網站經常要用到下載遠程圖片的功能,有時還要下載.doc文檔,所以就用php開發了一個下載遠程文件的類,這個類支持斷點續傳下載,源代碼中有具體的注釋及使用說明案例.

程序主要是使用 HTTP 協議下載文件,HTTP1.1協議必須指定文檔結束后關閉鏈接,否則讀取文檔時無法使用feof判斷結束,可以有兩種使用方法,具體請下載查看源碼,代碼如下:

1. <?php 
2. /** 
3.  * 下載遠程文件類支持斷點續傳  
4.  */ 
5. class HttpDownload { 
6.     private $m_url = ""; 
7.      private $m_urlpath = ""; 
8.      private $m_scheme = "http"; 
9.      private $m_host = ""; 
10.      private $m_port = "80"; 
11.      private $m_user = ""; 
12.      private $m_pass = ""; 
13.      private $m_path = "/"; 
14.      private $m_query = ""; 
15.      private $m_fp = ""; 
16.      private $m_error = ""; 
17.     private $m_httphead = "" ; 
18.     private $m_html = ""; 
19.  
20.     /** 
21.      * 初始化  
22.      */ 
23.     public function PrivateInit($url){ 
24.         $urls = ""; 
25.         $urls = @parse_url($url); 
26.         $this->m_url = $url; 
27.         if(is_array($urls)) { 
28.             $this->m_host = $urls["host"]; 
29.             if(!emptyempty($urls["scheme"])) $this->m_scheme = $urls["scheme"]; 
30.             if(!emptyempty($urls["user"])) $this->m_user = $urls["user"]; 
31.             if(!emptyempty($urls["pass"])) $this->m_pass = $urls["pass"]; 
32.             if(!emptyempty($urls["port"])) $this->m_port = $urls["port"]; 
33.             if(!emptyempty($urls["path"])) $this->m_path = $urls["path"]; 
34.             $this->m_urlpath = $this->m_path; 
35.             if(!emptyempty($urls["query"])) { 
36.                  $this->m_query = $urls["query"]; 
37.                  $this->m_urlpath .= "?".$this->m_query; 
38.              } 
39.           } 
40.     } 
41.  
42.     /** 
43.     * 打開指定網址 
44.     */ 
45.     function OpenUrl($url) { 
46.         #重設各參數 
47.         $this->m_url = ""; 
48.         $this->m_urlpath = ""; 
49.         $this->m_scheme = "http"; 
50.         $this->m_host = ""; 
51.         $this->m_port = "80"; 
52.         $this->m_user = ""; 
53.         $this->m_pass = ""; 
54.         $this->m_path = "/"; 
55.         $this->m_query = ""; 
56.         $this->m_error = ""; 
57.         $this->m_httphead = "" ; 
58.         $this->m_html = ""; 
59.         $this->Close(); 
60.         #初始化系統 
61.         $this->PrivateInit($url); 
62.         $this->PrivateStartSession(); 
63.     } 
64.  
65.     /** 
66.     * 獲得某操作錯誤的原因 
67.     */ 
68.     public function printError() { 
69.         echo "錯誤信息：".$this->m_error; 
70.         echo "具體返回頭：<br>"; 
71.         foreach($this->m_httphead as $k=>$v) {  
72.             echo "$k => $v <br>rn";  
73.         } 
74.     } 
75.  
76.     /** 
77.     * 判別用Get方法發送的頭的應答結果是否正確 
78.     */ 
79.     public function IsGetOK() { 
80.         if( ereg("^2",$this->GetHead("http-state")) ) {  
81.             return true;  
82.         } else { 
83.             $this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")."<br>"; 
84.             return false; 
85.         } 
86.     } 
87.      
88.     /** 
89.     * 看看返回的網頁是否是text類型 
90.     */ 
91.     public function IsText() { 
92.         if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) {  
93.             return true;  
94.         } else { 
95.             $this->m_error .= "內容為非文本類型<br>"; 
96.             return false; 
97.         } 
98.     } 
99.     /** 
100.     * 判斷返回的網頁是否是特定的類型 
101.     */ 
102.     public function IsContentType($ctype) { 
103.         if (ereg("^2",$this->GetHead("http-state")) && $this->GetHead("content-type") == strtolower($ctype)) {  
104.             return true;  
105.         } else { 
106.             $this->m_error .= "類型不對 ".$this->GetHead("content-type")."<br>"; 
107.             return false; 
108.         } 
109.     } 
110.      
111.     /** 
112.     * 用 HTTP 協議下載文件 
113.     */ 
114.     public function SaveToBin($savefilename) { 
115.         if (!$this->IsGetOK()) return false; 
116.         if (@feof($this->m_fp)) {  
117.             $this->m_error = "連接已經關閉！";  
118.             return false;  
119.         } 
120.         $fp = fopen($savefilename,"w") or die("寫入文件 $savefilename 失敗！"); 
121.         while (!feof($this->m_fp)) { 
122.             @fwrite($fp,fgets($this->m_fp,256)); 
123.         } 
124.         @fclose($this->m_fp); 
125.         return true; 
126.     } 
127.      
