Erstellen und implementieren Sie ein REST API mit einem AWS SDK

Erstellen Sie eine Klasse, die API Gateway-Operationen umschließt.

import argparse
import json
import logging
from pprint import pprint
import boto3
from botocore.exceptions import ClientError
import requests

logger = logging.getLogger(__name__)


class ApiGatewayToService:
    """
    Encapsulates Amazon API Gateway functions that are used to create a REST API that
    integrates with another AWS service.
    """

    def __init__(self, apig_client):
        """
        :param apig_client: A Boto3 API Gateway client.
        """
        self.apig_client = apig_client
        self.api_id = None
        self.root_id = None
        self.stage = None


    def create_rest_api(self, api_name):
        """
        Creates a REST API on API Gateway. The default API has only a root resource
        and no HTTP methods.

        :param api_name: The name of the API. This descriptive name is not used in
                         the API path.
        :return: The ID of the newly created API.
        """
        try:
            result = self.apig_client.create_rest_api(name=api_name)
            self.api_id = result["id"]
            logger.info("Created REST API %s with ID %s.", api_name, self.api_id)
        except ClientError:
            logger.exception("Couldn't create REST API %s.", api_name)
            raise

        try:
            result = self.apig_client.get_resources(restApiId=self.api_id)
            self.root_id = next(
                item for item in result["items"] if item["path"] == "/"
            )["id"]
        except ClientError:
            logger.exception("Couldn't get resources for API %s.", self.api_id)
            raise
        except StopIteration as err:
            logger.exception("No root resource found in API %s.", self.api_id)
            raise ValueError from err

        return self.api_id


    def add_rest_resource(self, parent_id, resource_path):
        """
        Adds a resource to a REST API.

        :param parent_id: The ID of the parent resource.
        :param resource_path: The path of the new resource, relative to the parent.
        :return: The ID of the new resource.
        """
        try:
            result = self.apig_client.create_resource(
                restApiId=self.api_id, parentId=parent_id, pathPart=resource_path
            )
            resource_id = result["id"]
            logger.info("Created resource %s.", resource_path)
        except ClientError:
            logger.exception("Couldn't create resource %s.", resource_path)
            raise
        else:
            return resource_id


    def add_integration_method(
        self,
        resource_id,
        rest_method,
        service_endpoint_prefix,
        service_action,
        service_method,
        role_arn,
        mapping_template,
    ):
        """
        Adds an integration method to a REST API. An integration method is a REST
        resource, such as '/users', and an HTTP verb, such as GET. The integration
        method is backed by an AWS service, such as Amazon DynamoDB.

        :param resource_id: The ID of the REST resource.
        :param rest_method: The HTTP verb used with the REST resource.
        :param service_endpoint_prefix: The service endpoint that is integrated with
                                        this method, such as 'dynamodb'.
        :param service_action: The action that is called on the service, such as
                               'GetItem'.
        :param service_method: The HTTP method of the service request, such as POST.
        :param role_arn: The Amazon Resource Name (ARN) of a role that grants API
                         Gateway permission to use the specified action with the
                         service.
        :param mapping_template: A mapping template that is used to translate REST
                                 elements, such as query parameters, to the request
                                 body format required by the service.
        """
        service_uri = (
            f"arn:aws:apigateway:{self.apig_client.meta.region_name}"
            f":{service_endpoint_prefix}:action/{service_action}"
        )
        try:
            self.apig_client.put_method(
                restApiId=self.api_id,
                resourceId=resource_id,
                httpMethod=rest_method,
                authorizationType="NONE",
            )
            self.apig_client.put_method_response(
                restApiId=self.api_id,
                resourceId=resource_id,
                httpMethod=rest_method,
                statusCode="200",
                responseModels={"application/json": "Empty"},
            )
            logger.info("Created %s method for resource %s.", rest_method, resource_id)
        except ClientError:
            logger.exception(
                "Couldn't create %s method for resource %s.", rest_method, resource_id
            )
            raise

