Have a look at this code
echo file_get_html('http://www.google.com)->plaintext;it will fetch full content from a website. So, my question is how to fetch limited words. Suppose it will fetch only 180 words.. any idea?
file_get_html creates a DOM object, which requires a full page load/parse so you can't necessarily grab by character count. You can, however, initiate a file handler and fread to a certain amount of bytes:
$fh = fopen('google.com');
$data = fread($fh,$length);
fclose($fh);
Or this:
$data = substr(file_get_contents('google.com'),$start,$end);
Related
I want to load a specific part of an HTML file into a variable like this:
$my_file = 'file.html';
$handle = fopen($my_file, 'r') or die('Cannot open file: '.$my_file); //implicitly creates file
Now, my question is how do I tell PHP which part of the HTML doc I want it to read?
That depends on what you mean by "part".
The most usefull approaches:
If you know a unique string that starts and finishes that part, e.g. and , you can load the complete file into a string, search the occurence of the first string, search the occurnece of the second one, then take the substring inbetween.
If you have less information, you might need regex.
If your HTML is valid XML, load it into an xml object and use xpath or alike... you see, the answer much depends on what you have, and what you want to achieve.
I've written a script to process html files from URLs, however, due to a 30's script runtime restriction with my cheap host provider I've had to alter the script to store the html as txt files and run it from a local WAMP server.
I am trying to load each file up, extract what I need, then move onto the next file.
URL's as source file_get_html was doing the job perfectly (I could ->find the required elements)
Txt file as source file_get_html is returning a blank object.
Based on some advice in the below post I changed file_get_html for file_get_contents which created an array with a single large string containing the contents of the text file.
First, make sure that file_get_contents can get data. If it can, file_get_html will be able to load data to simplehtml Dom
If file_get_contents returns a string, which it does, how would I "load data to simplehtml Dom?"
File not getting read using file_get_html
I then tried to convert the string into an object str_get_html, however, this didn't work either.
include('simple_html_dom.php');
$html = file_get_html('file.txt');
var_dump($html);
Returns: object(simple_html_dom)[1] but with no other contents or arrays.
include('simple_html_dom.php');
$html = file_get_contents('file.txt');
var_dump($html);
Returns: string < ! DOCTYPE html PUBLIC.....
Questions:
Can anyone give me any advice? What's the best way to load up a text file containing html markup into an object so that I can utilise the find method on it's contents. I want to avoid loading the file into an array of strings and using regex to process contents.
Are there any considerations I need to make if using a local WAMP server?
(Answered by the OP in a question. Converted to a community wiki answer. See Question with no answers, but issue solved in the comments (or extended in chat) )
The OP wrote:
I managed to solve this myself. I am sure i'd already tried to extract html from string, doh!
include('simple_html_dom.php');
$html = file_get_contents('file.txt');
$html = str_get_html($html);
var_dump($html)
Returns object(simple_html_dom)[1] including all expected arrays etc
Instead of trying to create the html object directly from the source file using file_get_html I've extracted the file contents file_get_contents then converted str to html using str_get_html which allows me to use the simple html dom methods e.g. find on attributes within the object e.g.
$html->find('a');
I want to extrat the content of a specific div in an external webpage, the div looks like this:
<dt>Win rate</dt><dd><div>50%</div></dd>
My target is the "50%". I'm actually using this php code to extract the content:
function getvalue($parameter,$content){
preg_match($parameter, $content, $match);
return $match[1];
};
$parameter = '#<dt>Score</dt><dd><div>(.*)</div></dd>#';
$content = file_get_contents('https://somewebpage.com');
Everything works fine, the problem is that this method is taking too much time, especially if I've to use it several times with diferents $content.
I would like to know if there's a better (faster, simplier, etc.) way to acomplish the same function? Thx!
You may use DOMDocument::loadHTML and navigate your way to the given node.
$content = file_get_contents('https://somewebpage.com');
$doc = new DOMDocument();
$doc->loadHTML($content);
Now to get to the desired node, you may use method DOMDocument::getElementsByTagName, e.g.
$dds = $doc->getElementsByTagName('dd');
foreach($dds as $dd) {
// process each <dd> element here, extract inner div and its inner html...
}
Edit: I see a point #pebbl has made about DomDocument being slower. Indeed it is, however, parsing HTML with preg_match is a call for trouble; In that case, I'd also recommend looking at event-driven SAX XML parser. It is much more lightweight, faster and less memory intensive as it does not build a tree. You may take a look at XML_HTMLSax for such a parser.
