Fix binary_support handling

[jait]

Description

The logic of handling response data when binary_support is True, was faulty. It base64-encoded every response, regardless of the content-type, which caused the user/browser to receive base64-encoded bodies if deployed with an API Gateway. ALB apparently supports base64-encoded responses and manages to decode them.

GitHub Issues

Relevant tickets:

• All responses are base64 encoded #1605
• bug: Error condition check for binary support #1871

[coveralls]

Coverage decreased (-0.04%) to 72.903% when pulling 222ea52 on jait:bugfix/fix-binary-support into f4e846f on Miserlou:master.

[jneves]

Thanks!

[martinv13]

There was indeed a bug in the logic with the condition being always true as discussed in #1605 .

However this PR broke my setup where response is compressed at application level (with flask_compress). The response is forced through response.get_data(as_text=True), which fails with gzipped payload.

I think a lighter change (just changing the "or" for a "and" in the following condition: not response.mimetype.startswith("text/") or response.mimetype != "application/json") would have fixed the problem without breaking the use case where the response is gzipped text.

I can send a new PR if you agree.
Thanks in advance!

[mzaglia]

I'm having the same problem as @martinv13 after compressing my response.