Fix APIGateway.Response with EncodingError

Author: stevapple

Sources/TencentSCFEvents/APIGateway/Response+Init.swift

@@ -31,8 +31,11 @@ extension APIGateway.Response {
                 encoding: .utf8
             ) ?? ""
             self.statusCode = statusCode
+        } catch let err as EncodingError {
+            self.body = #"{"error":"EncodingError","message":"\#("\(err)".jsonEncoded())"}"#
+            self.statusCode = .internalServerError
         } catch let err {
-            self.body = #"{"errorType":"FunctionError","errorMsg":"\#(err.localizedDescription)"}"#
+            self.body = #"{"error":"UnexpectedError","message":"\#("\(err)".jsonEncoded())"}"#
             self.statusCode = .internalServerError
         }
         self.isBase64Encoded = false

Sources/TencentSCFEvents/Utils/String.swift

@@ -0,0 +1,57 @@
+//===------------------------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftTencentSCFRuntime open source project
+//
+// Copyright (c) 2020 stevapple and the SwiftTencentSCFRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftTencentSCFRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===------------------------------------------------------------------------------------===//
+//
+// This source file was 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 http://github.com/swift-server/swift-aws-lambda-runtime/blob/master/CONTRIBUTORS.txt
+// for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===------------------------------------------------------------------------------------===//
+
+internal extension String {
+    func jsonEncoded() -> String {
+        var bytes = [UInt8]()
+        let stringBytes = self.utf8
+        var startCopyIndex = stringBytes.startIndex
+        var nextIndex = startCopyIndex
+
+        while nextIndex != stringBytes.endIndex {
+            switch stringBytes[nextIndex] {
+            case 0 ..< 32, UInt8(ascii: "\""), UInt8(ascii: "\\"):
+                // All Unicode characters may be placed within the
+                // quotation marks, except for the characters that MUST be escaped:
+                // quotation mark, reverse solidus, and the control characters (U+0000
+                // through U+001F).
+                // https://tools.ietf.org/html/rfc7159#section-7
+                // copy the current range over
+                bytes.append(contentsOf: stringBytes[startCopyIndex ..< nextIndex])
+                bytes.append(UInt8(ascii: "\\"))
+                bytes.append(stringBytes[nextIndex])
+
+                nextIndex = stringBytes.index(after: nextIndex)
+                startCopyIndex = nextIndex
+            default:
+                nextIndex = stringBytes.index(after: nextIndex)
+            }
+        }
+
+        return String(bytes: bytes, encoding: .utf8)!
+    }
+}

Tests/TencentSCFEventsTests/APIGatewayTests.swift

@@ -275,4 +275,33 @@ class APIGatewayTests: XCTestCase {
             XCTFail("Expect output JSON")
         }
     }
+
+    func testResponseEncodingWithEncodingError() {
+        struct NotReallyEncodable: Encodable {
+            let value: String = "NotReallyEncodable"
+
+            func encode(to encoder: Encoder) throws {
+                throw EncodingError.invalidValue(self.value, .init(codingPath: encoder.codingPath, debugDescription: "You're testing something not really Encodable! Good luck."))
+            }
+        }
+
+        let encoder = JSONEncoder()
+        encoder.outputFormatting = .sortedKeys
+
+        let resp = APIGateway.Response(
+            statusCode: .ok,
+            codableBody: NotReallyEncodable()
+        )
+        let expectedJson = #"{"body":"{\"error\":\"EncodingError\",\"message\":\"invalidValue(\\\"NotReallyEncodable\\\", Swift.EncodingError.Context(codingPath: [], debugDescription: \\\"You\\\\'re testing something not really Encodable! Good luck.\\\"\"}","headers":{"Content-Type":"application\/json"},"isBase64Encoded":false,"statusCode":500}"#
+
+        var data: Data?
+        XCTAssertNoThrow(data = try encoder.encode(resp))
+        if let data = data,
+            let json = String(data: data, encoding: .utf8)
+        {
+            XCTAssertEqual(json, expectedJson)
+        } else {
+            XCTFail("Expect output JSON")
+        }
+    }
 }