Parsing subelements of an RSS enclosure tag

idiparker

I know this is probably RTFM, but I'm on travel and don't have the Manuals right now so I thought I'd post here.

I'm trying to write a parser that will look at an RSS feed (RSS 2.0) and pull out the details of the enclosure tag. Enclosures have URL, TYPE and LENGTH as subelements (or attributes?) and I wanted to pull each of them out so I can put them into a database.

I can get the easy stuff out of the RSS like this:

$title=$myar[TITLE][$i];
$text=$myar[DESCRIPTION][$i];
$link=$myar[LINK][$i];

But how would I get the data out of the [ENCLOSURE]? Would it be something like [ENCLOSURE][URL][$i]; or is there some other syntax I'm missing.

I thought it would be easy, but I've spent the better part of a day trying to do this with php (4.0.2) to no avail. I've found C, Java and Python solutions, but I was wondering how to do it with PHP?

Thanks.

Weedpacket

Originally posted by idiparker
I know this is probably RTFM, but I'm on travel and don't have the Manuals right now so I thought I'd post here.

You've got this, but you haven't got http://www.php.net/manual/ ?

I can get the easy stuff out of the RSS like this:

$title=$myar[TITLE][$i];
$text=$myar[DESCRIPTION][$i];
$link=$myar[LINK][$i];

So let's see the code you're using to get that and it would be easier to point out which bits need adapting for the enclosure; there are a whole bunch of approaches for parsing XML, and we need to know which one you're using. Searching these forums for "RSS" might help, as well.

But how would I get the data out of the [ENCLOSURE]? Would it be something like [ENCLOSURE][URL][$i]; or is there some other syntax I'm missing.

I thought it would be easy, but I've spent the better part of a day trying to do this with php (4.0.2) to no avail. I've found C, Java and Python solutions, but I was wondering how to do it with PHP?

Thanks.

idiparker

I was using someone's simplePHP parser code, and trying to modify it for my purposes. You'll see where I try (unsuccessfully) to pull out the content I'm seeking. I have a few other scripts I was using, but this was the simplest and I wanted to build upon it.

I did find a successful way of doing it, where the script read every element and when it got to one called Enclosure specifically pulled out the attribute TYPE or URL, but I haven't had much luck modifying it to my needs just yet.

<?php

$url="http://rasterweb.net/raster/feeds/rwaudio.rss";

// Enter the url to an RSS feed

$data=@fread(fopen("$url","r"),10000) or die("Cant open $url!");

// Get the file contents

$myar=getXmlData($data);

// What ever it may be, the argument to this
// function should be the XML document's content

// Start the loop for reading what is inside.

for($i=0;
$i<=count($myar[TITLE]);
$i++) {

// Set up the variables to hold the relavant content.

$title=$myar[TITLE][$i];
$text=$myar[DESCRIPTION][$i];
$link=$myar[LINK][$i];
$pubdate=$myar[PUBDATE][$i];

   //  These are my unsuccessful attempts to get the attributes of the tag.

$simp=$myar[ENCLOSURE][$i];
$enclosure=$myar['ENCLOSURE']['URL']['LENGTH']['TYPE'][$i];
$enclosures=$myar['enclosure']['URL'][$i];

	//  This was just a test to see if I could see any of the variables I was searching for.


if($title) {

echo <<<EOF
<a href="$link">$title</a> 
The enclosure link is $enclosure or $GLOBALS['enclosure_url'] or $enclosures or last $lasttry simp $simp 
$text $pubdate

EOF;

}
// ends both loops

function getXmlData($xml_doc) {

$n=0; // Counter used for arraying the XML data
$ar=array(); // The main array for storing parsed xml using xml_parse_into_struct()

// Parse the XML document

$parser = xml_parser_create();
xml_parse_into_struct($parser,$xml_doc,$vals,$index) or die(xml_error_string(xml_get_error_code($parser)));
xml_parser_free($parser);

$ttags=array(); // Temporary arry for storing tag names

// The main part. This is MY CREATION
// and this piece of code makes this script simple 🙂
// This is the "MAGIC LOOP" !! 🙂

for($n=0;$n<=count($vals)-1;$n++) {
if(trim($vals[$n][value])) {
$ar[$vals[$n][tag]][count($ar[$vals[$n][tag]])]=$vals[$n][value];
$ttags[$vals[$n][tag]]=$vals[$n][tag];

}

// Array for storing all the tag names
// This array will hold all the Tag names found in the XML document
// eg: ("TITLE","LINK","AUTHOR","DOMAIN")..
// Use this if you need it.

