[Multipart] Validation sequence

Sources/OpenAPIRuntime/Base/ContentDisposition.swift

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+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+/// A parsed representation of the `content-disposition` header described by RFC 6266 containing only
+/// the features relevant to OpenAPI multipart bodies.
+struct ContentDisposition: Hashable {
+
+    /// A `disposition-type` parameter value.
+    enum DispositionType: Hashable {
+
+        /// A form data value.
+        case formData
+
+        /// Any other value.
+        case other(String)
+
+        /// Creates a new disposition type value.
+        /// - Parameter rawValue: A string representation of the value.
+        init(rawValue: String) {
+            switch rawValue.lowercased() {
+            case "form-data": self = .formData
+            default: self = .other(rawValue)
+            }
+        }
+
+        /// A string representation of the value.
+        var rawValue: String {
+            switch self {
+            case .formData: return "form-data"
+            case .other(let string): return string
+            }
+        }
+    }
+
+    /// The disposition type value.
+    var dispositionType: DispositionType
+
+    /// A content disposition parameter name.
+    enum ParameterName: Hashable {
+
+        /// The name parameter.
+        case name
+
+        /// The filename parameter.
+        case filename
+
+        /// Any other parameter.
+        case other(String)
+
+        /// Creates a new parameter name.
+        /// - Parameter rawValue: A string representation of the name.
+        init(rawValue: String) {
+            switch rawValue.lowercased() {
+            case "name": self = .name
+            case "filename": self = .filename
+            default: self = .other(rawValue)
+            }
+        }
+
+        /// A string representation of the name.
+        var rawValue: String {
+            switch self {
+            case .name: return "name"
+            case .filename: return "filename"
+            case .other(let string): return string
+            }
+        }
+    }
+
+    /// The parameters of the content disposition value.
+    var parameters: [ParameterName: String] = [:]
+
+    /// The name parameter value.
+    var name: String? {
+        get { parameters[.name] }
+        set { parameters[.name] = newValue }
+    }
+
+    /// The filename parameter value.
+    var filename: String? {
+        get { parameters[.filename] }
+        set { parameters[.filename] = newValue }
+    }
+}
+
+extension ContentDisposition: RawRepresentable {
+
+    /// Creates a new instance with the specified raw value.
+    ///
+    /// https://datatracker.ietf.org/doc/html/rfc6266#section-4.1
+    /// - Parameter rawValue: The raw value to use for the new instance.
+    init?(rawValue: String) {
+        var components = rawValue.split(separator: ";").map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+        guard !components.isEmpty else { return nil }
+        self.dispositionType = DispositionType(rawValue: components.removeFirst())
+        let parameterTuples: [(ParameterName, String)] = components.compactMap { component in
+            let parameterComponents = component.split(separator: "=", maxSplits: 1)
+                .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            guard parameterComponents.count == 2 else { return nil }
+            let valueWithoutQuotes = parameterComponents[1].trimmingCharacters(in: ["\""])
+            return (.init(rawValue: parameterComponents[0]), valueWithoutQuotes)
+        }
+        self.parameters = Dictionary(parameterTuples, uniquingKeysWith: { a, b in a })
+    }
+
+    /// The corresponding value of the raw type.
+    var rawValue: String {
+        var string = ""
+        string.append(dispositionType.rawValue)
+        if !parameters.isEmpty {
+            for (key, value) in parameters.sorted(by: { $0.key.rawValue < $1.key.rawValue }) {
+                string.append("; \(key.rawValue)=\"\(value)\"")
+            }
+        }
+        return string
+    }
+}

Sources/OpenAPIRuntime/Multipart/MultipartPublicTypesExtensions.swift

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+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import HTTPTypes
+
+// MARK: - Extensions
+
+extension MultipartRawPart {
+
+    /// Creates a new raw part by injecting the provided name and filename into
+    /// the `content-disposition` header field.
+    /// - Parameters:
+    ///   - name: The name of the part.
+    ///   - filename: The file name of the part.
+    ///   - headerFields: The header fields of the part.
+    ///   - body: The body stream of the part.
+    public init(name: String?, filename: String? = nil, headerFields: HTTPFields, body: HTTPBody) {
+        var parameters: [ContentDisposition.ParameterName: String] = [:]
+        if let name { parameters[.name] = name }
+        if let filename { parameters[.filename] = filename }
+        let contentDisposition = ContentDisposition(dispositionType: .formData, parameters: parameters)
+        var headerFields = headerFields
+        headerFields[.contentDisposition] = contentDisposition.rawValue
+        self.init(headerFields: headerFields, body: body)
+    }
+
+    /// Returns the parameter value for the provided name.
+    /// - Parameter name: The parameter name.
+    /// - Returns: The parameter value. Nil if not found in the content disposition header field.
+    private func getParameter(_ name: ContentDisposition.ParameterName) -> String? {
+        guard let contentDispositionString = headerFields[.contentDisposition],
+            let contentDisposition = ContentDisposition(rawValue: contentDispositionString)
+        else { return nil }
+        return contentDisposition.parameters[name]
+    }
+
+    /// Sets the parameter name to the provided value.
+    /// - Parameters:
+    ///   - name: The parameter name.
+    ///   - value: The value of the parameter.
+    private mutating func setParameter(_ name: ContentDisposition.ParameterName, _ value: String?) {
+        guard let contentDispositionString = headerFields[.contentDisposition],
+            var contentDisposition = ContentDisposition(rawValue: contentDispositionString)
+        else {
+            if let value {
+                headerFields[.contentDisposition] =
+                    ContentDisposition(dispositionType: .formData, parameters: [name: value]).rawValue
+            }
+            return
+        }
+        contentDisposition.parameters[name] = value
+        headerFields[.contentDisposition] = contentDisposition.rawValue
+    }
+
+    /// The name of the part stored in the `content-disposition` header field.
+    public var name: String? {
+        get { getParameter(.name) }
+        set { setParameter(.name, newValue) }
+    }
+
+    /// The file name of the part stored in the `content-disposition` header field.
+    public var filename: String? {
+        get { getParameter(.filename) }
+        set { setParameter(.filename, newValue) }
+    }
+}