Preserve Query Order (#57)

Author: fonkadelic

Package.resolved

@@ -15,6 +15,7 @@ let package = Package(
   ],
   dependencies: [
     .package(url: "https://github.com/apple/swift-argument-parser", from: "0.5.0"),
+    .package(url: "https://github.com/apple/swift-collections", from: "1.0.3"),
     .package(url: "https://github.com/pointfreeco/swift-parsing", from: "0.10.0"),
     .package(url: "https://github.com/pointfreeco/xctest-dynamic-overlay", from: "0.3.0"),
     .package(name: "Benchmark", url: "https://github.com/google/swift-benchmark", from: "0.1.1"),
@@ -23,6 +24,7 @@ let package = Package(
     .target(
       name: "URLRouting",
       dependencies: [
+        .product(name: "OrderedCollections", package: "swift-collections"),
         .product(name: "Parsing", package: "swift-parsing"),
         .product(name: "XCTestDynamicOverlay", package: "xctest-dynamic-overlay"),
       ]

Package.swift

@@ -38,7 +38,6 @@ extension Cookies: ParserPrinter where Parsers: ParserPrinter {
 
     input.headers["cookie", default: []].prepend(
       cookies
-        .sorted(by: { $0.key < $1.key })
         .flatMap { name, values in values.map { "\(name)=\($0 ?? "")" } }
         .joined(separator: "; ")[...]
     )

Sources/URLRouting/Cookies.swift

@@ -103,6 +103,11 @@ extension Field: ParserPrinter where Value: ParserPrinter {
   @inlinable
   public func print(_ output: Value.Output, into input: inout URLRequestData.Fields) rethrows {
     if let defaultValue = self.defaultValue, isEqual(output, defaultValue) { return }
-    input[self.name, default: []].prepend(try valueParser.print(output))
+    try input.fields.updateValue(
+      forKey: input.isNameCaseSensitive ? self.name : self.name.lowercased(),
+      insertingDefault: [],
+      at: 0,
+      with: { $0.prepend(try self.valueParser.print(output)) }
+    )
   }
 }

Sources/URLRouting/Field.swift

@@ -46,7 +46,6 @@ extension Data {
   init(encoding fields: URLRequestData.Fields) {
     self.init(
       fields
-        .sorted(by: { $0.key < $1.key })
         .flatMap { pair -> [String] in
           let (name, values) = pair
           guard let name = name.addingPercentEncoding(withAllowedCharacters: .urlQueryParamAllowed)

Sources/URLRouting/FormData.swift

@@ -66,7 +66,6 @@ extension ParserPrinter where Input == URLRequestData {
       components.path = "/\(data.path.joined(separator: "/"))"
       if !data.query.isEmpty {
         components.queryItems = data.query
-          .sorted(by: { $0.key < $1.key })
           .flatMap { name, values in
             values.map { URLQueryItem(name: name, value: $0.map(String.init)) }
           }

Sources/URLRouting/Parsing/ParserPrinter.swift

@@ -36,9 +36,12 @@ extension URLRequestData {
         query[item.name, default: []].append(item.value)
       } ?? [:],
       fragment: components.fragment,
-      headers: request.allHTTPHeaderFields?.mapValues {
-        $0.split(separator: ",", omittingEmptySubsequences: false).map { String($0) }
-      } ?? [:],
+      headers: .init(
+        request.allHTTPHeaderFields?.map { key, value in
+          (key, value.split(separator: ",", omittingEmptySubsequences: false).map { String($0) })
+        } ?? [],
+        uniquingKeysWith: { $1 }
+      ),
       body: request.httpBody
     )
   }
@@ -78,7 +81,6 @@ extension URLComponents {
     self.path = "/\(data.path.joined(separator: "/"))"
     if !data.query.isEmpty {
       self.queryItems = data.query
-        .sorted(by: { $0.key < $1.key })
         .flatMap { name, values in
           values.map { URLQueryItem(name: name, value: $0.map(String.init)) }
         }
@@ -103,7 +105,7 @@ extension URLRequest {
     guard let url = URLComponents(data: data).url else { return nil }
     self.init(url: url)
     self.httpMethod = data.method
-    for (name, values) in data.headers.sorted(by: { $0.key < $1.key }) {
+    for (name, values) in data.headers {
       for value in values {
         if let value = value {
           self.addValue(String(value), forHTTPHeaderField: name)

