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Bug: HTTP API with router event handler fails on whitespace in path parameter

See original GitHub issue

Expected Behaviour

Calling GET /pets/{name} or GET /pets/{name}/vets should return a successful response with status code 200 when called with “Chester Mall” or “Chester%20Mall” (without ") as name. API Gateway will already decode encoded whitespaces as you can see in the example events.

GET /pets/Fiffi 
  {
      "version": "2.0",
      "routeKey": "GET /pets/{name}",
      "rawPath": "/pets/Fiffi",
      "rawQueryString": "",
      "headers": {
          "accept": "*/*",
          "accept-encoding": "gzip, deflate, br",
          "cache-control": "no-cache",
          "content-length": "0",
          "x-forwarded-port": "443",
          "x-forwarded-proto": "https"
      },
      "requestContext": {
          "http": {
              "method": "GET",
              "path": "/pets/Fiffi",
              "protocol": "HTTP/1.1"
          },
          "requestId": "QQCtFipSIAMEPNQ=",
          "routeKey": "GET /pets/{name}",
          "stage": "$default",
          "time": "08/Apr/2022:07:31:05 +0000",
          "timeEpoch": 1649403065999
      },
      "pathParameters": {
          "name": "Fiffi"
      },
      "isBase64Encoded": false
  }
GET /pets/Fiffi/vets 
  {
          "version": "2.0",
          "routeKey": "GET /pets/{name}/vets",
          "rawPath": "/pets/Fiffi/vets",
          "rawQueryString": "",
          "headers": {
              "accept": "*/*",
              "accept-encoding": "gzip, deflate, br",
              "cache-control": "no-cache",
              "content-length": "0",
              "x-forwarded-port": "443",
              "x-forwarded-proto": "https"
          },
          "requestContext": {
              "http": {
                  "method": "GET",
                  "path": "/pets/Fiffi/vets",
                  "protocol": "HTTP/1.1"
              },
              "requestId": "QQGmWiEcoAMEPqA=",
              "routeKey": "GET /pets/{name}/vets",
              "stage": "$default",
              "time": "08/Apr/2022:07:57:41 +0000",
              "timeEpoch": 1649404661221
          },
          "pathParameters": {
              "name": "Fiffi"
          },
          "isBase64Encoded": false
      }
GET /pets/Chester Mall 
{
      "version": "2.0",
      "routeKey": "GET /pets/{name}",
      "rawPath": "/pets/Chester Mall",
      "rawQueryString": "",
      "headers": {
          "accept": "*/*",
          "accept-encoding": "gzip, deflate, br",
          "cache-control": "no-cache",
          "content-length": "0",
          "x-forwarded-port": "443",
          "x-forwarded-proto": "https"
      },
      "requestContext": {
          "http": {
              "method": "GET",
              "path": "/pets/Chester Mall",
              "protocol": "HTTP/1.1"
          },
          "requestId": "QQCu1ioiIAMEPlg=",
          "routeKey": "GET /pets/{name}",
          "stage": "$default",
          "time": "08/Apr/2022:07:31:17 +0000",
          "timeEpoch": 1649403077140
      },
      "pathParameters": {
          "name": "Chester Mall"
      },
      "isBase64Encoded": false
  }
GET /pets/Chester Mall/vets 
 {
      "version": "2.0",
      "routeKey": "GET /pets/{name}/vets",
      "rawPath": "/pets/Chester Mall/vets",
      "rawQueryString": "",
      "headers": {
          "accept": "*/*",
          "accept-encoding": "gzip, deflate, br",
          "cache-control": "no-cache",
          "content-length": "0"
          "x-forwarded-port": "443",
          "x-forwarded-proto": "https"
      },
      "requestContext": {
          "http": {
              "method": "GET",
              "path": "/pets/Chester Mall/vets",
              "protocol": "HTTP/1.1"
          },
          "requestId": "QQGlpij8oAMEPig=",
          "routeKey": "GET /pets/{name}/vets",
          "stage": "$default",
          "time": "08/Apr/2022:07:57:36 +0000",
          "timeEpoch": 1649404656715
      },
      "pathParameters": {
          "name": "Chester Mall"
      },
      "isBase64Encoded": false
  }

Current Behaviour

Instead of a successful response a 404 “Not Found” is returned, with response body

