Hey there! That error you're hitting is super common when setting up Server-Sent Events (SSE) in CodeIgniter—your server is sending back a text/html content type instead of the required text/event-stream that EventSource expects. Let's walk through how to fix this step by step.

1. Set Correct Response Headers in Your Controller #

The core fix lies in ensuring your CodeIgniter controller method for the SSE endpoint sends the right HTTP headers. Here's how to update your video_calling method:

public function video_calling($client_user_id) {
    // Clear any existing output buffer to prevent extra content from being sent
    ob_end_clean();

    // Set SSE-specific response headers using CodeIgniter's output class
    $this->output
        ->set_content_type('text/event-stream')
        ->set_header('Cache-Control: no-cache')
        ->set_header('Connection: keep-alive');

    // Example SSE message structure (follow this format for all events)
    echo "data: {\"message\": \"Connection established\", \"client_id\": \"{$client_user_id}\"}\n\n";
    flush(); // Push the data to the client immediately

    // If you need ongoing updates, add a loop here with sleep()
    // Make sure to handle shutdowns properly to avoid hanging connections
}

Critical Notes for the Controller: #

• No extra output: Don't load any views, echo HTML, or leave trailing spaces/newlines in your controller file—even a single stray space will force the response to be text/html instead of text/event-stream.
• Buffer cleanup: ob_end_clean() clears any buffered content from earlier in the request (like from controller constructors or hooks) that might interfere with header settings.

2. Tweak Your Frontend Code (Optional but Helpful) #

Your frontend code is mostly solid, but here's a cleaned-up version with error handling to make debugging easier:

if(typeof(EventSource) !== "undefined") {
    // Combine URL construction for cleaner code
    var sseUrl = "<?php echo base_url('lawyer/consultation/video_calling/' . $client_user_id); ?>";
    var source = new EventSource(sseUrl);

    source.onmessage = function(event) {
        var imgUrl = "<?php echo base_url('assets/images/main...'); ?>";
        // Parse incoming data if you sent JSON
        var data = JSON.parse(event.data);
        console.log('Received SSE data:', data);
        // Update your UI here
    };

    // Add error handling to catch connection issues
    source.onerror = function(error) {
        console.error('SSE Connection Error:', error);
        source.close(); // Clean up the connection
    };
} else {
    // Fallback for browsers that don't support SSE
    alert('Your browser does not support Server-Sent Events.');
}

3. Troubleshooting Additional Issues #

If you're still seeing the error after setting the headers:

• Check for redirects: Ensure your SSE URL isn't redirecting (e.g., HTTP to HTTPS or trailing slash mismatch)—redirect responses often default to text/html.
• Verify server configuration: Confirm your web server (Apache/Nginx) isn't overriding the Content-Type header. CodeIgniter's headers usually take precedence, but check .htaccess rules or server configs just in case.
• Test the endpoint directly: Visit the SSE URL in your browser—you should see raw data: lines instead of an HTML page. If you see HTML, your controller is still outputting extra content.

内容的提问来源于stack exchange，提问作者Jenna Rose