PHPBeginner.net

Using SimpleXML to read feeds

Robert Gonzalez — Sun, 10 Jan 2010 18:36:00 +0000

A question was asked today on the Professional PHP Developer’s Google group related to SimpleXML and using it to read feeds. From time to time developers have a need to consume web service feeds, like RSS feeds, and use them in some capacity. Whether it be reading for display or for aggregation, the basic concept is A) get the feed source; B) parse it; and C) do what you need to with it.

The SimpleXML PHP extension provides a very easy to use way to do all of this.

First things first
The first thing we are going to need is a feed source. In today’s question, that source is the BBC News. The feed can be found at http://newsapi.bbc.co.uk/feeds/search/news+sport/test and a quick visit in your web browser should show you the contents of the feed we will be parsing.

But what fun would it be to just look at another application’s rendering of our feed. We should have a look using something we build, right?

Let’s get an idea of how the feed is structured first.

QUICK NOTE HERE: If you are not quite yet familiar with Object Oriented Programming this may seem a bit odd to you. Since this is a beginner web site I am not at all going to go into the concepts of OOP here. Just know that some of the stuff we are going to be doing here are going to be OOP related. Don’t get scared, I’ll be right by your side.

Feed me
Ok, let’s get our hands dirty on some code, shall we? Just to get a feel for what we are going to be working, let’s have a look at the feed source as a SimpleXML object by taking the following code and running it:


/**
 * Set the content type header to be plain jane text so we don't have to riddle
 * our output with "pre" tags
 */
header('Content-Type: text/plain');
 
/**
 * Load up our source feed as a SimpleXML object
 */
$xml = simplexml_load_file('http://newsapi.bbc.co.uk/feeds/search/news+sport/test');
 
/**
 * Let's look at it now, so we can see the structure of the feed
 */
print_r($xml);

I have clipped it for length but the basics of the output of this, as I run it (because feeds are time based, so your output will more than likely be different than mine) is [View the current output of this script]:

SimpleXMLElement Object
(
    [@attributes] => Array
        (
            [version] => 2.0
        )

    [channel] => SimpleXMLElement Object
        (
            [ttl] => 15
            [title] => BBC News and Sport Search: test
            [link] => http://newsapi.bbc.co.uk/feeds/search/news+sport/test
            [description] => BBC News and Sport Search: test
            [language] => en-gb
            [lastBuildDate] => Sun, 10 Jan 2010 17:26:19 GMT
            [item] => Array
                (
                    [0] => SimpleXMLElement Object
                        (
                            [title] => Battle to beat freeze continues
                            [link] => http://news.bbc.co.uk/go/rss/news/int/search/news%2Bsport/test/-/2/hi/uk_news/8450690.stm
                            [guid] => http://news.bbc.co.uk/2/hi/uk_news/8450690.stm
                            [pubDate] => Sun, 10 Jan 2010 17:18:24 GMT
                            [description] => The government pledges to do all it can to keep roads and schools open as the severe wintry weather eases its grip on the UK.
                        )

                    [1] => SimpleXMLElement Object
                        (
                            [title] => Gers sweat on key duo's fitness
                            [link] => http://news.bbc.co.uk/go/rss/news/int/search/news%2Bsport/test/-/sport2/hi/football/teams/r/rangers/8450831.stm
                            [guid] => http://news.bbc.co.uk/sport2/hi/football/teams/r/rangers/8450831.stm
                            [pubDate] => Sun, 10 Jan 2010 16:47:04 GMT
                            [description] => Rangers assistant manager Ally McCoist is hoping Steven Davis and Kris Boyd will be able to shrug off injuries sustained in the 3-3 draw at Hamilton.
                        )
                )

        )

)

Ok, settle down. Let’s not freak out over all that data. Looking at the structure we can see that the root element has a property called “channel” that the feed data lives in. The “channel” property has a collection of properties but the ones we are going to be most interested in are “title”, “lastBuildDate” and “item”.

Looking at these properties we can guess fairly well what they do. Title is the feed title, lastBuildDate is the last time to feed was built and item is going to be the collection of feed entries.

The item collection likewise has a collection of properties in each item, and the properties we are going to be most interested in are “title”, “link”, “pubDate” and “description”. Again, looking at these properties you can intuitively guess what each one does: title is the item title, link is the URL of the item, pubDate is the date the item was published and description is the text of the item.

