an error message.
        jq('#my_error_message').show()
        return jq
    ...
    # We display a success message.
    jq('#my_success_message').show()

    # If the JQueryProxy object is not returned, nothing happens.
    return jq

and finally, bind a jquery.pyproxy action to the button used to submit a form:

$(document).ready(function() {
  $('#submit_comment').pyproxy('click',
                               '/ajax_add_comment',
                               '#comment_form');
});

Using the JQueryPyproxy object

First, you need to import the correct JQueryProxy object:

• if you use Plone: from jquery.pyproxy.plone import JQueryProxy
• if you use Django: from jquery.pyproxy.jq_django import JQueryProxy

Both are based on the same object, defined in the base.py module:

>>> from jquery.pyproxy.base import JQueryProxy

The main idea behind this project was to be able to use the same syntax than with jQuery, so you can more or less copy-paste some samples on the web or some existing code. Of course, as we are using Python, we can not use the dollar sign as a identifier:

>>> $ = JQueryPyproxy()
Traceback (most recent call last):
...
SyntaxError: invalid syntax

So in our examples we declare our object as jq, which is the classic way in Plone to name the jQuery object:

>>> jq = JQueryProxy()

Currently, JQueryProxy supports all manipulation API of JQuery 1.4 and all the effect API.

>>> sorted(jq.grammar.keys())
['addClass', 'after', 'animate', 'append', 'appendTo',
 'attr', 'before', 'css', 'detach', 'empty', 'fadeIn',
 'fadeOut', 'fadeTo', 'find', 'hide', 'html', 'insertAfter',
 'insertBefore', 'parent', 'prepend', 'prependTo', 'remove',
 'removeAttr', 'removeClass', 'replaceAll', 'replaceWith',
 'show', 'slideDown', 'slideToggle', 'slideUp', 'text',
 'toggle', 'toggleClass', 'unwrap', 'wrap', 'wrapAll', 'wrapInner']

So if you know how to use them in jQuery, you know how to use them with pyproxy, for example:

>>> jq('#error_msg').html('Errors have been found, please correct them')
>>> jq('#error_email').show()

The way the jQuery methods are declared are matching the API of jQuery (except for the callbacks, see the 'Limitations' part). So if you use incorrect arguments, you will get errors in the Python code (which should help you a lot when debugging, at least you should have server logs):

>>> jq('.to_slide').slideDown()
Traceback (most recent call last):
...
TypeError: Method 'slideDown' takes exactly 1 arguments

>>> jq('.empty').empty('Spanish argument is like Spanish inquisition: no one expects it')
Traceback (most recent call last):
...
TypeError: Method 'empty' does not take any argument

>>> jq('.to_fade').fadeTo('something', 'wrong type')
Traceback (most recent call last):
...
TypeError: Argument 2 of method fadeTo must be: <type 'int'>

If you need to process a list of selectors, you can use the batch method of the JQueryObject. It takes five arguments:

• a list of selectors
• the method to apply
• the list of arguments for this method
• a prefix to add before each selector (optional)
• a substituion list on which the selector will be applied (optional)

That can be usefull for example when you have a list of error to display:

>>> my_errors = ['email', 'title', 'text']
>>> jq.batch(my_errors, 'addClass', ['error'], substitution='#%s_error')
>>> jq.list_calls()[-3:]
["jq('#email_error').addClass('error')",
 "jq('#title_error').addClass('error')",
 "jq('#text_error').addClass('error')"]

That is equivalent to:

>>> for err in my_errors:
...     jq('#' + err + '_error').addClass('error')
>>> jq.list_calls()[-3:]
["jq('#email_error').addClass('error')",
 "jq('#title_error').addClass('error')",
 "jq('#text_error').addClass('error')"]

You can also chain the jQuery calls as you would do on the Javascript side:

>>> jq('.nice_divs').css({'width': '200px'}).fadeIn(10)
>>> jq.list_calls()[-1]
"jq('.nice_divs').css({'width': '200px'}).fadeIn(10)"

Note that we don't check (yet) if the call returns something that can be chained.

When you need to have a clear overview of which calls have been done by the jq object, you can use the list_calls method:

>>> jq.list_calls()
["jq('#error_msg').html('Errors have been found, please correct them')",
 "jq('#error_email').show()",
 "jq('.to_slide').slideDown()",
 "jq('.empty').empty()",
 "jq('.to_fade').fadeTo()",
 "jq('#email_error').addClass('error')",
 "jq('#title_error').addClass('error')",
 "jq('#text_error').addClass('error')",
 "jq('#email_error').addClass('error')",
 "jq('#title_error').addClass('error')",
 "jq('#text_error').addClass('error')",
 "jq('.nice_divs').css({'width': '200px'}).fadeIn(10)"]

You can see that even failing calls are stored here (but not the parameters). This is due to the fact that we are in the doctests. In real-life use case, as a exception is raised your code will stop after the problem has been found.

