Build a JSON and PHP product gallery

As the title describes we’re going to look at making cross domain ajax requests using JSONP I’m also going to show you how to get data from a MySQL database and encode it into a JSON string which can be parsed using JavaScript. JSON stands for JavaScript Object Notation and essentially its a method which allows us to execute cross domain ajax requests without too much fuss. This post really follows on from my article about scraping content from a page but also allows you to send and receive GET variables through the JSON request.

What we’re going to build

To give this tutorial a valid example we’re going to display a selection of product in a gallery as seen in the image below, click here to see the demo page.

The PHP code

First we’re going to run through getting data from our database using a PHP while loop to get a selection of rows limited to 6. In the code below you can see that we’re getting the data and generating an array. After this we simply pass the array variable $rows into the PHP function json_encode() which will format our PHP array for us.

include('connect.php');	
	$sql = "SELECT title, image, description FROM json_demo LIMIT 6";	
	$result = mysql_query($sql);
		while($row = mysql_fetch_array($result))
		{	
			 $rows[] = array(
			"title" => $row['title'],
			"image" => $row['image'],
			"description" => $row['description']);
		}

$json = json_encode($rows);

$callback = $_GET['callback'];
echo $callback.'('. $json . ')';	
	

What the JSON looks like

Below is the structured output from our json.php file.

[ { "description" : "B&O is a Danish company that designs and manufactures audio products, television sets, and telephones. It was founded in 1925 by Peter Bang and Svend Olufsen",
    "image" : "1.jpg",
    "title" : "B&O 5.1"
  },
  { "description" : "B&O is a Danish company that designs and manufactures audio products, television sets, and telephones. It was founded in 1925 by Peter Bang and Svend Olufsen",
    "image" : "2.jpg",
    "title" : "B&O TV"
  },
  { "description" : "Market leader in the UK. Roberts produce a wide range of DAB digital radios. Roberts is a consumer electronics company producing DAB, analogue and wi-fi ...",
    "image" : "3.jpg",
    "title" : "Roberts Radio"
  },
  { "description" : "Toshiba is a diversified manufacturer and marketer of advanced electronic and electrical products, spanning information & communications equipment and systems",
    "image" : "4.jpg",
    "title" : "Toshiba TV"
  },
  { "description" : "B&O is a Danish company that designs and manufactures audio products, television sets, and telephones. It was founded in 1925 by Peter Bang and Svend Olufsen",
    "image" : "5.jpg",
    "title" : "B&O Audio"
  },
  { "description" : "B&O is a Danish company that designs and manufactures audio products, television sets, and telephones. It was founded in 1925 by Peter Bang and Svend Olufsen",
    "image" : "6.jpg",
    "title" : "B&O Remote"
  }
]

Now we have the JSON format built we just need some JavaScript to parse the file and output our data. generating an ajax request for JSON is pretty straight forward. because what we’re doing is designed to work cross domain you can put an absolute URI in the request. With JSONP we must add a callback parameter which is passed into the beginning of the JSON string.

Once we have the data we’re cycling through the results and appending a div with the results into the page.

$("document").ready(function () {

    $.getJSON('http://papermashup.com/demos/jquery-json-php/json.php?callback=?', function (data) {
        $("#content").html('');
        $.each(data, function (i, item) {

            $("#content").append('<div class="product"><img src="http://papermashup.com/demos/jquery-json-php/images/' + item.image + '" width="135" height="138"/><div class="title">' + item.title + '</div><div class="description">' + item.description + '</div><div class="clear"></div></div>');

        });


    });
    $("#content").fadeIn(2000);
});