lambda-proxy

A zero-requirement proxy linking AWS API Gateway {proxy+} requests and AWS Lambda.

Install

$ pip install -U pip
$ pip install lambda-proxy

Or install from source:

$ git clone https://github.com/vincentsarag/lambda-proxy.git
$ cd lambda-proxy
$ pip install -U pip
$ pip install -e .

Usage

Lambda proxy is designed to work well with both API Gateway's REST API and the newer and cheaper HTTP API. If you have issues using with the HTTP API, please open an issue.

With GET request

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.route('/test/tests/<id>', methods=['GET'], cors=True)
def print_id(id):
    return ('OK', 'plain/text', id)

With POST request

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.route('/test/tests/<id>', methods=['POST'], cors=True)
def print_id(id, body):
    return ('OK', 'plain/text', id)

Note

Starting in version 5.2.0, users can now add route using @APP.get and @APP.post removing the need to add methods=[**]

Binary body

Starting from version 5.0.0, lambda-proxy will decode base64 encoded body on POST message.

Pre 5.0.0

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.route('/test', methods=['POST']e)
def print_id(body):
    body = json.loads(base64.b64decode(body).decode())

Post 5.0.0

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.route('/test', methods=['POST']e)
def print_id(body):
    body = json.loads(body)

Routes

Route schema is simmilar to the one used in Flask

Variable parts in the route can be specified with angular brackets /user/<username>. By default a variable part in the URL accepts any string without a slash however a different converter can be specified as well by using <converter:name>.

Converters:

• int: integer
• string: string
• float: float number
• uuid: UUID

example:

• /app/<user>/<id> (user and id are variables)
• /app/<string:value>/<float:num> (value will be a string, while num will be a float)

Regex

You can also add regex parameters descriptions using special converter regex()

example:

@APP.get("/app/<regex([a-z]+):regularuser>")
def print_user(regularuser):
    return ('OK', 'plain/text', f"regular {regularuser}")

@APP.get("/app/<regex([A-Z]+):capitaluser>")
def print_user(capitaluser):
    return ('OK', 'plain/text', f"CAPITAL {capitaluser}")

Warning

when using regex() you must use different variable names or the route might not show up in the documentation.

@APP.get("/app/<regex([a-z]+):user>")
def print_user(user):
    return ('OK', 'plain/text', f"regular {user}")

@APP.get("/app/<regex([A-Z]+):user>")
def print_user(user):
    return ('OK', 'plain/text', f"CAPITAL {user}")

This app will work but the documentation will only show the second route because in openapi.json, route names will be /app/{user} for both routes.

Route Options

• path: the URL rule as string
• methods: list of HTTP methods allowed, default: ["GET"]
• cors: allow CORS, default: False
• token: set access_token validation
• payload_compression_method: Enable and select an output body compression
• binary_b64encode: base64 encode the output body (API Gateway)
• ttl: Cache Control setting (Time to Live) (Deprecated in 6.0.0)
• cache_control: Cache Control setting
• description: route description (for documentation)
• tag: list of tags (for documentation)

Cache Control

Add a Cache Control header with a Time to Live (TTL) in seconds.

from lambda_proxy.proxy import API
APP = API(app_name="app")

@APP.get('/test/tests/<id>', cors=True, cache_control="public,max-age=3600")
def print_id(id):
   return ('OK', 'plain/text', id)

Note: If function returns other then "OK", Cache-Control will be set to no-cache

Binary responses

When working with binary on API-Gateway we must return a base64 encoded string

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.get('/test/tests/<filename>.jpg', cors=True, binary_b64encode=True)
def print_id(filename):
    with open(f"{filename}.jpg", "rb") as f:
        return ('OK', 'image/jpeg', f.read())

Compression

Enable compression if "Accept-Encoding" if found in headers.

