Error and Outage Handling
You will have to deal with two specific kinds of error:
- When MetaPack’s system cannot be located, is working too slowly or is not working properly.
- When MetaPack’s system is working, but is rejecting requests as they have invalid parameters.
From your customer’s perspective, the first one should be irrelevant, seamless. If that situation occurs, there’s nothing they can do to correct the situation (and nor can you). Therefore, reverting to a default delivery option is the best route forward. It is best that this be configurable (unless the business logic of determining which is applicable is simply too complex).
The second type of error deal with things like invalid postcodes, negative dimensions etc. These should all be corrected (perhaps by the customer).