Event Source -> Server returns event stream in bulk rather then returning in chunk
event-stream, html, javascript, linux, php
Solution
Your best method to return chucked data to the browser is to use Web Sockets get the client to open a socket to your file reader then you can chunk the data to the browser without a problem.
Then once it has finished you can close the socket.
a good tutorial for web sockets http://www.phpbuilder.com/articles/application-architecture/optimization/creating-real-time-applications-with-php-and-websockets.html
with this method you can then if you wanted implement verification so the server is not just sending chunks it's sends the chunks on request by javascript
So your Client could say i need chunk 5 and your server implement something like
$requestedChunk = 5; // this would be set by the javascript sending the request
$chunkSize = 256; // this would be your chunk size;
$readPossition = $requestedChunk * $chunkSize;
Link no longer works so here is one built on Ratchet: https://blog.samuelattard.com/the-tutorial-for-php-websockets-that-i-wish-had-existed/
Problem
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: Server configuration on which the code is not responding as desired, i.e. ``` OS: Linux PHP Version 5.4.36-0+deb7u3 Server API: CGI/FastCGI Memory_limit: 128M output_buffering: no value ``` As I have said, the code is working properly on another server which has the almost same configuration, i.e. ``` OS: Linux PHP Version 5.4.37 Server API: CGI/FastCGI Memory_limit: 256MB output_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++; } ?> ``` Below is my client page on which I need response: ``` <!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> ```