Yes, you can configure an Ory Oathkeeper mutator to add the session id of the current user session as a request header. This can be achieved using the

header

mutator. The

header

mutator allows you to pass the credentials to the upstream application via the headers. Here is an example of how you can configure the

header

mutator to add a session id as a request header:

yaml # Global configuration file oathkeeper.yml   mutators:    header:    # Set enabled to true if the authenticator should be enabled and false to disable the authenticator. Defaults to false.    enabled: true    config:    headers:    X-Session-ID: "{{ print .Extra.session_id }}"

In this example,

X-Session-ID

is the name of the header, and

{{ print .Extra.session_id }}

is the value of the header. The value is a string which will be parsed by the Go

text/template

package for value substitution, receiving the

AuthenticationSession

struct. Please note that the session id must be available in the

extra

field of the

AuthenticationSession

struct. If it's not, you might need to use the

hydrator

mutator to fetch additional data from external APIs before the

header

mutator. For more details, please check the [Ory Oathkeeper documentation](https://www.ory.sh/docs/oathkeeper/pipeline/mutator#header).

The

AuthenticationSession

struct does not directly contain a field for the session id. Here is the structure as per the provided knowledge source:

go type AuthenticationSession struct {    Subject string    Extra map[string]interface{}    Header http.Header    MatchContext MatchContext   }      type MatchContext struct {    RegexpCaptureGroups []string    URL *url.URL    Method string    Header http.Header   }

As you can see, the

AuthenticationSession

struct contains

Subject

,

Extra

,

Header

, and

MatchContext

fields. The

Extra

field is a map that can contain additional data. If the session id is available, it would likely be stored in this

Extra

field. However, the session id is not automatically included in the

AuthenticationSession

struct. You might need to use a custom authenticator or the

hydrator

mutator to fetch the session id and add it to the

Extra

field. For more details, please check the [Ory Oathkeeper documentation](https://www.ory.sh/docs/oathkeeper/pipeline#session).

If the session id is stored in the

.Extra.id

field of the

AuthenticationSession

struct, you can configure the

header

mutator to add this session id as a request header. Here's how you can do it:

yaml # Global configuration file oathkeeper.yml   mutators:    header:    # Set enabled to true if the authenticator should be enabled and false to disable the authenticator. Defaults to false.    enabled: true    config:    headers:    X-Session-ID: "{{ print .Extra.id }}"

In this configuration,

X-Session-ID

is the name of the header, and

{{ print .Extra.id }}

is the value of the header. The value is a string which will be parsed by the Go

text/template

package for value substitution, receiving the

AuthenticationSession

struct. For more details, please check the [Ory Oathkeeper documentation](https://www.ory.sh/docs/oathkeeper/pipeline/mutator#header).