async-http-client/Sources/AsyncHTTPClient/Utils.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the AsyncHTTPClient open source project
//
// Copyright (c) 2018-2020 Apple Inc. and the AsyncHTTPClient project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

import Foundation
#if canImport(Network)
    import Network
#endif
import NIO
import NIOHTTP1
import NIOHTTPCompression
import NIOSSL
import NIOTransportServices

internal extension String {
    var isIPAddress: Bool {
        var ipv4Addr = in_addr()
        var ipv6Addr = in6_addr()

        return self.withCString { ptr in
            inet_pton(AF_INET, ptr, &ipv4Addr) == 1 ||
                inet_pton(AF_INET6, ptr, &ipv6Addr) == 1
        }
    }
}

public final class HTTPClientCopyingDelegate: HTTPClientResponseDelegate {
    public typealias Response = Void

    let chunkHandler: (ByteBuffer) -> EventLoopFuture<Void>

    public init(chunkHandler: @escaping (ByteBuffer) -> EventLoopFuture<Void>) {
        self.chunkHandler = chunkHandler
    }

    public func didReceiveBodyPart(task: HTTPClient.Task<Void>, _ buffer: ByteBuffer) -> EventLoopFuture<Void> {
        return self.chunkHandler(buffer)
    }

    public func didFinishRequest(task: HTTPClient.Task<Void>) throws {
        return ()
    }
}

extension ClientBootstrap {
    fileprivate func makeClientTCPBootstrap(
        host: String,
        requiresTLS: Bool,
        configuration: HTTPClient.Configuration
    ) throws -> NIOClientTCPBootstrap {
        // if there is a proxy don't create TLS provider as it will be added at a later point
        if configuration.proxy != nil {
            return NIOClientTCPBootstrap(self, tls: NIOInsecureNoTLS())
        } else {
            let tlsConfiguration = configuration.tlsConfiguration ?? TLSConfiguration.forClient()
            let sslContext = try NIOSSLContext(configuration: tlsConfiguration)
            let hostname = (!requiresTLS || host.isIPAddress || host.isEmpty) ? nil : host
            let tlsProvider = try NIOSSLClientTLSProvider<ClientBootstrap>(context: sslContext, serverHostname: hostname)
            return NIOClientTCPBootstrap(self, tls: tlsProvider)
        }
    }
}

extension NIOClientTCPBootstrap {
    /// create a TCP Bootstrap based off what type of `EventLoop` has been passed to the function.
    fileprivate static func makeBootstrap(
        on eventLoop: EventLoop,
        host: String,
        requiresTLS: Bool,
        configuration: HTTPClient.Configuration
    ) throws -> NIOClientTCPBootstrap {
        let bootstrap: NIOClientTCPBootstrap
        #if canImport(Network)
            // if eventLoop is compatible with NIOTransportServices create a NIOTSConnectionBootstrap
            if #available(OSX 10.14, iOS 12.0, tvOS 12.0, watchOS 6.0, *), let tsBootstrap = NIOTSConnectionBootstrap(validatingGroup: eventLoop) {
                // if there is a proxy don't create TLS provider as it will be added at a later point
                if configuration.proxy != nil {
                    bootstrap = NIOClientTCPBootstrap(tsBootstrap, tls: NIOInsecureNoTLS())
                } else {
                    // create NIOClientTCPBootstrap with NIOTS TLS provider
                    let tlsConfiguration = configuration.tlsConfiguration ?? TLSConfiguration.forClient()
                    let parameters = tlsConfiguration.getNWProtocolTLSOptions()
                    let tlsProvider = NIOTSClientTLSProvider(tlsOptions: parameters)
                    bootstrap = NIOClientTCPBootstrap(tsBootstrap, tls: tlsProvider)
                }
            } else if let clientBootstrap = ClientBootstrap(validatingGroup: eventLoop) {
                bootstrap = try clientBootstrap.makeClientTCPBootstrap(host: host, requiresTLS: requiresTLS, configuration: configuration)
            } else {
                preconditionFailure("Cannot create bootstrap for the supplied EventLoop")
            }
        #else
            if let clientBootstrap = ClientBootstrap(validatingGroup: eventLoop) {
                bootstrap = try clientBootstrap.makeClientTCPBootstrap(host: host, requiresTLS: requiresTLS, configuration: configuration)
            } else {
                preconditionFailure("Cannot create bootstrap for the supplied EventLoop")
            }
        #endif

        // don't enable TLS if we have a proxy, this will be enabled later on
        if requiresTLS, configuration.proxy == nil {
            return bootstrap.enableTLS()
        }
        return bootstrap
    }

    static func makeHTTPClientBootstrapBase(
        on eventLoop: EventLoop,
        host: String,
        port: Int,
        requiresTLS: Bool,
        configuration: HTTPClient.Configuration
    ) throws -> NIOClientTCPBootstrap {
        return try self.makeBootstrap(on: eventLoop, host: host, requiresTLS: requiresTLS, configuration: configuration)
            .channelOption(ChannelOptions.socket(SocketOptionLevel(IPPROTO_TCP), TCP_NODELAY), value: 1)
            .channelInitializer { channel in
                let channelAddedFuture: EventLoopFuture<Void>
                switch configuration.proxy {
                case .none:
                    channelAddedFuture = eventLoop.makeSucceededFuture(())
                case .some:
                    channelAddedFuture = channel.pipeline.addProxyHandler(host: host, port: port, authorization: configuration.proxy?.authorization)
                }
                return channelAddedFuture
            }
    }
}

extension Connection {
    func removeHandler<Handler: RemovableChannelHandler>(_ type: Handler.Type) -> EventLoopFuture<Void> {
        return self.channel.pipeline.handler(type: type).flatMap { handler in
            self.channel.pipeline.removeHandler(handler)
        }.recover { _ in }
    }
}