Vividus sends header "Connection" twice and it cause "Bad chunk header:" for API with strict headers policy

[DKalkaev]

We encountered an issue after updating Vividus from version 0.6.3 to 0.6.14.

The problem is related to the new header management in Vividus. Some GET API calls started returning the following error:
"Bad chunk header: {%body of JSON response%}"

We found that this issue is connected to a stricter header policy enforced by some APIs.

Background

In our tests, we set up a few additional custom headers:

• X-Request-Id
• X-Mashery-Oauth-Client-Id
• Authorization
• Content-Type
• X-Mashery-Oauth-Scope
• X-Mashery-Oauth-User-Context

After adding these custom headers, Vividus automatically adds some "default" headers.

Vividus Default Headers Comparison

Old Versions (0.6.3 - 0.6.13):

Accept-Encoding: gzip, x-gzip, deflate, br  
Host: XXXXXXXXXXXXXXXXXXX  
Connection: keep-alive  
User-Agent: Apache-HttpClient/5.2.1 (Java/17.0.1)  
Cookie: YYYYYYYYYYYYYYYYYYYY  

New Version (0.6.14):

Accept-Encoding: gzip, x-gzip, deflate, br  
Host: XXXXXXXXXXXXXXXXXXX  
Connection: keep-alive  
User-Agent: Apache-HttpClient/5.4.1 (Java/21.0.4)  
Upgrade: TLS/1.2  
Connection: Upgrade  
Cookie: YYYYYYYYYYYYYYYYYYYY  

Issue Details

The issue occurs with the Connection header. In the latest version, Vividus sends this header twice (keep-alive and Upgrade), which causes conflicts.

We replicated the issue using Postman, which confirmed this theory.

Suggestion

Could we introduce a feature to manage these cases and allow control over certain "default" headers?

Artifacts

• Screenshot (Left is new version of Vividus, right is a old version of Vividus)
  

**Execution environment **

• Vividus version: [e.g. 0.6.14]
• OS: [e.g. Linux, Windows]
• Java: [e.g. OpenJDK 64-Bit Server VM (build 21)]

Additional context
Link to StackOverflow with similar issue and same resolution
https://stackoverflow.com/questions/71615000/postman-error-parse-error-invalid-character-in-chunk-size

[valfirst]

@DKalkaev please try 0.6.15-SNAPSHOT version