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[WSGI] Upgrade serverless_wsgi.py to version 3.0.5 #384

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Merged
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Feb 7, 2025
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[WSGI] Upgrade serverless_wsgi.py to version 3.0.5 #384

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232 changes: 160 additions & 72 deletions awslambda/serverless_wsgi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,14 +12,22 @@
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
"""
This module converts an AWS API Gateway proxied request to a WSGI request.

Inspired by: https://github.com/miserlou/zappa

Author: Logan Raarup <logan@logan.dk>
"""
import base64
import io
import json
import os
import sys
from io import BytesIO
from urllib.parse import urlencode, unquote, unquote_plus

from werkzeug.datastructures import Headers, MultiDict, iter_multi_items
from werkzeug.datastructures import Headers, iter_multi_items
from werkzeug.http import HTTP_STATUS_CODES
from werkzeug.urls import url_encode, url_unquote, url_unquote_plus
from werkzeug.wrappers import Response

# List of MIME types that should not be base64 encoded. MIME types within `text/*`
Expand Down Expand Up @@ -86,21 +94,32 @@ def is_alb_event(event):


def encode_query_string(event):
params = event.get(u"multiValueQueryStringParameters")
params = event.get("multiValueQueryStringParameters")
if not params:
params = event.get("queryStringParameters")
if not params:
params = event.get(u"queryStringParameters")
params = event.get("query")
if not params:
params = ""
if is_alb_event(event):
params = MultiDict((url_unquote_plus(k), url_unquote_plus(v)) for k, v in iter_multi_items(params))
return url_encode(params)
params = [
(unquote_plus(k), unquote_plus(v))
for k, v in iter_multi_items(params)
]
return urlencode(params, doseq=True)


def get_script_name(headers, request_context):
strip_stage_path = os.environ.get("STRIP_STAGE_PATH", "").lower().strip() in ["yes", "y", "true", "t", "1"]

if u"amazonaws.com" in headers.get(u"Host", u"") and not strip_stage_path:
script_name = "/{}".format(request_context.get(u"stage", ""))
strip_stage_path = os.environ.get("STRIP_STAGE_PATH", "").lower().strip() in [
"yes",
"y",
"true",
"t",
"1",
]

if "amazonaws.com" in headers.get("Host", "") and not strip_stage_path:
script_name = "/{}".format(request_context.get("stage", ""))
else:
script_name = ""
return script_name
Expand All @@ -110,7 +129,7 @@ def get_body_bytes(event, body):
if event.get("isBase64Encoded", False):
body = base64.b64decode(body)
if isinstance(body, str):
body = body.encode(encoding="utf-8", errors="strict")
body = body.encode("utf-8")
return body


Expand All @@ -127,96 +146,112 @@ def setup_environ_items(environ, headers):


def generate_response(response, event):
returndict = {u"statusCode": response.status_code}
returndict = {"statusCode": response.status_code}

if u"multiValueHeaders" in event:
returndict[u"multiValueHeaders"] = group_headers(response.headers)
if "multiValueHeaders" in event and event["multiValueHeaders"]:
returndict["multiValueHeaders"] = group_headers(response.headers)
else:
returndict[u"headers"] = split_headers(response.headers)
returndict["headers"] = split_headers(response.headers)

if is_alb_event(event):
# If the request comes from ALB we need to add a status description
returndict["statusDescription"] = u"%d %s" % (response.status_code, HTTP_STATUS_CODES[response.status_code])
returndict["statusDescription"] = "%d %s" % (
response.status_code,
HTTP_STATUS_CODES[response.status_code],
)

if response.data:
mimetype = response.mimetype or "text/plain"
if (mimetype.startswith("text/") or mimetype in TEXT_MIME_TYPES) and not response.headers.get(
"Content-Encoding", ""
):
if (
mimetype.startswith("text/") or mimetype in TEXT_MIME_TYPES
) and not response.headers.get("Content-Encoding", ""):
returndict["body"] = response.get_data(as_text=True)
returndict["isBase64Encoded"] = False
else:
returndict["body"] = base64.b64encode(response.data).decode("utf-8")
returndict["body"] = base64.b64encode(
response.data).decode("utf-8")
returndict["isBase64Encoded"] = True

return returndict


def strip_express_gateway_query_params(path):
"""Contrary to regular AWS lambda HTTP events, Express Gateway
(https://github.com/ExpressGateway/express-gateway-plugin-lambda)
adds query parameters to the path, which we need to strip.
"""
if "?" in path:
path = path.split("?")[0]
return path


def handle_request(app, event, context):
if event.get("source") in ["aws.events", "serverless-plugin-warmup"]:
# Lambda warming event received, skipping handler
print("Lambda warming event received, skipping handler")
return {}

