Discuss in detail how to implement PHP HTML interception code_PHP tutorial

What we will bring to you today is about the requirement: intercept a piece of text to a certain physical length and display it. Note that what is to be intercepted is not the number of bytes of the string, UFT-8 The encoded Chinese characters are 3 bytes or 4 bytes, and when displayed, Chinese characters will occupy two characters, and English characters will only occupy one, and it is different when it is full-width.

And the data given is an HTML code string, such as this:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">div</span><span> </span><span class="attribute">class</span><span>=”aaa”</span><span class="tag">></span></span></span></li>
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=”/aaa.php?</span><span class="attribute">id</span><span>=</span><span class="attribute-value">1</span><span>″</span><span class="tag">></span></span></span></li>
<li class="alt"><span><span>张三</span></span></li>
<li class="alt"><span><span class="tag"><span> /a</span><span class="tag">></span><span> </span></span></span></li>
<li class="alt"><span><span>评论了 </span></span></li>
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=”/aaa.php?</span><span class="attribute">id</span><span>=</span><span class="attribute-value">444</span><span>″</span><span class="tag">></span></span></span></li>
<li class="alt"><span><span>李四</span></span></li>
<li class="alt"><span><span class="tag"><span> /a</span><span class="tag">></span><span> </span></span></span></li>
<li class="alt"><span><span>分享的 </span></span></li>
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">a</span><span> </span><span class="attribute">href</span><span>=”bbb.html”</span><span class="tag">></span></span></span></li>
<li class="alt"><span><span>一篇文章文章一长串的东西</span></span></li>
<li class="alt"><span><span class="tag"><span> /a</span><span class="tag">></span></span></span></li>
<li class="alt"><span><span class="tag"><span> /div</span><span class="tag">></span><span> </span></span></span></li>
</ol>

When PHP HTML intercepts the code, it needs to intercept the content inside the div tag, and the HTML tag must be retained, just for The text is processed. For example, I may just intercept the word "李" in "李思", but if I put it on the front end like this, the a tag in front of "李思" will not be closed, so after intercepting, I need to ensure that the HTML syntax is correct.
This problem is really not easy to solve, and it made me depressed for two days. Please note that this is just a string, but the content is HTML code and there is no DOM. It would be easier if it were processed on the front end. You can directly obtain the DOM, then process the nodes inside, and finally output things like innerHTML. It doesn't work now, I have to change my mind. My colleague’s idea is this:

Traverse each character of the string. Set a tag, and set it to 1 when it encounters the tag . When processing the string inside the label, you must first determine whether the current character encoding may be Chinese. Generally speaking, the length of UTF-8 encoded Chinese characters in PHP is 3, so if you encounter a Chinese character encoding , I have to skip two uncounted ones... At this point, my head is starting to get big. Personally, I think this method is very unpleasant. First of all, this kind of exquisite logic is not easy to control, and the length of Chinese generated under UFT-8 encoding may be 3 or 4, so the tightness of the code is questionable.

My personal idea is to use Tidy (please see the PHP manual for specific usage). I studied Tidy yesterday and found that this thing is quite useful. First, convert this string into a Tidy object, like this:

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute">tidy</span><span> = </span><span class="attribute-value">tidy_parse_string<br></span><span>($str, array(), ‘utf8′);   </span></span></li>
<li><span>// 最后一个是设置编码的，注意，<br>这里是utf8 ，不是utf-8，没有中间那个连线。 </span></li>
</ol>

Then get the body in $tidy (because after conversion, $tidy will automatically add tags such as

) :
$body = tidy_get_body($tidy);
At this time you can use var_dump to look at some $body structures, and you will find that it turns each tag into a corresponding object with corresponding attributes. . For example, sdf , some attributes corresponding to such a statement are:

name=>”a”
value => "sdf"
child=> array{[0]=>A text node object, value is sdf}
attribute=array{"href ”=>”#”}
…..Other attributes

As you can see, we can actually process the value of the text node under the corresponding node of the a tag separately, so that the PHP HTML interception code It won't break any HTML integrity. Originally, I thought that after changing the value of the text node in the a tag, the value of the a tag would also change accordingly. In that case, it would be OK if I directly returned the value of the node corresponding to the a tag. I didn't expect it to be like that. Alas, so I processed the text in it. Then you still have to spell out the new HTML yourself.
After knowing the structure of the Tidy object, everything is easy to handle. Just traverse all the nodes. For this requirement, it is to find the div tag and then start processing the nodes inside. The code is as follows:

<ol class="dp-xml">
<li class="alt"><span><span>if(mb_strwidth($subchild-</span><span class="tag">></span><span>value, <br>‘utf-8′) </span><span class="tag">></span><span>= $len)   </span></span></li>
<li><span>{   </span></li>
<li class="alt">
<span>$subchild-</span><span class="tag">></span><span class="attribute">value</span><span> = </span><span class="attribute-value">mb_strimwidth<br></span><span>($subchild-</span><span class="tag">></span><span>value, 0, $len, ‘…', ‘utf-8′);   </span>
</li>
<li>
<span>$trimed_str </span><span class="attribute">.</span><span>= $subchild-</span><span class="tag">></span><span>value;   </span>
</li>
<li class="alt"><span>break;   </span></li>
<li><span>}   </span></li>
<li class="alt"><span>else   </span></li>
<li><span>{   </span></li>
<li class="alt">
<span>$trimed_str </span><span class="attribute">.</span><span>= $subchild-</span><span class="tag">></span><span>value;   </span>
</li>
<li>
<span>$</span><span class="attribute">len</span><span> = $len - mb_strwidth($subchild-</span><span class="tag">><br></span><span>value, ‘utf-8′);   </span>
</li>
<li class="alt"><span>}  </span></li>
</ol>

The $subchild inside is a child node. Note that mb_strwidth is used here to obtain the string length. I strongly recommend this mb_strwidth, it is very useful, it will treat Chinese as two characters in length, which exactly meets the needs here! Moreover, mb_strimwidth is used when PHP HTML intercepts code. This function will also treat Chinese as two characters in length. The function starting with mb_ is really easy to use.

I won’t write out the specific PHP HTML interception code, because it is written based on a requirement and not made into a universal form. One day I have time to make it universal and publish it.
In addition, it is a pity that FireFox does not support the text-overflow attribute, otherwise there would be no need to work so hard in the background to truncate it. If you have a better method, please suggest it! Any help is greatly appreciated.

http://www.bkjia.com/PHPjc/446217.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446217.htmlTechArticleWhat we will bring to you today is about the requirements: intercept a piece of text to a certain physical length and display it. Note, What you want to intercept is not the number of bytes of the string. The encoded Chinese characters of UFT-8 are...