{
    "statusCode": 404,
    "message": "Not found"
}

Code snippet

import aws_lambda_powertools.event_handler.api_gateway
from aws_lambda_powertools import Logger
from aws_lambda_powertools.event_handler import APIGatewayHttpResolver
from aws_lambda_powertools.logging import correlation_paths

logger = Logger()
app = APIGatewayHttpResolver()

# Add to code to handle whitespaces in path parameters
# aws_lambda_powertools.event_handler.api_gateway._UNSAFE_URI = "%<> \[\]{}|^"
# aws_lambda_powertools.event_handler.api_gateway._NAMED_GROUP_BOUNDARY_PATTERN = rf"(?P\1[{aws_lambda_powertools.event_handler.api_gateway._SAFE_URI}{aws_lambda_powertools.event_handler.api_gateway._UNSAFE_URI}\\w]+)"


@app.get("/pets/<name>")
def get_petname(name):
    return {"name": name}


@app.get("/pets/<name>/vets")
def get_petname(name):
    return {"pet_name": name, "vets": []}


@logger.inject_lambda_context(
    correlation_id_path=correlation_paths.API_GATEWAY_HTTP, log_event=True
)
def lambda_handler(event, context):
    return app.resolve(event, context)

Possible Solution

Change the _UNSAFE_URI constant in aws_lambda_powertools/event_handler/api_gateway from:

_UNSAFE_URI = "%<>\[\]{}|^"

to

# whitespace between <> and \[\]
_UNSAFE_URI = "%<> \[\]{}|^"

Steps to Reproduce

  1. Deploy reproducible example (https://github.com/sthuber90/aws-python-http-api-project)
  2. Call /pets/{name} and /pets/{name}/vets endpoint with different names

AWS Lambda Powertools for Python version

latest (layer version 16)

