如何从PHP中的字符串中提取URL？

I'm using PHP's "simplexml_load_file" to get some data from Flickr.

我正在使用PHP的“simplexml_load_file”从Flickr获取一些数据。

My goal is to get the photo url.

我的目标是获取照片网址。

I'm able to get the following value (assigned to PHP variable):

我能够得到以下值(分配给PHP变量):

<p><a href="http://www.flickr.com/people/19725893@N00/">codewrecker</a> posted a photo:</p>

<p><a href="http://www.flickr.com/photos/19725893@N00/2302759205/" title="Santa Monica Pier"><img src="http://farm3.static.flickr.com/2298/2302759205_4fb109f367_m.jpg" width="180" height="240" alt="Santa Monica Pier" /></a></p>

How can I extract just this part of it?

我怎样才能提取它的这一部分?

http://farm3.static.flickr.com/2298/2302759205_4fb109f367_m.jpg

Just in case it helps, here's the code I'm working with:

万一它有帮助,这是我正在使用的代码:

<?php
$xml = simplexml_load_file("http://api.flickr.com/services/feeds/photos_public.gne?id=19725893@N00&lang=en-us&format=xml&tags=carousel");
foreach($xml->entry as $child) {
    $flickr_content = $child->content; // gets html including img url
    // how can I get the img url from "$flickr_content"???
 }
?>

4 个解决方案

#1

You can probably get away with using a regular expression for this, assuming that the way the HTML is formed is pretty much going to stay the same, e.g.:

你可以放弃使用正则表达式,假设HTML的形成方式几乎保持不变,例如:

if (preg_match('/<img src="([^"]+)"/i', $string, $matches)) {
    $imageUrl = $matches[1];   
}

This is fairly un-robust, and if the HTML is going to change (e.g. the order of parameters in the <img> tag, risk of malformed HTML etc.), you would be better off using an HTML parser.

这是相当不健壮的,如果HTML将要改变(例如如何从PHP中的字符串中提取URL？标签中的参数顺序,HTML格式错误的风险等),您最好使用HTML解析器。

#2

It's not solving your problem(and probably total overkill), but worth mentioning because I've used the library on 2 projects and it's well written.

这不是解决你的问题(也可能是完全矫枉过正),但值得一提的是因为我在2个项目中使用了这个库而且编写得很好。

phpFlickr - http://phpflickr.com/

#3

Easy way: Combination of substr and strpos to extract first the tag and then the src='...' value, and finally the target string.

简单方法:substr和strpos的组合首先提取标签,然后提取src ='...'值,最后提取目标字符串。

Slightly more difficult way (BUT MUCH MORE ROBUST): Use an XML parsing library such as simpleXML

稍微更困难的方式(但更强大):使用XML解析库,如simpleXML

#4

I hope this is helpful. I enjoy using xpath to cut through the XML I get back from SimpleXML:

我希望这是有帮助的。我喜欢使用xpath来切换从SimpleXML返回的XML:

<?php
$xml = new SimpleXMLElement("http://api.flickr.com/services/feeds/photos_public.gne?id=19725893@N00&lang=en-us&format=xml&tags=carousel", NULL, True);
$images = $xml->xpath('//img');  //use xpath on the XML to find the img tags

foreach($images as $image){  
    echo $image['src'] ;  //here is the image URL
}
?>

#1