这篇文章主要介绍了php生成RSS订阅的方法,较为详细的分析了一个RSS订阅类及其具体使用技巧,非常具有实用价值,需要的朋友可以参考下

本文实例讲述了php生成RSS订阅的方法。分享给大家供大家参考。具体分析如下：

RSS（简易信息聚合，也叫聚合内容）是一种描述和同步网站内容的格式。RSS可以是以下三个解释的其中一个： Really Simple Syndication；RDF (Resource Description Framework) Site Summary； Rich Site Summary。但其实这三个解释都是指同一种Syndication的技术。RSS目前广泛用于网上新闻频道，blog和wiki。使用RSS订阅能更快地获取信息，网站提供RSS输出，有利于让用户获取网站内容的最新更新。网络用户可以在客户端借助于支持RSS的聚合工具软件，在不打开网站内容页面的情况下阅读支持RSS输出的网站内容。

从技术上来说一个RSS文件就是一段规范的XML数据，该文件一般以rss，xml或者rdf作为后缀，下面是一段 rss 文件的内容示例：

1. <?xml version="1.0" encoding="utf-8"?> 
2. <rss version="2.0"> 
3. <channel> 
4. <title>php粉丝网</title> 
5. <link>https://www.phpfensi.com/</link> 
6. <description>php粉丝网</description> 
7. <item> 
8. <title>RSS Tutorial</title> 
9. <link>网站地址/rss</link> 
10. <description>New RSS tutorial on W3School</description> 
11. </item> 
12. <item> 
13. <title>XML Tutorial</title> 
14. <link>网站地址/xml</link> 
15. <description>New XML tutorial on W3School</description> 
16. </item> 
17. </channel> 
18. </rss> 

下面分享一段使用 php 动态生成 RSS 的代码示例：

1. <?php 
2. /** 
3. ** php 动态生成 RSS 类 
4. **/ 
5. define("TIME_ZONE",""); 
6. define("FEEDCREATOR_VERSION","www.phpfensi.com");//您的网址 
7. class FeedItem extends HtmlDescribable{ 
8.     var $title,$description,$link; 
9.     var $author,$authorEmail,$image,$category,$comments,$guid,$source,$creator; 
10.     var $date; 
11.     var $additionalElements=Array(); 
12. } 
13.  
14. class FeedImage extends HtmlDescribable{ 
15.     var $title,$url,$link; 
16.     var $width,$height,$description; 
17. } 
18.  
19. class HtmlDescribable{ 
20.     var $descriptionHtmlSyndicated; 
21.     var $descriptionTruncSize; 
22.  
23.     function getDescription(){ 
24.         $descriptionField=new FeedHtmlField($this->description); 
25.         $descriptionField->syndicateHtml=$this->descriptionHtmlSyndicated; 
26.         $descriptionField->truncSize=$this->descriptionTruncSize; 
27.         return $descriptionField->output(); 
28.     } 
29. } 
30.  
31. class FeedHtmlField{ 
32.     var $rawFieldContent; 
33.     var $truncSize,$syndicateHtml; 
34.     function FeedHtmlField($parFieldContent){ 
35.         if($parFieldContent){ 
36.             $this->rawFieldContent=$parFieldContent; 
37.         } 
38.     } 
39.     function output(){ 
40.         if(!$this->rawFieldContent){ 
41.             $result=""; 
42.         }    elseif($this->syndicateHtml){ 
43.             $result="<![CDATA[".$this->rawFieldContent."]]>"; 
44.         }else{ 
45.             if($this->truncSize and is_int($this->truncSize)){ 
46.                 $result=FeedCreator::iTrunc(htmlspecialchars($this->rawFieldContent),$this->truncSize); 
47.             }else{ 
48.                 $result=htmlspecialchars($this->rawFieldContent); 
49.             } 
50.         } 
51.         return $result; 
52.     } 
53. } 
54.  