Putting it all together
Knowing all of this we can now put together a very simple page that will consume this feed and render it. To do that, run this script in your browser [View the output of this script]:


/**
 * Get the data source feed as a SimpleXML object
 */
$data = simplexml_load_file('http://newsapi.bbc.co.uk/feeds/search/news+sport/test');
?>


	BBC News Sports Feed
	


 /* Make a title for this page taken from the feed title */ ?>
 echo $data->channel->title ?>
 /* For user experience, let them know the last time this feed updated */ ?>
Last updated  echo $data->channel->lastBuildDate ?>

/**
 * Now loop through the channel items to get the item information. Because
 * SimpleXML implements the countable and iterator interfaces we can loop
 * over just about any SimpleXML element recursively.
 * 
 * For styling, we are going to alternate row color
 */
// Set the row coloring flag
$color = true;
 
// Loop the feed items
foreach ($data->channel->item as $item):
?>
 /* Handle row color switching */ ?>
 if ($color): ?>-on endif; ?>">
	 /* Make a title for this item, linking back to its original source*/ ?>
	 echo $item->link ?>"> echo $item->title ?>
	 /* Show the body of the item with the publication date */ ?>
	 echo $item->description ?>
	 echo $item->pubDate ?>

 /* Reset the row colorizer as needed */ ?>
 $color = !$color; endforeach; ?>

And there you have it, a nice little parsed output of an RSS feed using SimpleXML. See, that wasn’t so bad, was it?

Simple PHP Excel exports

Robert Gonzalez — Sun, 08 Nov 2009 22:43:43 +0000

From time to time developers may need to be able to export data to an Excel spreadsheet. And there are lots of tools that allow developers to do just that, in many different, robust ways.

But what if you just need to put something together quickly that allows your users to be able to take a data set – for example a database query result – and download that in the form of an Excel spreadsheet? It is easier to do than you might think.

Let’s say your boss just called you into his office and said that he would like you to put an Excel spreadsheet together that will let him see all of the employees in your company. And let’s say that you have an intranet page that shows all of your employees on the screen in a table. Since there is a good chance that your boss isn’t the only person that might find an Excel spreadsheet of the employee list useful, you decide you’re going to take the employee list from the intranet and allow your entire company to download a copy of it in Excel format.

Before we get started, we will need a data set to work with. For this example we are going to keep our employee list very simple:




$employees = array(
	array('fname' => 'Hans', 'lname' => 'Auf', 'room' => '1D', 'ext' => '1145'),
	array('fname' => 'Yung', 'lname' => 'Ling', 'room' => '3C', 'ext' => '1220'),
	array('fname' => 'Mike', 'lname' => 'Rowe', 'room' => '4E', 'ext' => '1232'),
	array('fname' => 'Joe', 'lname' => 'Shmoe', 'room' => '2B', 'ext' => '1159'),
	array('fname' => 'Mary', 'lname' => 'Smith', 'room' => '1A', 'ext' => '1111'),
);
?>

Now, to add a little more complexity to our simple example (because we can ) we are going to make a listing of column headers for our employee table. This will also serve as our spreadsheet header row as well:




$columns = array(
	'fname' => 'First Name',
	'lname' => 'Last Name',
	'room'  => 'Office Address',
	'ext'   => 'Phone Number',
);
?>

If you look closely you can see that we mapped the columns array keys to the query result column names. The reason we are doing this is because as we present our HTML table of this data we can control the column order and column heading text with this array. Let’s have a look at that:




/**
 * Build a mock data set as though it were a database query result
 */
$employees = array(
	array('fname' => 'Hans', 'lname' => 'Auf', 'room' => '1D', 'ext' => '1145'),
	array('fname' => 'Yung', 'lname' => 'Ling', 'room' => '3C', 'ext' => '1220'),
	array('fname' => 'Mike', 'lname' => 'Rowe', 'room' => '4E', 'ext' => '1232'),
	array('fname' => 'Joe', 'lname' => 'Shmoe', 'room' => '2B', 'ext' => '1159'),
	array('fname' => 'Mary', 'lname' => 'Smith', 'room' => '1A', 'ext' => '1111'),
);
 
