javascript - h5 has Server-sent Events, how to write it on the php side?-PHP Tutorial-php.cn

javascript - h5 has Server-sent Events, how to write it on the php side?

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Release： 2016-08-10 09:07:25

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<code>
public static function pushEvent(){
    header('Content-Type: text/event-stream');
    header('Cache-Control: no-cache'); // 建议不要缓存SSE数据
    header('Connection: keep-alive');
    //header('X-Accel-Buffering: no');//有可能用nginx的需要设置这个才能把缓冲数据刷出去

    $serverTime = time();
    $hasData = hFile::cache('pushEvent');//读缓存
    if($hasData){
        hFile::cache('pushEvent',0);//存缓存
        self::sendMsg($serverTime, 'server time: ' . date("h:i:s"),'myevent',100000);
    }else
        self::sendMsg('','','',100);//多少毫秒内无数据,再重连
}


/**
 * @param string $id Timestamp/id of this connection.
 * @param string $msg Line of text that should be transmitted.
 * @param $event string
 */
private static function sendMsg($id='', $msg='',$event='',$retry=''){
    if(!($id||$event||$msg||$retry))
        return;

    if($retry) echo "retry: $retry" .PHP_EOL;
    if($id) echo "id: $id" . PHP_EOL;
    if($event) echo "event: {$event}" . PHP_EOL;
    if($msg) echo "data: $msg" . PHP_EOL;
    echo PHP_EOL;//表示本条数据结束
    ob_flush();
    flush();
}
</code>

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I wrote it like this (part of the code was copied). The problem is that every time the front end establishes a connection, PHP can only return data once. If you want the next data, rely on this lineself::sendMsg('','','',100);//How many milliseconds There is no data in it, then reconnect. This line will tell the front end how many milliseconds it will take before re-establishing the connection. This seems to be a waste of resources, and each time you want to output data, you have to read the cache to see if there is a message sent to the user. Way, is there any other good way?

Reply content:

<code>
public static function pushEvent(){
    header('Content-Type: text/event-stream');
    header('Cache-Control: no-cache'); // 建议不要缓存SSE数据
    header('Connection: keep-alive');
    //header('X-Accel-Buffering: no');//有可能用nginx的需要设置这个才能把缓冲数据刷出去

    $serverTime = time();
    $hasData = hFile::cache('pushEvent');//读缓存
    if($hasData){
        hFile::cache('pushEvent',0);//存缓存
        self::sendMsg($serverTime, 'server time: ' . date("h:i:s"),'myevent',100000);
    }else
        self::sendMsg('','','',100);//多少毫秒内无数据,再重连
}


/**
 * @param string $id Timestamp/id of this connection.
 * @param string $msg Line of text that should be transmitted.
 * @param $event string
 */
private static function sendMsg($id='', $msg='',$event='',$retry=''){
    if(!($id||$event||$msg||$retry))
        return;

    if($retry) echo "retry: $retry" .PHP_EOL;
    if($id) echo "id: $id" . PHP_EOL;
    if($event) echo "event: {$event}" . PHP_EOL;
    if($msg) echo "data: $msg" . PHP_EOL;
    echo PHP_EOL;//表示本条数据结束
    ob_flush();
    flush();
}
</code>

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Please refer to this article of mine: https://segmentfault.com/a/11...

The most important thing is the following paragraph:

<code>ob_flush();
flush();
//等待3秒钟，开始下一次查询
sleep(3);
</code>

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After flushing, do not disconnect, but sleep for 3 seconds and then enter the loop again, so that the connection can be maintained and will not be disconnected and reconnected.

Why not do something like this via websocket?