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Dynamic Redirect
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‎FlyingFox/Sources/HTTPHandler.swift‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -56,6 +56,10 @@ public extension HTTPHandler where Self == RedirectHTTPHandler {
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static func redirect(to location: String) -> RedirectHTTPHandler {
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RedirectHTTPHandler(location: location)
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}
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static func redirect(via base: String, serverPath: String? = nil) -> RedirectHTTPHandler {
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RedirectHTTPHandler(base: base, serverPath: serverPath)
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}
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}
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public extension HTTPHandler where Self == ProxyHTTPHandler {

‎FlyingFox/Sources/Handlers/RedirectHTTPHandler.swift‎

Lines changed: 87 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -33,19 +33,101 @@ import Foundation
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public struct RedirectHTTPHandler: HTTPHandler {
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36-
private let location: String
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private let destination: Destination
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private let statusCode: HTTPStatusCode
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private let serverPath: String?
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public init(location: String) {
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self.location = location
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public init(base: String, statusCode: HTTPStatusCode = .movedPermanently, serverPath: String? = nil) {
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self.destination = .base(base, serverPath: serverPath)
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self.statusCode = statusCode
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self.serverPath = serverPath
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}
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public init(location: String, statusCode: HTTPStatusCode = .movedPermanently) {
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self.destination = .location(location)
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self.statusCode = statusCode
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self.serverPath = nil
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}
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public func handleRequest(_ request: HTTPRequest) async throws -> HTTPResponse {
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guard let url = URL(string: location) else {
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switch destination {
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case let .location(location):
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guard let url = URL(string: location) else {
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throw URLError(.badURL)
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}
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return try handleRedirect(to: url)
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case let .base(base, serverPath):
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let url = try makeRedirectLocation(for: request, via: base, serverPath: serverPath ?? "")
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return try handleRedirect(to: url)
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}
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}
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private enum Destination {
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case location(String)
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case base(String, serverPath: String?)
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}
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private func handleRedirect(to url: URL) throws -> HTTPResponse {
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guard Self.isRedirect(statusCode) else {
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throw URLError(.badURL)
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}
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return HTTPResponse(
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statusCode: .movedPermanently,
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statusCode: statusCode,
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headers: [.location: url.absoluteString]
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)
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}
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private func makeRedirectLocation(for request: HTTPRequest, via base: String, serverPath: String) throws -> URL {
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guard let base = URL(string: base) else {
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throw URLError(.badURL)
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}
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let compsA = serverPath
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.split(separator: "/", omittingEmptySubsequences: true)
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.joined(separator: "/")
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let compsB = request.path
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.split(separator: "/", omittingEmptySubsequences: true)
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.joined(separator: "/")
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guard !compsA.isEmpty else {
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return try base.appendingRequest(request)
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}
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guard compsB.hasPrefix(compsA) else {
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throw URLError(.badURL)
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}
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var request = request
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request.path = String(compsB.dropFirst(compsA.count))
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return try base.appendingRequest(request)
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}
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static let redirectStatusCodes: Set<HTTPStatusCode> = [.movedPermanently, .found, .seeOther, .temporaryRedirect, .permanentRedirect]
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static func isRedirect(_ code: HTTPStatusCode) -> Bool {
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redirectStatusCodes.contains(code)
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}
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}
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private extension URL {
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func appendingRequest(_ request: HTTPRequest) throws -> URL {
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guard var comps = URLComponents(url: appendingPathComponent(request.path), resolvingAgainstBaseURL: false) else {
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throw URLError(.badURL)
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}
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var items = comps.queryItems ?? []
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items.append(
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contentsOf: request.query.map { URLQueryItem(name: $0.name, value: $0.value) }
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)
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if !items.isEmpty {
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comps.queryItems = items
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}
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guard let url = comps.url else {
129+
throw URLError(.badURL)
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}
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return url
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}
51133
}

