Why does the requests library add extra headers to the ones I set?

Question

I am trying to do a post request on python utilizing the requests library, when I set my custom headers which are the following:

User-Agent: MBAM-C
Content-Type: application/json
Authorization: True
Content-Length: 619
Connection: Close

However when It send the request with the custom headers it adds its own headers which give a bad request response from the server..

User-Agent: MBAM-C
Accept-Encoding: gzip, deflate
Accept: */*
Connection: Close
Content-Type: application/json
Authorization: True
Content-Length: 559

Answer 1

It is due to the design goals of the requests project.

This behavior is documented here . You may want to use a lower level library, if it is problematic for the library to be correcting content length or adding desirable headers. Requests bills itself as: "an elegant and simple HTTP library for Python, built for human beings." and a part of that is advertising that it can accept compressed content and all mime types.

Note: Custom headers are given less precedence than more specific sources of information . For instance:

Authorization headers set with headers= will be overridden if credentials are specified in .netrc, which in turn will be overridden by the auth= parameter. Authorization headers will be removed if you get redirected off-host. Proxy-Authorization headers will be overridden by proxy credentials provided in the URL. Content-Length headers will be overridden when we can determine the length of the content .