feat(api-gateway): add support for custom serializer

[michaelbrewer]

Issue #, if available:

• Add support for serializing Enum values automatically in API Gateway Event Handler #519

Description of changes:

Add support a custom serializer to allow for:

• Output to xml
• Support for serializing Enum or Sets and other complex types
• Support alternative json libraries like ujson or orjson

Example usage:

import json
from enum import Enum
from json import JSONEncoder
from typing import Dict

class CustomEncoder(JSONEncoder):
    """Your customer json encoder"""
    def default(self, obj):
        if isinstance(obj, Enum):
            return obj.value
        try:
            iterable = iter(obj)
        except TypeError:
            pass
        else:
            return sorted(iterable)
        return JSONEncoder.default(self, obj)

def custom_serializer(obj) -> str:
    """Your custom serializer - can even output xml 😨"""
    return json.dumps(obj, cls=CustomEncoder)

# Assigning your custom serializer
app = ApiGatewayResolver(serializer=custom_serializer)

class Color(Enum):
    RED = 1
    BLUE = 2

@app.get("/colors")
def get_color() -> Dict:
    return {
        "color": Color.RED,
        "variations": {"light", "dark"},
    }

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Merging #568 (f5f4123) into develop (1135314) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #568   +/-   ##
========================================
  Coverage    99.86%   99.86%           
========================================
  Files          113      113           
  Lines         4485     4489    +4     
  Branches       243      244    +1     
========================================
+ Hits          4479     4483    +4     
  Misses           3        3           
  Partials         3        3           

Impacted Files	Coverage Δ
aws_lambda_powertools/event_handler/api_gateway.py	100.00% <100.00%> (ø)

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[michaelbrewer]

@marcioemiranda @heitorlessa my initial PR is up

[heitorlessa]

Thanks a lot Mike, including the illustrious XML example haha

Q: Do we need a deserializer for event source data classes too?

[michaelbrewer]

Thanks a lot Mike, including the illustrious XML example haha

i should try it out :)

Q: Do we need a deserializer for event source data classes too?

Like we did for idempotent utility?

[heitorlessa]

Like we did for Logger: https://awslabs.github.io/aws-lambda-powertools-python/latest/core/logger/#bring-your-own-json-serializer

It can be done in a separate PR. This PR already addresses the serialization ask, deserializing would be a sensible ask by anyone looking to understand why orjson hasn't optimized their high traffic API end-to-end (json_body uses json.loads)

Note: AFAIK XML wouldn't work here because this feature requires API GW Proxy Resource.

[heitorlessa]

Syntactic sugar to ease maintenance later

[michaelbrewer]

Like we did for Logger: https://awslabs.github.io/aws-lambda-powertools-python/latest/core/logger/#bring-your-own-json-serializer

It can be done in a separate PR. This PR already addresses the serialization ask, deserializing would be a sensible ask by anyone looking to understand why orjson hasn't optimized their high traffic API end-to-end (json_body uses json.loads)

Note: AFAIK XML wouldn't work here because this feature requires API GW Proxy Resource.

In the BaseProxyEvent.json_body method?

[heitorlessa]

In the BaseProxyEvent.json_body method?

Yep. Any places where we'd deserialize, and one would want to have orjson or something else with their defaults in place... since we're allowing them for serialization.

I'm merging this as is now, thanks a lot!!!!!!

[marcioemiranda]

Thanks a lot, this looks good. Any idea when this feature would be released?

[heitorlessa]

If all goes well, this coming Friday (7th). I try releasing every two weeks, though this time there’s a major new utility - feature flags - which we are currently documenting it

…

On Sat, 31 Jul 2021 at 16:57, marcioemiranda ***@***.***> wrote: Thanks a lot, this looks good. Any idea when this feature would be released? — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#568 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZPQBAV6WE3GUSBJSAMSJLT2QFNFANCNFSM5BCTX2CA> .