After an upgrade from 11g to 12c, an application using the external procedural gateway (EPG) and basic authentication got a 401: not authorized.
It appears that in 12c, the EPG uses digest authentication in stead of basic authentication by default. You won’t notice this using a browser or WGET, but applications using CURL will fail.
Digest is a two-step way of authenticating, returning a so called nonce first to be used to encrypt the username and password in the request.
Using CURL, this can be solved by adding – -digest before the request.
An other option is to reset EPG (actually XDB) to use basic again by editing xdbconfig.xml (a row in the table XDB$CONFIG).
This can be done using this call:
Don’t forget to commit…