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javascript - 事件源 -> 服务器批量返回事件流而不是 block 返回

转载 作者：IT王子 更新时间：2023-10-29 00:31:58 26 4
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I have a php script that import large data from csv files with validations.
For that I need to show progress to the user. I have used Event Streaming for that.
When I echo something, I want it to be transferred to client one by one instead of server sent whole output in bulk.
I had already played around with ob_start(), ob_implicit_flush() & ob_flush(), but they didn't work.
My script is working perfect on another server. Below server configurations are given:

代码未按预期响应的服务器配置，即

OS: LinuxPHP Version 5.4.36-0+deb7u3Server API: CGI/FastCGI Memory_limit: 128Moutput_buffering: no value

As I have said, the code is working properly on another server which has the almost same configuration, i.e.

OS: LinuxPHP Version 5.4.37Server API: CGI/FastCGI Memory_limit: 256MBoutput_buffering: no value

Below is my sample code for sending event:

<?php
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
header("Access-Control-Allow-Origin: *");

$lastEventId = floatval(isset($_SERVER["HTTP_LAST_EVENT_ID"]) ? $_SERVER["HTTP_LAST_EVENT_ID"] : 0);
if ($lastEventId == 0) {
    $lastEventId = floatval(isset($_GET["lastEventId"]) ? $_GET["lastEventId"] : 0);
}

echo ":" . str_repeat(" ", 2048) . "\n"; // 2 kB padding for IE
echo "retry: 2000\n";

// event-stream
$i = $lastEventId;

while ($i <= 100) {
    if($i==100){
        echo "data: stop\n";
        ob_flush();
        flush();
        break;
    } else {
        echo "id: " . $i . "\n";
        echo "data: " . $i . ";\n\n";
        ob_flush();
        flush();
        sleep(1);
    }
    $i++;
}
?>

以下是我需要回复的客户页面:

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <title>EventSource example</title>
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <script src="../jquery/eventsource.js"></script>
    <script>
        var es = new EventSource("events.php");
        var listener = function(event) {
            console.log(event.data);
            var type = event.type;
            if (event.data == 'stop') {
                es.close();
            } else {
                var div = document.createElement("div");
                div.appendChild(document.createTextNode(type + ": " + (type === "message" ? event.data : es.url)));
                document.body.appendChild(div);
            }
        };
        var errlistener = function(event) {
            es.close();
        }
        es.addEventListener("open", listener);
        es.addEventListener("message", listener);
        es.addEventListener("error", errlistener);
    </script>
</head>

<body>
</body>

</html>

最佳答案

将截取的数据返回到浏览器的最佳方法是使用 Web 套接字让客户端打开一个套接字到您的文件阅读器，然后您可以毫无问题地将数据分 block 到浏览器。

然后一旦完成，您就可以关闭套接字。

一个很好的网络套接字教程 http://www.phpbuilder.com/articles/application-architecture/optimization/creating-real-time-applications-with-php-and-websockets.html

使用这种方法，如果您想要实现验证，那么服务器不仅会发送数据 block ，还会根据 javascript 的请求发送数据 block

所以你的客户可以说我需要 block 5 而你的服务器实现类似的东西

$requestedChunk = 5; // this would be set by the javascript sending the request
$chunkSize = 256; // this would be your chunk size;

$readPossition = $requestedChunk * $chunkSize;

链接不再有效，所以这是一个基于 Ratchet 的链接:https://blog.samuelattard.com/the-tutorial-for-php-websockets-that-i-wish-had-existed/

关于javascript - 事件源 -> 服务器批量返回事件流而不是 block 返回，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28607708/

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