Add custom Decodable conformance (#80)

sebsto · web-flow · commit 334d865f8abc · 2024-12-03T23:55:08.000+01:00
Add custom Decodable conformance. Closes #73 Duplicate of #76 created by @twistinside **Motivation:** Absent collections would fail to decode, when in reality it is possible to have empty headers, for example. This allows processing to continue in the context of the Lambda runtime where users can handle the collections as dictated by their code. **Modifications:** Custom Decodable conformance has been added to both API Gateway request objects to optionally decode absent collections to empty collections. Unit testa have been added for the same. **Result:** This will make the swift lambda runtime more accepting of input, allowing processing to proceed in the rare cases where collection fields would be absent in the JSON received by the runtime. This will unlock certain functionality in edge cases such as testing lambda code from API Gateway console with empty headers (the use case that prompted this change). This change will require users to update their code to remove optional handling for the collections involved, potentially also requiring extra logic to validate that the collections they've received aren't empty. --------- Authored-by: twistinside <twistinside@users.noreply.github.com>
diff --git a/Sources/AWSLambdaEvents/APIGateway+V2.swift b/Sources/AWSLambdaEvents/APIGateway+V2.swift
@@ -15,7 +15,7 @@
 import HTTPTypes
 
 /// `APIGatewayV2Request` contains data coming from the new HTTP API Gateway.
-public struct APIGatewayV2Request: Codable, Sendable {
+public struct APIGatewayV2Request: Encodable, Sendable {
     /// `Context` contains information to identify the AWS account and resources invoking the Lambda function.
     public struct Context: Codable, Sendable {
         public struct HTTP: Codable, Sendable {
@@ -96,13 +96,13 @@ public struct APIGatewayV2Request: Codable, Sendable {
     public let rawPath: String
     public let rawQueryString: String
 
-    public let cookies: [String]?
+    public let cookies: [String]
     public let headers: HTTPHeaders
-    public let queryStringParameters: [String: String]?
-    public let pathParameters: [String: String]?
+    public let queryStringParameters: [String: String]
+    public let pathParameters: [String: String]
 
     public let context: Context
-    public let stageVariables: [String: String]?
+    public let stageVariables: [String: String]
 
     public let body: String?
     public let isBase64Encoded: Bool
@@ -147,3 +147,26 @@ public struct APIGatewayV2Response: Codable, Sendable {
         self.cookies = cookies
     }
 }
+
+extension APIGatewayV2Request: Decodable {
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.version = try container.decode(String.self, forKey: .version)
+        self.routeKey = try container.decode(String.self, forKey: .routeKey)
+        self.rawPath = try container.decode(String.self, forKey: .rawPath)
+        self.rawQueryString = try container.decode(String.self, forKey: .rawQueryString)
+
+        self.cookies = try container.decodeIfPresent([String].self, forKey: .cookies) ?? []
+        self.headers = try container.decodeIfPresent(HTTPHeaders.self, forKey: .headers) ?? HTTPHeaders()
+        self.queryStringParameters =
+            try container.decodeIfPresent([String: String].self, forKey: .queryStringParameters) ?? [:]
+        self.pathParameters = try container.decodeIfPresent([String: String].self, forKey: .pathParameters) ?? [:]
+
+        self.context = try container.decode(Context.self, forKey: .context)
+        self.stageVariables = try container.decodeIfPresent([String: String].self, forKey: .stageVariables) ?? [:]
+
+        self.body = try container.decodeIfPresent(String.self, forKey: .body)
+        self.isBase64Encoded = try container.decode(Bool.self, forKey: .isBase64Encoded)
+    }
+}
diff --git a/Sources/AWSLambdaEvents/APIGateway.swift b/Sources/AWSLambdaEvents/APIGateway.swift
@@ -24,7 +24,7 @@ import Foundation
 // https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html
 
 /// `APIGatewayRequest` contains data coming from the API Gateway.
-public struct APIGatewayRequest: Codable, Sendable {
+public struct APIGatewayRequest: Encodable, Sendable {
     public struct Context: Codable, Sendable {
         public struct Identity: Codable, Sendable {
             public let cognitoIdentityPoolId: String?
@@ -64,12 +64,12 @@ public struct APIGatewayRequest: Codable, Sendable {
     public let path: String
     public let httpMethod: HTTPRequest.Method
 
