AWS API Gateway - Examples

README.md

API Gateway - Examples

• Mocked endpoint: https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45
• Using passthrough (without manipulation):

curl "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/dev/api/just-passthrough" -H "Authorization: Basic <base64encodeduserpassword>"

• Using passthrough (manipulating response payload):

curl "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/dev/api/passthrough-extract-json" -H "Authorization: Basic <base64encodeduserpassword>"

• Using lambda function to process request:

curl "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/dev/api/using-lambda" -H "Authorization: Basic <base64encodeduserpassword>"

• Using mocked response (no backend):

curl "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/dev/api/using-mock" -H "Authorization: Basic <base64encodeduserpassword>"

References

• https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-mock-integration.html
• https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-mapping-template-reference.html
• https://aws.amazon.com/blogs/compute/amazon-api-gateway-mapping-improvements/
• https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-override-request-response-parameters.html
• https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-export-api.html
• https://medium.com/@Da_vidgf/http-basic-auth-with-api-gateway-and-serverless-5ae14ad0a270

lamba-basic-authorizer.js

const USER = "<some-user-here>";
const PASSWORD = "<some-password-here>";

exports.handler = function (event, context, callback) {
  var authorizationHeader = event.headers.authorization

  if (!authorizationHeader) return callback('Unauthorized')

  var encodedCreds = authorizationHeader.split(' ')[1]
  var plainCreds = (new Buffer(encodedCreds, 'base64')).toString().split(':')
  var username = plainCreds[0]
  var password = plainCreds[1]
  
  console.log(`username: ${username}`);
  console.log(`password: ${password}`);

  if (!(username === USER && password === PASSWORD)) return callback('Unauthorized')

  var authResponse = buildAllowAllPolicy(event, username)

  callback(null, authResponse)
}

function buildAllowAllPolicy (event, principalId) {
  var apiOptions = {}
  var tmp = event.methodArn.split(':')
  var apiGatewayArnTmp = tmp[5].split('/')
  var awsAccountId = tmp[4]
  var awsRegion = tmp[3]
  var restApiId = apiGatewayArnTmp[0]
  var stage = apiGatewayArnTmp[1]
  var apiArn = 'arn:aws:execute-api:' + awsRegion + ':' + awsAccountId + ':' +
    restApiId + '/' + stage + '/*/*'
  const policy = {
    principalId: principalId,
    policyDocument: {
      Version: '2012-10-17',
      Statement: [
        {
          Action: 'execute-api:Invoke',
          Effect: 'Allow',
          Resource: [apiArn]
        }
      ]
    }
  }
  return policy
}

lambda-extract-json.js

const https = require("https")

function fetchJson(url) {
    return new Promise((resolve, reject) => {
      https.get(url, res => {
        let data = "";
      
        res.on("data", d => {
          data += d
        });
        
        res.on("end", () => {
          const json = JSON.parse(data).entries[0].json
          resolve(json);
        });
        
        res.on("error", err => {
          reject(err);
        })
      });
    });
}

exports.handler = async (event) => {
    const url = "https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45";
    const response = await fetchJson(url);
    return response;
};

open-api-3+api-gateway-extensions.json

{
  "openapi": "3.0.1",
  "info": {
    "title": "my-api",
    "version": "2021-06-27T19:56:31Z"
  },
  "servers": [
    {
      "url": "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/{basePath}",
      "variables": {
        "basePath": {
          "default": "/dev"
        }
      }
    }
  ],
  "paths": {
    "/api/using-mock": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "type": "mock",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "{\n    \"some_key\": \"some value from mock\"\n}"
              }
            }
          },
          "requestTemplates": {
            "application/json": "{\"statusCode\": 200}"
          },
          "passthroughBehavior": "when_no_match"
        }
      }
    },
    "/api/using-lambda": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "type": "aws",
          "httpMethod": "POST",
          "uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:706689456704:function:extract-json/invocations",
          "responses": {
            "default": {
              "statusCode": "200"
            }
          },
          "passthroughBehavior": "when_no_match",
          "contentHandling": "CONVERT_TO_TEXT"
        }
      }
    },
    "/api/just-passthrough": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "type": "http",
          "httpMethod": "GET",
          "uri": "https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45",
          "responses": {
            "default": {
              "statusCode": "200"
            }
          },
          "passthroughBehavior": "when_no_match"
        }
      }
    },
    "/api/passthrough-extract-json": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "type": "http",
          "httpMethod": "GET",
          "uri": "https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "$input.json('$.entries[0].json')"
              }
            }
          },
          "passthroughBehavior": "when_no_match"
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Empty": {
        "title": "Empty Schema",
        "type": "object"
      }
    }
  }
}

