Category Archives: PHP

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

Powerful PHP: Less Known String Manipulation

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Yet another thing that’s great in PHP is the power you have when doing some string manipulation/operation. Here’s something that is really useful, but I think it remains a bit unknown. Let’s imagine you need to take the first (or whatever) character of a string. Most developers go to the obvious:

$str = 'hello world';
echo substr($str, 0, 1); // outputs "h"

But here’s something better and cleaner.

echo $str{0}; // outputs "h"

This code chunk return the first character of $str, but it can be used with the same success for any other character of the string. In my opinion this is more cleaner and its really syntactically self documented.

This approach can be useful when trying to check whether the first symbol for instance is “?” or “/”.

PHP: Fetch $_GET as String with http_build_query()

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PHP is really full of functions for everything! Most of the time when you try to do something with strings, there’s a function that can do it better and faster.

The Route from $_GET to String

The global arrays in PHP contain request parameters. Either GET or POST. As you know if the page address is something like:

http://www.example.com/index.php?a=b&key=value

This means that you pass to the index.php file two parameters – “a” and “key” with their values: “b” and “value”. Now in this case you can dump the $_GET global array somewhere in index.php and you’ll receive something like this.

array(
	"a"   => "b",
	"key" => "value",
);

This is however pseudocode, but in fact $_GET will be very similar to this sample array. Continue reading PHP: Fetch $_GET as String with http_build_query() →

PHP Strings: How to Get the Extension of a File

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EXE or GIF or DLL or …

Most of the code chunks I’ve seen about getting a file extension from a string are based on some sort of string manipulation.

Get the Filename Extension with PHP
If you want to get the filename extension with PHP is better to use pathinfo() than string manipulations

$filename = '/my/path/image.jpeg';
echo substr($filename, strrpos($filename, '.') + 1);

Howerver there is a more elegant solution.

$filename = '/my/path/image.jpeg';
echo strtolower(pathinfo($filename, PATHINFO_EXTENSION));

Thus you rely on PHP built in functions and it’s harder to overlook the exact string manipulation approach.

A JavaScript Trick You Should Know

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JavaScript Strings

You should know that in JavaScript you cannot simply write a multilined code chunk, i.e. something like this:

var str = 'hello
world';

This will result in an error, which can be a problem when you deal with large strings. Imagine a string containing some HTML that should be injected via innerHTML. Now one possible solution is to concatenate two or more strings, by splitting the initial string.

var str = 'hello'
        + 'world';

Howerver this solution result in some additional operations like concatenation. It can be very nice if there was something like the PHP multiline string format.

The PHP Example

In PHP you have the same use case with strings. You can have a string concatenated over multiple lines, but you cannot split lines like so:

// the following line is wrong
$str = 'hello
world'; 
 
// a possible solution to the line above is
$str = 'hello'
     . 'world';
// which is very similar to the js solution in the second example
 
// ... but in PHP there is the so called HEREDOC
$str = <<<EOD
hello
world
EOD;

The heredoc gives us the power to write multiline strings.

The JavaScript Trick

Actually in JavaScript there is something that’s exactly what Heredoc is meant to be for PHP. Take a look at the last example:

var text = <>
this <br />
is
my
multi-line
text
</>.toString();
 
document.body.innerHTML = text;

Thus you can write multiline strings in the JavaScript code.