        try:
            self.apig_client.put_integration(
                restApiId=self.api_id,
                resourceId=resource_id,
                httpMethod=rest_method,
                type="AWS",
                integrationHttpMethod=service_method,
                credentials=role_arn,
                requestTemplates={"application/json": json.dumps(mapping_template)},
                uri=service_uri,
                passthroughBehavior="WHEN_NO_TEMPLATES",
            )
            self.apig_client.put_integration_response(
                restApiId=self.api_id,
                resourceId=resource_id,
                httpMethod=rest_method,
                statusCode="200",
                responseTemplates={"application/json": ""},
            )
            logger.info(
                "Created integration for resource %s to service URI %s.",
                resource_id,
                service_uri,
            )
        except ClientError:
            logger.exception(
                "Couldn't create integration for resource %s to service URI %s.",
                resource_id,
                service_uri,
            )
            raise


    def deploy_api(self, stage_name):
        """
        Deploys a REST API. After a REST API is deployed, it can be called from any
        REST client, such as the Python Requests package or Postman.

        :param stage_name: The stage of the API to deploy, such as 'test'.
        :return: The base URL of the deployed REST API.
        """
        try:
            self.apig_client.create_deployment(
                restApiId=self.api_id, stageName=stage_name
            )
            self.stage = stage_name
            logger.info("Deployed stage %s.", stage_name)
        except ClientError:
            logger.exception("Couldn't deploy stage %s.", stage_name)
            raise
        else:
            return self.api_url()



    def api_url(self, resource=None):
        """
        Builds the REST API URL from its parts.

        :param resource: The resource path to append to the base URL.
        :return: The REST URL to the specified resource.
        """
        url = (
            f"https://{self.api_id}.execute-api.{self.apig_client.meta.region_name}"
            f".amazonaws.com/{self.stage}"
        )
        if resource is not None:
            url = f"{url}/{resource}"
        return url

Stellen Sie a bereit REST API und rufen Sie es mit dem Requests-Paket auf.

def usage_demo(table_name, role_name, rest_api_name):
    """
    Demonstrates how to used API Gateway to create and deploy a REST API, and how
    to use the Requests package to call it.

    :param table_name: The name of the demo DynamoDB table.
    :param role_name: The name of the demo role that grants API Gateway permission to
                      call DynamoDB.
    :param rest_api_name: The name of the demo REST API created by the demo.
    """
    gateway = ApiGatewayToService(boto3.client("apigateway"))
    role = boto3.resource("iam").Role(role_name)

    print("Creating REST API in API Gateway.")
    gateway.create_rest_api(rest_api_name)

    print("Adding resources to the REST API.")
    profiles_id = gateway.add_rest_resource(gateway.root_id, "profiles")
    username_id = gateway.add_rest_resource(profiles_id, "{username}")

    # The DynamoDB service requires that all integration requests use POST.
    print("Adding integration methods to read and write profiles in Amazon DynamoDB.")
    gateway.add_integration_method(
        profiles_id,
        "GET",
        "dynamodb",
        "Scan",
        "POST",
        role.arn,
        {"TableName": table_name},
    )
    gateway.add_integration_method(
        profiles_id,
        "POST",
        "dynamodb",
        "PutItem",
        "POST",
        role.arn,
        {
            "TableName": table_name,
            "Item": {
                "username": {"S": "$input.path('$.username')"},
                "name": {"S": "$input.path('$.name')"},
                "title": {"S": "$input.path('$.title')"},
            },
        },
    )
    gateway.add_integration_method(
        username_id,
        "GET",
        "dynamodb",
        "GetItem",
        "POST",
        role.arn,
        {
            "TableName": table_name,
            "Key": {"username": {"S": "$method.request.path.username"}},
        },
    )

    stage = "test"
    print(f"Deploying the {stage} stage.")
    gateway.deploy_api(stage)

    profiles_url = gateway.api_url("profiles")
    print(
        f"Using the Requests package to post some people to the profiles REST API at "
        f"{profiles_url}."
    )
    requests.post(
        profiles_url,
        json={"username": "will", "name": "William Shakespeare", "title": "playwright"},
    )
    requests.post(
        profiles_url,
        json={
            "username": "ludwig",
            "name": "Ludwig van Beethoven",
            "title": "composer",
        },
    )
    requests.post(
        profiles_url,
        json={"username": "jane", "name": "Jane Austen", "title": "author"},
    )
    print("Getting the list of profiles from the REST API.")
    profiles = requests.get(profiles_url).json()
    pprint(profiles)
    print(f"Getting just the profile for username 'jane' (URL: {profiles_url}/jane).")
    jane = requests.get(f"{profiles_url}/jane").json()
    pprint(jane)