Ajax Response Helper for PHP
In Ajax programming development, passing data back and forth between client and server is a common task. There are two major data formats that one can use for this purpose, namely XML and JSON. My personal preference is JSON because I find it's less verbose and easier to parse.
Although latest PHP provides a very handy function (json_encode) for outputting data in JSON format, for almost every Ajax request I handle on the server side, I have to routinely format the data in a certain way so I can use it conveniently on the client side. For example, to indicate whether it is a valid Ajax request, I embed an field called has_error in every response. I find it's getting annoying after a while, so I wrote a class to automate things a bit.
The Code
To use this class, just include the class file in your source code:
include 'AjaxResult.class.php';
$r = new AjaxResult();
echo $r;
//JSON output
{"has_error":false,"result":[]}
Adding data to the response:
include 'AjaxResult.class.php';
$r = new AjaxResult();
$data = array(
'data1'=>5,
'data2'=>10
);
$r->setResult($data);
echo $r;
//JSON output
{"has_error":false,"result":{"data1":5,"data2":10}}
Indicating there's an error in the request and adding error(s). Notice that by adding error messages, the class will automatically change has_error filed in the response to true:
include 'AjaxResult.class.php';
$r = new AjaxResult();
$r->addError('Something is wrong');
echo $r;
//JSON output, has_error changed to true
{"has_error":true,"errors":["Something is wrong"],"result":[]}
If you happened to use jQuery, this is how you can process this response:
<script type="text/javascript">
$.get('example.php', {}, function(data){
if(data.has_error){
alert(data.errors[0]);
return;
}
//do stuff as usual
var result = data.result;
...
}, 'json');
</script>
Pretty neat hut? Here's something more fun. When making server response, you can combine all the steps above into one:
include 'AjaxResult.class.php';
//Another way of creating AjaxResult instance:
AjaxResult::create()
->setResult(array('a'=>'aa')) //this one is optional
->addError('a is not aa')
->toJSON(true); //true means output insteand of returning the string
//JSON output
{"has_error":true,"errors":["a is not aa"],"result":{"a":"aa"}}
You can assign a key to the error message while adding error message by calling addErrorAssoc method. You can even combine associate and non-associative ones:
include 'AjaxResult.class.php';
AjaxResult::create()
->addError('a is not aa')
->addErrorAssoc('message', 'this is an error message')
->toJSON(true);
//JSON output
{"has_error":true,"errors":{"0":"a is not aa","message":"this is an error message"},"result":[]}
//In JavaScript (assuming you are using the jQuery example a few sections above):
alert(data.errors[0]);
alert(data.errors.message);
For PHP 4 or PHP 5 < 5.2.0
AjaxResult employs native PHP function json_encode. However json_encode hasn't been added until 5.20. So if you are using a PHP which version is lower than that, you need to create this function manually. I included a quick fix for this issue. To emulate this function, include JSONFix.inc.php (provided in the zip file) to your source code.
Conclusion
As always, bug fix, comment, suggestion are welcome.
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