55. class UniversalFeedCreator extends FeedCreator{ 
56.     var $_feed; 
57.     function _setFormat($format){ 
58.         switch (strtoupper($format)){ 
59.             case "2.0": 
60.                 // fall through 
61.             case "RSS2.0": 
62.                 $this->_feed=new RSSCreator20(); 
63.                 break; 
64.             case "0.91": 
65.                 // fall through 
66.             case "RSS0.91": 
67.                 $this->_feed=new RSSCreator091(); 
68.                 break; 
69.             default: 
70.                 $this->_feed=new RSSCreator091(); 
71.                 break; 
72.         } 
73.         $vars=get_object_vars($this); 
74.         foreach ($vars as $key => $value){ 
75.             // prevent overwriting of properties "contentType","encoding"; do not copy "_feed" itself 
76.             if(!in_array($key, array("_feed","contentType","encoding"))){ 
77.                 $this->_feed->{$key}=$this->{$key}; 
78.             } 
79.         } 
80.     } 
81.  
82.     function createFeed($format="RSS0.91"){ 
83.         $this->_setFormat($format); 
84.         return $this->_feed->createFeed(); 
85.     } 
86.  
87.     function saveFeed($format="RSS0.91",$filename="",$displayContents=true){ 
88.         $this->_setFormat($format); 
89.         $this->_feed->saveFeed($filename,$displayContents); 
90.     } 
91.  
92.     function useCached($format="RSS0.91",$filename="",$timeout=3600){ 
93.         $this->_setFormat($format); 
94.         $this->_feed->useCached($filename,$timeout); 
95.     } 
96. } 
97.  
98. class FeedCreator extends HtmlDescribable{ 
99.     var $title,$description,$link; 
100.     var $syndicationURL,$image,$language,$copyright,$pubDate,$lastBuildDate,$editor,$editorEmail,$webmaster,$category,$docs,$ttl,$rating,$skipHours,$skipDays; 
101.     var $xslStyleSheet=""; 
102.     var $items=Array(); 
103.     var $contentType="application/xml"; 
104.     var $encoding="utf-8"; 
105.     var $additionalElements=Array(); 
106.  
107.     function addItem($item){ 
108.         $this->items[]=$item; 
109.     } 
110.  
111.     function clearItem2Null(){ 
112.         $this->items=array(); 
113.     } 
114.  
115.     function iTrunc($string,$length){ 
116.         if(strlen($string)<=$length){ 
117.             return $string; 
118.         } 
119.  
120.         $pos=strrpos($string,"."); 
121.         if($pos>=$length-4){ 
122.             $string=substr($string,0,$length-4); 
123.             $pos=strrpos($string,"."); 
124.         } 
125.         if($pos>=$length*0.4){ 
126.             return substr($string,0,$pos+1)." ..."; 
127.         } 
128.  
129.         $pos=strrpos($string," "); 
130.         if($pos>=$length-4){ 
131.             $string=substr($string,0,$length-4); 
132.             $pos=strrpos($string," "); 
133.         } 
134.         if($pos>=$length*0.4){ 
135.             return substr($string,0,$pos)." ..."; 
136.         } 
137.  
138.         return substr($string,0,$length-4)." ..."; 
139.     } 
140.  
141.     function _createGeneratorComment(){ 
142.         return "<!-- generator=\"".FEEDCREATOR_VERSION."\" -->\n"; 
143.     } 
144.  
145.     function _createAdditionalElements($elements,$indentString=""){ 
146.         $ae=""; 
147.         if(is_array($elements)){ 
148.             foreach($elements AS $key => $value){ 
149.                 $ae.= $indentString."<$key>$value</$key>\n"; 
150.             } 
151.         } 
152.         return $ae; 
153.     } 
154.  
155.     function _createStylesheetReferences(){ 
156.         $xml=""; 
157.         if($this->cssStyleSheet) $xml .= "<?xml-stylesheet href=\"".$this->cssStyleSheet."\" type=\"text/css\"?>\n"; 
158.         if($this->xslStyleSheet) $xml .= "<?xml-stylesheet href=\"".$this->xslStyleSheet."\" type=\"text/xsl\"?>\n"; 
159.         return $xml; 
160.     } 
161.  
162.     function createFeed(){} 
163.  
164.     function _generateFilename(){ 
165.         $fileInfo=pathinfo($_SERVER["PHP_SELF"]); 
166.         return substr($fileInfo["basename"],0,-(strlen($fileInfo["extension"])+1)).".xml"; 
167.     } 
168.  
