PHP 远程文件下载的进度条实现

 1 <?php ?2 // 当前文件：download.php 3 ?4 $action = @$_GET[‘action‘]; 5 ?6 // 自己获取这些信息 7 $remote_url ?= get_remote_file_url(); 8 $file_size ??= get_remote_file_size($remote_url); 9 $tmp_path ???= get_tmp_path();10 11 switch ($action) {12 ????case ‘prepare-download‘:13 ????????// 下载缓存文件夹14 ????????$download_cache = __DIR__."/download_cache";15 16 ????????if (!is_dir($download_cache)) {17 ????????????if (false === mkdir($download_cache)) {18 ????????????????exit(‘创建下载缓存文件夹失败，请检查目录权限。‘);19 ????????????}20 ????????}21 22 ????????$tmp_path = $download_cache."/update_".time().".zip";23 24 ????????save_tmp_path(); // 这里保存临时文件地址25 26 ????????return json(compact(‘remote_url‘, ‘tmp_path‘, ‘file_size‘));27 28 ????????break;29 30 ????case ‘start-download‘:31 32 ????????// 这里检测下 tmp_path 是否存在33 34 ????????try {35 ????????????set_time_limit(0);36 37 ????????????touch($tmp_path);38 39 ????????????// 做些日志处理40 41 ????????????if ($fp = fopen($remote_url, "rb")) {42 43 ????????????????if (!$download_fp = fopen($tmp_path, "wb")) {44 ????????????????????exit;45 ????????????????}46 47 ????????????????while (!feof($fp)) {48 49 ????????????????????if (!file_exists($tmp_path)) {50 ????????????????????????// 如果临时文件被删除就取消下载51 ????????????????????????fclose($download_fp);52 53 ????????????????????????exit;54 ????????????????????}55 56 ????????????????????fwrite($download_fp, fread($fp, 1024 * 8 ), 1024 * 8);57 ????????????????}58 59 ????????????????fclose($download_fp);60 ????????????????fclose($fp);61 62 ????????????} else {63 ????????????????exit;64 ????????????}65 66 ????????} catch (Exception $e) {67 ????????????Storage::remove($tmp_path);68 69 ????????????exit(‘发生错误：‘.$e->getMessage());70 ????????}71 72 ????????return json(compact(‘tmp_path‘));73 74 ????????break;75 76 ????case ‘get-file-size‘:77 78 ????????// 这里检测下 tmp_path 是否存在79 80 ????????if (file_exists($tmp_path)) {81 ????????????// 返回 JSON 格式的响应82 ????????????return json([‘size‘ => filesize($tmp_path)]);83 ????????}84 85 ????????break;86 87 ????default:88 ????????# code...89 ????????break;90 }

 1 // 咋触发这个函数我就不举例了 2 function downloadFile() { 3 ????var file_size = 0; 4 ????var progress ?= 0; 5 ?6 ????console.log("Prepared to download"); 7 ?8 ????$.ajax({ 9 ????????url: ‘./download.php?action=prepare-download‘,10 ????????type: ‘GET‘,11 ????????dataType: ‘json‘,12 ????????beforeSend: function() {13 ????????????$(‘#update-button‘).html(‘<i class="fa fa-spinner fa-spin"></i> 正在准备‘).prop(‘disabled‘, ‘disabled‘);14 ????????},15 ????})16 ????.done(function(json) {17 ????????console.log(json);18 19 ????????file_size = json.file_size;20 21 ????????$(‘#file-size‘).html(file_size);22 23 ????????// 显示进度条24 25 ????????console.log("started downloading");26 ????????$.ajax({27 ????????????url: ‘./download.php?action=start-download‘,28 ????????????type: ‘POST‘,29 ????????????dataType: ‘json‘30 ????????})31 ????????.done(function(json) {32 ????????????// set progress to 100 when got the response33 ????????????progress = 100;34 35 ????????????console.log("Downloading finished");36 ????????????console.log(json);37 ????????})38 ????????.fail(showAjaxError);39 40 ????????var interval_id = window.setInterval(function() {41 42 ????????????$(‘#imported-progress‘).html(progress);43 ????????????$(‘.progress-bar‘).css(‘width‘, progress+‘%‘).attr(‘aria-valuenow‘, progress);44 45 ????????????if (progress == 100) {46 ????????????????clearInterval(interval_id);47 ??????????????48 ????????????????// 到此远程文件下载完成，继续其他逻辑49 ????????????} else {50 ????????????????$.ajax({51 ????????????????????url: ‘./download.php?action=get-file-size‘,52 ????????????????????type: ‘GET‘53 ????????????????})54 ????????????????.done(function(json) {55 ????????????????????progress = (json.size / file_size * 100).toFixed(2);56 ??????????????????57 ????????????????????updateProgress(progress);58 59 ????????????????????console.log("Progress: "+progress);60 ????????????????})61 ????????????????.fail(showAjaxError);62 ????????????}63 64 ????????}, 300);65 66 ????})67 ????.fail(showAjaxError);68 69 }