Geek asks and answers

Stream splits 4GB XML file in PHP

I try and need some help doing the following:

I want the stream to parse a large XML file (4 GB) with PHP. I cannot use plain XML or DOM because they load the entire file into memory, so I need something that can transfer the file.

How can I do this in PHP?

What I'm trying to do is navigate through a series of elements <doc>. And write some of their children to a new XML file.

The XML file I'm trying to execute is as follows:

<feed>
    <doc>
        <title>Title of first doc is here</title>
        <url>URL is here</url>
        <abstract>Abstract is here...</abstract>
        <links>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
       </link>
    </doc>
    <doc>
        <title>Title of second doc is here</title>
        <url>URL is here</url>
        <abstract>Abstract is here...</abstract>
        <links>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
            <sublink>Link is here</sublink>
       </link>
    </doc>
</feed>

I am trying to get / copy all the children of each element <doc>into a new XML file, except for the element <links>and its children.

So, I want the new XML file to look like this:

<doc>
    <title>Title of first doc is here</title>
    <url>URL is here</url>
    <abstract>Abstract is here...</abstract>
</doc>
<doc>
    <title>Title of second doc is here</title>
    <url>URL is here</url>
    <abstract>Abstract is here...</abstract>
</doc>

/ /, XML, XML PHP.

+5
2

. , :

<?php

$interestingNodes = array('title','url','abstract');
$xmlObject = new XMLReader();
$xmlObject->open('bigolfile.xml');

$xmlOutput = new XMLWriter();
$xmlOutput->openURI('destfile.xml');
$xmlOutput->setIndent(true);
$xmlOutput->setIndentString("   ");
$xmlOutput->startDocument('1.0', 'UTF-8');

while($xmlObject->read()){
    if($xmlObject->name == 'doc'){
        $xmlOutput->startElement('doc');
        $xmlObject->readInnerXML();
        if(array_search($xmlObject->name, $interestingNodes)){
             $xmlOutput->startElement($xmlObject->name);
             $xmlOutput->text($xmlObject->value);
             $xmlOutput->endElement(); //close the current node
        }
        $xmlOutput->endElement(); //close the doc node
    }
}

$xmlObject->close();
$xmlOutput->endDocument();
$xmlOutput->flush();

?>
+4

DOM, , - , , , , SAX- (event/stream oriented), , (doc, title, url, abstract) node XML .

:

XML- PHP?

( ) :

<?php
    $file = "bigfile.xml";
    $fh = fopen("out.xml", 'a') or die("can't open file");
    $currentNodeTag = "";    
    $tags = array("doc", "title", "url", "abstract");

    function startElement($parser, $name, $attrs) {
        global $tags;

        if (isset($tags[strtolower($name)])) {
            $currentNodeTag = strtolower($name);
            fwrite($fh, sprintf("<%s>\n"));
        }
    }

    function endElement($parser, $name) {
        global $tags;

        if (isset($tags[strtolower($name)])) {
            fwrite($fh, sprintf("</%s>\n"));
            $currentNodeTag = "";
        }
    }

    function characterData($parser, $data) {
        if (!empty($currentNodeTag)) {
            fwrite($fh, $data);
        }
    }    

    $xmlParser = xml_parser_create();
    xml_set_element_handler($xmlParser, "startElement", "endElement");
    xml_set_character_data_handler ($xmlParser, "characterData");

    if (!($fp = fopen($file, "r"))) {
        die("could not open XML input");
    }

    while ($data = fread($fp, 4096)) {
        if (!xml_parse($xmlParser, $data, feof($fp))) {
            die(sprintf("XML error: %s at line %d",
                        xml_error_string(xml_get_error_code($xmlParser)),
                        xml_get_current_line_number($xmlParser)));
        }
    }

    xml_parser_free($xmlParser);
    fclose($fh);
?>
0

More articles: