OpenFaaS Python HTTP Templates

The Python HTTP template gives you additional control of the HTTP response for your function and access to the HTTP request details.

Status of the Template

This template is a work in progress and makes use of the incubator project of-watchdog.

Downloading the Template

$ faas template pull https://github.com/kturcios/python-http-template
$ faas new --lang python2.7-http

Event and Context Data

The function handler is passed two arguments, event and context.

event contains the prominent data about the request, including:

• body
• headers
• method
• query
• path

context contains basic information about the function, including:

• hostname

Response Bodies

By default, flask will automatically attempt to set the correct Content-Type header for you based on the type of response. For example, returning a dict object type will automatically attach the header Content-Type: application/json and returning a string type will automatically attach the Content-Type: text/html, charset=utf-8 for you.

Examples

Custom Status Codes and Response Bodies

Successful response status code and JSON response body

def handle(event, context):
    return {
        "response": {
            "key": "value"
        },
        "status_code": 200
    }

Successful response status code and string response body

def handle(event, context):
    return {
        "response": "Object successfully created",
        "status_code": 201
    }

Failure response status code and JSON error message

def handle(event, context):
    return {
        "response": {
            "error": "Bad request"
        },
        "status_code": 400
    }

Custom Response Headers

Setting custom response headers

def handle(event, context):
    return {
        "response": {
            "key": "value"
        },
        "status_code": 200,
        "headers": [
            ("Location", "https://www.example.com/")
        ]
    }

Accessing Event Data

Accessing request body

def handle(event, context):
    return {
        "response": "You said: " + str(event.body),
        "status_code": 200
    }

Accessing request method

def handle(event, context):
    if event.method == 'GET':
        return {
            "response": "GET request",
            "status_code": 200
        }
    else:
        return {
            "response": "Method not allowed",
            "status_code": 405
        }

Accessing request query string arguments

def handle(event, context):
    return {
        "response": {
            "name": event.query['name']
        },
        "status_code": 200
    }

Accessing request headers

def handle(event, context):
    return {
        "response": {
            "content-type-received": event.headers['Content-Type']
        },
        "status_code": 200
    }