There are basically three main things you can do to improve the speed of your code:
Off load the external page load to another time (i.e. use cron)
On a linux based server I would know what to suggest but seeing as you use Windows I'm not sure what the equivalent would be, but Cron for linux allows you to fire off scripts at certain schedule time offsets - in the background - so not using a browser. Basically I would recommend that you create a script who's sole purpose is to go and fetch the website pages at a particular time offset (depending on how frequently you need to update your data) and then write those webpages to files on your local system.
$listOfSites = array(
'http://www.something.com/page.htm',
'http://www.something-else.co.uk/index.php',
);
$dirToContainSites = getcwd() . '/sites';
foreach ( $listOfSites as $site ) {
$content = file_get_contents( $site );
/// i've just simply converted the URL into a filename here, there are
/// better ways of handling this, but this at least keeps things simple.
/// the following just converts any non letter or non number into an
/// underscore... so, http___www_something_com_page_htm
$file_name = preg_replace('/[^a-z0-9]/i','_', $site);
file_put_contents( $dirToContainSites . '/' . $file_name, $content );
}
Once you've created this script, you then need to set the server up to execute it as regularly as you need. Then you can modify your front-end script that displays the stats to read from local files, this would give a significant speed increase.
You can find out how to read files from a directory here:
http://uk.php.net/manual/en/function.dir.php
Or the simpler method (but prone to possible problems) is just to re-step your array of sites, convert the URLs to file names using the preg_replace above, and then check for the file's existence in the folder.
Cache the result of calculating your statistics
It's quite likely this being a stats page that you'll want to visit it quite frequently (not as frequent as a public page, but still). If the same page is visited more often than the cron-based script is executed then there is no reason to do all the calculation again. So basically all you have to do to cache your output is do something similar to the following:
$cachedVersion = getcwd() . '/cached/stats.html';
/// check to see if there is a cached version of this page
if ( file_exists($cachedVersion) ) {
/// if so, load it and echo it to the browser
echo file_get_contents($cachedVersion);
}
else {
/// start output buffering so we can catch what we send to the browser
ob_start();
/// DO YOUR STATS CALCULATION HERE AND ECHO IT TO THE BROWSER LIKE NORMAL
/// end output buffering and grab the contents so we now have a string
/// of the page we've just generated
$content = ob_get_contents(); ob_end_clean();
/// write the content to the cached file for next time
file_put_contents($cachedVersion, $content);
echo $content;
}
Once you start caching things you need to be aware of when you should delete or clear your cache - otherwise if you don't your stats output will never change. With regards to this situation, the best time to clear your cache is at the point you go and fetch the external web pages again. So you should add this line to the bottom of your "cron" script.
$cachedVersion = getcwd() . '/cached/stats.html';
unlink( $cachedVersion ); /// will delete the file
There are other speed improvements you could make to the caching system (you could even record the modified times of the external webpages and load only when they have been updated) but I've tried to keep things easy to explain.
Don't use a HTML Parser for this situation
Scanning a HTML file for one particular unique value does not require the use of a fully-blown or even lightweight HTML Parser. Using RegExp incorrectly seems to be one of those things that lots of start-up programmers fall into, and is a question that is always asked. This has led to lots of automatic knee-jerk reactions from more experience coders to automatically adhere to the following logic:
if ( $askedAboutUsingRegExpForHTML ) {
$automatically->orderTheSillyPersonToUse( $HTMLParser );
} else {
$soundAdvice = $think->about( $theSituation );
print $soundAdvice;
}
HTMLParsers should be used when the target within the markup is not so unique, or your pattern to match relies on such flimsy rules that it'll break the second an extra tag or character occurs. They should be used to make your code more reliable, not if you want to speed things up. Even parsers that do not build a tree of all the elements will still be using some form of string searching or regular expression notation, so unless the library-code you are using has been compiled in an extremely optimised manner, it will not beat well coded strpos/preg_match logic.
Considering I have not seen the HTML you are hoping to parse, I could be way off, but from what I've seen of your snippet it should be quite easy to find the value using a combination of strpos and preg_match. Obviously if your HTML is more complex and might have random multiple occurances of <dt>Win rate</dt><dd><div>50%</div></dd> it will cause problems - but even so - a HTMLParser would still have the same problem.
