6CS028 Workshop - Web Services

Main Page >> Advanced Web Development >> Workbook >> Week 05

Important: this is a CodeIgniter example, but it is easily adaptable to Laravel.

REST - The Wikipedia API

Let’s simply find all all the Wikipedia pages that link to my website www.bdtheque.com :o)

With REST, it's all about calling the right URL, passing in the right parameters... here is the URL we need:

Click me! (look at the address bar)

Note that we are passing the following parameters:

• action = query
• list = exturlusage (the service we are requesting)
• format = xml (the format of the response)
• euquery = www.bdtheque.com (the parameter required for this service)

If you click on the URL, your browser simply display the XML data (try looking at the page's source code).

The controller

Create a new Apis.php controller:

<?php

namespace App\Controllers;

use App\Models\NewsModel;

class Apis extends BaseController
{
	public function wikipedia()
	{
		// Since 2010 a user agent is required
		ini_set('user_agent', 'University of Wolverhampton');

		$website = "www.bdtheque.com";

		$url = "http://en.wikipedia.org/w/api.php?"
			."action=query&"
			."list=exturlusage&"
			."eulimit=500&"
			."format=xml&"
			."euquery=".$website;
		  
		// Get data from URL and store in object
		$data['links'] = simplexml_load_file($url);
		$data['title'] = "Wikipedia API";

		echo view('templates/header', $data);
		echo view('apis/wikipedia', $data);
		echo view('templates/footer', $data);		
	}
}

Please note:

• We are using XML in this example, but you could try using JSON.
• Once we have the XML data, but simply pass it on to a new view (see below).

The view

Next, create a new view (Views/apis/wikipedia.php):

<?php foreach($links->query->exturlusage->eu as $link):?>
    <h2><?=$link['title']?></h2>
    <p>Links to: <a href='<?=$link['url']?>'><?=$link['url']?></a></p>
    <p>pageid: <?=$link['pageid']?></p>
<?php endforeach?> 

Please note:

• It's a simple foreach loop, that displays all items.
• Here is my working example: https://mi-linux.wlv.ac.uk/~in9352/ci4/public/apis/wikipedia

REST - Authentication via CURL

Some APIs will ask you to authenticate, by providing specific HTTP headers. This can be achieved using the cURL PHP library, which "allows you to connect and communicate to many different types of servers with many different types of protocols."

Reed.co.uk example

The Reed API located here explains that "You will need to include your api key for all requests in a basic authentication http header as the username, leaving the password empty."

You can achieve this in PHP like this:

<?php

// Set connection details
$login = 'PUT YOUR REED API KEY HERE';
$password = '';
$url = 'https://www.reed.co.uk/api/1.0/search?keywords=laravel&location=wolverhampton&distancefromlocation=15';

// Create CURL object with options
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_USERPWD, "$login:$password");

// Make CURL call, and convert result to JSON object
$jobs = curl_exec($ch);
$jobs = json_decode($jobs);
curl_close($ch);  

// Display results
foreach($jobs->results as $job) {
	print($job->jobTitle . "<br>");
}

Here is my working example

• https://mi-linux.wlv.ac.uk/~in9352/apis/reed.php

Going further: the OpenWeatherMap API

Adapt the example above to obtain current weather data for Wolverhampton, from the OpenWeatherMap API:

• https://openweathermap.org/current
• You'll need to register for a free API Key
• Like the Wikipedia API, the OpenWeatherMap API supports both XML and JSON.