Extending JQuery proxy

If you want to be able to use jQuery methods that are not known by default, you have to extend the list of methods known by JQueryPyproxy. In our example, we'll consider that you want to use a showDialog method from an extra-plugin. By default, it does not works (which is logical as pyproxy does not have a clue of which jQuery plugins you are using):

>>> jq('.bla').showDialog()
Traceback (most recent call last):
...
AttributeError: 'JQueryCommand' object has no attribute 'showDialog'

To be able to use the method, you need to define the list of extra methods you want to use and the parameters expected. Here we only define the showDialog method, taking three parameters (the first one is a string or unicode, the second one an int, a string or a unicode and the last one a optional dictionnary):

>>> from types import NoneType
>>> my_plugin = {'showDialog': [[str, unicode],
...                             [str, unicode, int],
...                             [dict, NoneType]]}

Then, you can use the extend_grammar method so your methods are recognized:

>>> jq.extend_grammar(my_plugin)
>>> 'showDialog' in jq.grammar
True
>>> jq.grammar['showDialog']
[[<type 'str'>, <type 'unicode'>],
 [<type 'str'>, <type 'unicode'>, <type 'int'>],
 [<type 'dict'>, <type 'NoneType'>]]
>>> jq('#my_dialog').showDialog('some text', 42, dict(opt1 = 2, opt2 = False))

And of course it respects the grammar you defined:

>>> jq('.bla').showDialog()
Traceback (most recent call last):
...
TypeError: Method 'showDialog' takes between 2 and 3 arguments

>>> jq('.bla').showDialog(1, 2, 3)
Traceback (most recent call last):
...
TypeError: Argument 1 of method showDialog must have one of the following types: [<type 'str'>, <type 'unicode'>]

>>> jq('.grep').showDialog('blabla', 'fich')

If you need to use custom methods in all your Ajax views, it will be painfull to extend the grammar every time. You have some options to solve this.

1) if you use the source code of jquery.pyproxy: add a file called my_plugin.py in jquery.pyproxy/jquery/pyproxy/plugins. In this file, describe your plugin with the dictionnary as explained before. This dictionnary must be called grammar.

2) you do not use the source, just the egg. Create a new Python class, subclassing JQueryProxy. Declare a base_grammar property in this object that describes your grammar:

>>> class MyJQueryProxy(JQueryProxy):
...     base_grammar = {'showDialog': [[str, unicode],
...                                    [str, unicode, int],
...                                    [dict, NoneType]]}
>>> my_jq = MyJQueryProxy()
>>> my_jq('.bla').showDialog('a', 2)

and in your views, use this class instead of the JQueryProxy class.

3) integrate your grammar in the next release. In any case, do not hesitate to submit the grammars you defined so it can be integrated in the next release of jquery.pyproxy.

Limitations

There is currently two (at least) major limitations.

First, you can not store your selector, like this:

>>> jq = JQueryProxy()
>>> divs = jq('.nice_divs')
>>> divs.css({'width': '200px'})
>>> divs.fadeIn(10)

It seems to work fine, but if we have a close looks to what has been stored by the jq object, we can see that only the last call was saved and the call to 'css({width': '200px'})' will never be executed:

>>> jq.list_calls()
["jq('.nice_divs').fadeIn(10)"]

The proper way to write this code is:

>>> jq = JQueryProxy()
>>> jq('.nice_divs').css({'width': '200px'})
>>> jq('.nice_divs').fadeIn(10)

Now if we look at what has ben stored by the object, we see all wanted calls:

>>> jq.list_calls()
["jq('.nice_divs').css({'width': '200px'})",
 "jq('.nice_divs').fadeIn(10)"]

The second one is that the callback are not handled, so you can not use something like this:

>>> jq('.animated').show(10, 'my_callback')
Traceback (most recent call last):
...
TypeError: Method 'show' takes between 0 and 1 arguments

Even if the jQuery doc tells that the show method can take multiple arguments (which is true, but not here).

Is there some samples available ?

If you use Plone, add the following to one available configure.zcml file (the one from your theme from example):

<include package="jquery.pyproxy.samples.plone" />

Restart the instance and then open http://localhost:8080/your_plone_site/pyproxy_samples.

If you use Django, some samples will be added later.

Testing the module

There are tests embedded in this package to ensure it works correctly. To run the tests on the python side, you can run:

bin/instance test -m jquery.pyproxy (for Plone users)
bin/django test pyproxy (for Django users with a buildout)
./manage.py test pyproxy (for Django users without buildout)

There is also qUnit tests to ensure the jQuery library works correclty. For the moment it is only available for Plone users. First, you have to load the 'tests.zcml' file from jquery.pyproxy. For example in the main configure.zcml of a product you develop:

<include package="jquery.pyproxy"
         file="tests.zcml" />

Then, in the ZMI, go to the portal_setup, then the import tab. Select jquery.pyproxy tests in the list, select the Skins tools step and then click on Import selected steps. In the portal_skins tool, you should see a new folder called pyproxy_tests. Now open http://localhost:8080/your_plone_site/pyproxy_tests and you will see the qUnit tests running.

I use Python but not Django or Plone

You should use Django.

If this solution is not acceptable, you can still update the @jquery decorator to work with your framework. The only thing this decorator does is to transform the JQueryProxy object returned by the function into JSON. To make the transformation, this code is enough:

>>> import simplejson as json
>>> jq_to_json = json.dumps(jq.json_serializable())
>>> jq_to_json
'[{"args": [{"width": "200px"}], "call": "css", "selector": ".nice_divs"}, {"args": [10], "call": "fadeIn", "selector": ".nice_divs"}, {"args": [], "call": "show", "selector": ".animated"}]'

Then, the jq_to_json object must be returned according to your framework system (for example for Plone we just return it, for Django we wrap it into a HttpResponse object).

If you ported the @jquery decorator to any framework, please let me know so it can be integrated in the next release.

Compatibility

Tested with:

• jQuery 1.2, 1.4, 1.7 (probably all 1.x)
• Python 2.4, 2.6, and 2.7
• Plone 3.3, 4.0-4.3 and 5.0
• Firefox
• Chrome
• Safari
• IE