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ericlaw1979/ServerSentEvents.ms

Last active December 4, 2019 16:15
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MeddlerScript for testing ServerSentEvents. See https://textslashplain.com/2019/12/04/the-pitfalls-of-eventsource-over-http-1-1/ for discussion.
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ServerSentEvents.ms
import Meddler;
import System;
import System.Net.Sockets;
import System.Windows.Forms;
class Handlers
{
static function OnConnection(oSession: Session)
{
try {
if (oSession.ReadRequest()){
var oHeaders: ResponseHeaders = new ResponseHeaders();
oHeaders.Status = "200 OK";
if (oSession.urlContains("eventsource.cgi?")) {
oHeaders["Connection"] = "keep-alive";
oHeaders["Content-Type"] = "text/event-stream";
oSession.WriteString(oHeaders);
var myId = oSession.url.Substring(oSession.url.IndexOf('eventsource.cgi'));
oSession.WriteString("data: This is the first event from " + myId + "\n\n");
// Ten minutes
for(var i:int = 0; i < 600; i++){
oSession.WriteString("data: from " + myId + ": The server time is: " + DateTime.Now.ToString("h:mm:ss") + "\n\n");
System.Threading.Thread.Sleep(1000);
}
oSession.WriteString("data: This is the last event from " + myId + "\n\n");
}
else if (oSession.urlContains(".jpg"))
{
oHeaders["Connection"] = "close";
oHeaders["Content-Type"] = "image/jpg";
oHeaders["Cache-Control"] = "no-store";
oSession.WriteString(oHeaders);
oSession.WriteBytes(Fuzz.NewJPG("TestJPG...", Fuzz.NewInteger(40,100), 20));
}
else if (oSession.urlContains('frame')) {
oHeaders["Connection"] = "close";
oHeaders["Content-Type"] = "text/html";
oHeaders["Cache-Control"] = "no-store";
oSession.WriteString(oHeaders);
oSession.WriteString("<!doctype html><html><body>");
for (var x:int = 0; x < 15; x++) {
oSession.WriteString("<iframe src='/?" + Fuzz.NewInteger(100, 1000) + "' width=600 height=400></iframe>");
}
oSession.WriteString("</body></html>");
}
else {
oHeaders["Connection"] = "close";
oHeaders["Content-Type"] = "text/html";
oHeaders["Cache-Control"] = "no-store";
oSession.WriteString(oHeaders);
oSession.WriteString("<!doctype html><html><body style='background-color: #FFA4A4'><img id='imgTop' src='" + Fuzz.NewInteger(0, 999999) + ".jpg' />");
oSession.WriteString("<h1>EventSource Connection Limit Test</h1>This page uses an EventSource for serversentevents. Use it to test connection limits by opening multiple tabs to this same page.");
oSession.WriteString("<hr /><a href='/?"+Fuzz.NewInteger(0,10000) +"' target='_blank'>Open another tab</a><hr />");
oSession.WriteString("<h2>Latest Message</h2><div id='divLatest'></div>");
oSession.WriteString("<script>function addImg() { let a=document.createElement('img'); a.src='dyn'+Math.random(99999)+'.jpg'; document.body.appendChild(a);} setInterval(addImg, 400); var evtSource = new EventSource('eventsource.cgi?" + Fuzz.NewInteger(0,999999) + "');var latestEvent = document.getElementById('divLatest');evtSource.onmessage = function(e) {" +
"let bFirst= e.data.includes('first'); if (bFirst) document.body.style='background-color: #D9EAC8'; latestEvent.style = 'font-weight: 500; font-size: 24px; '+ (bFirst ? 'color:red' : 'color:green'); latestEvent.textContent = e.data;}</script>");
oSession.WriteString("</body></html>");
}
}
oSession.CloseSocket();
}
catch (e) {
MeddlerObject.Log.LogString(e.message);
}
}
}
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