@classmethod
    def build_security_headers(cls, context):
        header = {}

        # fwd on actor specific information, according to common message format spec
        actor_id            = context.get('ion-actor-id', None)
        actor_roles         = context.get('ion-actor-roles', None)
        actor_tokens        = context.get('ion-actor-tokens', None)
        expiry              = context.get('expiry', None)
        container_id        = context.get('origin-container-id', None)
        original_conv_id    = context.get('original-conv-id', None)
        conv_id             = context.get('conv-id', None)

        #If an actor-id is specified then there may be other associated data that needs to be passed on
        if actor_id:
            header['ion-actor-id'] = actor_id
            if actor_roles:     header['ion-actor-roles']   = actor_roles

        #This set of tokens is set independently of the actor
        if actor_tokens:    header['ion-actor-tokens']   = actor_tokens

        if expiry:          header['expiry']                = expiry
        if container_id:    header['origin-container-id']   = container_id

        #Since this is not the originating message, this must be a requests within an existing conversation,
        #so track original conversation
        if original_conv_id:
            header['original-conv-id'] = original_conv_id
        else:
            if conv_id:
                header['original-conv-id'] = conv_id

        return header
Examining context, builds a set of headers containing necessary forwarded items.
dataset/ETHPy150Open ooici/pyon/pyon/ion/endpoint.py/ProcessEndpointUnitMixin.build_security_headers