Caching PHP Simple HTML DOM Parser

Question

I am using the PHP HTML DOM Parser to pull data from an external website. To reduce load and speed up page rendering time I want to cache data I pull for a certain period. How can I do this?

dtbarne · Accepted Answer · 2011-05-18 02:57:03Z

7

I wrote this file cache function which basically just replaces file_get_contents. You can specify the amount of time the cache should last for in $offset or completely override the cache with $override. If you don't want to use /tmp/, just change that directory to something you can read/write to.

function cache_get_contents($url, $offset = 600, $override = false) {
    $file = '/tmp/file_cache_' . md5($url);
    if (!$override && file_exists($file) && filemtime($file) > time() - $offset)
        return file_get_contents($file);

    $contents = file_get_contents($url);
    if ($contents === false)
        return false;

    file_put_contents($file, $contents);
    return $contents;
}

answered May 18, 2011 at 2:57

dtbarne

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3 Comments

Matthew Hui Over a year ago

Right now I am using file_get_html which returns a DOM object. Right now yours returns a string

dtbarne Over a year ago

Use str_get_html() on the string.

dtbarne Over a year ago

Are you sure you have write permissions for /tmp? Is file_get_contents() failing? You can try to debug the value of $contents after the 6th line of the above code.

Andrew · Accepted Answer · 2011-05-18 02:32:56Z

1

You could create local files with the HTML and then keep track of the file paths in the $SESSION. If you have the disk space and can run a database, you could use a database to do the same thing. A database connection and query on the URL you're looking for won't add much overhead at all.

answered May 18, 2011 at 2:32

Andrew

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Comments

Jason McCreary · Accepted Answer · 2011-05-18 02:33:08Z

1

One way would be to save the data to a database or local file. You could then use a timestamp column or file modification time to determine whether to continue using the cache or pull and save a fresh copy.

If you have access to some kind of memory caching (e.g. memcached) that would be ideal.

answered May 18, 2011 at 2:33

Jason McCreary

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2 Comments

dtbarne Over a year ago

memcached is a good idea unless you have to store large amounts of data. It sounds like a file cache is more ideal in this situation.

Jason McCreary Over a year ago

@dtbame, fair enough. The OP didn't specify the amount of data. So I offered it as a secondary.

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