(Added in V6.12)

When the IMAP4 CAPABILITY command is received, VPOP3 generates a capability string based on settings, then calls

DoCapability(ipaddr, capabilities)

• ipaddr = IP address of the client computer
• capabilities = generated capabilities (a space is added at the beginning and end to make finding words simpler)

The function should return a new capabilities string. To do nothing, return the 'capabilities' argument. You can remove capabilities from the string by using string modification functions. We do not recommend adding capabilities as they will not be supported by the rest of the IMAP4 service, so could lead to email client problems.

e.g.

function DoCapability(ipaddr, caps)
  --Remove IDLE from the list of capabilities
  caps = string.gsub(caps, " IDLE ", " ")
  return caps
end

			if (m_Lua.Call("DoListResult", false, f->first, strFlags, strExtra))
			{
				m_Lua.GetReturnIndexString(1, strFlags);
				m_Lua.GetReturnIndexString(2, strExtra);
			}

When the IMAP4 LIST command is received, for each folder to be returned by the command, VPOP3 calls

DoListResult(foldername, attributes, extended)

• foldername = the name of the folder
• attributes = the attributes which will be returned for the list
• extended = extra information to be returned for the list (eg CHILDINFO data)

The function should return a three values

1. boolean to indicate whether the folder response should be sent (true) or hidden (false)
2. new attributes
3. new extended data

If the folder response is sent, it is formatted as: * (<attributes>) “/” “<foldername>”<extended>

e.g.

function DoListResult(folder, attributes, extended)
-- do nothing
  return true, attributes, extended
end  

(Added in version 8.7)

When a connection is established, this lets the script define the encryption mode for this connection

GetEncryption(ipaddr, server addr, server port, default encryption mode)

• ipaddr - client IP address
• server addr - server IP address (eg if different IP addresses have bindings)
• server port - server port (eg if different ports have bindings)
• default encryption mode - 0 = no encryption/STARTTLS, 1 = SSL/TLS, 3 = Force STARTTLS

returns a single number of the new encryption mode

e.g. This will set SSL/TLS for connections to port 993 (bind the service to both ports 143 and 993, and set the encryption mode for None/STARTTLS or STARTTLS, which will still apply to connections to port 143)

function GetEncryption(client, svr, svrport, enc)
  if (svrport==993) then
      enc = 1;
  end
  return enc;
end