php open gzipped xml

Question

Hi,

I am struggling to read gzipped xml files in php.

I did succeed in reading normal xml files, using XMLReader() like this:

$xml = new XMLReader();
$xml->open($linkToXmlFile);

However, this does not work when the xml file is gzipped. How can I unzip the file and read it with the XMLReader?

Answer 1

Maybe the function gzdecode could help you : the manual says (quote) :

Decodes a gzip compressed string

So, you'd have to :

• download the XML data
• get it as a string
• decompress it with gzdecode
• work on it with XMLReader

That would depend on the right extension (zlib I guess) beeing installed on your server, though...

Answer 2

Expanding on Pascal's post, here is some example code that should work for you

$xmlfile = fopen($linkToXmlFile,'rb');
$compressedXml = fread($xmlfile, filesize($linkToXmlFile));
fclose($xmlfile);
$uncompressedXml = gzdecode($compressedXml); 

$xml = new XMLReader();
$xml->xml($uncompressedXml);

Answer 3

As you didn't specify a PHP version, I am going to assume you are using PHP5.

I am wondering why people haven't suggested using the built in PHP compression streams API.

$linkToXmlFile = "compress.zlib:///path/to/xml/file.gz";
$xml = new XMLReader();
$xml->open($linkToXmlFile);

From what I understand, under the covers, it will transparently decompress the file for you and allow you to read it as if were a plain xml file. Now, that may be a gross understatement.