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.get(
   '/test/tests/<filename>.jpg',
   cors=True,
   binary_b64encode=True,
   payload_compression_method="gzip"
)
def print_id(filename):
    with open(f"{filename}.jpg", "rb") as f:
       return ('OK', 'image/jpeg', f.read())

Simple Auth token

Lambda-proxy provide a simple token validation system.

• a "TOKEN" variable must be set in the environment
• each request must provide a "access_token" params (e.g curl http://myurl/test/tests/myid?access_token=blabla)

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.get('/test/tests/<id>', cors=True, token=True)
def print_id(id):
    return ('OK', 'plain/text', id)

URL schema and request parameters

QueryString parameters are passed as function's options.

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.get('/<id>', cors=True)
def print_id(id, name=None):
    return ('OK', 'plain/text', f"{id}{name}")

requests:

$ curl /000001
   0001

$ curl /000001?name=vincent
   0001vincent

Multiple Routes

from lambda_proxy.proxy import API
APP = API(name="app")

@APP.get('/<id>', cors=True)
@APP.get('/<id>/<int:number>', cors=True)
def print_id(id, number=None, name=None):
    return ('OK', 'plain/text', f"{id}-{name}-{number}")

requests:

$ curl /000001
   0001--

$ curl /000001?name=vincent
   0001-vincent-

$ curl /000001/1?name=vincent
   0001-vincent-1

Advanced features

Context and Event passing

Pass event and context to the handler function.

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.get("/<id>", cors=True)
@APP.pass_event
@APP.pass_context
def print_id(ctx, evt, id):
    print(ctx)
    print(evt)
    return ('OK', 'plain/text', f"{id}")

Automatic OpenAPI documentation

By default the APP (lambda_proxy.proxy.API) is provided with three (3) routes:

• /openapi.json: print OpenAPI JSON definition

• /docs: swagger html UI

• /redoc: Redoc html UI

Function annotations

To be able to render full and precise API documentation, lambda_proxy uses python type hint and annotations link.

from lambda_proxy.proxy import API

APP = API(name="app")

@APP.route('/test/<int:id>', methods=['GET'], cors=True)
def print_id(id: int, num: float = 0.2) -> Tuple(str, str, str):
    return ('OK', 'plain/text', id)

In the example above, our route /test/<int:id> define an input id to be a INT, while we also add this hint to the function print_id we also specify the type (and default) of the num option.

Custom Domain and path mapping

Since version 4.1.1, lambda-proxy support custom domain and path mapping (see https://github.com/vincentsarago/lambda-proxy/issues/16).

Note: When using path mapping other than root (/), / route won't be available.

from lambda_proxy.proxy import API

api = API(name="api", debug=True)


# This route won't work when using path mapping
@api.get("/", cors=True)
# This route will work only if the path mapping is set to /api
@api.get("/api", cors=True)
def index():
    html = """<!DOCTYPE html>
    <html>
        <header><title>This is title</title></header>
        <body>
            Hello world
        </body>
    </html>"""
    return ("OK", "text/html", html)


@api.get("/yo", cors=True)
def yo():
    return ("OK", "text/plain", "YOOOOO")

Plugin

• Add cache layer: https://github.com/vincentsarago/lambda-proxy-cache

Examples

• https://github.com/vincentsarago/lambda-proxy/tree/master/example
• https://github.com/RemotePixel/remotepixel-tiler

Contribution & Devellopement

Issues and pull requests are more than welcome.

Dev install & Pull-Request

$ git clone https://github.com/vincentsarago/lambda-proxy.git
$ cd lambda-proxy
$ pip install -e .[dev]

Python3.7 only

This repo is set to use pre-commit to run mypy, flake8, pydocstring and black ("uncompromising Python code formatter") when committing new code.

$ pre-commit install
$ git add .
$ git commit -m'my change'
   black.........................Passed
   Flake8........................Passed
   Verifying PEP257 Compliance...Passed
   mypy..........................Passed
$ git push origin

License

See LICENSE.txt.

Authors

See AUTHORS.txt.

Changes

See CHANGES.txt.