Hello there,
I am currently working on a Shopify solution for a client. I have taken a peak around the API and I am currently developing using a private app. I ran into a couple stumbling blocks and was wondering if what I wanted to do is even possibly using Shopify. Here's my requirements:
The external database is a PostgreSQL database in a PHP environment.
1. Link Shopify products with external database inventory.
2. Get product qunatities from database, and on a sale, push new quantity back. (this seems possible from my query testing)
3. Link Shopify users with external database customers.
4. Limit quantity based on the user data pulled back from external database (reset monthly).
5. Cancel/stop order if quantity is too high for the user this month.
6. Ship to a location set in the external database (not Shopify set).
The biggest disconnect I am seeing is being able to overwrite some of the core Shopify workflow, like registration and check-out. The only thing I could think of was using ajax to load in this custom functionality via external PHP scripts; however, that's not very fool-proof.
If you could tell me if this would be possible using the API (and possibly what to look at) I would be very grateful.
Thanks!