$tags=array();

// Extract and save the tag names to the array

foreach($ttags as $tagi) { array_push($tags,$tagi); }

Weedpacket

It's a bit hard to see what's happening (you've missed at least a couple of lines off the end of the function, and "MAGIC LOOP" isn't entirely self-explanatory). After patching things up so it was producing something more useful than piles of error messages, I find I'm still not clear on what the MAGIC LOOP is supposed to be doing; but what I can see is that the reason why you're not geting attributes from any ENCLOSURE tags is at least partly due to the fact that ENCLOSURE tags - being empty - don't have any values; the line

if(isset($vals[$n]['value']) && trim($vals[$n]['value']))

(Where the changes from your test are due to fixing those error messages I mentioned) explictly skips tags that have no value.

idiparker

When you look at the actual RSS file, you'll see the ENCLOSURE lines have something in them, but I'm still having problems digging it out of there. I searched around this board and apparently there are a few others who have battled the attribute fight as well. To date, I've only found one website that has some code that works, though my attempts to dupe some of his code into mine has led to failure.

I dumped the code I was using earlier because I too, couldn't figure out what some of it was doing. Here is what I'm operating off of now, and it works for most of the stuff I want, just not enclosures. I know my syntax for grabbing the attribute is messed, but I haven't figured it out just yet.

When I asked it to echo tagName, I'll get ENCLOSURE but when I run things, it looks like it isn't registering as being "TRUE". Ugh.

((By the way, this code worked once from here: http://www.ipportunities.nl/wordpress/index.php?m=20040824 but now I messed it up and have dropped it in favor of what I have below)).

<?php
// Global variables for function use.
$GLOBALS['title'] = false;
$GLOBALS['link'] = false;
$GLOBALS['description'] = false;
$GLOBALS['enclosure'] = false;
$GLOBALS['pubdate'] = false;
$GLOBALS['item'] = false;
$GLOBALS['titletext'] = null;
$GLOBALS['linktext'] = null;
$GLOBALS['desctext'] = null;
$GLOBALS['url'] = null;
$GLOBALS['enclosuretext'] = null;
$GLOBALS['pubdatetext'] = null;
$GLOBALS['enclosure_url']= null;

// function: startElement
// Deals with the starting element

function startElement( $parser, $tagName, $attrs='' ) {

// By setting global variable of tag name
// I can determine which tag I am currently
// parsing.

switch( $tagName ) {
case 'ITEM':
$GLOBALS['item'] = true;
break;
case 'TITLE':
$GLOBALS['title'] = true;
break;
case 'LINK':
$GLOBALS['link'] = true;
break;
case 'DESCRIPTION':
$GLOBALS['description'] = true;
break;
case 'PUBDATE':
$GLOBALS['pubdate'] = true;
break;
case 'ENCLOSURE':
$GLOBALS['enclosure'] = true;
break;

}
}

// function: endElement
// Deals with the ending element

function endElement( $parser, $tagName ) {

switch( $tagName ) {

case 'TITLE':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": " . $GLOBALS['titletext'] . " ";
}
$GLOBALS['title'] = false;
$GLOBALS['titletext'] = "";
break;

case 'LINK':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": <a href=\"". $linkurl . "\">View Article</a> ";
}
$GLOBALS['link'] = false;
$GLOBALS['linktext'] = "";
break;

case 'DESCRIPTION':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo": " . $GLOBALS['desctext'] . " ";
}
$GLOBALS['description'] = false;
$GLOBALS['desctext'] = "";
break;

case 'PUBDATE':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": " . $GLOBALS['pubdatetext'] . " ";
}
$GLOBALS['pubdate'] = false;
$GLOBALS['pubdatetext'] = "";
break;

case 'ENCLOSURE':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": " . $GLOBALS['enclosuretext'] . "";
}
$GLOBALS['enclosure'] = false;
$GLOBALS['enclosuretext'] = "Crap";
break;

}
}

// function: charElement
// Deals with the character elements (text)

function charElement( $parser, $text ) {

// Verify the tag that text belongs to.
// I set the global tag name to true
// when I am in that tag.

if( $GLOBALS['title'] == true ) {
$GLOBALS['titletext'] .= htmlspecialchars( trim($text) );
} else if( $GLOBALS['link'] == true ) {
$GLOBALS['linktext'] .= trim( $text );
} else if( $GLOBALS['description'] == true ) {
$GLOBALS['desctext'] .= htmlspecialchars( trim( $text ) );
} else if( $GLOBALS['pubdate'] == true ) {
$GLOBALS['pubdatetext'].= trim( $text) ;
} else if( $tagName == 'enclosure') {
$GLOBALS['ENCLOSURE'][$attrs['URL']] = $attrs['VALUE'];
$GLOBALS['enclosuretext'] .= $GLOBALS['ENCLOSURE'][$attrs['URL']] ;

// This is just crap above. It doesn't work.

