how to keep key case sensitive in request header using golang?

Question

I am recently using golang library "net/http",while add some header info to request, I found that the header keys are changing, e.g

request, _ := &http.NewRequest("GET", fakeurl, nil)
request.Header.Add("MyKey", "MyValue")
request.Header.Add("MYKEY2", "MyNewValue")
request.Header.Add("DONT-CHANGE-ME","No")

however, when I fetch the http message package, I found the header key changed like this:

Mykey: MyValue
Mykey2: MyNewValue
Dont-Change-Me:  No

I using golang 1.3, then how to keep key case sensitive or keep its origin looking? thx.

Answer 1

The http.Header Add and Set methods canonicalize the header name when adding values to the header map. You can sneak around the canonicalization by adding values using map operations:

request.Header["MyKey"] = []string{"MyValue"}
request.Header["MYKEY2"] = []string{"MyNewValue"}
request.Header["DONT-CHANGE-ME"] = []string{"No"}

As long as you use canonical names for headers known to the transport, this should work.