169.     function _redirect($filename){ 
170.         Header("Content-Type: ".$this->contentType."; charset=".$this->encoding."; filename=".basename($filename)); 
171.         Header("Content-Disposition: inline; filename=".basename($filename)); 
172.         readfile($filename,"r"); 
173.         die(); 
174.     } 
175.  
176.     function useCached($filename="",$timeout=3600){ 
177.         $this->_timeout=$timeout; 
178.         if($filename==""){ 
179.             $filename=$this->_generateFilename(); 
180.         } 
181.         if(file_exists($filename) && (time()-filemtime($filename) < $timeout)){ 
182.             $this->_redirect($filename); 
183.         } 
184.     } 
185.  
186.     function saveFeed($filename="",$displayContents=true){ 
187.         if($filename==""){ 
188.             $filename=$this->_generateFilename(); 
189.         } 
190.         $feedFile=fopen($filename,"w+"); 
191.         if($feedFile){ 
192.             fputs($feedFile,$this->createFeed()); 
193.             fclose($feedFile); 
194.             if($displayContents){ 
195.                 $this->_redirect($filename); 
196.             } 
197.         }else{ 
198.             echo "<br /><b>Error creating feed file, please check write permissions.</b><br />"; 
199.         } 
200.     } 
201. } 
202.  
203. class FeedDate{ 
204.     var $unix; 
205.     function FeedDate($dateString=""){ 
206.         if($dateString=="") $dateString=date("r"); 
207.         if(is_integer($dateString)){ 
208.             $this->unix=$dateString; 
209.             return; 
210.         } 
211.         if(preg_match("~(?:(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun),\\s+)?(\\d{1,2})\\s+([a-zA-Z]{3})\\s+(\\d{4})\\s+(\\d{2}):(\\d{2}):(\\d{2})\\s+(.*)~",$dateString,$matches)){ 
212.             $months=Array("Jan"=>1,"Feb"=>2,"Mar"=>3,"Apr"=>4,"May"=>5,"Jun"=>6,"Jul"=>7,"Aug"=>8,"Sep"=>9,"Oct"=>10,"Nov"=>11,"Dec"=>12); 
213.             $this->unix=mktime($matches[4],$matches[5],$matches[6],$months[$matches[2]],$matches[1],$matches[3]); 
214.             if(substr($matches[7],0,1)=='+' OR substr($matches[7],0,1)=='-'){ 
215.                 $tzOffset=(substr($matches[7],0,3) * 60 + substr($matches[7],-2)) * 60; 
216.             }else{ 
217.                 if(strlen($matches[7])==1){ 
218.                     $oneHour=3600; 
219.                     $ord=ord($matches[7]); 
220.                     if($ord < ord("M")){ 
221.                         $tzOffset=(ord("A") - $ord - 1) * $oneHour; 
222.                     } elseif($ord >= ord("M") && $matches[7]!="Z"){ 
223.                         $tzOffset=($ord - ord("M")) * $oneHour; 
224.                     } elseif($matches[7]=="Z"){ 
225.                         $tzOffset=0; 
226.                     } 
227.                 } 
228.                 switch ($matches[7]){ 
229.                     case "UT": 
230.                     case "GMT":    $tzOffset=0; 
231.                 } 
232.             } 
233.             $this->unix += $tzOffset; 
234.             return; 
235.         } 
236.         if(preg_match("~(\\d{4})-(\\d{2})-(\\d{2})T(\\d{2}):(\\d{2}):(\\d{2})(.*)~",$dateString,$matches)){ 
237.             $this->unix=mktime($matches[4],$matches[5],$matches[6],$matches[2],$matches[3],$matches[1]); 
238.             if(substr($matches[7],0,1)=='+' OR substr($matches[7],0,1)=='-'){ 
239.                 $tzOffset=(substr($matches[7],0,3) * 60 + substr($matches[7],-2)) * 60; 
240.             }else{ 
241.                 if($matches[7]=="Z"){ 
242.                     $tzOffset=0; 
243.                 } 
244.             } 
245.             $this->unix += $tzOffset; 
246.             return; 
247.         } 
248.         $this->unix=0; 
249.     } 
250.  
