Signer should return string being the value of the authorization header

[numbat]

See comments in: #58

And: https://github.com/Covata/delta-sdk-python/blob/master/src/main/python/covata/delta/signer.py

My proposal is to shift the the insertion of extra header values into the ApiClient, specifically into either the individual request methods or into the signer. My preference is for verbosity so that we are explicit about the request construction and manually add it into the header section (I feel this will also help make reading the requests easier for people that want to pattern or craft their own requests manually):

        response = requests.post(
            url="{base_url}{resource}".format(
                base_url=self.DELTA_URL,
                resource=self.RESOURCE_SECRETS),
            headers={
                "cvt-date": datetime.utcnow().strftime(CVT_DATE_FORMAT),
                "host": self.DELTA_URL
            },
            ....

This refactor would result in the sign_request method in ApiClient receiving a str response instead of the current dict[str,str] and result in some possible simplifications of the test_signer module.

[myuwono]

how about modifying sign request as follows:

    def signer(self, identity_id):
        def sign_request(r):
            # type: (requests.PreparedRequest) -> requests.PreparedRequest
            signing_key = self.key_store.get_private_signing_key(identity_id)
            r.headers["Cvt-Date"] = datetime.utcnow().strftime(CVT_DATE_FORMAT)
            r.headers["Host"] = self.DELTA_URL
            r.headers["Authorization"] = signer.get_authorization_header(
                identity_id=identity_id,
                method=r.method,
                url=r.url,
                headers=r.headers,
                payload=r.body,
                private_signing_key=signing_key)
            return r
        return sign_request

this way we can reduce code duplication since all requests calling self.signer(identity_id) will implicitly have their headers updated.

What do you think?

[numbat]

Yes that looks pretty good and reads very well.

[behlrattan]

Yes this is more readable, so all this code in get_signature_material function will move to api client?