Danger log 4.10: When a new purchase request created at the front-end, it should notify back-end.
So we created a socket for communications between front-end and back-end. Front-end will first store the package into database and then notify the daemon by sending the id.
4.11: Make the communication process asynchronous.
We created three separate threads for different communication purpose, ont thread for handling request from Django front-end, one thread used to listen the connection from UPS and one for communicate wth the world.
For asynchronous functions like toPurchase() and toPack(), thread-pool is used and functions will return immediately.
4.12: Users that are not login shouldn't get access to purchasing, modifying profile and other web pages.
So we added "@login_required" for related functions in views.py and fixed other model-related bugs.
4.13: Basic process realized with mocked-UPS, mocked-UPS only support two trucks for now, so can only buy two packages at the same time.
4.14: Fixed multi-thread problem related to sequence number, use synchronized methods to make the process of getting seqnum thread-safe.
Fixed asynchronous problem, we use a map to store the mapping between sequence number and request, and has a separate thread only for receiving information from the world, once receive it will loop through all field, update the corresponding package status, ack all requests and send back corresponding ack.
4.15-4.22: More front-end web pages and functionalities are added, user experience improved.
4.17: Fixed synchronize-related problems.
4.18: Fixed bugs in shopping-cart web page, make it more user friendly.
4.19: The database has empty tables when first created(in docker or in new environment), no items will be listed on the webpage.
So we use signals provided by django to create some default users, categories, items and warehouses after first migration.
4.22: Fixed bugs in showing the total price of an order and in modifying a selling product.