How can I decide if a website is using Ajax technology? What are the characteristics that I should I look in the website to tell it is an ajax application?
Search the javascript for XMLHttpRequest. Beyond that, the working definition of Ajax is rather too broad to look for, say, specific behaviours.
You can just look into the javascript source code and search for .ajax, .post and .get . If you find any of these they use ajax technologies.
You can also look at the network requests a page sends, if the page sends requests after loading the full page without you seeing it refreshing it probably uses ajax.
There's nothing special about websites using AJAX, it just means they make an asynchronous call to the server at some point. You can't know for certain that the website will make such a call unless you run it.
This question has an answer that basically says to make template groups and templates act like controllers and output JSON like data.
Is this the correct way to do this in ExpressionEngine? or are there native, more "natural" way to do Ajax?
The best approach here likely depends on the data that you're working with. If you are looking to output JSON-formatted content from the core channel entries module then I'd recommend using Rob Sanchez's ExpressionEngine JSON plugin.
If you're working with a custom-built module then you might as well extend that a little further and implement a JSON method. For example, if you have a Widgets module you could create a json() method within that and then utilise it within templates via {exp:widgets:json var="foo"}.
I'm working on a website that uses AJAX to retrieve data from the server and display it on the page. Django renders the initial page content using its template engine (so it will be indexed by search engines). When the user takes an action, jQuery fetches the new data via AJAX and the response is returned as JSON. I would like to have jQuery render this new content without violating the DRY Principle. Therefore I would like to use a templating engine that is "shared" between Django and jQuery. I've been running in circles trying to find the best solution but always seem to run into a road block.
Has this already been done? Here are the options I have thought of:
Use regular expressions to transform the Django template into correct jQuery template syntax, and render it in its raw form to the page. jQuery will then pick it up and use it to render the new data.
Extend the jQuery template engine to recognize the Django template syntax, again rendering the raw Django template to the page for jQuery to use.
Has this been successfully done before? Either way seems like a lot of work for anything but the simplest of Django templates because of the plethora of Django tags and filters that would need accounted for.
Your best bet is to pick a template language that has both Javascript and Python support, and use that everywhere.
As far as I know, Mustache is your best bet.
I haven't found a perfect solution since I asked this question, but for the sake of development time I resorted to sending back both JSON and HTML in the AJAX response. This way the django templates still perform the HTML generation, but javascript is still free to utilize the data without having to parse the HTML.
I am sending approximately twice the data over the network, but I'm going to live with it until my application grows to the point where a smaller response is beneficial. At that point I will probably look into something like Mustache as Rob mentioned.
I'm working on an ajax-based Wordpress site and I want to know if there is a way to get a particular page content with theme structure applied in.
One workaround is to use
wget
or
file_get_contents(page_url)
but it'd be cleaner to use Wordpress built-in functions.
Thanks.
I'd go with file_get_contents. I'm not aware of a built-in WP function to do this, but even if there was one I would expect it to be based on file_get_contents
FYI, don't use any of these methods I mentioned above because it's way too slow. I ended up utilizing the Loop and include_once(); to get the content with the theme structure.
I am trying to find the optimal architecture for an ajax-heavy Django application I'm currently building. I'd like to keep a consistent way of doing forms, validation, fetching data, JSON message format but find it exceedingly hard to find a solution that can be used consistently.
Can someone point me in the right direction or share their view on best practice?
I make everything as normal views which display normally in the browser. That includes all the replies to AJAX requests (sub pages).
When I want to make bits of the site more dynamic I then use jQuery to do the AJAX, or in this case AJAH and just load the contents of one of the divs in the sub page into the requesting page.
This technique works really well - it is very easy to debug the sub pages as they are just normal pages, and jQuery makes your life very easy using these as part of an AJA[XH]ed page.
For all the answers to this, I can't believe no one's mentioned django-piston yet. It's mainly promoted for use in building REST APIs, but it can output JSON (which jQuery, among others, can consume) and works just like views in that you can do anything with a request, making it a great option for implementing AJAX interactions (or AJAJ [JSON], AJAH, etc whatever). It also supports form validation.
I can't think of any standard way to insert ajax into a Django application, but you can have a look to this tutorial.
You will also find more details on django's page about Ajax
Two weeks ago I made a write up how I implement sub-templates to use them in "normal" and "ajax" request (for Django it is the same). Maybe it is helpful for you.
+1 to Nick for pages displaying normally in the browser. That seems to be the best starting point.
The problem with the simplest AJAX approaches, such as Nick and vikingosegundo propose, is that you'll have to rely on the innerHTML property in your Javascript. This is the only way to dump the new HTML sent in the JSON. Some would consider this a Bad Thing.
Unfortunately I'm not aware of a standard way to replicate the display of forms using Javascript that matches the Django rendering. My approach (that I'm still working on) is to subclass the Django Form class so it outputs bits of Javascript along with the HTML from as_p() etc. These then replicate the form my manipulating the DOM.
From experience I know that managing an application where you generate the HTML on the server side and just "insert" it into your pages, becomes a nightmare. It is also impossible to test using the Django test framework. If you're using Selenium or a similar tool, it's ok, but you need to wait for the ajax request to go return so you need tons of sleeps in your test script, which may slow down your test suite.
If the purpose of using the Ajax technique is to create a good user interface, I would recommend going all in, like the GMail interface, and doing everything in the browser with JavaScript. I have written several apps like this using nothing but jQuery, state machines for managing UI state and JSON with ReST on the backend. Django, IMHO, is a perfect match for the backend in this case. There are even third party software for generating a ReST-interface to your models, which I've never used myself, but as far as I know they are great at the simple things, but you of course still need to do your own business logic.
With this approach, you do run into the problem of duplicating code in the JS and in your backend, such as form handling, validation, etc. I have been thinking about solving this with generating structured information about the forms and validation logic which I can use in JS. This could be compiled at deploy-time and be loaded as any other JS file.
Also, avoid XML. The browsers are slow at parsing it, it is a pain to generate and a pain to work with in the browser. Use JSON.
Im currently testing:
jQuery & backbone.js client-side
django-piston (intermediate layer)
Will write later my findings on my blog http://blog.sserrano.com