feat(foundation): Foundation API (#1)

Author: pjechris

.github/workflows/test.yml

@@ -0,0 +1,20 @@
+name: Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    runs-on: macos-11
+
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v2
+
+    - name: Run tests
+      run: swift test --enable-test-discovery

Sources/Pinata/Foundation/Publisher+Validate.swift

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+#if canImport(Combine)
+
+import Foundation
+import Combine
+
+/// A function converting data when a http error occur into a custom error
+public typealias DataErrorConverter = (Data) throws -> Error
+
+extension Publisher where Output == URLSession.DataTaskPublisher.Output {
+    /// validate publisher result optionally converting HTTP error into a custom one
+    /// - Parameter converter: called when error is `HTTPError` and data was found in the output. Use it to convert
+    /// data in a custom `Error` that will be returned of the http one.
+    public func validate(_ converter: DataErrorConverter? = nil) -> AnyPublisher<Output, Error> {
+        tryMap { output in
+            do {
+                try (output.response as? HTTPURLResponse)?.validate()
+                return output
+            }
+            catch {
+                if let _ = error as? HTTPError, let convert = converter, !output.data.isEmpty {
+                    throw try convert(output.data)
+                }
+                
+                throw error
+            }
+        }
+        .eraseToAnyPublisher()
+    }
+}
+
+#endif

Sources/Pinata/Foundation/URLRequest+Encode.swift

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+import Foundation
+
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+public extension URLRequest {
+    func encodedBody<T: Encodable>(_ body: T, encoder: JSONEncoder) throws -> Self {
+        var request = self
+        
+        try request.encodeBody(body, encoder: encoder)
+        
+        return request
+    }
+    
+    /// Use a `JSONEncoder` object as request body and set the "Content-Type" header associated to the encoder
+    mutating func encodeBody<T: Encodable>(_ body: T, encoder: JSONEncoder) throws {
+        httpBody = try encoder.encode(body)
+        setValue("Content-Type", forHTTPHeaderField: "application/json")
+    }
+    
+}

Sources/Pinata/Foundation/URLResponse+Validate.swift

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+import Foundation
+
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+extension HTTPURLResponse {
+    /// check whether a response is valid or not
+    public func validate() throws {
+        guard (200..<300).contains(statusCode) else {
+            throw HTTPError(statusCode: statusCode)
+        }
+    }
+}

Sources/Pinata/HTTP/HTTPError.swift

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+import Foundation
+
+/// An error generated by a HTTP response
+public struct HTTPError: Error, Equatable, ExpressibleByIntegerLiteral {
+    public let statusCode: Int
+    
+    public init(statusCode: Int) {
+        self.statusCode = statusCode
+    }
+    
+    public init(integerLiteral value: IntegerLiteralType) {
+        self.init(statusCode: value)
+    }
+}
+
+public extension HTTPError {
+    static let badRequest: Self = 400
+    
+    static let unauthorized: Self = 401
+    
+    /// Request contained valid data and was understood by the server, but the server is refusing action
+    static let forbidden: Self = 403
+    
+    static let notFound: Self = 404
+    
+    static let requestTimeout: Self = 408
+    
+    /// Generic error message when an unexpected condition was encountered and no more specific message is suitable
+    static let serverError: Self = 500
+    
+    /// Server was acting as a gateway or proxy and received an invalid response from the upstream server
+    static let badGateway: Self = 502
+    
+    /// Server cannot handle the request (because it is overloaded or down for maintenance)
+    static let serviceUnavailable: Self = 503
+    
+    /// Server was acting as a gateway or proxy and did not receive a timely response from the upstream server
+    static let gatewayTimeout: Self = 504
+}

Tests/PinataTests/Foundation/PublisherTests+Validate.swift

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+import XCTest
+import Combine
+import Pinata
+
+class PublisherValidateTests: XCTestCase {
+    var cancellables: Set<AnyCancellable> = []
+    
+    override func tearDown() {
+        cancellables = []
+    }
+    
+    func test_validate_responseIsError_dataIsEmpty_converterIsNotCalled() throws {
+        let output: URLSession.DataTaskPublisher.Output = (data: Data(), response: HTTPURLResponse.notFound)
+        let transformer: DataErrorConverter = { _ in
+            XCTFail("transformer should not be called when data is empty")
+            throw NSError()
+        }
+        
+        Just(output)
+            .validate(transformer)
+            .sink(receiveCompletion: { _ in }, receiveValue: { _ in })
+            .store(in: &cancellables)
+    }
+    
+    func test_validate_responseIsError_dataIsNotEmpty_returnCustomError() throws {
+        let customError = CustomError(code: 22, message: "custom message")
+        let output: URLSession.DataTaskPublisher.Output = (
+            data: try JSONEncoder().encode(customError),
+            response: HTTPURLResponse.notFound
+        )
+        let transformer: DataErrorConverter = { data in
+            return try JSONDecoder().decode(CustomError.self, from: data)
+        }
+        
+        Just(output)
+            .validate(transformer)
+            .sink(
+                receiveCompletion: {
+                    guard case let .failure(error) = $0 else {
+                        return XCTFail()
+                    }
+                    
+                    XCTAssertEqual(error as? CustomError, customError)
+                },
+                receiveValue: { _ in })
+            .store(in: &cancellables)
+    }
+}
+
+private struct CustomError: Error, Equatable, Codable {
+    let code: Int
+    let message: String
+}

Tests/PinataTests/Foundation/URLRequestsTests+Encode.swift

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+import XCTest
+import Pinata
+
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+class URLRequestEncodeTests: XCTest {
+    
+    func test_encodedBody_itSetContentTypeHeader() throws {
+        let body: [String:String] = [:]
+        let request = try URLRequest(url: URL(string: "/")!)
+            .encodedBody(body, encoder: JSONEncoder())
+        
+        XCTAssertEqual(request.allHTTPHeaderFields?["Content-Type"], "application/json")
+    }
+}

Tests/PinataTests/Foundation/URLResponseValidateTests.swift

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+import XCTest
+import Pinata
+
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+class URLResponseValidateTests: XCTest {
+    let url = URL(string: "/")!
+    
+    func test_validate_statusCodeIsOK_itThrowNoError() throws {
+        try HTTPURLResponse(url: url, statusCode: 200, httpVersion: nil, headerFields: nil)!.validate()
+    }
+    
+    // we should never have redirection that's why we consider it as an error
+    func test_validate_statusCodeIsRedirection_itThrow() {
+        XCTAssertThrowsError(
+            try HTTPURLResponse(url: url, statusCode: 302, httpVersion: nil, headerFields: nil)!.validate()
+        )
+    }
+    
+    func test_validate_statusCodeIsClientError_itThrow() {
+        XCTAssertThrowsError(
+            try HTTPURLResponse(url: url, statusCode: 404, httpVersion: nil, headerFields: nil)!.validate()
+        )
+    }
+}

Tests/PinataTests/HTTPURLResponse+Fixture.swift

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+import Foundation
+
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
+extension HTTPURLResponse {
+  convenience init(statusCode: Int) {
+    self.init(url: URL(string: "/")!, statusCode: statusCode, httpVersion: nil, headerFields: nil)!
+  }
+}
+
+extension URLResponse {
+  static let success = HTTPURLResponse(statusCode: 200)
+  static let unauthorized = HTTPURLResponse(statusCode: 401)
+  static let notFound = HTTPURLResponse(statusCode: 404)
+}