}
}

// Create an xml parser
$xmlParser = xml_parser_create();

// Set up element handler
xml_set_element_handler( $xmlParser, "startElement", "endElement" );

// Set up character handler
xml_set_character_data_handler( $xmlParser, "charElement" );

// Open connection to RSS XML file for parsing.
$fp = fopen( "http://rasterweb.net/raster/feeds/rwaudio.rss", "r" )
or die( "Cannot read RSS data file." );

// Parse XML data from RSS file.
while( $data = fread( $fp, 4096 ) ) {
xml_parse( $xmlParser, $data, feof( $fp ) );
}

// Close file open handler
fclose( $fp );

// Free xml parser from memory
xml_parser_free( $xmlParser );

idiparker

Well, I say solved but let's more accurately say "got it working".

For the record, the problem appears to be my attempts to set a variable including the attributes of element in a function that didn't call up the attributes. I was doing most of my work in a function that dealt with ending the element, while I should have been doing it in the starting of the element (for there, it was looking at the attribute--$attrs).

Now I have it. I set the value of the attribute ENCLOSURE->URL as a global just for style / layout reasons.

The relevant syntax for parsing the URL out of the enclosure was this: $GLOBALS['linkurl'] = $attrs[URL]; I'm posting that part here because I saw on this site that many other people were looking for a similar function to parse out attributes of elements. I hope this helps.

By the way, thanks WEEDPACKET for your suggestions.....

I'm going to go get some pizza.

// function: startElement
// Deals with the starting element

function startElement( $parser, $tagName, $attrs='' ) {

// By setting global variable of tag name
// I can determine which tag I am currently
// parsing.

}
}

// function: endElement
// Deals with the ending element

function endElement( $parser, $tagName ) {

switch( $tagName ) {

case 'TITLE':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": " . $GLOBALS['titletext'] . " ";
}
$GLOBALS['title'] = false;
$GLOBALS['titletext'] = "";
break;

case 'LINK':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": <a href=\"". $linkurl . "\">View Article</a> ";
}
$GLOBALS['link'] = false;
$GLOBALS['linktext'] = "";
break;

case 'DESCRIPTION':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo": " . $GLOBALS['desctext'] . " ";
}
$GLOBALS['description'] = false;
$GLOBALS['desctext'] = "";
break;

case 'PUBDATE':
if( $GLOBALS['item'] == true ) {
echo $tagName;
echo ": " . $GLOBALS['pubdatetext'] . " ";
}
$GLOBALS['pubdate'] = false;
$GLOBALS['pubdatetext'] = "";
break;

case 'ENCLOSURE':
echo $tagName;
echo ": " . $GLOBALS['linkurl']. "";

if ($GLOBALS['enclosure'] = false){
$GLOBALS['enclosuretext'] = "Crap";
}
break;

}
}

// function: charElement
// Deals with the character elements (text)

function charElement( $parser, $text ) {

// Verify the tag that text belongs to.
// I set the global tag name to true
// when I am in that tag.

if( $GLOBALS['title'] == true ) {
$GLOBALS['titletext'] .= htmlspecialchars( trim($text) );
} else if( $GLOBALS['link'] == true ) {
$GLOBALS['linktext'] .= trim( $text );
} else if( $GLOBALS['description'] == true ) {
$GLOBALS['desctext'] .= htmlspecialchars( trim( $text ) );
} else if( $GLOBALS['pubdate'] == true ) {
$GLOBALS['pubdatetext'].= trim( $text) ;
} else if( $GLOBALS['enclosure'] == true) {
$GLOBALS['enclosuretext'] .= trim( $text) ;
}
}

// Create an xml parser
$xmlParser = xml_parser_create();

// Set up element handler
xml_set_element_handler( $xmlParser, "startElement", "endElement" );

// Set up character handler
xml_set_character_data_handler( $xmlParser, "charElement" );

// Open connection to RSS XML file for parsing.
$fp = fopen( "http://rasterweb.net/raster/feeds/rwaudio.rss", "r" )
or die( "Cannot read RSS data file." );

// Parse XML data from RSS file.
while( $data = fread( $fp, 4096 ) ) {
xml_parse( $xmlParser, $data, feof( $fp ) );
}

// Close file open handler
fclose( $fp );

// Free xml parser from memory
xml_parser_free( $xmlParser );