本教程提供了三款获取上传文件与图片类型的方法,方法也是很简单的前二种,是先把类型定义好,再用in_array判断,最后一步是利用了fopen再读取前二个字节,判断.

代码如下:

1. //获得图片的格式，包括jpg,png,gif
2. function get_type($img_name)//获取图像文件类型
3. {
4. if (preg_match("/.(jpg|jpeg|gif|png|bmp)$/i", $img_name, $matches)){
5. $type = strtolower($matches[1]);
6. }else{
7. $type = "string";
8. }
9. return $type;
10. }
11. //判断上传文件类型
12. $allowedextensions = array("txt","csv","htm","html","xml",
13. "css教程","doc","xls","rtf","ppt","pdf","swf","flv","avi",
14. "wmv","mov","jpg","jpeg","gif","png");
15. foreach ($_files as $file) {
16. if ($file['tmp_name'] > '') {
17. if (!in_array(end(explode(".",
18. strtolower($file['name']))),
19. $allowedextensions)) {
20. die($file['name'].' is an invalid file type!<br/>'.
21. '<a href="网页特效:history.go(-1);">'.
22. '&lt;&lt go back</a>');
23. }
24. }
25. }
26. //另类的读取文件与图片类型
27. function checktitle($filename) {
28. $file = fopen($filename, "rb");
29. $bin = fread($file, 2); //只读2字节
30. fclose($file);
31. $strinfo = @unpack("c2chars", $bin);
32. $typecode = intval($strinfo['chars1'].$strinfo['chars2']);
33. $filetype = "";
34. switch ($typecode)
35. {
36. case 7790:
37. $filetype = 'exe';
38. break;
39. case 7784:
40. $filetype = 'midi';
41. break;
42. case 8297:
43. $filetype = 'rar';
44. break;
45. case 255216:
46. $filetype = 'jpg';
47. break;
48. case 7173:
49. $filetype = 'gif';
50. break;
51. case 6677:
52. $filetype = 'bmp';
53. break;
54. case 13780:
55. $filetype = 'png';
56. break;
57. default:
58. $filetype = 'unknown'.$typecode;
59. }
60. //fix
61. if ($strinfo['chars1']=='-1' && $strinfo['chars2']=='-40' ) {
62. return 'jpg';
63. }
64. if ($strinfo['chars1']=='-119' && $strinfo['chars2']=='80' ) {
65. return 'png';
66. }
67. return $filetype;
68. }
69. ?>