php追加xml子串

Question

在下面的xml中，我必須追加所有位於展示標記下的url。

<Ad id="32716">   
<InLine>    
    <AdSystem>BrightRoll</AdSystem>   
    <AdTitle/>   
    <Impression><![CDATA[http://2901.btrll.com/imp/2901/12446/PreRoll.911.123806/start;Video;1358769313]]> 
    </Impression>   
    <Impression><![CDATA[http://brxserv.btrll.com/v1/epix/6835361/3850628/20799/32716/TbwKgCbwBkAABQ_SyhAABRPwAAf8wAOsGEAAAAAAAfYQiqTYrVDQ/event.imp/r_64.aHR0cDovL2Iuc2NvcmVjYXJkcmVzZWFyY2guY29tL3A_YzE9MSZjMj02MDAwMDA2JmMzPSZjND1icngmYzU9MDEwMDAwJmM2PTY4MzUzNjEmYzEwPSZjQTE9OCZjQTI9NjAwMDAwNiZjQTM9MjA3OTkmY0E0PTM4NTA2MjgmY0E1PTQ3NDcmY0E2PTY4MzUzNjEmY0ExMD0zMjcxNiZjdj0xLjcmY2o9JnJuPTEzNTg3NjkzMTMmcj1odHRwJTNBJTJGJTJGcGl4ZWwucXVhbnRzZXJ2ZS5jb20lMkZwaXhlbCUyRnAtY2I2QzB6RkY3ZFdqSS5naWYlM0ZsYWJlbHMlM0RwLjY4MzUzNjEuMzg1MDYyOC4wJTJDYS40NzQ3LjIwNzk5LjMyNzE2JTJDdS45NjguMHgwJTNCbWVkaWElM0RhZCUzQnIlM0QxMzU4NzY5MzEz]]> 
    </Impression>   
    <Impression><![CDATA[http://ib.adnxs.com/seg?add=362896&t=2&cb=1358769313]]> 
    </Impression>   
    <Impression><![CDATA[http://rc.rlcdn.com/361686.gif]]> 
    </Impression>   
    <Impression><![CDATA[http://mobile.btrll.com/event/impression?ts=1358769313920&siteId=3850628&lineItemId=20799]]> 
    </Impression>   
    <Creatives>    
     <Creative sequence="1">     
      <Linear>       
       <Duration>00:00:14</Duration>      
       <TrackingEvents>        
        <Tracking event="midpoint"><![CDATA[http://brxserv.btrll.com/v1/epix/6835361/3850628/20799/32716/TbwKgCbwBkAABQ_SyhAABRPwAAf8wAOsGEAAAAAAAfYQiqTYrVDQ/event.mid/r_64.aHR0cDovLzI5MDEuYnRybGwuY29tL2ltcC8yOTAxLzEyNDQ2L1ByZVJvbGwuOTExLjEyMzgwNi9taWQ7VmlkZW87MTM1ODc2OTMxMw]]> 
        </Tracking>       
        <Tracking event="complete"><![CDATA[http://brxserv.btrll.com/v1/epix/6835361/3850628/20799/32716/TbwKgCbwBkAABQ_SyhAABRPwAAf8wAOsGEAAAAAAAfYQiqTYrVDQ/event.end/r_64.aHR0cDovLzI5MDEuYnRybGwuY29tL2ltcC8yOTAxLzEyNDQ2L1ByZVJvbGwuOTExLjEyMzgwNi9kb25lO1ZpZGVvOzEzNTg3NjkzMTM]]> 
        </Tracking>       
        <Tracking event="complete"><![CDATA[http://mobile.btrll.com/event/completion?ts=1358769313921&siteId=3850628&lineItemId=20799]]> 
        </Tracking>      
       </TrackingEvents>      
       <VideoClicks>       
        <ClickThrough><![CDATA[http://brxserv.btrll.com/v1/epix/6835361/3850628/20799/32716/TbwKgCbwBkAABQ_SyhAABRPwAAf8wAOsGEAAAAAAAfYQiqTYrVDQ/event.click/r_64.aHR0cDovLzI5MDEuYnRybGwuY29tL2Nsay8yOTAxLzEyNDQ2L1ByZVJvbGwuOTExLjEyMzgwNi9ub25lLztWaWRlbzsxMzU4NzY5MzEz]]> 
        </ClickThrough>       
        <ClickTracking><![CDATA[http://brxserv.btrll.com/v1/epix/6835361/3850628/20799/32716/TbwKgCbwBkAABQ_SyhAABRPwAAf8wAOsGEAAAAAAAfYQiqTYrVDQ/event.c_trk/r_64.aHR0cDovLzI5MDEuYnRybGwuY29tL2Nsay8yOTAxLzEyNDQ2L1ByZVJvbGwuOTExLjEyMzkyNy9ub25lLztWaWRlbzsxMzU4NzY5MzEz]]> 
        </ClickTracking>        
        <ClickTracking><![CDATA[http://mobile.btrll.com/event/click?ts=1358769313921&siteId=3850628&lineItemId=20799]]> 
        </ClickTracking>       
       </VideoClicks>      
       <MediaFiles>        
        <MediaFile delivery="progressive" type="video/mp4" bitrate="400" height="240" width="320"><![CDATA[http://brxcdn2.btrll.com/production/134980/Home_Depot_MuddyBoots_640x480_15sec.mp4]]> 
        </MediaFile>       
       </MediaFiles>     
      </Linear>     
     </Creative>    
     <Creative sequence="1">     
      <CompanionAds>     </CompanionAds>    
     </Creative>   
    </Creatives>   
</InLine> 

在現有<Impression>和</Impression>之間的內容，希望增加更多的字符串。

我該如何做到這一點？

我試圖像這樣

$pattern = '<Impression>.*?</Impression>';  
preg_match($pattern, $jsaved, $matchesarr); 

Answer 1

東西在大多數情況下*，你不應該使用正則表達式解析HTML或XML。它並不是這項工作的正確工具，而且很可能令人沮喪且容易出錯。 See this question for better ways of doing this in PHP。

這就是說，您的正則表達式失敗，因爲默認情況下，.與換行符不匹配。這意味着只有匹配<Impression>...</Impression>，如果全部出現在單行上。

爲了解決這個問題，你必須添加多行開關（m）：

$pattern = '|<Impression>.*?</Impression>|m';

**也有例外。正則表達式可以很好，如果你的輸入是非常明確的，並且始終遵循可預測的格式。但是，絕對值得考慮XML解析器是否會更好。*