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Editorial Team
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Asked: 2026-06-15T13:30:06+00:00

I developed a very quick and simple PHP application for reading classified ads from

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I developed a very quick and simple PHP application for reading classified ads from an XML file and allowing the user to perform CRUD operations on it (this was a homework assignment).

I’m now tasked with developing this application to a RESTful service. The professor actually doesn’t seem to have any experience with RESTful services, because he said my application was find to hand in for the next assignment, when my research indicates it doesn’t really fulfil all the RESTful requirements.

Regardless, I want to do this correctly for learning purposes, even if I can hand in my old assignment and get a good grade. I’m having trouble learning where to begin though; I’m not sure exactly what a RESTful service really is.

I think the best way to get advice is to post sample code from my previous assignment to see how I handled things and how I need to handle things instead.

For instance, here is how I create new classifieds.

Create.php

//Basically just a list of <INPUT TYPE = "text" NAME = "something"> in the <body> fields

CreateSuccess.php

<html><head><?php $simplerXML = simplexml_load_file('file.xml'); 
//Generate the basic ad information
$newAd = $simplerXML->addChild('advertisement','');
$newAd->addAttribute('category', $_POST["category"]);
$title = $newAd->addChild('title', $_POST["title"]);
$title->addAttribute('ID', $_POST["ID"]);
$pageTitle = $newAd->addChild('pagetitle', $_POST["pagetitle"]);
//etc, for all the SUBMIT boxes

//save the XML
$simplerXML->asXML('file.xml');
echo "<script type='text/javascript'>
//redirect back to ad listing page
window.onload = function () { top.location.href = 'ads.php'; };
</script>";
?></head>
<body></body></html>

I’m also using URL parameters for the RUD actions. I’ve heard URL parameters are not allowed as well?

Thanks.

EDIT:
So the SWITCH statement, does it go in the index.php file? And then each case will call a function, ie CreateXML for the POST method?
Then the parameters it needs will be the object type, object id, and content type? How do I get the values to update the XML with, do I just send it to the Create.php file containing the list of input boxes?

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1 Answer

  1. Editorial Team

    If your service supports all CRUD operations, it’s always advisable to implement a RESTful interface. It’s not super-hard to do so. I’ve outlined some of the basics below.

    A RESTful service simply does a few things:

    1. It uses HTTP request method for communication of the CRUD action
    2. It uses HTTP status code to communicate response status, and
    3. It uses the URI to define your resource (file, database item you’re accessing, etc).
    4. It is stateless

    The idea is to minimize the development of custom communications for these things that are already defined in the HTTP spec.

    1 – REQUEST METHOD

    The 4 HTTP request methods you’re required to support for a RESTful service are:

    1. POST
    2. GET
    3. PUT
    4. DELETE

    and you may optionally support

    1. PATCH
    2. HEAD

    You can map these directly to your CRUD actions as follows:

    • POST = Create
    • GET = Retrieve
    • PUT = Update
    • DELETE = Delete
    • PATCH = Edit (a partial update, e.g. “change password”. PUT becomes “replace”)
    • HEAD = Header only (metadata about the resource)

    To do this, route requests properly with a simple request method router as follows:

    switch ($_SERVER["REQUEST_METHOD"]) {
    case "POST":
        // Create action
        break;
    case "GET":
        // Retrieve action
        break;
    case "PUT":
        // Update action
        break;
    case "DELETE":
        // Delete action
        break;
}

    2 – STATUS CODE
    You should further implement HTTP status codes from your service to communicate status back to the client, e.g.:

    • 20x = success
    • 30x = redirection
    • 40x = communication issues
    • 50x = server error

    To do this, simply prepend your response with the proper HTTP header output, e.g.:

    header("Status: 500 Internal Server Error");

    You can reference the full list of implemented HTTP status codes here: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

    3 – URIs
    For URIs, RESTful services usually follow a top-down approach to categorized naming, e.g.

    /object_type/id.content_type

    Examples:

    POST /user
PUT /user/1
GET /user/1.json
GET /user/1.html

    You can implement a very rudimentary RESTful router for the above convention using Apache with mod_rewrite in an .htaccess file, as follows:

    RewriteEngine On
RewriteRule ^([^\/]+)\/([^\.]+)\.(\w+)$  index.php?object_type=$1&object_id=$2&content_type=$3

    You would then have index.php Look for the appropriate object_type and id to route appropriately, e.g.:

    $object = $_GET["object_type"];
$id = (int) $_GET["object_id"];
$content_type = $_GET["content_type"];

// Route from here to a class with the name of the object (e.g. UserController) via __autoload
// or to a file (e.g. user.php) via include, and pass id and content_type as params

    4 – STATELESSNESS
    Simply stated, the server maintains no “state” for the client. No requirements for storing session or status. Each request represents a complete transaction. I.e. if I GET user/1, the server won’t remember that I did that, and future requests won’t be dependent upon or affected by previous ones.

    If you implement these standards, congrats, you’ve built a RESTful service!

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