Tag Archives: communication

PHP: Does SimpleXMLElement have toString() method? No, better use asXML()!

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SimpleXML is a PHP extension that “provides a very simple and easily usable toolset to convert XML to an object” [1]. Thus you can pass a link to an XML file and SimpleXML will return an object.

$xml = simplexml_load_file('path_to_the_file');

Sometimes you’d need to dump or save the entire XML as a string, but there’s no toString method! As you can see $xml is an instance of the SimpleXMLElement class.

var_dump($xml); // object(SimpleXMLElement)...

Actually if you take a closer look:

$xml->toString();

will return “Call to an undefined method toString()”, which is frustrating because the developers community is used to use toString() when converting an object into a string.

XML
PHP's SimpleXML doesn't have toString() method. asXML() is used instead!

The solution

In fact there’s a method doing exactly what’s needed. This is SimpleXMLElement::asXML

As described in the manual page: “SimpleXMLElement::asXML — Return a well-formed XML string based on SimpleXML element” [2].

Besides that it does exactly what’s needed it sounds irrelevant, because you’ve an XML object and the name “asXML” doesn’t describe correctly what’s expected.

$xml->asXML() // ?!
  1. SimpleXMLElement::asXML
  2. SimpleXML Introduction

Send Html Mails with Zend_Mail

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Zend_Mail
Typically you’d never like to send a non-html formatted mail from your web system. It’s ugly and it’s difficult to read. Instead of sending pure text, you’d like to add some images and styles. The way you can do it with Zend_Mail is simple enough. Replace the setBody method with setBodyHtml. Isn’t that natural?

// before
$mail = new Zend_Mail('utf-8');
$mail->setFrom('sender@example.com', 'Sender Name');
$mail->setBody('message in Html');
$mail->addTo('recipient@example.com', 'Recepient Name');
$mail->setSubject('Subject');
$mail->send();
// after
$mail = new Zend_Mail('utf-8');
$mail->setFrom('sender@example.com', 'Sender Name');
$mail->setBodyHtml('message in Html');
$mail->addTo('recipient@example.com', 'Recepient Name');
$mail->setSubject('Subject');
$mail->send();

document.forms[‘myform’].submit() is not a function?

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.submit()

You want to submit the form by clicking on a link or some other element on the page and this is a simple task. You know that by simply adding something like document.forms[‘the-form-name’].submit() this will work.

<form method="post" name="myform">
    <input type="text" name="user" />
    <a href="#" onclick="document.forms['myform'].submit();return false">Submit</a>
</form>

However you’d like to submit the form not only by clicking on that particular element, but also by clicking on the Enter while the focus is on a input field, and this wont work! That’s because you don’t have a input type=”submit”.

OK, first thing is to add a hidden input type=”submit” – than by clicking both on the Enter keyboard button and on the link with the onclick=”document.blah.blah.blah” will submit the form.

<form method="post" name="myform">
    <input type="text" name="user" />
    <input type="submit" name="submit" value="submit" style="display:hidden" />
    <a href="#" onclick="document.forms['myform'].submit();return false">Submit</a>
</form>

But this is not true!

Than you’ll receive the following message:

document.forms['myform'].submit() is not a function

Why? This isn’t working, but ever line seems to be OK. The answer is – don’t name the input type=”submit” with the trivial – “submit”. Just give it another name:

<form method="post" name="myform">
    <input type="text" name="user" />
    <input type="submit" name="something" value="something" style="display:hidden" />
    <a href="#" onclick="document.forms['myform'].submit();return false">Submit</a>
</form>

How to Sanitize User Input in PHP?

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It’s a question almost every PHP developer asks yourself. By me the most simple way to sanitize the user input is to save everything in the database with no loosing of tags or whatever HTML markup and than on displaying this on the client side to strip_tags if needed.

In example when saving a HTML formatted text you can use simply the htmlspecialchars method

$description = htmlspecialchars($_POST['description']);

Than you can be sure everything’s in the database, but it’s not actually HTML. Thus you don’t have any tags at all in the database field.

When you show this in the client side and you’d like to strip some tags, i.e. to keep only the <a> tag you can do this:

echo strip_tags(htmlspecialchars_decode($description), '<a>');

That’s the most simple way to keep everything as the original source. By me it’s better to keep whatever HTML markup there is on the input.

CSS sprites. Go beyond the limits with base64!

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Why should I optimize CSS?

In fact how and why should I optimize CSS is the right question. Actually CSS is simply one ore more files loaded from the server to the client, usually a browser, with CSS specific rules that must be applied by the browser to the web page you’re seeing. That’s in general. Of course there are exceptions when CSS can be inline or added directly to the HTML tags, which is bad practice because thus the HTML markup becomes larger and even worse the browser cannot cache it and than load it quickly. In fact that’s why usually the CSS of a web page is put in one single file. Primary because that makes only one request to the server and in second hand because it can be cached by the browser.

Just because the nature of the CSS is that firstly it’s loaded and than executed one of the primary techniques of optimizing it is to make it smaller and therefore load faster. There are several methods of doing so. Enabling GZIP support of the web server and minifying the file are the most common ones. But one of the tricks you cannot optimizing just for second is using the so called CSS sprites.

CSS sprites

What are these? To answer this question I’ll simply try to give you an example. Let’s assume there are three CSS classes each one with its own background image. This makes four requests to the server. One for the CSS file and one per every background image. But what we’d like to achieve is to make less requests as we can. Than one of the things we can do is to make one single image and to change only the background-position CSS property to position it on the right place and to make it appear correctly.

Be careful! When you join all of the images into one single CSS sprite you may add one class with that background-image and every other class with only background-position property. Than every DOM element with that background must have both class names. Only than you can be sure the server will make two requests. One for the CSS file and one for the sprite.

base64 to encode images

In other hand most of the web projects are pretty big, and unfortunately it’s too difficult to make only one single sprite just because it’s too difficult to manage it after the project has become very large. That’s why mostly in the practice there are several sprites for the main components. But the problem is that again there are more HTTP requests.

Is there any way to make only one request?

Yes there is. Simply by converting your CSS sprite into a base64 encoded image. In breve base64 is an encoding where you can practically make any data into a string. Thus the image can be represented by a string containing the same information as the image. Hopefully most of the browser, except of course MSIE, does read the so called data urls, or:

<img src="data:image/png;base64,..... " />

and that’s enough to get started with base64 and the single request. The sprite has become a string!

CSS and base64

The natural question is now how to merge all this? You now have one CSS file with one or more sprites. Than you can convert them into a base64 encoded strings and put them all into the CSS.

There is a problem, of course, what happens with MSIE. As I said before MSIE doesn’t read base64 encoded images. Hopefully there is a solution described very well by Stoyan Stefanov in his blog post here.

Finally …

now there is only one request and everything works pretty fine. This technique can be really helpful to someone who’s trying to optimize the CSS performance to the limits.