251.     function rfc822(){ 
252.         $date=gmdate("Y-m-d H:i:s",$this->unix); 
253.         if(TIME_ZONE!="") $date .= " ".str_replace(":","",TIME_ZONE); 
254.         return $date; 
255.     } 
256.  
257.     function iso8601(){ 
258.         $date=gmdate("Y-m-d H:i:s",$this->unix); 
259.         $date=substr($date,0,22) . ':' . substr($date,-2); 
260.         if(TIME_ZONE!="") $date=str_replace("+00:00",TIME_ZONE,$date); 
261.         return $date; 
262.     } 
263.  
264.     function unix(){ 
265.         return $this->unix; 
266.     } 
267. } 
268.  
269. class RSSCreator10 extends FeedCreator{ 
270.     function createFeed(){ 
271.         $feed="<?xml version=\"1.0\" encoding=\"".$this->encoding."\"?>\n"; 
272.         $feed.= $this->_createGeneratorComment(); 
273.         if($this->cssStyleSheet==""){ 
274.             $cssStyleSheet="http://www.w3.org/2000/08/w3c-synd/style.css"; 
275.         } 
276.         $feed.= $this->_createStylesheetReferences(); 
277.         $feed.= "<rdf:RDF\n"; 
278.         $feed.= "    xmlns=\"http://purl.org/rss/1.0/\"\n"; 
279.         $feed.= "    xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"\n"; 
280.         $feed.= "    xmlns:slash=\"http://purl.org/rss/1.0/modules/slash/\"\n"; 
281.         $feed.= "    xmlns:dc=\"http://purl.org/dc/elements/1.1/\">\n"; 
282.         $feed.= "    <channel rdf:about=\"".$this->syndicationURL."\">\n"; 
283.         $feed.= "        <title>".htmlspecialchars($this->title)."</title>\n"; 
284.         $feed.= "        <description>".htmlspecialchars($this->description)."</description>\n"; 
285.         $feed.= "        <link>".$this->link."</link>\n"; 
286.         if($this->image!=null){ 
287.             $feed.= "        <image rdf:resource=\"".$this->image->url."\" />\n"; 
288.         } 
289.         $now=new FeedDate(); 
290.         $feed.= "       <dc:date>".htmlspecialchars($now->iso8601())."</dc:date>\n"; 
291.         $feed.= "        <items>\n"; 
292.         $feed.= "            <rdf:Seq>\n"; 
293.         for ($i=0;$i<count($this->items);$i++){ 
294.             $feed.= "                <rdf:li rdf:resource=\"".htmlspecialchars($this->items[$i]->link)."\"/>\n"; 
295.         } 
296.         $feed.= "            </rdf:Seq>\n"; 
297.         $feed.= "        </items>\n"; 
298.         $feed.= "    </channel>\n"; 
299.         if($this->image!=null){ 
300.             $feed.= "    <image rdf:about=\"".$this->image->url."\">\n"; 
301.             $feed.= "        <title>".$this->image->title."</title>\n"; 
302.             $feed.= "        <link>".$this->image->link."</link>\n"; 
303.             $feed.= "        <url>".$this->image->url."</url>\n"; 
304.             $feed.= "    </image>\n"; 
305.         } 
306.         $feed.= $this->_createAdditionalElements($this->additionalElements,"    "); 
307.  
308.         for ($i=0;$i<count($this->items);$i++){ 
309.             $feed.= "    <item rdf:about=\"".htmlspecialchars($this->items[$i]->link)."\">\n"; 
310.             //$feed.= "        <dc:type>Posting</dc:type>\n"; 
311.             $feed.= "        <dc:format>text/html</dc:format>\n"; 
312.             if($this->items[$i]->date!=null){ 
313.                 $itemDate=new FeedDate($this->items[$i]->date); 
314.                 $feed.= "        <dc:date>".htmlspecialchars($itemDate->iso8601())."</dc:date>\n"; 
315.             } 
316.             if($this->items[$i]->source!=""){ 
317.                 $feed.= "        <dc:source>".htmlspecialchars($this->items[$i]->source)."</dc:source>\n"; 
318.             } 
319.             if($this->items[$i]->author!=""){ 
320.                 $feed.= "        <dc:creator>".htmlspecialchars($this->items[$i]->author)."</dc:creator>\n"; 
321.             } 
322.             $feed.= "        <title>".htmlspecialchars(strip_tags(strtr($this->items[$i]->title,"\n\r","  ")))."</title>\n"; 
323.             $feed.= "        <link>".htmlspecialchars($this->items[$i]->link)."</link>\n"; 
324.             $feed.= "        <description>".htmlspecialchars($this->items[$i]->description)."</description>\n"; 
325.             $feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,"        "); 
326.             $feed.= "    </item>\n"; 
327.         } 
328.         $feed.= "</rdf:RDF>\n"; 
329.         return $feed; 
330.     } 
331. } 
332.  
