receipt-processor-api

This is a contrived API and an implementation of the receipt processor challenge. See this reddit thread for more info.

Notes about this project / feedback

• Due to time constraints, not a lot of validation is being done on data posted.
• It's odd that numbers are being represented in incoming JSON as strings. I probably would have implemented a custom Unmarshal to normalize the data if I had more time to keep my downstream logic more pristine.
• I found it odd that there was a total at the receipt level when it could be calculated by the items. Perhaps an attempt to get developers to make note of that?
• I have been writing software professionally for almost 20 years and I have yet to see a requirement like "If the trimmed length of the item description is a multiple of 3, multiply the price by 0.2 and round up to the nearest integer". I understand the rationale, but, it would have been more fun if they had attempted to find real-world stuff like "if the receipt originated in WA, apply a tax rate of X to the total".
• Some things were (probably intentionally) ambiguous. Like "If the trimmed length of some string...". Length in what sense? String length is complicated. From the docs: "But what about the lower case grave-accented letter ‘A’, à? That’s a character, and it’s also a code point (U+00E0), but it has other representations. For example we can use the “combining” grave accent code point, U+0300, and attach it to the lower case letter a, U+0061, to create the same character à".
• I clearly decided to go the barebones route. A single file and very few dependencies. I think this is inline with idiomatic code for small projects.

Running the project

Make sure you have Go installed. Then run the following commands:

# First, download dependencies
go mod tidy
# Next, run the project.
go run main.go

To test, you can use curl to post data:

curl -d '{ "retailer": "M&M Corner Market", "purchaseDate": "2022-03-20", "purchaseTime": "14:33", "items": [ { "shortDescription": "Gatorade", "price": "2.25" },{ "shortDescription": "Gatorade", "price": "2.25" },{ "shortDescription": "Gatorade", "price": "2.25" },{ "shortDescription": "Gatorade", "price": "2.25" } ], "total": "9.00" }' -H "Content-Type: application/json" -X POST http://localhost:8080/receipts/process

Take note of the returned ID. You can either just open http://localhost:8080/receipts/{the ID you recorded}/points in your browser, or use another curl command to check it:

curl localhost:8080/receipts/{the ID you recorded}/points

Testing the project

Run go test to run unit tests.