if (
event.get("version") is None
and event.get("isBase64Encoded") is None
and event.get("requestPath") is not None
and not is_alb_event(event)
):
return handle_lambda_integration(app, event, context)

if event.get("version") == "2.0":
return handle_payload_v2(app, event, context)

return handle_payload_v1(app, event, context)


def handle_payload_v1(app, event, context):
if u"multiValueHeaders" in event:
headers = Headers(event[u"multiValueHeaders"])
if "multiValueHeaders" in event and event["multiValueHeaders"]:
headers = Headers(event["multiValueHeaders"])
else:
headers = Headers(event[u"headers"])
headers = Headers(event["headers"])

script_name = get_script_name(headers, event.get("requestContext", {}))

# If a user is using a custom domain on API Gateway, they may have a base
# path in their URL. This allows us to strip it out via an optional
# environment variable.
path_info = event[u"path"]
path_info = strip_express_gateway_query_params(event["path"])
base_path = os.environ.get("API_GATEWAY_BASE_PATH")
if base_path:
script_name = "/" + base_path

if path_info.startswith(script_name):
path_info = path_info[len(script_name) :] # noqa: E203
path_info = path_info[len(script_name):]

body = event[u"body"] or ""
body = event.get("body") or ""
body = get_body_bytes(event, body)

environ = {
"CONTENT_LENGTH": str(len(body)),
"CONTENT_TYPE": headers.get(u"Content-Type", ""),
"PATH_INFO": url_unquote(path_info),
"CONTENT_TYPE": headers.get("Content-Type", ""),
"PATH_INFO": unquote(path_info),
"QUERY_STRING": encode_query_string(event),
"REMOTE_ADDR": event.get(u"requestContext", {}).get(u"identity", {}).get(u"sourceIp", ""),
"REMOTE_USER": event.get(u"requestContext", {}).get(u"authorizer", {}).get(u"principalId", ""),
"REQUEST_METHOD": event.get(u"httpMethod", {}),
"REMOTE_ADDR": event.get("requestContext", {})
.get("identity", {})
.get("sourceIp", ""),
"REMOTE_USER": (event.get("requestContext", {})
.get("authorizer") or {})
.get("principalId", ""),
"REQUEST_METHOD": event.get("httpMethod", {}),
"SCRIPT_NAME": script_name,
"SERVER_NAME": headers.get(u"Host", "lambda"),
"SERVER_PORT": headers.get(u"X-Forwarded-Port", "80"),
"SERVER_NAME": headers.get("Host", "lambda"),
"SERVER_PORT": headers.get("X-Forwarded-Port", "443"),
"SERVER_PROTOCOL": "HTTP/1.1",
"wsgi.errors": sys.stderr,
"wsgi.input": BytesIO(body),
"wsgi.input": io.BytesIO(body),
"wsgi.multiprocess": False,
"wsgi.multithread": False,
"wsgi.run_once": False,
"wsgi.url_scheme": headers.get(u"X-Forwarded-Proto", "http"),
"wsgi.url_scheme": headers.get("X-Forwarded-Proto", "https"),
"wsgi.version": (1, 0),
"serverless.authorizer": event.get(u"requestContext", {}).get(u"authorizer"),
"serverless.authorizer": event.get("requestContext", {}).get("authorizer"),
"serverless.event": event,
"serverless.context": context,
# TODO: Deprecate the following entries, as they do not comply with the WSGI
# spec. For custom variables, the spec says:
#
# Finally, the environ dictionary may also contain server-defined variables.
# These variables should be named using only lower-case letters, numbers, dots,
# and underscores, and should be prefixed with a name that is unique to the
# defining server or gateway.
"API_GATEWAY_AUTHORIZER": event.get(u"requestContext", {}).get(u"authorizer"),
"event": event,
"context": context,
}

environ = setup_environ_items(environ, headers)
Expand All @@ -228,49 +263,51 @@ def handle_payload_v1(app, event, context):


def handle_payload_v2(app, event, context):
headers = Headers(event[u"headers"])
headers = Headers(event["headers"])

script_name = get_script_name(headers, event.get("requestContext", {}))

path_info = event[u"rawPath"]
path_info = strip_express_gateway_query_params(event["rawPath"])
base_path = os.environ.get("API_GATEWAY_BASE_PATH")
if base_path:
script_name = "/" + base_path

if path_info.startswith(script_name):
path_info = path_info[len(script_name):]

body = event.get("body", "")
body = get_body_bytes(event, body)

headers["Cookie"] = "; ".join(event.get("cookies", []))

