好用的php header下载函数

3. /**

4. * 发送文件
5. *
6. * @param string $fileName 文件名称或路径
7. * @param string $fancyName 自定义的文件名,为空则使用filename
8. * @param boolean $forceDownload 是否强制下载
9. * @param integer $speedLimit 速度限制,单位为字节,0为不限制,不支持windows服务器
10. * @param string $$contentType 文件类型,默认为application/octet-stream
11. *
12. * @return boolean
13. */
14. function sendFile($fileName, $fancyName = '', $forceDownload = true, $speedLimit = 0, $contentType = '')
15. {
16. if (!is_readable($fileName))
17. {
18. header("HTTP/1.1 404 Not Found");
19. return false;
20. }
21. $fileStat = stat($fileName);
22. $lastModified = $fileStat['mtime'];

23. $md5 = md5($fileStat['mtime'] .'='. $fileStat['ino'] .'='. $fileStat['size']);

24. $etag = '"' . $md5 . '-' . crc32($md5) . '"';
25. header('Last-Modified: ' . gmdate("D, d M Y H:i:s", $lastModified) . ' GMT');
26. header("ETag: $etag");

27. if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= $lastModified)

28. {
29. header("HTTP/1.1 304 Not Modified");
30. return true;
31. }
32. if (isset($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) {
33. header("HTTP/1.1 304 Not Modified");
34. return true;
35. }
36. if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && $_SERVER['HTTP_IF_NONE_MATCH'] == $etag)
37. {
38. header("HTTP/1.1 304 Not Modified");
39. return true;
40. }
41. if ($fancyName == '')
42. {
43. $fancyName = basename($fileName);
44. }

45. if ($contentType == '')

46. {
47. $contentType = 'application/octet-stream';
48. }
49. $fileSize = $fileStat['size'];

50. $contentLength = $fileSize;

51. $isPartial = false;
52. if (isset($_SERVER['HTTP_RANGE']))
53. {
54. if (preg_match('/^bytes=(d*)-(d*)$/', $_SERVER['HTTP_RANGE'], $matches))
55. {
56. $startPos = $matches[1];
57. $endPos = $matches[2];
58. if ($startPos == '' && $endPos == '')
59. {
60. return false;
61. }

62. if ($startPos == '')

63. {
64. $startPos = $fileSize - $endPos;
65. $endPos = $fileSize - 1;
66. }
67. else if ($endPos == '')
68. {
69. $endPos = $fileSize - 1;
70. }
71. $startPos = $startPos $endPos = $endPos > $fileSize - 1 ? $fileSize - 1 : $endPos;
72. $length = $endPos - $startPos + 1;
73. if ($length {
74. return false;
75. }
76. $contentLength = $length;
77. $isPartial = true;
78. }
79. }

80. // send headers

81. if ($isPartial)
82. {
83. header('HTTP/1.1 206 Partial Content');
84. header("Content-Range: bytes $startPos-$endPos/$fileSize");

85. }

86. else
87. {
88. header("HTTP/1.1 200 OK");
89. $startPos = 0;
90. $endPos = $contentLength - 1;
91. }
92. header('Pragma: cache');
93. header('Cache-Control: public, must-revalidate, max-age=0');
94. header('Accept-Ranges: bytes');
95. header('Content-type: ' . $contentType);
96. header('Content-Length: ' . $contentLength);

97. if ($forceDownload)

98. {
99. header('Content-Disposition: attachment; filename="' . rawurlencode($fancyName). '"');//汉字自动转为URL编码
100. header('Content-Disposition: attachment; filename="' . $fancyName. '"');
101. }
102. header("Content-Transfer-Encoding: binary");
103. // header函数实现文件下载

104. $bufferSize = 2048;

105. if ($speedLimit != 0)
106. {
107. $packetTime = floor($bufferSize * 1000000 / $speedLimit);
108. }
109. $bytesSent = 0;
110. $fp = fopen($fileName, "rb");
111. fseek($fp, $startPos);
112. //fpassthru($fp);

113. while ($bytesSent {

114. if ($speedLimit != 0)
115. {
116. list($usec, $sec) = explode(" ", microtime());
117. $outputTimeStart = ((float)$usec + (float)$sec);
118. } // bbs.it-home.org
119. $readBufferSize = $contentLength - $bytesSent $buffer = fread($fp, $readBufferSize);
120. echo $buffer;
121. ob_flush();
122. flush();
123. $bytesSent += $readBufferSize;

124. if ($speedLimit != 0)

125. {
126. list($usec, $sec) = explode(" ", microtime());
127. $outputTimeEnd = ((float)$usec + (float)$sec);

128. $useTime = ((float) $outputTimeEnd - (float) $outputTimeStart) * 1000000;

129. $sleepTime = round($packetTime - $useTime);
130. if ($sleepTime > 0)
131. {
132. usleep($sleepTime);
133. }
134. }
135. }
136. return true;
137. }
138. ?>

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