PHP cache for websites

Cache is widely used in actual use, which can reduce access to the server database and improve the running speed. Currently, many CMS Content Management systems frequently use caching mechanisms to improve system operation efficiency. The following is a well-written cache class. You can refer to the caching mechanism and writing method.

The cache. php code is as follows:

[Php]View plaincopy

1. <?
2. /*
3. Constants that need to be defined in advance:
4. _ CachePath _ template cache path
5. _ CacheEnable _ whether the automatic cache mechanism is enabled. If it is undefined or empty, the automatic cache mechanism is disabled.
6. _ ReCacheTime _ automatic cache re-caching interval, in seconds. If it is undefined or empty, automatic cache re-caching is disabled.
7. */
9. Class cache
10. {
11. Var $ cachefile;
12. Var $ cachefilevar;
14. Function cache ()
15. {
16. // Generate the name of the Cache group for the current page $ this-> cachefilevar and the name $ this-> cachefile
17. // Different dynamic page parameters correspond to different Cache files, but all the Cache files on each dynamic page have the same file name, but the extensions are different.
18. $ S = array (".", "/"); $ r = array ("_","");
19. $ This-> cachefilevar = str_replace ($ s, $ r, $ _ SERVER ["SCRIPT_NAME"]). "_". $ _ GET [_ ActionVar _];
20. $ This-> cachefile = $ this-> cachefilevar. ".". md5 ($ _ SERVER ["REQUEST_URI"]);
21. }
23. // Delete the cache of the current page/Module
24. Function delete ()
25. {
26. // Delete the cache of the current page
27. $ D = dir (_ CachePath _);
28. $ Strlen = strlen ($ this-> cachefilevar );
29. // Return all Cache file groups on the current page
30. While (false! ==( $ Entry = $ d-> read ()))
31. {
32. If (substr ($ entry, 0, $ strlen) = $ this-> cachefilevar)
33. {
34. If (! Unlink (_ CachePath _. "/". $ entry) {echo "the Cache directory cannot be written"; exit ;}
35. }
36. }
37. }
39. // Determine whether or not the Cache has been cached and whether the Cache is required
40. Function check ()
41. {
42. // If the cache Update Interval _ ReCacheTime _ is set _
43. If (_ ReCacheTime _ + 0> 0)
44. {
45. // Return the Last Update Time of the current page Cache
46. $ Var = @ file (_ CachePath _. "/". $ this-> cachefilevar); $ var = $ var [0];
47. // Delete the Cache file if the update time exceeds the Update Interval
48. If (time ()-$ var> _ ReCacheTime _)
49. {
50. $ This-> delete (); $ ischage = true;
51. }
52. }
53. // Return the Cache of the current page
54. $ File = _ CachePath _. "/". $ this-> cachefile;
55. // Determine whether the current page Cache exists and whether the Cache function is enabled
56. Return (file_exists ($ file) and _ CacheEnable _ and! $ Ischange );
57. }
59. // Read Cache
60. Function read ()
61. {
62. // Return the Cache of the current page
63. $ File = _ CachePath _. "/". $ this-> cachefile;
64. // Read the content of the Cache file
65. If (_ CacheEnable _) return readfile ($ file );
66. Else return false;
67. }
69. // Generate Cache
70. Function write ($ output)
71. {
72. // Return the Cache of the current page
73. $ File = _ CachePath _. "/". $ this-> cachefile;
74. // If the Cache function is enabled
75. If (_ CacheEnable _)
76. {
77. // Write the output content to the Cache file
78. $ Fp = @ fopen ($ file, 'w ');
79. If (! @ Fputs ($ fp, $ output) {echo "template Cache write failed"; exit ;}
80. @ Fclose ($ fp );
81. // If the cache Update Interval _ ReCacheTime _ is set _
82. If (_ ReCacheTime _ + 0> 0)
83. {
84. // Update the Last Update Time of the current page Cache
85. $ File = _ CachePath _. "/". $ this-> cachefilevar;
86. $ Fp = @ fopen ($ file, 'w ');
87. If (! @ Fwrite ($ fp, time () {echo "the Cache directory cannot be written"; exit ;}
88. @ Fclose ($ fp );
89. }
90. }
91. }
92. }
93. ?>

 

 

Class usage:

[Php]View plaincopy

1. <? Php
2. Define ("_ CachePath _", "./cache /");
3. Define ("_ CacheEnable _", "1 ");
4. Define ("_ ReCacheTime _", "43200 ");
5. Include ('cache. php ');
6. $ Cache = new cache ();
7. If ($ cache-> check ())
8. {
9. $ Template = $ cache-> read ();
10. }
11. Else
12. {
13. Ob_start ();
14. Ob_implicit_flush (0 );
15. ?>
16. Page content ....
17. <? Php
18. $ Template = ob_get_contents ();
19. $ Cache-> write ($ template );
20. }
21. ?>