This package provides an HTTP Client library built on top of SwiftNIO.
This library provides the following:
- First class support for Swift Concurrency
- Asynchronous and non-blocking request methods
- Simple follow-redirects (cookie headers are dropped)
- Streaming body download
- TLS support
- Automatic HTTP/2 over HTTPS
- Cookie parsing (but not storage)
Add the following entry in your Package.swift to start using HTTPClient:
.package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0")and AsyncHTTPClient dependency to your target:
.target(name: "MyApp", dependencies: [.product(name: "AsyncHTTPClient", package: "async-http-client")]),The code snippet below illustrates how to make a simple GET request to a remote server.
import AsyncHTTPClient
/// MARK: - Using Swift Concurrency
let request = HTTPClientRequest(url: "https://apple.com/")
let response = try await HTTPClient.shared.execute(request, timeout: .seconds(30))
print("HTTP head", response)
if response.status == .ok {
let body = try await response.body.collect(upTo: 1024 * 1024) // 1 MB
// handle body
} else {
// handle remote error
}
/// MARK: - Using SwiftNIO EventLoopFuture
HTTPClient.shared.get(url: "https://apple.com/").whenComplete { result in
switch result {
case .failure(let error):
// process error
case .success(let response):
if response.status == .ok {
// handle response
} else {
// handle remote error
}
}
}If you create your own HTTPClient instances, you should shut them down using httpClient.shutdown() when you're done using them. Failing to do so will leak resources.
Please note that you must not call httpClient.shutdown before all requests of the HTTP client have finished, or else the in-flight requests will likely fail because their network connections are interrupted.
Examples for the async/await API can be found in the Examples folder in this Repository.
The default HTTP Method is GET. In case you need to have more control over the method, or you want to add headers or body, use the HTTPClientRequest struct:
import AsyncHTTPClient
do {
var request = HTTPClientRequest(url: "https://apple.com/")
request.method = .POST
request.headers.add(name: "User-Agent", value: "Swift HTTPClient")
request.body = .bytes(ByteBuffer(string: "some data"))
let response = try await HTTPClient.shared.execute(request, timeout: .seconds(30))
if response.status == .ok {
// handle response
} else {
// handle remote error
}
} catch {
// handle error
}import AsyncHTTPClient
var request = try HTTPClient.Request(url: "https://apple.com/", method: .POST)
request.headers.add(name: "User-Agent", value: "Swift HTTPClient")
request.body = .string("some-body")
HTTPClient.shared.execute(request: request).whenComplete { result in
switch result {
case .failure(let error):
// process error
case .success(let response):
if response.status == .ok {
// handle response
} else {
// handle remote error
}
}
}The globally shared instance HTTPClient.shared follows redirects by default. If you create your own HTTPClient, you can enable the follow-redirects behavior using the client configuration:
let httpClient = HTTPClient(eventLoopGroupProvider: .singleton,
configuration: HTTPClient.Configuration(followRedirects: true))Timeouts (connect and read) can also be set using the client configuration:
let timeout = HTTPClient.Configuration.Timeout(connect: .seconds(1), read: .seconds(1))
let httpClient = HTTPClient(eventLoopGroupProvider: .singleton,
configuration: HTTPClient.Configuration(timeout: timeout))or on a per-request basis:
httpClient.execute(request: request, deadline: .now() + .milliseconds(1))When dealing with larger amount of data, it's critical to stream the response body instead of aggregating in-memory. The following example demonstrates how to count the number of bytes in a streaming response body:
do {
let request = HTTPClientRequest(url: "https://apple.com/")
let response = try await HTTPClient.shared.execute(request, timeout: .seconds(30))
print("HTTP head", response)
// if defined, the content-length headers announces the size of the body
let expectedBytes = response.headers.first(name: "content-length").flatMap(Int.init)
var receivedBytes = 0
// asynchronously iterates over all body fragments
// this loop will automatically propagate backpressure correctly
for try await buffer in response.body {
// for this example, we are just interested in the size of the fragment
receivedBytes += buffer.readableBytes
if let expectedBytes = expectedBytes {
