PHP function: Determine whether the remote file has an instance code

This article introduces PHP functions-how to determine whether a remote file exists in the instance code

1. <? Php
2. /*
3. Function: remote_file_exists
4. Function: determines whether a remote file exists.
5. Parameter: $ url_file-Remote File URL
6. Return: If yes, true is returned. If not, false is returned for other reasons.
7. */
8. Function remote_file_exists ($ url_file ){
9. // Check input
10. $ Url_file = trim ($ url_file );
11. If (empty ($ url_file) {return false ;}
12. $ Url_arr = parse_url ($ url_file );
13. If (! Is_array ($ url_arr) | empty ($ url_arr) {return false ;}
15. // Obtain request data
16. $ Host = $ url_arr [host];
17. $ Path = $ url_arr [path]. "? ". $ Url_arr [query];
18. $ Port = isset ($ url_arr [port])? $ Url_arr [port]: "80 ";
20. // Connect to the server
21. $ Fp = fsockopen ($ host, $ port, $ err_no, $ err_str, 30 );
22. If (! $ Fp) {return false ;}
24. // Construct the request protocol
25. $ Request_str = "GET". $ path. "HTTP/1.1 ";
26. $ Request_str. = "Host:". $ host ."";
27. $ Request_str. = "Connection: Close ";
29. // Send the request
30. Fwrite ($ fp, $ request_str );
31. $ First_header = fgets ($ fp, 1024 );
32. Fclose ($ fp );
34. // Determine whether a file exists
35. If (trim ($ first_header) = "") {return false ;}
36. If (! Preg_match ("/200/", $ first_header )){
37. Return false;
38. }
39. Return true;
40. }
42. // Test code
43. $ Str_url = http://www.ite5e.com/newsinfo.php? Nid = 1493;
44. $ Exits = remote_file_exists ($ str_url );
45. Echo $ exists? "Exists": "Not exists ";
46. ?>