# 利用 AWS Lambda REQUEST 授权方来控制对 WebSocket API 的访问 WebSocket API 中的 Lambda 授权方函数类似于 [REST API](apigateway-use-lambda-authorizer.md#api-gateway-lambda-authorizer-lambda-function-create) 的授权方函数，但有以下例外情况： + 您只能对 `$connect` 路由使用 Lambda 授权方函数。 + 您不能使用路径变量 (`event.pathParameters`)，因为路径是固定的。 + `event.methodArn` 与 REST API 等效变量不同，因为它没有 HTTP 方法。如果是 `$connect`，则 `methodArn` 以 `"$connect"` 结尾： ``` arn:aws:execute-api:region:account-id:api-id/stage-name/$connect ``` + `event.requestContext` 中的上下文变量与 REST API 的上下文变量不同。 以下示例显示了适用于 WebSocket API 的 `REQUEST` 授权方的输入： ``` { "type": "REQUEST", "methodArn": "arn:aws:execute-api:us-east-1:123456789012:abcdef123/default/$connect", "headers": { "Connection": "upgrade", "content-length": "0", "HeaderAuth1": "headerValue1", "Host": "abcdef123.execute-api.us-east-1.amazonaws.com", "Sec-WebSocket-Extensions": "permessage-deflate; client_max_window_bits", "Sec-WebSocket-Key": "...", "Sec-WebSocket-Version": "13", "Upgrade": "websocket", "X-Amzn-Trace-Id": "...", "X-Forwarded-For": "...", "X-Forwarded-Port": "443", "X-Forwarded-Proto": "https" }, "multiValueHeaders": { "Connection": [ "upgrade" ], "content-length": [ "0" ], "HeaderAuth1": [ "headerValue1" ], "Host": [ "abcdef123.execute-api.us-east-1.amazonaws.com" ], "Sec-WebSocket-Extensions": [ "permessage-deflate; client_max_window_bits" ], "Sec-WebSocket-Key": [ "..." ], "Sec-WebSocket-Version": [ "13" ], "Upgrade": [ "websocket" ], "X-Amzn-Trace-Id": [ "..." ], "X-Forwarded-For": [ "..." ], "X-Forwarded-Port": [ "443" ], "X-Forwarded-Proto": [ "https" ] }, "queryStringParameters": { "QueryString1": "queryValue1" }, "multiValueQueryStringParameters": { "QueryString1": [ "queryValue1" ] }, "stageVariables": {}, "requestContext": { "routeKey": "$connect", "eventType": "CONNECT", "extendedRequestId": "...", "requestTime": "19/Jan/2023:21:13:26 +0000", "messageDirection": "IN", "stage": "default", "connectedAt": 1674162806344, "requestTimeEpoch": 1674162806345, "identity": { "sourceIp": "..." }, "requestId": "...", "domainName": "abcdef123.execute-api.us-east-1.amazonaws.com", "connectionId": "...", "apiId": "abcdef123" } } ``` 以下示例 Lambda 授权方函数是[其他 Lambda 授权方函数示例](apigateway-use-lambda-authorizer.md#api-gateway-lambda-authorizer-lambda-function-create)中 REST API 的 Lambda 授权方函数的 WebSocket 版本： ------ #### [ Node.js ] ``` // A simple REQUEST authorizer example to demonstrate how to use request // parameters to allow or deny a request. In this example, a request is // authorized if the client-supplied HeaderAuth1 header and QueryString1 query parameter // in the request context match the specified values of // of 'headerValue1' and 'queryValue1' respectively. export const handler = function(event, context, callback) { console.log('Received event:', JSON.stringify(event, null, 2)); // Retrieve request parameters from the Lambda function input: var headers = event.headers; var queryStringParameters = event.queryStringParameters; var stageVariables = event.stageVariables; var requestContext = event.requestContext; // Parse the input for the parameter values var tmp = event.methodArn.split(':'); var apiGatewayArnTmp = tmp[5].split('/'); var awsAccountId = tmp[4]; var region = tmp[3]; var ApiId = apiGatewayArnTmp[0]; var stage = apiGatewayArnTmp[1]; var route = apiGatewayArnTmp[2]; // Perform authorization to return the Allow policy for correct parameters and // the 'Unauthorized' error, otherwise. var authResponse = {}; var condition = {}; condition.IpAddress = {}; if (headers.HeaderAuth1 === "headerValue1" && queryStringParameters.QueryString1 === "queryValue1") { callback(null, generateAllow('me', event.methodArn)); } else { callback(null, generateDeny('me', event.methodArn)); } } // Helper function to generate an IAM policy var generatePolicy = function(principalId, effect, resource) { // Required