实现篇:

一般情况,用php实现上传进度条就下面两种方法:

1.apc扩展（作者是php教程的创始人，5.2后php已经加入apc扩展）

2.pecl扩展模块 uploadprogress

不论是apc还是uploadprogress,都需要编译源码,因为原有的php函数根本不可能读取到临时文件夹里的东西,下面来看如何使用以及关键的代码:apc实现方法:

1.安装apc

2.配置php.ini,设置参数 apc.rfc1867=1

3.关键代码:

1. if ($_server['request_method'] == ‘post’) { //上传请求
2. $status = apc_fetch(’upload_’ . $_post['apc_upload_progress']);
3. $status['done'] = 1;//开源代码phpfensi.com
4. echo json_encode($status); //输出给用户端页面里的ajax调用，相关文档请自己寻找
5. exit;
6. } elseif (isset($_get['progress_key'])) { //读取上传进度
7. $status = apc_fetch(’upload_’.$_get['progress_key']);
8. echo json_encode($status);
9. exit;
10. }

uploadprogress实现方法:

1.使用pecl 安装uploadprogress

2.php.ini里面设置 uploadprogress.file.filename_template = “/tmp/upd_%s.txt”

3.关键代码如下:

1. if($_server['request_method']==’post’) {
2. if (is_uploaded_file($_files['upfile']['tmp_name'])) {
3. $upload_dir = ‘your_path/’;
4. $ext = strrchr($_files['video']['name'], ‘.’);
5. $sessid = $_post['upload_identifier'] ;
6. $tmpfile = $upload_dir . $sessid;
7. $sessfile = $upload_dir . $sessid .$ext;
8. if (move_uploaded_file($_files['upfile']['tmp_name'],$tmpfile)) {
9. //上传成功
10. }
11. }
12. } elseif (!emptyempty($_get['sessid'])) {
13. header(”expires: mon, 26 jul 1997 05:00:00 gmt”);
14. header(”last-modified: ” . gmdate(”d, d m y h:i:s”) . ” gmt”);
15. header(”cache-control: no-store, no-cache, must-revalidate”);
16. header(”cache-control: post-check=0, pre-check=0′, false);
17. header(”pragma: no-cache”);
18. header(”content-type:text/html;charset=utf-8′);
19. $unique_id = $_get['sessid'];
20. $uploadvalues = uploadprogress_get_info($unique_id);
21. if (is_array($uploadvalues)) {
22. echo json_encode($uploadvalues);
23. } else {
24. //读取进度失败，另外处理逻辑
25. }
26. }

二.原理篇

注意上一篇中的红色函数,下载到uploadprogress1.0.1进行源码分析,在代码中作了注释,代码如下:

1. static void uploadprogress_file_php_get_info(char * id, zval * return_value)
2. {
3. char s[1024];
4. char * filename;
5. char * template;
6. file *f;
7. tsrmls_fetch();
8. template = ini_str(”uploadprogress.file.filename_template”); <<这里读取设置好的模板
9. if (strcmp(template, “”) == 0) {
10. return;
11. } else {
12. filename = uploadprogress_mk_filename( id, template );<<<存在的话，会创建
13. if (!filename) return;
14. f = vcwd_fopen(filename, “rb”);
15. if (f) {
16. array_init(return_value);
17. while ( fgets(s, 1000, f) ) {<<<从流中读取一字符串 *s结果数据的首地址；1000-1:一次读入数据块的长度,其默认值为1k，即1024;f文件指针
18. char *k, *v, *e;
19. int index = 0;
20. e = strchr(s,’='); <<<查找字符串s中首次出现字符=的位置
21. if (!e) continue;
22. *e = 0; /* break the line into 2 parts */
23. v = e+1;
24. k = s;
25. /* trim spaces in front of the name/value */
26. while (*k && *k <= 32) k++;
27. while (*v && *v <= 32) v++;
28. /* trim spaces everywhere in the name */
29. for (e=k; *e; e++) if (*e <= 32) { *e = 0; break; }
30. /* trim spaces only at the end of the value */
31. /* http://111cn.net */
32. //for (e=v; *e; e++) if (*e <= 32) { *e = 0; break; }
33. if (v != null) {<<<当文件有内容时
34. for (index = strlen(v); index > 0; index–) {
35. if (v[index] > 32) break;<<<累计
36. v[index] = 0;
37. }
38. }
39. add_assoc_string( return_value, k, v, 1 );
40. }
41. fclose(f);
42. }
43. if (filename) efree(filename);
44. return;
45. }
46. }

在源码中还能发现如下代码:

1. php_minit_function(uploadprogress)
2. {
3. register_ini_entries();
4. php_rfc1867_callback = uploadprogress_php_rfc1867_file;
5. return success;
6. }

在minit中修改了php_rfc1867_callback,抽取uploadprogress_php_rfc1867_file的关键代码,代码如下:

1. upload_id = emalloc(strlen(*e_data->value) + 1);
2. strcpy(upload_id, *e_data->value);
3. progress->upload_id = upload_id;
4. progress->time_last = time(null);
5. progress->speed_average = 0;
6. progress->speed_last = 0;
7. progress->bytes_uploaded = read_bytes;
8. progress->files_uploaded = 0;
9. progress->est_sec = 0;
10. progress->identifier = uploadprogress_mk_filename(upload_id, template);<<<在指定的模板位置放下了临时文件
11. progress->identifier_tmp = emalloc(strlen( progress->identifier) + 4);
12. sprintf( progress->identifier_tmp, “%s.wr”, progress->identifier );