‎FlyingFox/Tests/Handlers/RedirectHTTPHandlerTests.swift‎

Lines changed: 93 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,93 @@
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//
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// RedirectHTTPHandlerTests.swift
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// FlyingFox
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//
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// Created by Simon Whitty on 13/09/2025.
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// Copyright © 2025 Simon Whitty. All rights reserved.
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//
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// Distributed under the permissive MIT license
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// Get the latest version from here:
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//
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// https://github.com/swhitty/FlyingFox
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25+
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26+
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27+
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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//
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@testable import FlyingFox
33+
import Foundation
34+
import Testing
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struct RedirectHTTPHandlerTests {
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@Test
39+
func location_is_not_replaced() async throws {
40+
let handler = RedirectHTTPHandler(location: "http://www.fish.com")
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42+
var response = try await handler.handleRequest(.make(path: "/"))
43+
#expect(response.statusCode == .movedPermanently)
44+
#expect(response.headers[.location] == "http://www.fish.com")
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response = try await handler.handleRequest(.make(path: "/chips", query: [.init(name: "fish", value: "true")]))
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#expect(response.headers[.location] == "http://www.fish.com")
48+
}
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@Test
51+
func location_statuscode() async throws {
52+
let handler = RedirectHTTPHandler(location: "http://www.fish.com", statusCode: .temporaryRedirect)
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54+
let response = try await handler.handleRequest(.make(path: "/"))
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#expect(response.statusCode == .temporaryRedirect)
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}
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58+
@Test
59+
func base_appends_request() async throws {
60+
let handler: any HTTPHandler = .redirect(via: "http://fish.com")
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62+
var response = try await handler.handleRequest(.make(path: "/chips/shrimp"))
63+
#expect(response.statusCode == .movedPermanently)
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#expect(response.headers[.location] == "http://fish.com/chips/shrimp")
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66+
response = try await handler.handleRequest(.make(path: "/chips/shrimp", query: [.init(name: "fish", value: "true")]))
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#expect(response.headers[.location] == "http://fish.com/chips/shrimp?fish=true")
68+
}
69+
70+
@Test
71+
func base_removes_serverPath() async throws {
72+
let handler: any HTTPHandler = .redirect(via: "http://fish.com", serverPath: "chips/shrimp")
73+
74+
var response = try await handler.handleRequest(.make(path: "/chips/shrimp/1/2", query: [.init(name: "fish", value: "true")]))
75+
#expect(response.statusCode == .movedPermanently)
76+
#expect(response.headers[.location] == "http://fish.com/1/2?fish=true")
77+
78+
response = try await handler.handleRequest(.make(path: "/chips/shrimp/1", query: [.init(name: "fish", value: "true")]))
79+
#expect(response.headers[.location] == "http://fish.com/1?fish=true")
80+
81+
await #expect(throws: URLError.self) {
82+
try await handler.handleRequest(.make(path: "/foo"))
83+
}
84+
}
85+
86+
@Test
87+
func base_statuscode() async throws {
88+
let handler = RedirectHTTPHandler(base: "http://fish.com", statusCode: .temporaryRedirect, serverPath: "/chips/shrimp")
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90+
let response = try await handler.handleRequest(.make(path: "/chips/shrimp"))
91+
#expect(response.statusCode == .temporaryRedirect)
92+
}
93+
}

‎README.md‎

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -151,6 +151,22 @@ await server.appendRoute("GET /fish/*", to: .redirect(to: "https://pie.dev/get")
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// Location: https://pie.dev/get
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```
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154+
Or dynamically redirected via a base URL:
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```swift
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await server.appendRoute("GET /fish/*", to: .redirect(via: "https://pie.dev"))
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// GET /fish/chips ---> HTTP 301
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// Location: https://pie.dev/fish/chips
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```
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Providing a serverPath allows for the removal of a prefix before redirecting:
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164+
```swift
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await server.appendRoute("GET /fish/*", to: .redirect(via: "https://pie.dev", serverPath: "/fish"))
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// GET /fish/chips ---> HTTP 301
167+
// Location: https://pie.dev/chips
168+
```
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### WebSocketHTTPHandler
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156172
Requests can be routed to a websocket by providing a `WSMessageHandler` where a pair of `AsyncStream<WSMessage>` are exchanged:

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