OpenAPI definitions of sample API integrated with a Lambda function

{
  "swagger": "2.0",
  "info": {
    "version": "2017-04-20T04:08:08Z",
    "title": "LambdaCalc"
  },
  "host": "uojnr9hd57.execute-api.us-east-1.amazonaws.com",
  "basePath": "/test",
  "schemes": [
    "https"
  ],
  "paths": {
    "/calc": {
      "get": {
        "consumes": [
          "application/json"
        ],
        "produces": [
          "application/json"
        ],
        "parameters": [
          {
            "name": "operand2",
            "in": "query",
            "required": true,
            "type": "string"
          },
          {
            "name": "operator",
            "in": "query",
            "required": true,
            "type": "string"
          },
          {
            "name": "operand1",
            "in": "query",
            "required": true,
            "type": "string"
          }
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Result"
            },
            "headers": {
              "operand_1": {
                "type": "string"
              },
              "operand_2": {
                "type": "string"
              },
              "operator": {
                "type": "string"
              }
            }
          }
        },
        "x-amazon-apigateway-request-validator": "Validate query string parameters and headers",
        "x-amazon-apigateway-integration": {
          "credentials": "arn:aws:iam::123456789012:role/apigAwsProxyRole",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseParameters": {
                "method.response.header.operator": "integration.response.body.op",
                "method.response.header.operand_2": "integration.response.body.b",
                "method.response.header.operand_1": "integration.response.body.a"
              },
              "responseTemplates": {
                "application/json": "#set($res = $input.path('$'))\n{\n    \"result\": \"$res.a, $res.b, $res.op => $res.c\",\n  \"a\" : \"$res.a\",\n  \"b\" : \"$res.b\",\n  \"op\" : \"$res.op\",\n  \"c\" : \"$res.c\"\n}"
              }
            }
          },
          "uri": "arn:aws:apigateway:us-west-2:lambda:path/2015-03-31/functions/arn:aws:lambda:us-west-2:123456789012:function:Calc/invocations",
          "passthroughBehavior": "when_no_match",
          "httpMethod": "POST",
          "requestTemplates": {
            "application/json": "{\n    \"a\":  \"$input.params('operand1')\",\n    \"b\":  \"$input.params('operand2')\", \n    \"op\": \"$input.params('operator')\"   \n}"
          },
          "type": "aws"
        }
      },
      "post": {
        "consumes": [
          "application/json"
        ],
        "produces": [
          "application/json"
        ],
        "parameters": [
          {
            "in": "body",
            "name": "Input",
            "required": true,
            "schema": {
              "$ref": "#/definitions/Input"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Result"
            }
          }
        },
        "x-amazon-apigateway-request-validator": "Validate body",
        "x-amazon-apigateway-integration": {
          "credentials": "arn:aws:iam::123456789012:role/apigAwsProxyRole",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "#set($inputRoot = $input.path('$'))\n{\n  \"a\" : $inputRoot.a,\n  \"b\" : $inputRoot.b,\n  \"op\" : $inputRoot.op,\n  \"c\" : $inputRoot.c\n}"
              }
            }
          },
          "uri": "arn:aws:apigateway:us-west-2:lambda:path/2015-03-31/functions/arn:aws:lambda:us-west-2:123456789012:function:Calc/invocations",
          "passthroughBehavior": "when_no_templates",
          "httpMethod": "POST",
          "type": "aws"
        }
      }
    },
    "/calc/{operand1}/{operand2}/{operator}": {
      "get": {
        "consumes": [
          "application/json"
        ],
        "produces": [
          "application/json"
        ],
        "parameters": [
          {
            "name": "operand2",
            "in": "path",
            "required": true,
            "type": "string"
          },
          {
            "name": "operator",
            "in": "path",
            "required": true,
            "type": "string"
          },
          {
            "name": "operand1",
            "in": "path",
            "required": true,
            "type": "string"
          }
        ],
        "responses": {
          "200": {
            "description": "200 response",
            "schema": {
              "$ref": "#/definitions/Result"
            }
          }
        },
        "x-amazon-apigateway-integration": {
          "credentials": "arn:aws:iam::123456789012:role/apigAwsProxyRole",
          "responses": {
            "default": {
              "statusCode": "200",
              "responseTemplates": {
                "application/json": "#set($inputRoot = $input.path('$'))\n{\n  \"input\" : {\n    \"a\" : $inputRoot.a,\n    \"b\" : $inputRoot.b,\n    \"op\" : \"$inputRoot.op\"\n  },\n  \"output\" : {\n    \"c\" : $inputRoot.c\n  }\n}"
              }
            }
          },
          "uri": "arn:aws:apigateway:us-west-2:lambda:path/2015-03-31/functions/arn:aws:lambda:us-west-2:123456789012:function:Calc/invocations",
          "passthroughBehavior": "when_no_templates",
          "httpMethod": "POST",
          "requestTemplates": {
            "application/json": "{\n   \"a\": \"$input.params('operand1')\",\n   \"b\": \"$input.params('operand2')\",\n   \"op\": #if($input.params('operator')=='%2F')\"/\"#{else}\"$input.params('operator')\"#end\n   \n}"
          },
          "contentHandling": "CONVERT_TO_TEXT",
          "type": "aws"
        }
      }
    }
  },
  "definitions": {
    "Input": {
      "type": "object",
      "required": [
        "a",
        "b",
        "op"
      ],
      "properties": {
        "a": {
          "type": "number"
        },
        "b": {
          "type": "number"
        },
        "op": {
          "type": "string",
          "description": "binary op of ['+', 'add', '-', 'sub', '*', 'mul', '%2F', 'div']"
        }
      },
      "title": "Input"
    },
    "Output": {
      "type": "object",
      "properties": {
        "c": {
          "type": "number"
        }
      },
      "title": "Output"
    },
    "Result": {
      "type": "object",
      "properties": {
        "input": {
          "$ref": "#/definitions/Input"
        },
        "output": {
          "$ref": "#/definitions/Output"
        }
      },
      "title": "Result"
    }
  },
  "x-amazon-apigateway-request-validators": {
    "Validate body": {
      "validateRequestParameters": false,
      "validateRequestBody": true
    },
    "Validate query string parameters and headers": {
      "validateRequestParameters": true,
      "validateRequestBody": false
    }
  }
}