Command filter for Postgres

The command filter is invoked whenever a command packet is received from the client. This can include the following packet types:

• Bind

• Close

• Describe

• Execute

• Flush

• FunctionCall

• Parse

• Query

• Sync

• Terminate

Parameters

• Packet types : optional. If specified, a comma-separated list of packet types for which this filter should be called, for instance: Parse,Bind,Close. Spaces are ignored. If this is not specified, all packet types will qualify.

Example

A typical use for this filter would be to set the Packet types parameter to Parse and modify certain SQL statements:

if (context.connectionContext.userName === 'henry' && sql.match(/^delete\s+from\s+customers\b/)) {
log.debug("Ignoring delete from customers for Henry");
context.packet.setQuery("delete from customers where first_name='IgnoreIgnoreIgnore'");
}

This will ensure that the delete will not actually delete anything, yes the database will respond appropriately.