HTTP server for Hummingbird the lightweight, flexible web application framework written in Swift

What's New



Patch release changes

  • Fix issue where connection was being closed before HTTP payload had been sent. PR #68


Swift NIO based HTTP server. The core HTTP server component for the Hummingbird web framework.


HummingbirdCore contains a Swift NIO based HTTP server. When starting the server you provide it with a struct that conforms to HBHTTPResponder to define how the server should respond to requests. For example the following is a responder that always returns a response containing the word "Hello" in the body.

struct HelloResponder: HBHTTPResponder {
    func respond(to request: HBHTTPRequest, context: ChannelHandlerContext, onComplete: @escaping (Result<HBHTTPResponse, Error>) -> Void) {
        let responseHead = HTTPResponseHead(version: .init(major: 1, minor: 1), status: .ok)
        let responseBody = "Hello")
        let response = HBHTTPResponse(head: responseHead, body: .byteBuffer(responseBody))

The following will start up a server using the above HelloResponder.

let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
let server = HBHTTPServer(
    group: eventLoopGroup, 
    configuration: .init(address: .hostname("", port: 8080))
try server.start(responder: HelloResponder()).wait()
// Wait until server closes which never happens as server channel is never closed
try server.wait()

Swift service lifecycle

If you are using HummingbirdCore outside of Hummingbird ideally you would use it along with the swift-server library swift-service-lifecycle. This gives you a framework for clean initialization and shutdown of your server. The following sets up a Lifecycle that initializes the HTTP server and stops it when the application shuts down.

import Lifecycle
import LifecycleNIOCompat

let lifecycle = ServiceLifecycle()
    label: "HTTP Server",
    start: .eventLoopFuture { self.server.start(responder: MyResponder()) },
    shutdown: .eventLoopFuture(self.server.stop)
lifecycle.start { error in
    if let error = error {
        print("ERROR: \(error)")

HummingbirdCore Extensions

The HummingbirdCore can be extended to support TLS and HTTP2 via the HummingbirdTLS and HummingbirdHTTP2 libraries. The following will add TLS support

import HummingbirdTLS
server.addTLS(tlsConfiguration: myTLSConfiguration)

and this will add an HTTP2 upgrade option

import HummingbirdHTTP2
server.addHTTP2Upgrade(tlsConfiguration: myTLSConfiguration)

As the HTTP2 upgrade requires a TLS connection this is added automatically when enabling HTTP2 upgrade. So don't call both function as this will setup two TLS handlers.


Reference documentation for both HummingbirdCore and Hummingbird can be found here


  • Swift Tools 5.6.0
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Last updated: Wed May 29 2024 06:39:40 GMT-0900 (Hawaii-Aleutian Daylight Time)