-    public let queryStringParameters: [String: String]?
-    public let multiValueQueryStringParameters: [String: [String]]?
+    public let queryStringParameters: [String: String]
+    public let multiValueQueryStringParameters: [String: [String]]
     public let headers: HTTPHeaders
     public let multiValueHeaders: HTTPMultiValueHeaders
-    public let pathParameters: [String: String]?
-    public let stageVariables: [String: String]?
+    public let pathParameters: [String: String]
+    public let stageVariables: [String: String]
 
     public let requestContext: Context
     public let body: String?
@@ -99,3 +99,28 @@ public struct APIGatewayResponse: Codable, Sendable {
         self.isBase64Encoded = isBase64Encoded
     }
 }
+
+extension APIGatewayRequest: Decodable {
+    public init(from decoder: any Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.resource = try container.decode(String.self, forKey: .resource)
+        self.path = try container.decode(String.self, forKey: .path)
+        self.httpMethod = try container.decode(HTTPRequest.Method.self, forKey: .httpMethod)
+
+        self.queryStringParameters =
+            try container.decodeIfPresent([String: String].self, forKey: .queryStringParameters) ?? [:]
+        self.multiValueQueryStringParameters =
+            try container.decodeIfPresent([String: [String]].self, forKey: .multiValueQueryStringParameters) ?? [:]
+        self.headers = try container.decodeIfPresent(HTTPHeaders.self, forKey: .headers) ?? HTTPHeaders()
+        self.multiValueHeaders =
+            try container.decodeIfPresent(HTTPMultiValueHeaders.self, forKey: .multiValueHeaders)
+            ?? HTTPMultiValueHeaders()
+        self.pathParameters = try container.decodeIfPresent([String: String].self, forKey: .pathParameters) ?? [:]
+        self.stageVariables = try container.decodeIfPresent([String: String].self, forKey: .stageVariables) ?? [:]
+
+        self.requestContext = try container.decode(Context.self, forKey: .requestContext)
+        self.body = try container.decodeIfPresent(String.self, forKey: .body)
+        self.isBase64Encoded = try container.decode(Bool.self, forKey: .isBase64Encoded)
+    }
+}
diff --git a/Tests/AWSLambdaEventsTests/APIGateway+V2Tests.swift b/Tests/AWSLambdaEventsTests/APIGateway+V2Tests.swift
@@ -73,6 +73,46 @@ class APIGatewayV2Tests: XCTestCase {
         }
         """
 
+    static let exampleGetEventBodyNilHeaders = """
+        {
+            "routeKey":"GET /hello",
+            "version":"2.0",
+            "rawPath":"/hello",
+            "requestContext":{
+                "timeEpoch":1587750461466,
+                "domainPrefix":"hello",
+                "authorizer":{
+                    "jwt":{
+                        "scopes":[
+                            "hello"
+                        ],
+                        "claims":{
+                            "aud":"customers",
+                            "iss":"https://hello.test.com/",
+                            "iat":"1587749276",
+                            "exp":"1587756476"
+                        }
+                    }
+                },
+                "accountId":"0123456789",
+                "stage":"$default",
+                "domainName":"hello.test.com",
+                "apiId":"pb5dg6g3rg",
+                "requestId":"LgLpnibOFiAEPCA=",
+                "http":{
+                    "path":"/hello",
+                    "userAgent":"Paw/3.1.10 (Macintosh; OS X/10.15.4) GCDHTTPRequest",
+                    "method":"GET",
+                    "protocol":"HTTP/1.1",
+                    "sourceIp":"91.64.117.86"
+                },
+                "time":"24/Apr/2020:17:47:41 +0000"
+            },
+            "isBase64Encoded":false,
+            "rawQueryString":"foo=bar"
+        }
+        """
+
     static let fullExamplePayload = """
         {
             "version": "2.0",
@@ -156,7 +196,7 @@ class APIGatewayV2Tests: XCTestCase {
 
