spb/zyquo-router Public MIT

1//2//  SSEWriter.swift3//  Zyquo Router4//5//  Author: Simon-Pierre Boucher6//  Mail: contact@spboucher.ai7//8//  Spec-exact Server-Sent Events emission for /v1/chat/completions streaming:9//  each event is `data: <json>\n\n`, the stream ends with `data: [DONE]\n\n`.10//  Every write flushes; a write against a disconnected client throws, which11//  cancels the calling route task and, with it, the upstream provider call.12//1314import Foundation15import NIOCore16import NIOHTTP11718struct SSEWriter {19    let outbound: NIOAsyncChannelOutboundWriter<HTTPServerResponsePart>2021    private static let encoder: JSONEncoder = {22        let encoder = JSONEncoder()23        encoder.outputFormatting = [.withoutEscapingSlashes]24        return encoder25    }()2627    /// Emits one `data:` event carrying an encodable payload (a chunk object).28    func send<T: Encodable>(_ payload: T) async throws {29        try await send(raw: Self.encoder.encode(payload))30    }3132    /// Emits one `data:` event carrying pre-serialized JSON (pass-through path).33    func send(raw json: Data) async throws {34        var buffer = ByteBuffer()35        buffer.writeString("data: ")36        buffer.writeBytes(json)37        buffer.writeString("\n\n")38        try await outbound.write(.body(.byteBuffer(buffer)))39    }4041    /// Emits an SSE comment line (keep-alive heartbeat).42    func sendHeartbeat() async throws {43        try await outbound.write(.body(.byteBuffer(ByteBuffer(string: ": keep-alive\n\n"))))44    }4546    /// Terminates the stream per the OpenAI contract.47    func sendDone() async throws {48        try await outbound.write(.body(.byteBuffer(ByteBuffer(string: "data: [DONE]\n\n"))))49    }50}51