open-api-3.json

{
  "openapi": "3.0.1",
  "info": {
    "title": "my-api",
    "version": "2021-06-27T19:56:31Z"
  },
  "servers": [
    {
      "url": "https://ocywyw3jq5.execute-api.us-east-1.amazonaws.com/{basePath}",
      "variables": {
        "basePath": {
          "default": "/dev"
        }
      }
    }
  ],
  "paths": {
    "/api/using-mock": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        }
      }
    },
    "/api/using-lambda": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        }
      }
    },
    "/api/just-passthrough": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        }
      }
    },
    "/api/passthrough-extract-json": {
      "get": {
        "responses": {
          "200": {
            "description": "200 response",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Empty"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Empty": {
        "title": "Empty Schema",
        "type": "object"
      }
    }
  }
}

swagger+api-gateway-extensions.json

{
  "swagger": "2.0",
  "info": {
    "version": "2021-06-27T19:56:31Z",
    "title": "my-api"
  },
  "host": "ocywyw3jq5.execute-api.us-east-1.amazonaws.com",
  "basePath": "/dev",
  "schemes": [
    "https"
  ],
  "paths": {
    "/api/just-passthrough": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "httpMethod": "GET",
          "uri": "https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45",
          "responses": {
            "default": {
              "statusCode": "200"
            }
          },
          "passthroughBehavior": "when_no_match",
          "type": "http"
        }
      }
    },
    "/api/passthrough-extract-json": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "httpMethod": "GET",
          "uri": "https://run.mocky.io/v3/a89f3fb6-a34c-4ca1-9854-bbf97a108d45",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "$input.json('$.entries[0].json')"
              }
            }
          },
          "passthroughBehavior": "when_no_match",
          "type": "http"
        }
      }
    },
    "/api/using-lambda": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "httpMethod": "POST",
          "uri": "arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:706689456704:function:extract-json/invocations",
          "responses": {
            "default": {
              "statusCode": "200"
            }
          },
          "passthroughBehavior": "when_no_match",
          "contentHandling": "CONVERT_TO_TEXT",
          "type": "aws"
        }
      }
    },
    "/api/using-mock": {
      "get": {
        "consumes": [
          "application/json"
        ],
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "{\n    \"some_key\": \"some value from mock\"\n}"
              }
            }
          },
          "requestTemplates": {
            "application/json": "{\"statusCode\": 200}"
          },
          "passthroughBehavior": "when_no_match",
          "type": "mock"
        }
      }
    }
  },
  "definitions": {
    "Empty": {
      "type": "object",
      "title": "Empty Schema"
    }
  }
}

swagger.json

{
  "swagger": "2.0",
  "info": {
    "version": "2021-06-27T19:56:31Z",
    "title": "my-api"
  },
  "host": "ocywyw3jq5.execute-api.us-east-1.amazonaws.com",
  "basePath": "/dev",
  "schemes": [
    "https"
  ],
  "paths": {
    "/api/just-passthrough": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        }
      }
    },
    "/api/passthrough-extract-json": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        }
      }
    },
    "/api/using-lambda": {
      "get": {
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        }
      }
    },
    "/api/using-mock": {
      "get": {
        "consumes": [
          "application/json"
        ],
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Empty"
            }
          }
        }
      }
    }
  },
  "definitions": {
    "Empty": {
      "type": "object",
      "title": "Empty Schema"
    }
  }
}