gue*_*314 10 javascript php language-agnostic multithreading file-upload
题:
如何在服务器和客户端上实时读取和回显正在服务器上写入的上传文件的文件大小？
语境:
文件上传的进展被写入从服务器POST请求通过由fetch(),其中body被设置为Blob,File,TypedArray,或ArrayBuffer对象.
当前实现将File对象设置为body传递给第二个参数的对象fetch().
需求:
读取echo并向客户端写入正在写入服务器文件系统的文件的文件大小text/event-stream.GET在写入作为查询字符串参数的脚本作为变量提供的所有字节时停止.文件的读取当前发生在一个单独的脚本环境中,其中GET应该读取文件的脚本调用是在POST将文件写入服务器的脚本之后进行的.
没有达到将文件写入服务器或读取文件以获取当前文件大小的潜在问题的错误处理,尽管这将是echo文件大小部分完成后的下一步.
目前正试图满足要求使用php.虽然也有兴趣在c,bash,nodejs,python,或其他可用于执行相同任务的语言或方法.
客户端javascript部分不是问题.简而言之,在php万维网上使用的最常见的服务器端语言之一,实现该模式而不包括不必要的部分.
动机:
有关:
问题:
入门
PHP Notice: Undefined index: HTTP_LAST_EVENT_ID in stream.php on line 7
在terminal.
另外,如果替代
while(file_exists($_GET["filename"])
&& filesize($_GET["filename"]) < intval($_GET["filesize"]))
对于
while(true)
产生错误EventSource.
如果没有sleep()电话,正确的文件大小被派往message事件的3.3MB文件3321824,被印在console 61921,26214和38093次,分别在上传同一文件三次.在写入文件时,预期结果是文件的文件大小
stream_copy_to_stream($input, $file);
而不是上传的文件对象的文件大小.是fopen()或stream_copy_to_stream()阻止其他不同的php流程stream.php？
到目前为止尝试过:
php 归因于
php
// can we merge `data.php`, `stream.php` to same file?
// can we use `STREAM_NOTIFY_PROGRESS`
// "Indicates current progress of the stream transfer
// in bytes_transferred and possibly bytes_max as well" to read bytes?
// do we need to call `stream_set_blocking` to `false`
// data.php
<?php
$filename = $_SERVER["HTTP_X_FILENAME"];
$input = fopen("php://input", "rb");
$file = fopen($filename, "wb");
stream_copy_to_stream($input, $file);
fclose($input);
fclose($file);
echo "upload of " . $filename . " successful";
?>
// stream.php
<?php
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
header("Connection: keep-alive");
// `PHP Notice: Undefined index: HTTP_LAST_EVENT_ID in stream.php on line 7` ?
$lastId = $_SERVER["HTTP_LAST_EVENT_ID"] || 0;
if (isset($lastId) && !empty($lastId) && is_numeric($lastId)) {
$lastId = intval($lastId);
$lastId++;
}
// else {
// $lastId = 0;
// }
// while current file size read is less than or equal to
// `$_GET["filesize"]` of `$_GET["filename"]`
// how to loop only when above is `true`
while (true) {
$upload = $_GET["filename"];
// is this the correct function and variable to use
// to get written bytes of `stream_copy_to_stream($input, $file);`?
$data = filesize($upload);
// $data = $_GET["filename"] . " " . $_GET["filesize"];
if ($data) {
sendMessage($lastId, $data);
$lastId++;
}
// else {
// close stream
// }
// not necessary here, though without thousands of `message` events
// will be dispatched
// sleep(1);
}
function sendMessage($id, $data) {
echo "id: $id\n";
echo "data: $data\n\n";
ob_flush();
flush();
}
?>
javascript
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<input type="file">
<progress value="0" max="0" step="1"></progress>
<script>
const [url, stream, header] = ["data.php", "stream.php", "x-filename"];
const [input, progress, handleFile] = [
document.querySelector("input[type=file]")
, document.querySelector("progress")
, (event) => {
const [file] = input.files;
const [{size:filesize, name:filename}, headers, params] = [
file, new Headers(), new URLSearchParams()
];
// set `filename`, `filesize` as search parameters for `stream` URL
Object.entries({filename, filesize})
.forEach(([...props]) => params.append.apply(params, props));
// set header for `POST`
headers.append(header, filename);
// reset `progress.value` set `progress.max` to `filesize`
[progress.value, progress.max] = [0, filesize];
const [request, source] = [
new Request(url, {
method:"POST", headers:headers, body:file
})
// https://stackoverflow.com/a/42330433/
, new EventSource(`${stream}?${params.toString()}`)
];
source.addEventListener("message", (e) => {
// update `progress` here,
// call `.close()` when `e.data === filesize`
// `progress.value = e.data`, should be this simple
console.log(e.data, e.lastEventId);
}, true);
source.addEventListener("open", (e) => {
console.log("fetch upload progress open");
}, true);
source.addEventListener("error", (e) => {
console.error("fetch upload progress error");
}, true);
// sanity check for tests,
// we don't need `source` when `e.data === filesize`;
// we could call `.close()` within `message` event handler
setTimeout(() => source.close(), 30000);
// we don't need `source' to be in `Promise` chain,
// though we could resolve if `e.data === filesize`
// before `response`, then wait for `.text()`; etc.