// if the body size is known, we calculate a progress indicator
let progress = Double(receivedBytes) / Double(expectedBytes)
print("progress: \(Int(progress * 100))%")
}
}
print("did receive \(receivedBytes) bytes")
} catch {
print("request failed:", error)
}import NIOCore
import NIOHTTP1
class CountingDelegate: HTTPClientResponseDelegate {
typealias Response = Int
var count = 0
func didSendRequestHead(task: HTTPClient.Task<Response>, _ head: HTTPRequestHead) {
// this is executed right after request head was sent, called once
}
func didSendRequestPart(task: HTTPClient.Task<Response>, _ part: IOData) {
// this is executed when request body part is sent, could be called zero or more times
}
func didSendRequest(task: HTTPClient.Task<Response>) {
// this is executed when request is fully sent, called once
}
func didReceiveHead(
task: HTTPClient.Task<Response>,
_ head: HTTPResponseHead
) -> EventLoopFuture<Void> {
// this is executed when we receive HTTP response head part of the request
// (it contains response code and headers), called once in case backpressure
// is needed, all reads will be paused until returned future is resolved
return task.eventLoop.makeSucceededFuture(())
}
func didReceiveBodyPart(
task: HTTPClient.Task<Response>,
_ buffer: ByteBuffer
) -> EventLoopFuture<Void> {
// this is executed when we receive parts of the response body, could be called zero or more times
count += buffer.readableBytes
// in case backpressure is needed, all reads will be paused until returned future is resolved
return task.eventLoop.makeSucceededFuture(())
}
func didFinishRequest(task: HTTPClient.Task<Response>) throws -> Int {
// this is called when the request is fully read, called once
// this is where you return a result or throw any errors you require to propagate to the client
return count
}
func didReceiveError(task: HTTPClient.Task<Response>, _ error: Error) {
// this is called when we receive any network-related error, called once
}
}
let request = try HTTPClient.Request(url: "https://apple.com/")
let delegate = CountingDelegate()
HTTPClient.shared.execute(request: request, delegate: delegate).futureResult.whenSuccess { count in
print(count)
}Based on the HTTPClientResponseDelegate example above you can build more complex delegates,
the built-in FileDownloadDelegate is one of them. It allows streaming the downloaded data
asynchronously, while reporting the download progress at the same time, like in the following
example:
let request = try HTTPClient.Request(
url: "https://swift.org/builds/development/ubuntu1804/latest-build.yml"
)
let delegate = try FileDownloadDelegate(path: "/tmp/latest-build.yml", reportProgress: {
if let totalBytes = $0.totalBytes {
print("Total bytes count: \(totalBytes)")
}
print("Downloaded \($0.receivedBytes) bytes so far")
})
HTTPClient.shared.execute(request: request, delegate: delegate).futureResult
.whenSuccess { progress in
if let totalBytes = progress.totalBytes {
print("Final total bytes count: \(totalBytes)")
}
print("Downloaded finished with \(progress.receivedBytes) bytes downloaded")
}Connecting to servers bound to socket paths is easy:
HTTPClient.shared.execute(
.GET,
socketPath: "/tmp/myServer.socket",
urlPath: "/path/to/resource"
).whenComplete (...)Connecting over TLS to a unix domain socket path is possible as well:
HTTPClient.shared.execute(
.POST,
secureSocketPath: "/tmp/myServer.socket",
urlPath: "/path/to/resource",
body: .string("hello")
).whenComplete (...)Direct URLs can easily be constructed to be executed in other scenarios:
let socketPathBasedURL = URL(
httpURLWithSocketPath: "/tmp/myServer.socket",
uri: "/path/to/resource"
)
let secureSocketPathBasedURL = URL(
httpsURLWithSocketPath: "/tmp/myServer.socket",
uri: "/path/to/resource"
)The exclusive use of HTTP/1 is possible by setting httpVersion to .http1Only on HTTPClient.Configuration:
var configuration = HTTPClient.Configuration()
configuration.httpVersion = .http1Only
let client = HTTPClient(
eventLoopGroupProvider: .singleton,
configuration: configuration
)Please have a look at SECURITY.md for AsyncHTTPClient's security process.
The most recent versions of AsyncHTTPClient support Swift 5.6 and newer. The minimum Swift version supported by AsyncHTTPClient releases are detailed below:
| AsyncHTTPClient | Minimum Swift Version |
|---|---|
1.0.0 ..< 1.5.0 |
5.0 |
1.5.0 ..< 1.10.0 |
5.2 |
1.10.0 ..< 1.13.0 |
5.4 |
1.13.0 ..< 1.18.0 |
5.5.2 |
1.18.0 ..< 1.20.0 |
5.6 |
1.20.0 ..< 1.21.0 |
5.7 |
1.21.0 ... |
5.8 |