environ = {
"CONTENT_LENGTH": str(len(body)),
"CONTENT_TYPE": headers.get(u"Content-Type", ""),
"PATH_INFO": url_unquote(path_info),
"QUERY_STRING": url_encode(event.get(u"queryStringParameters", {})),
"REMOTE_ADDR": event.get("requestContext", {}).get(u"http", {}).get(u"sourceIp", ""),
"REMOTE_USER": event.get("requestContext", {}).get(u"authorizer", {}).get(u"principalId", ""),
"REQUEST_METHOD": event.get("requestContext", {}).get("http", {}).get("method", ""),
"CONTENT_LENGTH": str(len(body or "")),
"CONTENT_TYPE": headers.get("Content-Type", ""),
"PATH_INFO": unquote(path_info),
"QUERY_STRING": event.get("rawQueryString", ""),
"REMOTE_ADDR": event.get("requestContext", {})
.get("http", {})
.get("sourceIp", ""),
"REMOTE_USER": event.get("requestContext", {})
.get("authorizer", {})
.get("principalId", ""),
"REQUEST_METHOD": event.get("requestContext", {})
.get("http", {})
.get("method", ""),
"SCRIPT_NAME": script_name,
"SERVER_NAME": headers.get(u"Host", "lambda"),
"SERVER_PORT": headers.get(u"X-Forwarded-Port", "80"),
"SERVER_NAME": headers.get("Host", "lambda"),
"SERVER_PORT": headers.get("X-Forwarded-Port", "443"),
"SERVER_PROTOCOL": "HTTP/1.1",
"wsgi.errors": sys.stderr,
"wsgi.input": BytesIO(body),
"wsgi.input": io.BytesIO(body),
"wsgi.multiprocess": False,
"wsgi.multithread": False,
"wsgi.run_once": False,
"wsgi.url_scheme": headers.get(u"X-Forwarded-Proto", "http"),
"wsgi.url_scheme": headers.get("X-Forwarded-Proto", "https"),
"wsgi.version": (1, 0),
"serverless.authorizer": event.get("requestContext", {}).get(u"authorizer"),
"serverless.authorizer": event.get("requestContext", {}).get("authorizer"),
"serverless.event": event,
"serverless.context": context,
# TODO: Deprecate the following entries, as they do not comply with the WSGI
# spec. For custom variables, the spec says:
#
# Finally, the environ dictionary may also contain server-defined variables.
# These variables should be named using only lower-case letters, numbers, dots,
# and underscores, and should be prefixed with a name that is unique to the
# defining server or gateway.
"API_GATEWAY_AUTHORIZER": event.get("requestContext", {}).get(u"authorizer"),
"event": event,
"context": context,
}

environ = setup_environ_items(environ, headers)
Expand All @@ -280,3 +317,54 @@ def handle_payload_v2(app, event, context):
returndict = generate_response(response, event)

return returndict


def handle_lambda_integration(app, event, context):
headers = Headers(event["headers"])

script_name = get_script_name(headers, event)

path_info = strip_express_gateway_query_params(event["requestPath"])

for key, value in event.get("path", {}).items():
path_info = path_info.replace("{%s}" % key, value)
path_info = path_info.replace("{%s+}" % key, value)

body = event.get("body", {})
body = json.dumps(body) if body else ""
body = get_body_bytes(event, body)

environ = {
"CONTENT_LENGTH": str(len(body or "")),
"CONTENT_TYPE": headers.get("Content-Type", ""),
"PATH_INFO": unquote(path_info),
"QUERY_STRING": urlencode(event.get("query", {}), doseq=True),
"REMOTE_ADDR": event.get("identity", {}).get("sourceIp", ""),
"REMOTE_USER": event.get("principalId", ""),
"REQUEST_METHOD": event.get("method", ""),
"SCRIPT_NAME": script_name,
"SERVER_NAME": headers.get("Host", "lambda"),
"SERVER_PORT": headers.get("X-Forwarded-Port", "443"),
"SERVER_PROTOCOL": "HTTP/1.1",
"wsgi.errors": sys.stderr,
"wsgi.input": io.BytesIO(body),
"wsgi.multiprocess": False,
"wsgi.multithread": False,
"wsgi.run_once": False,
"wsgi.url_scheme": headers.get("X-Forwarded-Proto", "https"),
"wsgi.version": (1, 0),
"serverless.authorizer": event.get("enhancedAuthContext"),
"serverless.event": event,
"serverless.context": context,
}

environ = setup_environ_items(environ, headers)

response = Response.from_app(app, environ)

returndict = generate_response(response, event)

if response.status_code >= 300:
raise RuntimeError(json.dumps(returndict))

return returndict