/**
 * Build a custom header array for column headings
 * 
 * NOTE[0]: You could have done this in the query by aliasing column names, but 
 * doing it this way gives us a little something more to learn. ;)
 * 
 * NOTE[1]: If you miss it the first time around, come back and look at this to
 * see how you can control the column display order with this array.
 */
$columns = array(
	'fname' => 'First Name',
	'lname' => 'Last Name',
	'room'  => 'Office Address',
	'ext'   => 'Phone Number',
);
 
?>


	Company employee list

 

Our company employee list
 // If there are employees list them ?>
 if (count($employees)): ?>

 // Let's build the header row first ?> 
	<tr>
		 foreach ($columns as $column): ?> 
		<th>php echo $column ?>th>
		 endforeach; ?> 
	tr>
	 // Now let's build the body ?>
	 foreach ($employees as $employee): ?> 
	 /* Let's make this a little dynamic... Yes, this is a lot of */ ?>
		 /* looping, but it is an exercise in what you can do         */ ?>
		 foreach($columns as $alias => $column) : ?> 
			 endforeach; ?> 
	 endforeach; ?> 

	
		 echo $employee[$alias] ?>
		
	
 else: ?> 
There are no employees on the list
 endif; ?>

So now we need a mechanism to allow our users to download this data as an Excel spreadsheet. We could use pretty much anything that lets the page know we want to export (like a simple link) but for this exercise we are going to use a form. Why? No reason really, other than it is sometimes easier to tell a user to “push the button” instead of “click on the link that says …”.

As part of this we are also going to tie in a process that checks for the form button based export request, and if it is set, build the necessary data to allow the download. We do that like this:




/**
 * Build a mock data set as though it were a database query result
 */
$employees = array(
	array('fname' => 'Hans', 'lname' => 'Auf', 'room' => '1D', 'ext' => '1145'),
	array('fname' => 'Yung', 'lname' => 'Ling', 'room' => '3C', 'ext' => '1220'),
	array('fname' => 'Mike', 'lname' => 'Rowe', 'room' => '4E', 'ext' => '1232'),
	array('fname' => 'Joe', 'lname' => 'Shmoe', 'room' => '2B', 'ext' => '1159'),
	array('fname' => 'Mary', 'lname' => 'Smith', 'room' => '1A', 'ext' => '1111'),
);
 
/**
 * Build a custom header array for column headings
 * 
 * NOTE[0]: You could have done this in the query by aliasing column names, but 
 * doing it this way gives us a little something more to learn. ;)
 * 
 * NOTE[1]: If you miss it the first time around, come back and look at this to
 * see how you can control the column display order with this array.
 */
$columns = array(
	'fname' => 'First Name',
	'lname' => 'Last Name',
	'room'  => 'Office Address',
	'ext'   => 'Phone Number',
);
 
/**
 * If the export request was sent, handle that here
 */
if (!empty($_POST['export'])) {
	// Set the field delimiter as a tab for Excel
	$delimiter = "\t";
 
	// Set the End Of Line character to force a new row
	$eol = "\n";
 
	// Start the spreadsheet by creating the header row based on our columns
	$sheet = implode($delimiter, $columns) . $eol;
 
	/** 
	 * Create the body of the spreadsheet by way of a loop, looping the columns
	 * array inside of each employee iteration so that column order matches.
	 */
	foreach ($employees as $employee) {
		// Create a row string for building each row
		$row = '';
 
		// Loop through the columns to make columnar data that matches the header
		foreach ($columns as $name => $text) {
			$row .= $employee[$name] . $delimiter;
		}
 
		// Pluck of the last tab and append a new line to the row
		$sheet .= trim($row, $delimiter) . $eol;
	}
 
	// Create the download file name - adding the date to make it a little unique
	$filename = 'employee-list-' . date('Ymd') . '.xls';
 
	// Send the appropriate response headers 
	header('Content-type: application/x-msdownload');
	header('Content-type: application/vnd.ms-excel');
	header('Content-Disposition: attachment; filename="'.$filename.'"');
	/** 
	 * Normally we would set our no-cache header here, but...
	 * Internet Explorer cannot handle SSL download saves if no-cache is set 
	 * anywhere. For most this would not be an issue, but if you are allowing
	 * exports to Excel over SSL then this will bite you in the butt when your 
	 * users are using IE
	 */
	//header("Pragma: no-cache");
	header("Expires: 0");
 