333. class RSSCreator091 extends FeedCreator{ 
334.     var $RSSVersion; 
335.  
336.     function RSSCreator091(){ 
337.         $this->_setRSSVersion("0.91"); 
338.         $this->contentType="application/rss+xml"; 
339.     } 
340.  
341.     function _setRSSVersion($version){ 
342.         $this->RSSVersion=$version; 
343.     } 
344.  
345.     function createFeed(){ 
346.         $feed="<?xml version=\"1.0\" encoding=\"".$this->encoding."\"?>\n"; 
347.         $feed.= $this->_createGeneratorComment(); 
348.         $feed.= $this->_createStylesheetReferences(); 
349.         $feed.= "<rss version=\"".$this->RSSVersion."\">\n"; 
350.         $feed.= "    <channel>\n"; 
351.         $feed.= "        <title>".FeedCreator::iTrunc(htmlspecialchars($this->title),100)."</title>\n"; 
352.         $this->descriptionTruncSize=500; 
353.         $feed.= "        <description>".$this->getDescription()."</description>\n"; 
354.         $feed.= "        <link>".$this->link."</link>\n"; 
355.         $now=new FeedDate(); 
356.         $feed.= "        <lastBuildDate>".htmlspecialchars($now->rfc822())."</lastBuildDate>\n"; 
357.         $feed.= "        <generator>".FEEDCREATOR_VERSION."</generator>\n"; 
358.  
359.         if($this->image!=null){ 
360.             $feed.= "        <image>\n"; 
361.             $feed.= "            <url>".$this->image->url."</url>\n"; 
362.             $feed.= "            <title>".FeedCreator::iTrunc(htmlspecialchars($this->image->title),100)."</title>\n"; 
363.             $feed.= "            <link>".$this->image->link."</link>\n"; 
364.             if($this->image->width!=""){ 
365.                 $feed.= "            <width>".$this->image->width."</width>\n"; 
366.             } 
367.             if($this->image->height!=""){ 
368.                 $feed.= "            <height>".$this->image->height."</height>\n"; 
369.             } 
370.             if($this->image->description!=""){ 
371.                 $feed.= "            <description>".$this->image->getDescription()."</description>\n"; 
372.             } 
373.             $feed.= "        </image>\n"; 
374.         } 
375.         if($this->language!=""){ 
376.             $feed.= "        <language>".$this->language."</language>\n"; 
377.         } 
378.         if($this->copyright!=""){ 
379.             $feed.= "        <copyright>".FeedCreator::iTrunc(htmlspecialchars($this->copyright),100)."</copyright>\n"; 
380.         } 
381.         if($this->editor!=""){ 
382.             $feed.= "        <managingEditor>".FeedCreator::iTrunc(htmlspecialchars($this->editor),100)."</managingEditor>\n"; 
383.         } 
384.         if($this->webmaster!=""){ 
385.             $feed.= "        <webMaster>".FeedCreator::iTrunc(htmlspecialchars($this->webmaster),100)."</webMaster>\n"; 
386.         } 
387.         if($this->pubDate!=""){ 
388.             $pubDate=new FeedDate($this->pubDate); 
389.             $feed.= "        <pubDate>".htmlspecialchars($pubDate->rfc822())."</pubDate>\n"; 
390.         } 
391.         if($this->category!=""){ 
392.             $feed.= "        <category>".htmlspecialchars($this->category)."</category>\n"; 
393.         } 
394.         if($this->docs!=""){ 
395.             $feed.= "        <docs>".FeedCreator::iTrunc(htmlspecialchars($this->docs),500)."</docs>\n"; 
396.         } 
397.         if($this->ttl!=""){ 
398.             $feed.= "        <ttl>".htmlspecialchars($this->ttl)."</ttl>\n"; 
399.         } 
400.         if($this->rating!=""){ 
401.             $feed.= "        <rating>".FeedCreator::iTrunc(htmlspecialchars($this->rating),500)."</rating>\n"; 
402.         } 
403.         if($this->skipHours!=""){ 
404.             $feed.= "        <skipHours>".htmlspecialchars($this->skipHours)."</skipHours>\n"; 
405.         } 
406.         if($this->skipDays!=""){ 
407.             $feed.= "        <skipDays>".htmlspecialchars($this->skipDays)."</skipDays>\n"; 
408.         } 
409.         $feed.= $this->_createAdditionalElements($this->additionalElements,"    "); 
410.  
