Sign cloud storage URLs

A Tulip API key is required to use the Tulip API. API key authentication uses HTTP Basic Authentication as defined by RFC 7617. HTTP Basic Authentication uses a generic username/password scheme to authenticate. For Tulip API requests, the password should be the API key's associated secret. The username should have the format {type}.{version}_{id}, where {type} is the API key type, {version} is the type's version number, and {id} is the id of the key. Tulip API keys currently are one of two types:

• apikey.2 - user API keys provisioned by creating a Tulip API Token. The key id is the token id.
• onetime.1 - temporary API keys provisioned using the /auth/temporary endpoint or using the One-Time API Key page. These keys are only valid for 30 seconds after provisioning.

Once you have determined the username and password you need to use, the Authorization header should be set to the value Basic {credentials}, where {credentials} is the base64-encoded value of the string {username}:{password}. See RFC 7617 for more details of this encoding.