So far we've covered parsing requests to determine exactly what the user is asking for, and also looked at routing to a controller to obtain the data or perform the action required. This post gives examples of how to return the data to the client in a good way.

She advocates using output handlers instead of the usual views you'd think of in a typical MVCish sort of application. The difference here is that there's not a lot of extra overhead to produce the results - it's literally an output directly from a class extending the base view (including the correct headers). She also briefly mentions the inclusion of JSONP functionality, allowing you to specify a local callback to execute when the request is returned. A few other "nice to haves" are also mentioned like the number of results returned and pagination support.

Location-aware applications rely on being able to locate where you are, and this is what geolocation is all about. After all, once the application knows your location, it can go on to find the nearest store, guide you through the appropriate route to a destination, or target relevant advertisements to you. Geolocation, then, is simply the mechanism for identifying your geographical location.

He mentions two challenges associated with geolocation - finding where someone is and describing the location. With Geonames, he shows how to call the service's "findNearbyPlaceName" method to find the closest "place" to a given latitude/longitude combination. Included is a bit of sample PHP to connect to the service and Javascript to request the user's current location.

We can't send post fields, because we want to send JSON, not pretend to be a form (the merits of an API which accepts POST requests with data in form-format is an interesting debate). Instead, we create the correct JSON data, set that as the body of the POST request, and also set the headers correctly so that the server that receives this request will understand what we sent.

She includes a code example (about ten lines) showing the POSTing process that sets up options using curl's curl_setopt. Be sure to set up the headers to send as "application/json" - that's the trick to letting the remote end know the format.

[This screencast is] part 2 in a series on building a JSON end-point. We're using simple RESTful verbage to grab a list of names from a session store.

You'll need to have the base scripts created in part one to follow along effectively. He picks up right where the previous part ends, creating a new view that uses some simple javascript (jQuery) code to pull the "names" values from his simple JSON endpoint. Also included is an example of a form for adding a new name to the list. The full source for the example can be found over on github.

You'll need some of the base that he created in this previous screencast to follow along (the basic structure, really). His takes his basic "hello world" application and builds on it to add a "model" to pull name data from and has the "/names" action respond with a JSON-formatted message (and an "application/json" content-type). His "model" pulls the data out with findAll() and find() methods.

You can grab the source to follow along.

Unless you're new to this web development lark, you'll know the 'X' in 'AJAX' stands for XML - eXtensible Markup Language. But you're probably not using XML. If you are, you'd probably prefer not to. All the cool kids are using JSON or JSON-P: it has a smaller payload, is easier to use and faster to process. [...] Fortunately, there are a couple of solutions which allow you to retain the benefits of XML data interchange but provide the ease of JSON in JavaScript. In this article, we're going to create an XML to JSON proxy server in PHP.

Of course, this will only work with well-formatted XML documents, but it's a quick little hack that pulls in the XML data with a curl request and parses it via SimpleXML and uses json_encode to push it back out as JSON.

Working on setting up the Rest Plugin for CakePHP helped me realize that i wanted to set up JSON output for some of my actions. This way, if you request for example "www.yourapp.com/app/post/view/1.json" in the url, you will be returned the JSON post data. This excellent tutorial here will help you achieve it.

Changes include updates to configuration for routing, using the RequestHandler component and setting your actions to output the data correctly when the ".json" is detected on the request.

The JSON format on which it rests guarantees maximum interoperability while ensuring good readability. The implementation done in the JsonDumper class operates all potentialities of the representation while providing maximum latitude to the developer to exploit its ability as desired, both in term of exposure of internal class mechanism for specialization and in terms of custom use, thanks to the callbacks that allow to intercept the JSON line by line and to adjust the dumping of objects or resources according to their type.

It isn't required to use the framework to use this tool, however. You can see an example of the output format in this example on the project's github page, complete with a guide to some of the advantages and disadvantages of some of the current, more common methods of output. Several types are included in the example including simple string/integer values, objects, classes, stream resources and the results of variable casting.

In my spare time I'm currently writing a shiny Web 2.0 application where I'm heavily using AJAX-like things, so what I do quite often in this application is, basically this: Check some pre-conditions (permissions etc.) then select some data from the database, do a fetch_all to get the complete result set as an array and run it through json_encode; Of course that example is simplified as I'm using the Symfony 2 framework for this project. [...] So I wrote a mysqlnd plugin.

His plugin (that he admits is "a hack") gives you the mysqlnd_query_to_json function that automagically transforms the results from the passed in query into JSON output. He notes some things lacking - like Unicode encoding and no MySQL bitfield support.

In the past few years, JSON, or JavaScript Object Notation has seemed to overtake XML and other data encoding methods on the web. [...] I've also seen numerous examples of developers who create their own sort of JSON encoder rather than either using json_encode or using Zend_Json. What inevitably comes back to bite them is when the data they are encoding contains a special character like quotes, colons, curly brackets, etc.

He demonstrates how the Zend_Json component helps to alleviate some of the worries with built-in features that handle everything from basic encoding/decoding, printing out results in a "pretty" way and a handy way to include executable Javascript (once it's evaled on the other side) in your payload. He finishes the tutorial off with a mention of a very handy method that will please those already having to work with XML - the fromXML() method that automagically converts the data over to JSON for you.