	// Output the spreadsheet as a download
	print $sheet; exit;
}
?>


	Company employee list

 

Our company employee list
 // If there are employees list them ?>
 if (count($employees)): ?>
 echo basename(__FILE__) ?>" id="export-form">
	
	
		
	

 

 // Let's build the header row first ?> 
	<tr>
		 foreach ($columns as $column): ?> 
		<th>php echo $column ?>th>
		 endforeach; ?> 
	tr>
	 // Now let's build the body ?>
	 foreach ($employees as $employee): ?> 
	 /* Let's make this a little dynamic... Yes, this is a lot of */ ?>
		 /* looping, but it is an exercise in what you can do         */ ?>
		 foreach($columns as $alias => $column) : ?> 
			 endforeach; ?> 
	 endforeach; ?> 

	
		 echo $employee[$alias] ?>
		
	
 else: ?> 
There are no employees on the list
 endif; ?>

And there you have it. A simple, dynamic Excel exporter that will take your current data and dump it into a downloadable spreadsheet for your users.

Maintaining processed form data

Robert Gonzalez — Fri, 30 Oct 2009 05:50:59 +0000

One of the questions that I see come up quite often from new developers is “How do I make it so that when someone enters something in a form and there is an error that the stuff they entered stays in the form?”. It is a perfectly logical question with an equally simple solution that many new developers might not immediately pick up on.

Keeping data entered in forms fresh boils down to keeping the posted form data inside of already declared variables so that, regardless of whether there is even a posted form, you can still display your form variables. But before we get into that, let’s create a simple HTML outline.



<html>
<head>
	<title>(Un)altered state</title>
</head>
 
<body>
 
</body>
</html>

So let’s say we want to take a simple form to collect a users name, gender, their favorite operating system and a brief explanation of why it is their favorite operating system. No, this is really not a practical example, other than the fact that we are going to be playing with a few different form elements, but it is acceptable for now.

So let’s build the form we are going to be using.



<html>
<head>
	<title>(Un)altered state</title>
</head>
 
<body>
<h1>Tell us a little about yourself</h1>
<form method="post" action="" id="collection-form">
	<p>Name: <input type="text" id="cf-name" name="name" size="50" /></p>
	<p>Gender: <input type="radio" name="gender" id="cf-gender-m" value="m" />M <input type="radio" name="gender" id="cf-gender-f" value="f" />F</p>
	<p>Favorite OS: <select name="os" id="cf-os"><option value="0">Please select one...</option></select></p>
	<p>Tell us why:<br /><textarea name="why" id="cf-why" cols="50" rows="5"></textarea></p>
	<p><input type="submit" name="submit" id="cf-submit" value="Let us know" /></p>
</form>
</body>
</html>

You’ll notice that in the markup we just posted that there is no PHP. We need to fix that, and at the same time add some dynamic features to our form like building our list items. But first we need to consider what type of data that we will be working with here. The “name” and “why” fields are pretty simple strings. But the “gender” and “OS” fields are a little more complex because they contain combination data. So for these we are going to be using arrays (and making the assumption that the data source for these arrays is a database result). To set up our “database results” we are going to be using the following arrays:




$genderrows = array(
	array('label' => 'm', 'value' => 'M'),
	array('label' => 'f', 'value' => 'F'),
);
$osrows = array(
	array('id' => 1, 'label' => 'Micro$ost Winblows'),
	array('id' => 2, 'label' => 'Proprietary Mac OSX'),
	array('id' => 3, 'label' => 'Ubuntu, the best OS ever'),
	array('id' => 4, 'label' => 'Some other crappy linux'),
	array('id' => 5, 'label' => 'Unix'),
	array('id' => 6, 'label' => 'What\'s an operating system?'),
);
?>

To make sure we can render our posted form values (or empty values if there is no posted form) we need to initialize some variables for use in the script. This is where the magic behind maintaining form state really comes into play. By doing this we are virtually guaranteed to have what was entered into the form in our possession for use in the form once again if we need it. And this is how we do it:




$name   = empty($_POST['name'])   ? null : $_POST['name'];
$gender = empty($_POST['gender']) ? null : $_POST['gender'];
$os     = empty($_POST['os'])     ? 0    : $_POST['os']; // 0 because our list option values are numbers
$why    = empty($_POST['why'])    ? null : $_POST['why'];
?>

If you look closely, what we managed to do here is capture all of the posted form data if there is any and, if there is no posted form data, default the variables to something (in our case, null) so we can still access those variables in our form. What this means is that we can now echo these variables as the values of our form elements regardless of whether we have posted form data.

