正则表达式从HTML提取图像-如何仅获取JPG？

Question

I am using this PHP function to grab all <img> tags within any given HTML.

function extract_images($content)
{
    $img    = strip_tags(html_entity_decode($content),'<img>');
    $regex  = '~src="[^"]*"~';    

    preg_match_all($regex, $img, $all_images);

    return $all_images;
}

This works and returns all images (gif, png, jpg, etc).

Anyone know how to change the regex...

~src="[^"]*"~

in order to only get files with JPG or JPEG extension?

Thanks a bunch.

Answer 1

Sooner or later the Regex Enforcement Agency will show up. It might as well be me :)

The proper way to do this is with a proper HTML DOM parser. Here's a DOMDocument solution. The usefulness of this is in that it's more robust than parsing the HTML by regex, and also gives you the ability to access or modify other HTML attributes on your <img> nodes at the same time.

$dom = new DOMDocument();
$dom->loadHTML($content);

// To hold all your links...
$links = array();

// Get all images
$imgs = $dom->getElementsByTagName("img");
foreach($imgs as $img) {
  // Check the src attr of each img
  $src = "";
  $src = $img->getAttribute("src");
  if (preg_match("/\.jp[e]?g$/i", $src) {

    // Add it onto your $links array.
    $links[] = $src;
}

See other answers for the simple regex solution, or adapt from the regex inside my foreach loop.

Answer 2

/src="[^"]*\.(jpg|jpeg)"/i

我->不区分大小写的匹配