Added AWSLambdaEvents library

Package.swift

@@ -24,7 +24,10 @@ let package = Package(
             .product(name: "NIOFoundationCompat", package: "swift-nio"),
         ]),
         .testTarget(name: "AWSLambdaRuntimeTests", dependencies: ["AWSLambdaRuntime"]),
-        .target(name: "AWSLambdaEvents", dependencies: []),
+        .target(name: "AWSLambdaEvents", dependencies: [
+            .product(name: "NIOHTTP1", package: "swift-nio"),
+            .product(name: "NIOFoundationCompat", package: "swift-nio"),
+        ]),
         .testTarget(name: "AWSLambdaEventsTests", dependencies: ["AWSLambdaEvents"]),
         // samples
         .target(name: "StringSample", dependencies: ["AWSLambdaRuntime"]),

Sources/AWSLambdaEvents/ALB.swift

@@ -0,0 +1,210 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2017-2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import class Foundation.JSONEncoder
+import NIOHTTP1
+
+// https://github.com/aws/aws-lambda-go/blob/master/events/alb.go
+public enum ALB {
+    /// ALBTargetGroupRequest contains data originating from the ALB Lambda target group integration
+    public struct TargetGroupRequest: DecodableBody {
+        /// ALBTargetGroupRequestContext contains the information to identify the load balancer invoking the lambda
+        public struct Context: Codable {
+            public let elb: ELBContext
+        }
+
+        public let httpMethod: HTTPMethod
+        public let path: String
+        public let queryStringParameters: [String: [String]]
+        public let headers: HTTPHeaders
+        public let requestContext: Context
+        public let isBase64Encoded: Bool
+        public let body: String?
+    }
+
+    /// ELBContext contains the information to identify the ARN invoking the lambda
+    public struct ELBContext: Codable {
+        public let targetGroupArn: String
+    }
+
+    public struct TargetGroupResponse {
+        public let statusCode: HTTPResponseStatus
+        public let statusDescription: String?
+        public let headers: HTTPHeaders?
+        public let body: String
+        public let isBase64Encoded: Bool
+
+        public init(
+            statusCode: HTTPResponseStatus,
+            statusDescription: String? = nil,
+            headers: HTTPHeaders? = nil,
+            body: String = "",
+            isBase64Encoded: Bool = false
+        ) {
+            self.statusCode = statusCode
+            self.statusDescription = statusDescription
+            self.headers = headers
+            self.body = body
+            self.isBase64Encoded = isBase64Encoded
+        }
+    }
+}
+
+// MARK: - Request -
+
+extension ALB.TargetGroupRequest: Decodable {
+    enum CodingKeys: String, CodingKey {
+        case httpMethod
+        case path
+        case queryStringParameters
+        case multiValueQueryStringParameters
+        case headers
+        case multiValueHeaders
+        case requestContext
+        case isBase64Encoded
+        case body
+    }
+
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        let method = try container.decode(String.self, forKey: .httpMethod)
+        self.httpMethod = HTTPMethod(rawValue: method)
+
+        self.path = try container.decode(String.self, forKey: .path)
+
+        // crazy multiple headers
+        // https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html#multi-value-headers
+
+        if let multiValueQueryStringParameters =
+            try container.decodeIfPresent([String: [String]].self, forKey: .multiValueQueryStringParameters) {
+            self.queryStringParameters = multiValueQueryStringParameters
+        } else {
+            let singleValueQueryStringParameters = try container.decode(
+                [String: String].self,
+                forKey: .queryStringParameters
+            )
+            self.queryStringParameters = singleValueQueryStringParameters.mapValues { [$0] }
+        }
+
+        if let multiValueHeaders =
+            try container.decodeIfPresent([String: [String]].self, forKey: .multiValueHeaders) {
+            self.headers = HTTPHeaders(awsHeaders: multiValueHeaders)
+        } else {
+            let singleValueHeaders = try container.decode(
+                [String: String].self,
+                forKey: .headers
+            )
+            let multiValueHeaders = singleValueHeaders.mapValues { [$0] }
+            self.headers = HTTPHeaders(awsHeaders: multiValueHeaders)
+        }
+
+        self.requestContext = try container.decode(Context.self, forKey: .requestContext)
+        self.isBase64Encoded = try container.decode(Bool.self, forKey: .isBase64Encoded)
+
+        let body = try container.decode(String.self, forKey: .body)
+        self.body = body != "" ? body : nil
+    }
+}
+
+// MARK: - Response -
+
+extension ALB.TargetGroupResponse: Encodable {
+    static let MultiValueHeadersEnabledKey =
+        CodingUserInfoKey(rawValue: "ALB.TargetGroupResponse.MultiValueHeadersEnabledKey")!
+
+    enum CodingKeys: String, CodingKey {
+        case statusCode
+        case statusDescription
+        case headers
+        case multiValueHeaders
+        case body
+        case isBase64Encoded
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(statusCode.code, forKey: .statusCode)
+
+        let multiValueHeaderSupport =
+            encoder.userInfo[ALB.TargetGroupResponse.MultiValueHeadersEnabledKey] as? Bool ?? false
+
+        switch (multiValueHeaderSupport, headers) {
+        case (true, .none):
+            try container.encode([String: String](), forKey: .multiValueHeaders)
+        case (false, .none):
+            try container.encode([String: [String]](), forKey: .headers)
+        case (true, .some(let headers)):
+            var multiValueHeaders: [String: [String]] = [:]
+            headers.forEach { name, value in
+                var values = multiValueHeaders[name] ?? []
+                values.append(value)
+                multiValueHeaders[name] = values
+            }
+            try container.encode(multiValueHeaders, forKey: .multiValueHeaders)
+        case (false, .some(let headers)):
+            var singleValueHeaders: [String: String] = [:]
+            headers.forEach { name, value in
+                singleValueHeaders[name] = value
+            }
+            try container.encode(singleValueHeaders, forKey: .headers)
+        }
+
+        try container.encodeIfPresent(statusDescription, forKey: .statusDescription)
+        try container.encodeIfPresent(body, forKey: .body)
+        try container.encodeIfPresent(isBase64Encoded, forKey: .isBase64Encoded)
+    }
+}
+
+extension ALB.TargetGroupResponse {
+    public init<Payload: Encodable>(
+        statusCode: HTTPResponseStatus,
+        statusDescription: String? = nil,
+        headers: HTTPHeaders? = nil,
+        payload: Payload,
+        encoder: JSONEncoder = JSONEncoder()
+    ) throws {
+        var headers = headers ?? HTTPHeaders()
+        if !headers.contains(name: "Content-Type") {
+            headers.add(name: "Content-Type", value: "application/json")
+        }
+
+        self.statusCode = statusCode
+        self.statusDescription = statusDescription
+        self.headers = headers
+
+        let data = try encoder.encode(payload)
+        self.body = String(decoding: data, as: Unicode.UTF8.self)
+        self.isBase64Encoded = false
+    }
+
+    public init(
+        statusCode: HTTPResponseStatus,
+        statusDescription: String? = nil,
+        headers: HTTPHeaders? = nil,
+        bytes: [UInt8]?
+    ) {
+        let headers = headers ?? HTTPHeaders()
+
+        self.statusCode = statusCode
+        self.statusDescription = statusDescription
+        self.headers = headers
+        if let bytes = bytes {
+            self.body = String(base64Encoding: bytes)
+        } else {
+            self.body = ""
+        }
+        self.isBase64Encoded = true
+    }
+}