128.     /** 
129.     * 保存網頁內容為 Text 文件 
130.     */ 
131.     public function SaveToText($savefilename) { 
132.         if ($this->IsText()) { 
133.             $this->SaveBinFile($savefilename); 
134.         } else { 
135.             return ""; 
136.         } 
137.     } 
138.      
139.     /** 
140.     * 用 HTTP 協議獲得一個網頁的內容 
141.     */ 
142.     public function GetHtml() { 
143.         if (!$this->IsText()) return ""; 
144.         if ($this->m_html!="") return $this->m_html; 
145.         if (!$this->m_fp||@feof($this->m_fp)) return ""; 
146.         while(!feof($this->m_fp)) { 
147.             $this->m_html .= fgets($this->m_fp,256); 
148.         } 
149.         @fclose($this->m_fp); 
150.         return $this->m_html; 
151.     } 
152.      
153.     /** 
154.     * 開始 HTTP 會話 
155.     */ 
156.     public function PrivateStartSession() { 
157.         if (!$this->PrivateOpenHost()) { 
158.             $this->m_error .= "打開遠程主機出錯!"; 
159.             return false; 
160.         } 
161.         if ($this->GetHead("http-edition")=="HTTP/1.1") { 
162.             $httpv = "HTTP/1.1"; 
163.         } else { 
164.             $httpv = "HTTP/1.0"; 
165.         } 
166.         fputs($this->m_fp,"GET ".$this->m_urlpath." $httpvrn"); 
167.         fputs($this->m_fp,"Host: ".$this->m_host."rn"); 
168.         fputs($this->m_fp,"Accept: */*rn"); 
169.         fputs($this->m_fp,"User-Agent: Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2)rn"); 
170.         #HTTP1.1協議必須指定文檔結束后關閉鏈接,否則讀取文檔時無法使用feof判斷結束 
171.         if ($httpv=="HTTP/1.1") { 
172.             fputs($this->m_fp,"Connection: Closernrn"); 
173.         } else { 
174.             fputs($this->m_fp,"rn"); 
175.         } 
176.         $httpstas = fgets($this->m_fp,256); 
177.         $httpstas = split(" ",$httpstas); 
178.         $this->m_httphead["http-edition"] = trim($httpstas[0]); 
179.         $this->m_httphead["http-state"] = trim($httpstas[1]); 
180.         $this->m_httphead["http-describe"] = ""; 
181.         for ($i=2;$i<count($httpstas);$i++) { 
182.             $this->m_httphead["http-describe"] .= " ".trim($httpstas[$i]); 
183.         } 
184.         while (!feof($this->m_fp)) { 
185.             $line = str_replace(""","",trim(fgets($this->m_fp,256))); 
186.             if($line == "") break; 
187.             if (ereg(":",$line)) { 
188.                 $lines = split(":",$line); 
189.                 $this->m_httphead[strtolower(trim($lines[0]))] = trim($lines[1]); 
190.             } 
191.         } 
192.     } 
193.      
194.     /** 
195.     * 獲得一個Http頭的值 
196.     */ 
197.     public function GetHead($headname) { 
198.         $headname = strtolower($headname); 
199.         if (isset($this->m_httphead[$headname])) { 
200.             return $this->m_httphead[$headname]; 
201.         } else { 
202.             return ""; 
203.         } 
204.     } 
205.      
206.     /** 
207.     * 打開連接 
208.     */ 
209.     public function PrivateOpenHost() { 
210.         if ($this->m_host=="") return false; 
211.         $this->m_fp = @fsockopen($this->m_host, $this->m_port, &$errno, &$errstr,10); 
212.         if (!$this->m_fp){ 
213.             $this->m_error = $errstr; 
214.             return false; 
215.         } else { 
216.             return true; 
217.         } 
218.     } 
219.      
220.     /** 
221.     * 關閉連接 
222.     */ 
223.     public function Close(){ 
224.         @fclose($this->m_fp); 
225.     } 
226. } 
227.  
228. #兩種使用方法，分別如下： 
229.  
230. #打開網頁 
231. $httpdown = new HttpDownload(); 
232. $httpdown->OpenUrl("http://www.google.com.hk"); 
233. echo $httpdown->GetHtml(); 
234. $httpdown->Close(); 
235.  
236.  
237. #下載文件 
238. $file = new HttpDownload(); # 實例化類 
239. $file->OpenUrl("http://www.survivalescaperooms.com/cn/lit/an/rust020/rust020.pdf"); # 遠程文件地址 
240. $file->SaveToBin("rust020.pdf"); # 保存路徑及文件名 
241. $file->Close(); # 釋放資源 
242. ?>