Sources/URLRouting/URLRequestData+Foundation.swift

@@ -1,4 +1,5 @@
 import Foundation
+import OrderedCollections
 
 /// A parseable URL request.
 ///
@@ -76,9 +77,9 @@ public struct URLRequestData: Equatable, _EmptyInitializable {
     host: String? = nil,
     port: Int? = nil,
     path: String = "",
-    query: [String: [String?]] = [:],
+    query: OrderedDictionary<String, [String?]> = [:],
     fragment: String? = nil,
-    headers: [String: [String?]] = [:],
+    headers: OrderedDictionary<String, [String?]> = [:],
     body: Data? = nil
   ) {
     self.body = body
@@ -99,13 +100,13 @@ public struct URLRequestData: Equatable, _EmptyInitializable {
   /// Used by ``URLRequestData`` to model query parameters and headers in a way that can be
   /// efficiently parsed.
   public struct Fields {
-    public var fields: [String: ArraySlice<Substring?>]
+    public var fields: OrderedDictionary<String, ArraySlice<Substring?>>
 
     @usableFromInline var isNameCaseSensitive: Bool
 
     @inlinable
     public init(
-      _ fields: [String: ArraySlice<Substring?>] = [:],
+      _ fields: OrderedDictionary<String, ArraySlice<Substring?>> = [:],
       isNameCaseSensitive: Bool
     ) {
       self.fields = [:]
@@ -152,9 +153,9 @@ extension URLRequestData: Codable {
       host: try container.decodeIfPresent(String.self, forKey: .host),
       port: try container.decodeIfPresent(Int.self, forKey: .port),
       path: try container.decodeIfPresent(String.self, forKey: .path) ?? "",
-      query: try container.decodeIfPresent([String: [String?]].self, forKey: .query) ?? [:],
+      query: try container.decodeIfPresent(OrderedDictionary<String, [String?]>.self, forKey: .query) ?? [:],
       fragment: try container.decodeIfPresent(String.self, forKey: .fragment),
-      headers: try container.decodeIfPresent([String: [String?]].self, forKey: .headers) ?? [:],
+      headers: try container.decodeIfPresent(OrderedDictionary<String, [String?]>.self, forKey: .headers) ?? [:],
       body: try container.decodeIfPresent(Data.self, forKey: .body)
     )
   }
@@ -219,27 +220,27 @@ extension URLRequestData: Hashable {
 }
 
 extension URLRequestData.Fields: Collection {
-  public typealias Element = Dictionary<String, ArraySlice<Substring?>>.Element
-  public typealias Index = Dictionary<String, ArraySlice<Substring?>>.Index
+  public typealias Element = OrderedDictionary<String, ArraySlice<Substring?>>.Element
+  public typealias Index = OrderedDictionary<String, ArraySlice<Substring?>>.Index
 
   @inlinable
   public var startIndex: Index {
-    self.fields.startIndex
+    self.fields.elements.startIndex
   }
 
   @inlinable
   public var endIndex: Index {
-    self.fields.endIndex
+    self.fields.elements.endIndex
   }
 
   @inlinable
   public subscript(position: Index) -> Element {
-    self.fields[position]
+    self.fields.elements[position]
   }
 
   @inlinable
   public func index(after i: Index) -> Index {
-    self.fields.index(after: i)
+    self.fields.elements.index(after: i)
   }
 }
 
@@ -253,11 +254,7 @@ extension URLRequestData.Fields: ExpressibleByDictionaryLiteral {
 extension URLRequestData.Fields: Equatable {
   @inlinable
   public static func == (lhs: Self, rhs: Self) -> Bool {
-    guard lhs.count == rhs.count else { return false }
-    for key in lhs.fields.keys {
-      guard lhs[key] == rhs[key] else { return false }
-    }
-    return true
+    lhs.fields == rhs.fields
   }
 }
 

Sources/URLRouting/URLRequestData.swift

@@ -79,6 +79,11 @@ class URLRoutingTests: XCTestCase {
     XCTAssertEqual("Blob", name)
     XCTAssertEqual(42, age)
     XCTAssertEqual(["debug": ["1"]], request.query)
+    
+    XCTAssertEqual(
+      try p.print(("Blob", 42)),
+      URLRequestData(query: ["name": ["Blob"], "age": ["42"]])
+    )
   }
 
   func testQueryDefault() throws {
@@ -190,7 +195,7 @@ class URLRoutingTests: XCTestCase {
       try p.parse(&request)
     )
     XCTAssertEqual(
-      URLRequestData(headers: ["cookie": ["isAdmin=true; userId=42"]]),
+      URLRequestData(headers: ["cookie": ["userId=42; isAdmin=true"]]),
       try p.print(Session(userId: 42, isAdmin: true))
     )
   }