Webbing Wednesdays Week #9

API Application Programming Interface

This webbing Wednesday, Techtic Solutions have come up with another interesting topic of API. Well, lot of times, working on the website, or rather bridging the website with some other source of information or bridging the website with some other website requires some sort of a interfact between the two. Website works on an application layer of the IP Protocol and hence the application programming interface is a necessity for such requirements. We call them API in regular terms. This is the simplest and most generic definition of any API.

Going into the depth of API Definition:

The API stands for Application Programming Interface.
It can be used to describe features of any library or functionalities or offering the means for utilizing third party features as an interface.
APIs are always supplied with the documentation for the same, which has all the features that it can take from some pool of data to anywhere necessary with the guidelines of authentications, functions, response codes, and much more.
API acts as a bridge between the two characters, one is a supplier of the features and one is the consumer for the same features, it acts as a third party in the given situation.

Does it mean that the API is very tough to create or takes too much efforts to build one for any given usage? Well there are few simple steps to build a basic API.

Creating an API

Well API needs a web page, which will try to locate some third party data and the database which is the third party data. In this situation the API will be written in a way that the web page will call some functions given in the API and API would authenticate the functions, act on the same and get the correct results from the database and showcase it to the web page.
An API consist of documentation, conditions, classes, functions, response codes and error message details.
The more user friendly and human readable the API is coded, the better it is for anyone to use the API and maximize the utilization of the same.
API needs to also describe a way to perform any particular task, the steps to be followed and the details required or supplied for the same.

Example:

<!--?php if(isset($_GET['format']) && intval($_GET['num'])) { //Set our variables $format = strtolower($_GET['format']); $num = intval($_GET['num']); //Connect to the Database $con = mysql_connect('localhost', 'root', '') or die ('MySQL Error.'); mysql_select_db('api', $con) or die('MySQL Error.'); //Run our query $result = mysql_query('SELECT * FROM recipes ORDER BY `post_id` DESC LIMIT ' . $num, $con) or die('MySQL Error.'); //Preapre our output if($format == 'json') { $recipes = array(); while($recipe = mysql_fetch_array($result)) { $recipes[] = array('post'=-->$recipe);
		}
 		$output = json_encode(array('posts' =&gt; $recipes));
	} 
	
	elseif($format == 'xml') 
	{
		header('Content-type: text/xml');
		$output  = "<!--?xml version="1.0"?-->n";
		$output .= "n";
 
		for($i = 0 ; $i &lt; mysql_num_rows($result) ; $i++)
		  {
			$row = mysql_fetch_assoc($result);
			$output .= " n";
			$output .= "&lt;post_id&gt;" . $row['post_id'] . " n";
			$output .= "&lt;post_name&gt;" . $row['post_name'] . " n";
			$output .= "&lt;post_poster&gt;" . $row['post_poster'] . " n";
			$output .= "&lt;post_quick_info&gt;" . $row['post_quick_info'] . " n";
			$output .= "&lt;post_link&gt;" . $row['post_link'] . " n";
			$output .= " n";
		  }
		  $output .= "";
		  } else {
		    	die('Improper response format.');
		  } 
		//Output the output.
		echo $output;
	}
?&gt;

$recipe);

}

$output = json_encode(array('posts' => $recipes));

}

elseif($format == 'xml')

{

header('Content-type: text/xml');

$output = "n";

$output .= "n";

for($i = 0 ; $i < mysql_num_rows($result) ; $i++)

{

$row = mysql_fetch_assoc($result);

$output .= " n";

$output .= "<post_id>" . $row['post_id'] . " n";

$output .= "<post_name>" . $row['post_name'] . " n";

$output .= "<post_poster>" . $row['post_poster'] . " n";

$output .= "<post_quick_info>" . $row['post_quick_info'] . " n";

$output .= "<post_link>" . $row['post_link'] . " n";

$output .= " n";

}

$output .= "";

} else {

die('Improper response format.');

}

//Output the output.

echo $output;

}

Functionality – Request – Response

Its true that API creation is not an overnight process and needs indepth knowledge regarding certain programming skills. Certainly, if you are building an API in PHP you have to know XML, JSON and CURL, because the responses that are received from the API are in XML JSON or string format. The request for requesting the information can be passed through CURL, which returns the response in string format.

Example

<!--?php 
       // create curl resource
        $ch = curl_init();

          // set url
 curl_setopt($ch, CURLOPT_URL, "  yoururl/api.php?format=xml&num=3");

        //return the transfer as a string
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

                  // $output contains the output string
        $output = curl_exec($ch);
		
        echo "
<pre-->";   print_r($output);

      // close curl resource to free up system resources
        curl_close($ch);    
?&gt;

<!--?php

// create curl resource

$ch = curl_init();

// set url

curl_setopt($ch, CURLOPT_URL, " yoururl/api.php?format=xml&num=3");

//return the transfer as a string

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

// $output contains the output string

$output = curl_exec($ch);

echo "

<pre-->"; print_r($output);

// close curl resource to free up system resources

curl_close($ch);

Security

Security is one of the major aspects of API as it is an interface with possibility to get connected to a huge chunk of data, which everyone should not be allowed to pull data from. For this reason for creating an API it is important to create an API_KEY, username and password. These are the parameters using which the user will be authenticated by the API for having the connection to the data. You can also set unique token for each request.

Popular API Examples

Google Maps API:

Google Maps APIs lets developers embed Google Maps on WebPages using a JavaScript interface which is an API.

YouTube APIs:

Embedding Youtube channels or some other YouTube live streaming can be integrated with the websites using the correct set of API usage provided by YouTube.

Twitter APIs:

Twitter offers two APIs. The REST API allows developers to access core Twitter data and the Search API provides methods for developers to interact with Twitter Search and trends data.

Thank you for reading this article and let us know your feedback and insights on the same. We would love to hear your inputs on the same.

Summary

Article Name

Architecture of API (Application Programming Interface)

Description

Application programming interface is by definition a bridge between the two web or database applications, acting as authenticated mediator for sharing data.

Author

Nisarg Mehta

Publisher Name

Techtic Solutions

Publisher Logo