Let me add a little more on to what David had said
Tagval is a special function that allows the parser to parse key value pair messages.
For example: user=bob, ip=1.2.3.4, host=globalDC
We could very easily create a standard parser for the above, however with some devices they may not send the "ip" key if there is no value. If that was the case you would get:
user=bob, host=globalDC.
If the above case, using a standard parser, the message would not parse as it is missing "ip="
If we use the Tagval function we get two benefits.
1. The Keys can be missing or not.
2. the Keys can come in any order.
There is one issue however.. The parser has to be built for all possible keys that are sent.
So in our above example-- if we send more keys that what was defined, such as --
user=bob, ip=1.2.3.4, host=globalDC, location=USA
That message would not parse as we have no definition for "location="
By adding the flag of "missfields" This allows the parser to skip over "location=" and still parse the message. The "location=" will no go anywhere, and it will no parse.
The right thing to do is to build the parser with all possible variations. The missfields is a stop gap until you can.
Hope that helps
Dave