$offset = 0;
/// loop through the occurances of 'Win rate'
while ( ($p = stripos ($html, 'win rate', $offset)) !== FALSE ) {
/// grab out a snippet of the surrounding HTML to speed up the RegExp
$snippet = substr($html, $p, $p + 50 );
/// I've extended your RegExp to try and account for 'white space' that could
/// occur around the elements. The following wont take in to account any random
/// attributes that may appear, so if you find some pages aren't working - echo
/// out the $snippet var using something like "echo '<xmp>'.$snippet.'</xmp>';"
/// and that should show you what is appearing that is breaking the RegExp.
if ( preg_match('#^win\s+rate\s*</dt>\s*<dd>\s*<div>\s*([0-9]+%)\s*<#i', $snippet, $regs) ) {
/// once you are here your % value will be in $regs[1];
break; /// exit the while loop as we have found our 'Win rate'
}
/// reset our offset for the next loop
$offset = $p;
}
Gotchas to be aware of
If you are new to PHP, as you state in a comment above, then the above may seem rather complicated - which it is. What you are trying to do is quite complex, especially if you want to do it optimally and fast. However, if you follow throught the code I've given and research any bits that you aren't sure of / haven't heard of (php.net is your friend), it should give you a better understanding of a good way to achieve what you are doing.
Guessing ahead however, here are some of the problems you might face with the above:
File Permission errors - in order to be able to read and write files to and from the local operating system you will need to have the correct permissions to do so. If you find you can not write files to a particular directory it might be that the host you are using wont allow you to do so. If this is the case you can either contact them to ask about how to get write permission to a folder, or if that isn't possible you can easily change the code above to use a database instead.
I can't see my content - when using output buffering all the echo and print commands do not get sent to the browser, they instead get saved up in memory. PHP should automatically output all the stored content when the script exits, but if you use a command like ob_end_clean() this actually wipes the 'buffer' so all the content is erased. This can lead to confusing situations when you know you are echoing something.. but it just isn't appearing.
(Mini Disclaimer :) I've typed all the above manually so you may find there are PHP errors, if so, and they are baffling, just write them back here and StackOverflow can help you out)
Instead of trying to not use preg_match why not just trim your document contents down in size? for example, you could dump everything before <body and everything after </body>. then preg_match will be searching less content already.
Also, you could try to do each one of these processes as a pseudo separate thread, so that way they aren't happening one at a time.
Good morning all, i have a new question:
I'm trying to save into mysql a set of data coming from a SIMBAD database query (it's a stellar objects dataabse).
If you enter this url into the browser: http://simbad.u-strasbg.fr/simbad/sim-id?output.format=ASCII&Ident=hd%201&OutputMode=VOTable
you get a result formated with separate lines, but if you use
<?php
$cadaart = 'http://simbad.u-strasbg.fr/simbad/sim-id?output.format=ASCII&Ident=hd%201';
$handler = curl_init($cadaart);
$response = curl_exec ($handler);
curl_close($handler);
echo $response;
?>
or a simple file_get_content and echo the response you get a single line with all information, which makes me impossible to parse... Any idea on how to solve this?
Thanks.
The string is already with line-break,
you can use file to convert contents from that URL into an array (each line is an array element)
A URL can be used as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename. See the Supported Protocols and Wrappers for links to information about what abilities the various wrappers have, notes on their usage, and information on any predefined variables they may provide.
It's probably just the difference between an LF and a CRLF. The output from your URL is LF, which, in where you're viewing it (browser?), is probably not parsed as a new line.
Try $response = str_replace("\n", "\r\n", $response); and see if this makes any difference
What I've been trying to do recently is to extract listing information from a given html file,
For example, I have an html page that has a list of many companys, with their phone number, address, etc'
Each company is in it's own table, every table started like that: <table border="0">
I tried to use PHP to get all of the information, and use it later, like put it in a txt file, or just import into a database.
I assume that the way to achieve my goal is by using regex, which is one of the things that I really have problems with in php,
I would appreciate if you guys could help me here.
(I only need to know what to look for, or atleast something that could help me a little, not a complete code or anything like that)
Thanks in advance!!
I recommend taking a look at the PHP DOMDocument and parsing the file using an actual HTML parser, not regex.
There are some very straight-forward ways of getting tables, such as the GetElementsByTagName method.
<?php
$htmlCode = /* html code here */
// create a new HTML parser
// http://php.net/manual/en/class.domdocument.php
$dom = new DOMDocument();
// Load the HTML in to the parser
// http://www.php.net/manual/en/domdocument.loadhtml.php
$dom->LoadHTML($htmlCode);
// Locate all the tables within the document
// http://www.php.net/manual/en/domdocument.getelementsbytagname.php
$tables = $dom->GetElementsByTagName('table');
// iterate over all the tables
$t = 0;
while ($table = $tables->item($t++))
{
// you can now work with $table and find children within, check for
// specific classes applied--look for anything that would flag this
// as the type of table you'd like to parse and work with--then begin
// grabbing information from within it and treating it as a DOMElement
// http://www.php.net/manual/en/class.domelement.php
}
If You're familiar with jQuery (and even if You're not as it's command are simple enough) I recommend this PHP counterpart: http://code.google.com/p/phpquery/
If your HTML is valid XML, as in XHTML, then you could parse it using SimpleXML