Build an HTTP API Endpoint

HTTP endpoints have become one of the most ubiquitous ways of delivering software to end users. Cdev provides a simple interface for creating HTTP APIs and connecting them to Serverless Functions. You can find more information about HTTP in the official documentation.

Create an API

Open the src/hello_world/resources.py file and start by importing the following resources:

    

        
            
            
    
    import json

from cdev.resources.simple.api import Api
from cdev.resources.simple.xlambda import simple_function_annotation

from cdev import Project as cdev_project

Create a route

Next, add lines 8, 10 and 12 to define your project, API and create your route.

    

        
            
            
    
    import json

from cdev.resources.simple.api import Api
from cdev.resources.simple.xlambda import simple_function_annotation

from cdev import Project as cdev_project

myProject = cdev_project.instance()

myApi = Api("demoApi")

hello_world_get_route = DemoApi.route("/hello_world", "GET")

Integrate GET route with a Serverless Function

Now, intergrate your route with a Serverless Function by adding lines 10 - 35.

    

        
            
            
    
    import json

from cdev.resources.simple.api import Api
from cdev.resources.simple.xlambda import simple_function_annotation

from cdev import Project as cdev_project

myProject = cdev_project.instance()

myApi = Api("demoApi")

hello_world_get_route = myApi.route("/hello_world", "GET")


@simple_function_annotation("demo_function", events=[hello_world_get_route.event()])
def hello_world(event, context):
    """
    This is an example function connected to an example API route
    """
    message = {
        "message": "Hello World from Lambda!"
    }

    return {
        "isBase64Encoded": False,
        "status_code": 200, 
        "body": json.dumps(message),
        "headers": {
            "Content-Type": "application/json"
        }
    }


myProject.display_output("Base API URL", myApi.output.endpoint)
myProject.display_output("Routes", myApi.output.endpoints)

Get your endpoint

Save and deploy your endpoint with the following commands:

cdev plan

cdev deploy

Get the live url for your endpoint:

cdev output <component_name>.api.demoApi.endpoint

You can test the endpoint with the following commands from your terminal:

curl <your_endpoint>/hello_world

Integrate POST route with data to a Serverless function

Using the same src/hello_world/resources.py file from the GET route example, make the following changes.

Replace lines 12 - 31 with:

send_data_route = myApi.route("/send_data", "POST")


@simple_function_annotation("send_data_handler", events=[send_data_route.event()])
def hello_world(event, context):
    
    """
    This is an example function connected to an example POST API route that can receive data
    """

    print(event)


    data = json.loads(event.get("body"))

    print(data)
    message = {
        "message": "Handled Data"
    }

    return {
        "isBase64Encoded": False,
        "status_code": 200, 
        "body": json.dumps(message),
        "headers": {
            "Content-Type": "application/json"
        }
    }

The src/hello_world/resources.py now looks like:

    

        
            
            
    
    import json

from cdev.resources.simple.api import Api
from cdev.resources.simple.xlambda import simple_function_annotation

from cdev import Project as cdev_project

myProject = cdev_project.instance()

myApi = Api("demoApi")

send_data_route = myApi.route("/send_data", "POST")


@simple_function_annotation("send_data_handler", events=[send_data_route.event()])
def hello_world(event, context):
    
    """
    This is an example function connected to an example POST API route that can receive data
    """

    print(event)

    data = json.loads(event.get("body"))

    print(data)
    message = {
        "message": "Handled Data"
    }

    return {
        "isBase64Encoded": False,
        "status_code": 200, 
        "body": json.dumps(message),
        "headers": {
            "Content-Type": "application/json"
        }
    }


myProject.display_output("Base API URL", myApi.output.endpoint)
myProject.display_output("Routes", myApi.output.endpoints)

Get your POST endpoint

Save and deploy your endpoint with the following commands:

cdev plan

cdev deploy

Get the live url for your endpoint:

cdev output <component_name>.api.demoApi.endpoint

You can test the endpoint with the follow commands from your terminal:

curl -X POST <your_endpoint>/send_data -H 'Content-Type: application/json' -d "{\"login\":\"my_login\"}"

Check the logs of your function

cdev run function.logs <component_name>.send_data_handler

Return Values from Function

From the AWS Documentation, API Gateway makes the following assumptions if your Lambda function returns valid JSON and does not return a statusCode:

• isBase64Encoded is false.
• statusCode is 200.
• content-type is application/json.
• body is the function's response.

Examples:

Function Response

return "Hello from Lambda!"

API Gateway Response

{
  "isBase64Encoded": false,
  "statusCode": 200,
  "body": "Hello from Lambda!",
  "headers": {
    "content-type": "application/json"
  }
}

Function Response

return { "message": "Hello from Lambda!" }

API Gateway Response

{
  "isBase64Encoded": false,
  "statusCode": 200,
  "body": "{ \"message\": \"Hello from Lambda!\" }",
  "headers": {
    "content-type": "application/json"
  }
}

If you want to customize your return value completely, it should have the form:

return {
    "cookies" : ["cookie1", "cookie2"],
    "isBase64Encoded": True|False,
    "statusCode": httpStatusCode,
    "headers": { "headername": "headervalue", ... },
    "body": "Hello from Lambda!"
}

return {
    "cookies" : ["cookie1", "cookie2"],
    "isBase64Encoded": True|False,
    "statusCode": httpStatusCode,
    "headers": { "headername": "headervalue", ... },
    "body": json.dumps({
        "message" :"Hello from Lambda!"
    })
}