output: var authResponse = {}; authResponse.principalId = principalId; if (effect && resource) { var policyDocument = {}; policyDocument.Version = '2012-10-17 '; // default version policyDocument.Statement = []; var statementOne = {}; statementOne.Action = 'execute-api:Invoke'; // default action statementOne.Effect = effect; statementOne.Resource = resource; policyDocument.Statement[0] = statementOne; authResponse.policyDocument = policyDocument; } // Optional output with custom properties of the String, Number or Boolean type. authResponse.context = { "stringKey": "stringval", "numberKey": 123, "booleanKey": true }; return authResponse; } var generateAllow = function(principalId, resource) { return generatePolicy(principalId, 'Allow', resource); } var generateDeny = function(principalId, resource) { return generatePolicy(principalId, 'Deny', resource); } ``` ------ #### [ Python ] ``` # A simple REQUEST authorizer example to demonstrate how to use request # parameters to allow or deny a request. In this example, a request is # authorized if the client-supplied HeaderAuth1 header and QueryString1 query parameter # in the request context match the specified values of # of 'headerValue1' and 'queryValue1' respectively. import json def lambda_handler(event, context): print(event) # Retrieve request parameters from the Lambda function input: headers = event['headers'] queryStringParameters = event['queryStringParameters'] stageVariables = event['stageVariables'] requestContext = event['requestContext'] # Parse the input for the parameter values tmp = event['methodArn'].split(':') apiGatewayArnTmp = tmp[5].split('/') awsAccountId = tmp[4] region = tmp[3] ApiId = apiGatewayArnTmp[0] stage = apiGatewayArnTmp[1] route = apiGatewayArnTmp[2] # Perform authorization to return the Allow policy for correct parameters # and the 'Unauthorized' error, otherwise. authResponse = {} condition = {} condition['IpAddress'] = {} if (headers['HeaderAuth1'] == "headerValue1" and queryStringParameters["QueryString1"] == "queryValue1"): response = generateAllow('me', event['methodArn']) print('authorized') return json.loads(response) else: response = generateDeny('me', event['methodArn']) print('unauthorized') return json.loads(response) # Help function to generate IAM policy def generatePolicy(principalId, effect, resource): authResponse = {} authResponse['principalId'] = principalId if (effect and resource): policyDocument = {} policyDocument['Version'] = '2012-10-17 ' policyDocument['Statement'] = [] statementOne = {} statementOne['Action'] = 'execute-api:Invoke' statementOne['Effect'] = effect statementOne['Resource'] = resource policyDocument['Statement'] = [statementOne] authResponse['policyDocument'] = policyDocument authResponse['context'] = { "stringKey": "stringval", "numberKey": 123, "booleanKey": True } authResponse_JSON = json.dumps(authResponse) return authResponse_JSON def generateAllow(principalId, resource): return generatePolicy(principalId, 'Allow', resource) def generateDeny(principalId, resource): return generatePolicy(principalId, 'Deny', resource) ``` ------ 要将前面的 Lambda 函数配置为 WebSocket API 的 `REQUEST` 授权方函数，请遵循与 [REST API](configure-api-gateway-lambda-authorization.md#configure-api-gateway-lambda-authorization-with-console) 相同的过程。 要将 `$connect` 路由配置为在控制台中使用此 Lambda 授权方，请选择或创建 `$connect` 路由。在**路由请求设置**部分中，选择**编辑**。在**授权**下拉菜单中选择您的授权方，然后选择**保存更改**。 要测试授权方，您将需要创建一个新连接。在 `$connect` 中更改授权方不会影响已连接的客户端。当您连接到 WebSocket API 时，需要为任何已配置的身份源提供值。例如，您可以通过使用 `wscat` 发送有效的查询字符串和标头进行连接，如以下示例所示： ``` wscat -c 'wss://myapi.execute-api.us-east-1.amazonaws.com/beta?QueryString1=queryValue1' -H HeaderAuth1:headerValue1 ``` 如果您尝试在没有有效身份值的情况下进行连接，您将收到 `401` 响应： ``` wscat -c wss://myapi.execute-api.us-east-1.amazonaws.com/beta error: Unexpected server response: 401 ```