         XCTAssertEqual(req?.rawPath, "/hello")
         XCTAssertEqual(req?.context.http.method, .get)
-        XCTAssertEqual(req?.queryStringParameters?.count, 1)
+        XCTAssertEqual(req?.queryStringParameters.count, 1)
         XCTAssertEqual(req?.rawQueryString, "foo=bar")
         XCTAssertEqual(req?.headers.count, 8)
         XCTAssertEqual(req?.context.authorizer?.jwt?.claims?["aud"], "customers")
@@ -176,4 +216,9 @@ class APIGatewayV2Tests: XCTestCase {
         XCTAssertEqual(clientCert?.validity.notBefore, "May 28 12:30:02 2019 GMT")
         XCTAssertEqual(clientCert?.validity.notAfter, "Aug  5 09:36:04 2021 GMT")
     }
+
+    func testDecodingNilCollections() {
+        let data = APIGatewayV2Tests.exampleGetEventBodyNilHeaders.data(using: .utf8)!
+        XCTAssertNoThrow(_ = try JSONDecoder().decode(APIGatewayV2Request.self, from: data))
+    }
 }
diff --git a/Tests/AWSLambdaEventsTests/APIGatewayTests.swift b/Tests/AWSLambdaEventsTests/APIGatewayTests.swift
@@ -34,6 +34,10 @@ class APIGatewayTests: XCTestCase {
           {"httpMethod": "POST", "body": "{\\"title\\":\\"a todo\\"}", "resource": "/todos", "requestContext": {"resourceId": "123456", "apiId": "1234567890", "domainName": "1234567890.execute-api.us-east-1.amazonaws.com", "resourcePath": "/todos", "httpMethod": "POST", "requestId": "c6af9ac6-7b61-11e6-9a41-93e8deadbeef", "accountId": "123456789012", "stage": "test", "identity": {"apiKey": null, "userArn": null, "cognitoAuthenticationType": null, "caller": null, "userAgent": "Custom User Agent String", "user": null, "cognitoIdentityPoolId": null, "cognitoAuthenticationProvider": null, "sourceIp": "127.0.0.1", "accountId": null}, "extendedRequestId": null, "path": "/todos"}, "queryStringParameters": null, "multiValueQueryStringParameters": null, "headers": {"Host": "127.0.0.1:3000", "Connection": "keep-alive", "Content-Length": "18", "Pragma": "no-cache", "Cache-Control": "no-cache", "Accept": "text/plain, */*; q=0.01", "Origin": "http://todobackend.com", "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.36 Safari/537.36 Edg/79.0.309.25", "Dnt": "1", "Content-Type": "application/json", "Sec-Fetch-Site": "cross-site", "Sec-Fetch-Mode": "cors", "Referer": "http://todobackend.com/specs/index.html?http://127.0.0.1:3000/todos", "Accept-Encoding": "gzip, deflate, br", "Accept-Language": "en-US,en;q=0.9", "X-Forwarded-Proto": "http", "X-Forwarded-Port": "3000"}, "multiValueHeaders": {"Host": ["127.0.0.1:3000"], "Connection": ["keep-alive"], "Content-Length": ["18"], "Pragma": ["no-cache"], "Cache-Control": ["no-cache"], "Accept": ["text/plain, */*; q=0.01"], "Origin": ["http://todobackend.com"], "User-Agent": ["Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.36 Safari/537.36 Edg/79.0.309.25"], "Dnt": ["1"], "Content-Type": ["application/json"], "Sec-Fetch-Site": ["cross-site"], "Sec-Fetch-Mode": ["cors"], "Referer": ["http://todobackend.com/specs/index.html?http://127.0.0.1:3000/todos"], "Accept-Encoding": ["gzip, deflate, br"], "Accept-Language": ["en-US,en;q=0.9"], "X-Forwarded-Proto": ["http"], "X-Forwarded-Port": ["3000"]}, "pathParameters": null, "stageVariables": null, "path": "/todos", "isBase64Encoded": false}
         """
 
+    static let postEventBodyNilHeaders = """
+          {"httpMethod": "POST", "body": "{\\"title\\":\\"a todo\\"}", "resource":"/todos", "requestContext": {"resourceId": "123456", "apiId": "1234567890", "domainName": "1234567890.execute-api.us-east-1.amazonaws.com", "resourcePath": "/todos", "httpMethod": "POST", "requestId": "c6af9ac6-7b61-11e6-9a41-93e8deadbeef", "accountId": "123456789012", "stage": "test", "identity": {"apiKey": null, "userArn": null,"cognitoAuthenticationType": null, "caller": null, "userAgent": "Custom User Agent String", "user": null, "cognitoIdentityPoolId": null, "cognitoAuthenticationProvider": null, "sourceIp": "127.0.0.1", "accountId": null}, "extendedRequestId": null, "path": "/todos"}, "multiValueHeaders": {"Host": ["127.0.0.1:3000"], "Connection": ["keep-alive"], "Content-Length": ["18"], "Pragma": ["no-cache"], "Cache-Control": ["no-cache"], "Accept": ["text/plain, */*; q=0.01"], "Origin": ["http://todobackend.com"], "User-Agent": ["Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.36 Safari/537.36 Edg/79.0.309.25"], "Dnt": ["1"], "Content-Type": ["application/json"], "Sec-Fetch-Site": ["cross-site"], "Sec-Fetch-Mode": ["cors"], "Referer": ["http://todobackend.com/specs/index.html?http://127.0.0.1:3000/todos"], "Accept-Encoding": ["gzip, deflate, br"], "Accept-Language": ["en-US,en;q=0.9"], "X-Forwarded-Proto": ["http"], "X-Forwarded-Port": ["3000"]}, "path": "/todos", "isBase64Encoded": false}
+        """
+
     // MARK: - Request -
 
     // MARK: Decoding
@@ -108,4 +112,9 @@ class APIGatewayTests: XCTestCase {
         XCTAssertEqual(json?.isBase64Encoded, resp.isBase64Encoded)
         XCTAssertEqual(json?.headers?["Server"], "Test")
     }
+
+    func testDecodingNilCollections() {
+        let data = APIGatewayTests.postEventBodyNilHeaders.data(using: .utf8)!
+        XCTAssertNoThrow(_ = try JSONDecoder().decode(APIGatewayRequest.self, from: data))
+    }
 }