And herein lies the solution to our challenge. By doing this we now have the data that was entered into the form. Which means if we choose to render the form as it was entered, all of the data entered into the form will still be in the form.

Our finished product looks like the below code, which you can copy and paste into a PHP file of your own, with any name, and run it from your local development environment (which is where all of your testing should take place ):




/**
 * Start setting some default values for populating the form fields.
 * 
 * Name and why fields will be strings. Gender and OS fields will be an array
 * replicating a database query result. Regardless, their posted form values
 * will always be strings.
 */
$name   = empty($_POST['name'])   ? null : $_POST['name'];
$gender = empty($_POST['gender']) ? null : $_POST['gender'];
$os     = empty($_POST['os'])     ? 0    : $_POST['os']; // 0 because our list option values are numbers
$why    = empty($_POST['why'])    ? null : $_POST['why'];
/**
 * Wait, what? Why all those question marks? That is the ternary operator in 
 * PHP and it acts as a sort of simple short hand if/else statement. Read more
 * on the ternary operator at:
 * http://php.net/ternary#language.operators.comparison.ternary
 */
 
/**
 * Now we need to make some arrays for our more complex data types
 */
$genderrows = array(
	array('label' => 'm', 'value' => 'M'),
	array('label' => 'f', 'value' => 'F'),
);
$osrows = array(
	array('id' => 1, 'label' => 'Micro$ost Winblows'),
	array('id' => 2, 'label' => 'Proprietary Mac OSX'),
	array('id' => 3, 'label' => 'Ubuntu, the best OS ever'),
	array('id' => 4, 'label' => 'Some other crappy linux'),
	array('id' => 5, 'label' => 'Unix'),
	array('id' => 6, 'label' => 'What\'s an operating system?'),
);
?>


	(Un)altered state

 

Tell us a little about yourself
 echo basename(__FILE__) ?>" id="collection-form">
	 /* Echo the $name var as the default value of this field */       ?> 
	
	Name:  echo $name ?>" />
 
	 /* While looping the genders list, see if there is a match to */   ?> 
	 /* the entered data and select it if there is */                   ?> 
	
	Gender:  foreach ($genderrows as $genderrow): ?> 
		 echo $genderrow['label'] ?>" 
			value=" echo $genderrow['label'] ?>"
			 if ($gender == $genderrow['label']): ?>checked="checked" endif; ?> 
		 /> 
		 echo $genderrow['value'] ?> 
	 endforeach; ?>
 
	 /* Same as the genders list, matching while looping */             ?> 
	
	Favorite OS: 
 
	 /* Echo the $why var as the default value of this textarea */       ?> 
	
	Tell us why:
<span style="color: #000000; font-weight: bold;"><?php</span> <span style="color: #b1b100;">echo</span> <span style="color: #000088;">$why</span> <span style="color: #000000; font-weight: bold;">?></span>

And there you have it. A completed form that maintains what was entered by the user. Try it for yourself and see what it does. See if you can spot how it does it. And start to think of ways to use this logic in your own code to allow for a more robust user experience for your users.

Note: Do not use this code as is in your production environment. There is no validation or filtration on any of the posted form values. This leaves you wide open to malicious attacks by would be bad guys. This tutorial was only for the sake of learning a simple method to maintain form state. Please treat it as that… simple.

PHP for anyone

Robert — Wed, 13 Aug 2008 18:02:45 +0000

Welcome to PHPBeginner.net, home of the n00B PHP developer manual and instruction guide! The goal of this site is to provide entry level instruction to developers that are looking to get into PHP development. No assumption of current programming knowledge is made, but we do assume you know your way around (X)HTML. We believe anyone, and we mean anyone, should be able to start right along with us.

If you are completely new to web development or programming in general we recommend you start at the beginning and work your way through. If you are already a programmer and are looking at picking up PHP to add to your mad skillset, start where you will. It should be fairly easy to get up to speed with how we do things.

We hope you enjoy this site and the content we bring you. If you have any questions, please visit the contact page to let us know what is on your mind.