AWS Lambda function runtime

{“label”=>“3.9”}

Packaging format used

{“label”=>“Lambda Layers”}

Debugging logs

timestamp,message
1649404657592,"START RequestId: 46aafc05-0539-4035-83cb-cbd4268db189 Version: $LATEST
"
1649404657592,"2022-04-08 07:57:37,592 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Adding route using rule /pets/<name> and methods: GET
"
1649404657593,"2022-04-08 07:57:37,592 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Adding route using rule /pets/<name>/vets and methods: GET
"
1649404657593,"2022-04-08 07:57:37,593 aws_lambda_powertools.logging.logger [DEBUG] Decorator called with parameters
"
1649404657596,"2022-04-08 07:57:37,595 aws_lambda_powertools.logging.logger [DEBUG] Event received
"
1649404657596,"{""level"":""INFO"",""location"":""decorate:352"",""message"":{""version"":""2.0"",""routeKey"":""GET /pets/{name}/vets"",""rawPath"":""/pets/Chester Mall/vets"",""rawQueryString"":"""",""headers"":{""accept"":""*/*"",""accept-encoding"":""gzip, deflate, br"",""cache-control"":""no-cache"",""content-length"":""0"",""host"":""938e36howc.execute-api.us-east-1.amazonaws.com"",""postman-token"":""d44c4268-96ea-4e76-a308-ac9f2b0eb952"",""user-agent"":""PostmanRuntime/7.29.0"",""x-amzn-trace-id"":""Root=1-624feaf0-4b992fda408853251e402d93"",""x-forwarded-for"":""95.208.248.101"",""x-forwarded-port"":""443"",""x-forwarded-proto"":""https""},""requestContext"":{""http"":{""method"":""GET"",""path"":""/pets/Chester Mall/vets"",""protocol"":""HTTP/1.1"",""userAgent"":""PostmanRuntime/7.29.0""},""requestId"":""QQGlpij8oAMEPig="",""routeKey"":""GET /pets/{name}/vets"",""stage"":""$default"",""time"":""08/Apr/2022:07:57:36 +0000"",""timeEpoch"":1649404656715},""pathParameters"":{""name"":""Chester Mall""},""isBase64Encoded"":false},""timestamp"":""2022-04-08 07:57:37,596+0000"",""service"":""service_undefined"",""cold_start"":true,""function_name"":""aws-python-http-api-project-dev-hello"",""function_memory_size"":""1024"",""function_arn"":""arn:aws:lambda:us-east-1:373270804851:function:aws-python-http-api-project-dev-hello"",""function_request_id"":""46aafc05-0539-4035-83cb-cbd4268db189"",""correlation_id"":""QQGlpij8oAMEPig="",""xray_trace_id"":""1-624feaf0-1f7281e9141a9e970179de6f""}
"
1649404657596,"2022-04-08 07:57:37,596 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Converting event to API Gateway HTTP API contract
"
1649404657596,"2022-04-08 07:57:37,596 aws_lambda_powertools.event_handler.api_gateway [DEBUG] No match found for path /pets/Chester Mall/vets and method GET
"
1649404657597,"END RequestId: 46aafc05-0539-4035-83cb-cbd4268db189
"
1649404657597,"REPORT RequestId: 46aafc05-0539-4035-83cb-cbd4268db189	Duration: 2.12 ms	Billed Duration: 3 ms	Memory Size: 1024 MB	Max Memory Used: 57 MB	Init Duration: 531.20 ms	
"
1649404661256,"START RequestId: 23baf67a-158c-4246-a950-4eea00efba7d Version: $LATEST
"
1649404661259,"2022-04-08 07:57:41,259 aws_lambda_powertools.logging.logger [DEBUG] Event received
"
1649404661259,"{""level"":""INFO"",""location"":""decorate:352"",""message"":{""version"":""2.0"",""routeKey"":""GET /pets/{name}/vets"",""rawPath"":""/pets/Fiffi/vets"",""rawQueryString"":"""",""headers"":{""accept"":""*/*"",""accept-encoding"":""gzip, deflate, br"",""cache-control"":""no-cache"",""content-length"":""0"",""host"":""938e36howc.execute-api.us-east-1.amazonaws.com"",""postman-token"":""7d1e6998-1851-44fc-b029-279c7cbce941"",""user-agent"":""PostmanRuntime/7.29.0"",""x-amzn-trace-id"":""Root=1-624feaf5-1cf0e266526a59a700b13d68"",""x-forwarded-for"":""95.208.248.101"",""x-forwarded-port"":""443"",""x-forwarded-proto"":""https""},""requestContext"":{""http"":{""method"":""GET"",""path"":""/pets/Fiffi/vets"",""protocol"":""HTTP/1.1"",""userAgent"":""PostmanRuntime/7.29.0""},""requestId"":""QQGmWiEcoAMEPqA="",""routeKey"":""GET /pets/{name}/vets"",""stage"":""$default"",""time"":""08/Apr/2022:07:57:41 +0000"",""timeEpoch"":1649404661221},""pathParameters"":{""name"":""Fiffi""},""isBase64Encoded"":false},""timestamp"":""2022-04-08 07:57:41,259+0000"",""service"":""service_undefined"",""cold_start"":false,""function_name"":""aws-python-http-api-project-dev-hello"",""function_memory_size"":""1024"",""function_arn"":""arn:aws:lambda:us-east-1:373270804851:function:aws-python-http-api-project-dev-hello"",""function_request_id"":""23baf67a-158c-4246-a950-4eea00efba7d"",""correlation_id"":""QQGmWiEcoAMEPqA="",""xray_trace_id"":""1-624feaf5-44c0297c56144d6e0eb23a2f""}
"
1649404661260,"2022-04-08 07:57:41,260 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Converting event to API Gateway HTTP API contract
"
1649404661260,"2022-04-08 07:57:41,260 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Found a registered route. Calling function
"
1649404661260,"2022-04-08 07:57:41,260 aws_lambda_powertools.event_handler.api_gateway [DEBUG] Simple response detected, serializing return before constructing final response
"
1649404661260,"END RequestId: 23baf67a-158c-4246-a950-4eea00efba7d
"
1649404661260,"REPORT RequestId: 23baf67a-158c-4246-a950-4eea00efba7d	Duration: 1.85 ms	Billed Duration: 2 ms	Memory Size: 1024 MB	Max Memory Used: 57 MB	
"

Issue Analytics

  • State:closed
  • Created a year ago
  • Reactions:1
  • Comments:8 (6 by maintainers)

github_iconTop GitHub Comments

2reactions
sthulbcommented, Apr 8, 2022

@sthuber90 thanks for the contribution.

@michaelbrewer thanks for trying to shepherd this, but the project maintainers have already validated it and merged it

1reaction
sthuber90commented, Apr 8, 2022

No worries. Thank you for this great project and the awesome support ❤️

Read more comments on GitHub >

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