Server-Sent Events (SSE) Example

SSE payloads with httpx.sse.Event.Writer, parsed back with httpx.sse.Event.Parser. See examples/sseServer.zig.

fn sseHandler(ctx: *httpx.router.Context) anyerror!httpx.router.Response {
    var out = std.ArrayList(u8).empty;
    var writer = httpx.sse.Event.Writer.init(ctx.allocator);
    try writer.writeEvent(&out, &[_][]const u8{"Connected to SSE live stream"}, "status", 1, 5000);
    try writer.writeEvent(&out, &[_][]const u8{"First data packet"}, "message", 2, null);
    return .{
        .status = 200,
        .body = out.items,
        .contentType = "text/event-stream; charset=utf-8",
    };
}

Parsed events carry eventType, data, id, and retryMs.

Expected Output

The handler produces SSE wire-format body text; a client GET /events (comparing examples/sseServer.zig) prints lines in this format (representative values shown):

GET /events -> status=200, body=retry:5000
id:1
event:status
data:Connected to SSE live stream

id:2
event:message
data:First data packet

Statuses, event payloads, ids, retry intervals, URLs, and ports vary with the handler logic and the ephemeral port selected at runtime.

Run

zig build run-sse-server

Checklist

• [x] SSE events use W3C wire format (event:, id:, data:)
• [x] Server returns Content-Type: text/event-stream
• [x] Client receives all events in order