Weird error using PHP Simple HTML DOM parser

Question 1

I am using this library (PHP Simple HTML DOM parser) to parse a link, here's the code:

function getSemanticRelevantKeywords($keyword){
    $results = array();
    $html = file_get_html("http://www.semager.de/api/keyword.php?q=". urlencode($keyword) ."&lang=de&out=html&count=2&threshold=");
    foreach($html->find('span') as $e){
            $results[] = $e->plaintext;
    }
    return $results;
}

but I am getting this error when I output the results:

Fatal error: Call to a member function find() on a non-object in /var/www/vhosts/efamous.de/subdomains/sandbox/httpdocs/getNewTrusts.php on line 25

(line 25 is the foreach loop), the odd thing is that it outputs everything (at least seemingly) correctly but I still get that error and can't figure out why.

Question 2

This error usually means that $html isn't an object.

It's odd that you say this seems to work. What happens if you output $html? I'd imagine that the url isn't available and that $html is null.

Edit: Looks like this may be an error in the parser. Someone has submitted a bug and added a check in his code as a workaround.

Question 3

The right code to get a div with class is:

$ret = $html->find('div.foo');
//OR
$ret = $html->find('div[class=foo]');

Basically you can get elements as you were using a CSS selector.

source: http://simplehtmldom.sourceforge.net/manual.htm
How to find HTML elements? section, tab Advanced

Question 4

In your example code, you have

echo $x = $html->find('h2[class="section-heading"]',1)->outertext;

as you are calling find() with a second parameter of 1, this will only return the 1 element. If instead you find all of them - you can do whatever you need with them...

$list = $html->find('h2[class="section-heading"]');
foreach ( $list as $item ) {
    echo $item->outertext . PHP_EOL;
}

The full code I've just tested is...

include(__DIR__."/simple_html_dom.php");
$html = file_get_html('http://campaignstudio.in/');

$list = $html->find('h2[class="section-heading"]');
foreach ( $list as $item ) {
    echo $item->outertext . PHP_EOL;
}

which gives the output...

<h2 class="section-heading text-white">We've got what you need!</h2>
<h2 class="section-heading">At Your Service</h2>
<h2 class="section-heading">Let's Get In Touch!</h2>

Question 5

The Manual explains why:

For this function to work, you will need either to set some ID attributes with DOMElement->setIdAttribute() or a DTD which defines an attribute to be of type ID. In the later case, you will need to validate your document with DOMDocument->validate() or DOMDocument->validateOnParse before using this function.

By all means, go for valid HTML & provide a DTD.

Quick fixes:

Call $dom->validate(); and put up with the errors (or fix them), afterwards you can use $dom->getElementById(), regardless of the errors for some reason.
Use XPath if you don't feel like validing: $x = new DOMXPath($dom); $el = $x->query("//*[@id='bid']")->item(0);
Come to think of it: if you just set validateOnParse to true before loading the HTML, if would also work ;P

.

$dom = new DOMDocument();
$html ='<html>
<body>Hello <b id="bid">World</b>.</body>
</html>';
$dom->validateOnParse = true; //<!-- this first
$dom->loadHTML($html);        //'cause 'load' == 'parse

$dom->preserveWhiteSpace = false;

$belement = $dom->getElementById("bid");
echo $belement->nodeValue;

Outputs 'World' here.

Question 6

The table cells you are looking for are not part of that HTML document. You first of all need to understand the basics of webscraping, I suggest you borrow some books about the topic and read through them.

Time for the library ;)

In case the table cells are in the document (it seems to vary, sometimes they are, sometimes they are not), the original example shows it, this also demonstrates how to iterate over a DOMNodeList:

$doc = new DOMDocument();

libxml_use_internal_errors(true);
$doc->loadHTMLFile('Catawba County Legacy Map Server.html');

$tds = $doc->getElementsByTagname('td');
foreach($tds as $td) {
    printf(" * %sn", $td->textContent);
}

Exemplary output:

php "test.php" (in directory: /home/hakre/php/test)
 *
 * Real Estate Search - Legacy
 *
 *
 *
 *
 *
 *
 *
 *
 *
 * Map Layers
 * visible
 *
 *
 * Parcels
 *
 * Parcel Annotation
 *
 * Address Points
 *
 * Misc. Lines
 *
 * Structures
 *
 * Contour Lines
 *
 * Soils
 *
 * Townships
 *
 * Water Features
 *
 * Tiles
 *
 * Flood Zone
 *
 * Agricultural District
 *
 * Aerial 2009
 *
 * Aerial 2005
 *
 * Aerial 2002
 *
 * Cities
 *
 * Print the Map  
 * Print Map and Parcel Report  
 * Print the Parcel Report  
 * Assessment Report  
 * List all Owners  
 * Deed History Report
 * Parcel Information:
 * Owner Information:
 * Parcel ID: 372215634301
 * Name: PENLEY TREASURE B
 * Parcel Address: 3152 7TH AV SE 
 * Name2:  
 * City: CONOVER 28613
 * Address: 5508 SWINGING BRIDGE RD
 * LRK(REID): 57186
 * Address2:  
 * Deed Book/Page: 1906/0741 Deed Image
 * City: CONOVER
 * Subdivision: FOREST HGTS
 * State/Zip: NC 28613-7415
 * Lots: 1-4
 *
 * Block: C
 *
 * Last Sale:
 * School Information:
 * Plat Book/Page: 8/119 Plat Image
 * School District: COUNTY
 * Calculated Acreage: 0.31
 * Elementary School: WEBB A MURRAY
 * Tax Map: 167H  04006A
 * Middle School: ARNDT
 * State Road:  
 * High School: ST STEPHENS
 * Township: HICKORY
 * School Map
 *  
 *  
 * Tax/Value Information:  Tax Rates(pdf)
 * Zoning Information:
 * Municipal Tax District:  
 * Zoning District: HICKORY
 * Fire District: HICKORY RURAL
 * Zoning1: OI
 * Tax Account Number:  
 * Zoning2:  
 * Market Building(s) Value: $55,400
 * Zoning3:  
 * Market Land Value: $20,300
 * Zoning Overlay:  
 * Market Total Value: $75,700
 * Small Area:  
 * Year Built/Remodeled: 1959  
 * Split Zoning District 1/2: 0/0
 * Current Tax Bill
 * Zoning Agency Phone Numbers
 * Miscellaneous:
 *  
 * Voter Precinct:P35
 * Firm Panel Date: 9/5/2007
 * Building Permits for this parcel
 * Firm Panel #: 3710372200J
 * WaterShed:  
 * 2010 Census Tract: 011000
 * WaterShed Split:  
 * 2010 Census Block: 3035
 * Parcel Report Data Descriptions
 * Agricultural District:  
 * FAQ's
 * Help
 * GIS Home
Compilation finished successfully.

Weird error using PHP Simple HTML DOM parser

Answers

php,html-parsing