用PHP发送服务器事件

Question

I have a web app which sends some data from a js script to a php server which inserts it into a mysql database. I also need to notify all other clients that the data has been sent and send it to them.

I'm trying to use Server-Sent Events to do this but I'm having some trouble grasping the concept. Here's my code:

$(document).ready(function() {
    var source = new EventSource("../Server/insertMessage.php");
    if(typeof(EventSource) == "undefined") {
        alert("event source doesnt work");
    } else { alert("event source works"); }

    source.onmessage = function(event) {
        alert(event.data);
        // do stuff with event.data
    };
});

Elsewhere in my js script, I send an AJAX request to insertMessage.php with POST parameters as the data details. Does this trigger the server-side event? Here's my server side code:

insertMessage.php

if(isset(// check POST to see if the right request was sent)) {
    // insert data into database
    // ...
    // ...

    // Send the new data to listeners
    header('Content-Type: text/event-stream');
    header('Cache-Control: no-cache');
    // Create data array
    $dataArray = array("data" => $data, "moreData" => $moreData);
    // Encode JSON
    $callback = json_encode($dataArray);
    // Send it
    echo "data: $callback";
    flush();
}

While the "event source works" alert is sent, I never get the event.data alert, even though I am making the AJAX call to insertMessage.php. I may not completely understand Server-Sent Events yet. What am I doing wrong?

Answer 1

The reason this isn't working is because when your JavaScript is creating the EventSource or is doing an HTTP GET. So your PHP code is not returning anything. You can't do POST requests with an EventSource.