// TODO: if and where to merge or branch `EventSource`,
// `fetch` to single or two `Promise` chains
const upload = fetch(request);
upload
.then(response => response.text())
.then(res => console.log(res))
.catch(err => console.error(err));
}
];
input.addEventListener("change", handleFile, true);
</script>
</body>
</html>
你需要clearstatcache来获得真正的文件大小.修复了很少的其他位,您的stream.php可能如下所示:
<?php
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
header("Connection: keep-alive");
// Check if the header's been sent to avoid `PHP Notice: Undefined index: HTTP_LAST_EVENT_ID in stream.php on line `
// php 7+
//$lastId = $_SERVER["HTTP_LAST_EVENT_ID"] ?? 0;
// php < 7
$lastId = isset($_SERVER["HTTP_LAST_EVENT_ID"]) ? intval($_SERVER["HTTP_LAST_EVENT_ID"]) : 0;
$upload = $_GET["filename"];
$data = 0;
// if file already exists, its initial size can be bigger than the new one, so we need to ignore it
$wasLess = $lastId != 0;
while ($data < $_GET["filesize"] || !$wasLess) {
// system calls are expensive and are being cached with assumption that in most cases file stats do not change often
// so we clear cache to get most up to date data
clearstatcache(true, $upload);
$data = filesize($upload);
$wasLess |= $data < $_GET["filesize"];
// don't send stale filesize
if ($wasLess) {
sendMessage($lastId, $data);
$lastId++;
}
// not necessary here, though without thousands of `message` events will be dispatched
//sleep(1);
// millions on poor connection and large files. 1 second might be too much, but 50 messages a second must be okay
usleep(20000);
}
function sendMessage($id, $data)
{
echo "id: $id\n";
echo "data: $data\n\n";
ob_flush();
// no need to flush(). It adds content length of the chunk to the stream
// flush();
}
几点需要注意:
安全.我的意思是好运.据我所知,它是一个概念证明,安全性是最不重要的问题,但免责声明应该存在.这种方法存在根本缺陷,只有在您不关心DOS攻击或有关文件的信息消失时才应使用.
中央处理器.没有usleep脚本将消耗单个核心的100%.如果长时间睡眠,您可能会在一次迭代中上传整个文件,并且永远不会满足退出条件.如果您在本地测试它,usleep应该完全删除,因为在本地上传MB是几毫秒.
打开连接.apache和nginx/fpm都有有限数量的php进程可以处理请求.单个文件上载将花费2上传文件所需的时间.对于慢带宽或伪造请求,此时间可能很长,并且Web服务器可能会开始拒绝请求.
客户端部分.您需要分析响应并最终在文件完全上载时停止侦听事件.
编辑:
为了使它或多或少生产友好,您需要一个内存存储,如redis或memcache来存储文件元数据.
发出帖子请求,添加标识文件的唯一标记和文件大小.
在你的javascript中:
const fileId = Math.random().toString(36).substr(2); // or anything more unique
...
const [request, source] = [
new Request(`${url}?fileId=${fileId}&size=${filesize}`, {
method:"POST", headers:headers, body:file
})
, new EventSource(`${stream}?fileId=${fileId}`)
];
....
在data.php中注册令牌并按块报告进度:
....
$fileId = $_GET['fileId'];
$fileSize = $_GET['size'];
setUnique($fileId, 0, $fileSize);
while ($uploaded = stream_copy_to_stream($input, $file, 1024)) {
updateProgress($id, $uploaded);
}
....
/**
* Check if Id is unique, and store processed as 0, and full_size as $size
* Set reasonable TTL for the key, e.g. 1hr
*
* @param string $id
* @param int $size
* @throws Exception if id is not unique
*/
function setUnique($id, $size) {
// implement with your storage of choice
}
/**
* Updates uploaded size for the given file
*
* @param string $id
* @param int $processed
*/
function updateProgress($id, $processed) {
// implement with your storage of choice
}
所以你的stream.php根本不需要点击磁盘,只要UX可以接受就可以睡觉:
....
list($progress, $size) = getProgress('non_existing_key_to_init_default_values');
$lastId = 0;
while ($progress < $size) {
list($progress, $size) = getProgress($_GET["fileId"]);
sendMessage($lastId, $progress);
$lastId++;
sleep(1);
}
.....
/**
* Get progress of the file upload.
* If id is not there yet, returns [0, PHP_INT_MAX]
*
* @param $id
* @return array $bytesUploaded, $fileSize
*/
function getProgress($id) {
// implement with your storage of choice
}
2个打开连接的问题无法解决,除非你放弃了旧的好拉动EventSource.没有循环的stream.php的响应时间是几毫秒,并且保持连接始终打开是非常浪费的,除非您每秒需要数百次更新.
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