SSE API

Server-Sent Events writers and parsers live in src/web/sse/.

Event

httpx.sse.Event contains the parsed event fields:

Field	Type	Description
eventType	[]const u8	Event name; defaults to "message"
data	[]const u8	Event payload, with multiple data lines joined by \n
id	?[]const u8	Event identifier, when supplied
retryMs	?u32	Reconnection delay in milliseconds

Writer

httpx.sse.Event.Writer serializes event blocks for a text/event-stream response:

var out = std.ArrayList(u8).empty;
var writer = httpx.sse.Event.Writer.init(ctx.allocator);
try writer.writeEvent(&out, &.{"payload"}, "message", 1, null);
return .{
    .status = 200,
    .body = out.items,
    .contentType = "text/event-stream; charset=utf-8",
};

writeEvent accepts data lines, an optional event name, an optional event ID, and an optional retry delay. writeComment emits a comment frame for keep-alives.

Parser

httpx.sse.Event.Parser is a stateful WHATWG stream parser:

var parser = httpx.sse.Event.Parser.init(allocator);
defer parser.deinit();

if (try parser.processLine("data: hello\n")) |event| {
    // event.data is valid until the next parser call or deinit.
}

Use feed to process a chunk and receive every completed event:

fn onEvent(context: *Context, event: httpx.sse.Event) void {
    _ = context;
    _ = event;
}

try parser.feed(chunk, &context, onEvent);

parseAll parses an in-memory stream and returns owned events. Release the result with freeEvents.