The 'OCSPRequest'
event is emitted when the client sends a certificate status
request. The listener callback is passed three arguments when called:
certificate
{Buffer} The server certificateissuer
{Buffer} The issuer’s certificatecallback
{Function} A callback function that must be invoked to provide the results of the OCSP request.
The server’s current certificate can be parsed to obtain the OCSP URL
and certificate ID; after obtaining an OCSP response, callback(null, resp)
is
then invoked, where resp
is a Buffer
instance containing the OCSP response.
Both certificate
and issuer
are Buffer
DER-representations of the
primary and issuer’s certificates. These can be used to obtain the OCSP
certificate ID and OCSP endpoint URL.
Alternatively, callback(null, null)
may be called, indicating that there was
no OCSP response.
Calling callback(err)
will result in a socket.destroy(err)
call.
The typical flow of an OCSP Request is as follows:
- Client connects to the server and sends an
'OCSPRequest'
(via the status info extension in ClientHello). - Server receives the request and emits the
'OCSPRequest'
event, calling the listener if registered. - Server extracts the OCSP URL from either the
certificate
orissuer
and performs an [OCSP request][] to the CA. - Server receives
'OCSPResponse'
from the CA and sends it back to the client via thecallback
argument - Client validates the response and either destroys the socket or performs a handshake.
The issuer
can be null
if the certificate is either self-signed or the
issuer is not in the root certificates list. (An issuer may be provided
via the ca
option when establishing the TLS connection.)
Listening for this event will have an effect only on connections established after the addition of the event listener.
An npm module like [asn1.js][] may be used to parse the certificates.