Localstack: `generic_proxy.py`'s `Connection` header handling should be case insensitive

[bobtiernay-okta]

Type of request:

• [x] bug report
• [ ] feature request

Detailed description

In 0.10.8, localstack/services/generic_proxy.py has regressed with respect to Connection header handling. HTTP headers are expected to be case insensitive.

In version 0.10.7 of generic_proxy.py:

if forward_headers.get('Connection', '').lower() != 'keep-alive':
  self.close_connection = 1

in 0.10.8 this was changed to

if forward_headers.get('Connection') not in ['keep-alive', None]:
  self.close_connection = 1

Note that the call to lower() was removed.

Expected behavior

Keep case insensitive Connection header handling.

Actual behavior

Case sensitive

Steps to reproduce

Send a request with Connection: Keep-Alive

Command used to start LocalStack

N/A

Client code (AWS SDK code snippet, or sequence of "awslocal" commands)

N/A

[whummer]

Thanks for reporting @bobtiernay-okta . This should be fixed in #2377 - can you please give it a try with the latest version of the Docker image? Please report here if the problem persists. Thanks!

[bobtiernay-okta]

@whummer I'm wondering about the logic:

        connection_header = forward_headers.get('Connection') or ''
        if connection_header.lower() not in ['keep-alive', '']:
            self.close_connection = 1

Why are 'keep-alive', '' and None treated the same? Shouldn't this logic be the following instead?

if forward_headers.get('Connection', '').lower() == 'close':
            self.close_connection = 1

or

if forward_headers.get('Connection', '').lower() != 'keep-alive':
            self.close_connection = 1

?

[bobtiernay-okta]

@whummer Per your ask, I've validated the fix and it looks like it does help quite a bit with our vast set of integration tests that invoke LocalStack in parallel. I have a feeling a number of reported issues will benefit from these (at least those using the Java AWS SDK). Looking forward to the next release so that we can move forward from 0.10.7.