411.         for ($i=0;$i<count($this->items);$i++){ 
412.             $feed.= "        <item>\n"; 
413.             $feed.= "            <title>".FeedCreator::iTrunc(htmlspecialchars(strip_tags($this->items[$i]->title)),100)."</title>\n"; 
414.             $feed.= "            <link>".htmlspecialchars($this->items[$i]->link)."</link>\n"; 
415.             $feed.= "            <description>".$this->items[$i]->getDescription()."</description>\n"; 
416.  
417.             if($this->items[$i]->author!=""){ 
418.                 $feed.= "            <author>".htmlspecialchars($this->items[$i]->author)."</author>\n"; 
419.             } 
420.             /* 
421.              // on hold 
422.              if($this->items[$i]->source!=""){ 
423.              $feed.= "            <source>".htmlspecialchars($this->items[$i]->source)."</source>\n"; 
424.              } 
425.              */ 
426.             if($this->items[$i]->category!=""){ 
427.                 $feed.= "            <category>".htmlspecialchars($this->items[$i]->category)."</category>\n"; 
428.             } 
429.             if($this->items[$i]->comments!=""){ 
430.                 $feed.= "            <comments>".htmlspecialchars($this->items[$i]->comments)."</comments>\n"; 
431.             } 
432.             if($this->items[$i]->date!=""){ 
433.                 $itemDate=new FeedDate($this->items[$i]->date); 
434.                 $feed.= "            <pubDate>".htmlspecialchars($itemDate->rfc822())."</pubDate>\n"; 
435.             } 
436.             if($this->items[$i]->guid!=""){ 
437.                 $feed.= "            <guid>".htmlspecialchars($this->items[$i]->guid)."</guid>\n"; 
438.             } 
439.             $feed.= $this->_createAdditionalElements($this->items[$i]->additionalElements,"        "); 
440.             $feed.= "        </item>\n"; 
441.         } 
442.         $feed.= "    </channel>\n"; 
443.         $feed.= "</rss>\n"; 
444.         return $feed; 
445.     } 
446. } 
447.  
448. class RSSCreator20 extends RSSCreator091{ 
449.  
450.     function RSSCreator20(){ 
451.         parent::_setRSSVersion("2.0"); 
452.     } 
453. } 

使用示例：

1. <?php 
2. header('Content-Type:text/html; charset=utf-8'); 
3. $db=mysql_connect('127.0.0.1','root','123456'); 
4. mysql_query("set names utf8"); 
5. mysql_select_db('dbname',$db); 
6. $brs=mysql_query('select * from article order by add_time desc limit 0,10',$db); 
7. $rss=new UniversalFeedCreator(); 
8. $rss->title="页面标题"; 
9. $rss->link="网址http://"; 
10. $rss->description="rss标题"; 
11. while($rowbrs=mysql_fetch_array($brs)){ 
12.     $item=new FeedItem(); 
13.     $item->title =$rowbrs['subject']; 
14.     $item->link='https://www.phpfensi.com/'; 
15.     $item->description =$rowbrs['description']; 
16.     $rss->addItem($item); 
17. } 
18. mysql_close($db); 
19. $rss->saveFeed("RSS2.0","rss.xml");

Tags: php生成RSS订阅

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