Exercise: Warehouse Stock Sync

Build a utility method to read, deserialize, update, serialize, and write JSON inventory data using asynchronous file operations.

Problem statement

A warehouse manages its inventory using a JSON configuration file. When a new shipment arrives, the automated system must use a utility method to read the current stock from the disk, increase the item's quantity, and save the updated inventory back to the disk in a clean, human-readable format.

Task requirements

In InventoryManager.cs, implement the AddStockAsync method.
Read the contents of the existing JSON file at filePath.
Deserialize the JSON string into an InventoryItem object.
Increase the StockQuantity of the retrieved item by the quantityToAdd parameter.
Serialize the updated object back into a JSON string, formatted with indentation (pretty-printing).
Overwrite the original file with the newly formatted JSON string.
Print “Inventory updated successfully.” to the console.
In Program.cs, read the initial JSON file using File.ReadAllTextAsync and print it to the console.
In Program.cs, call the utility method to add 50 units.
In Program.cs, read the updated JSON file using File.ReadAllTextAsync and print it to the console to verify the change.

Constraints

Use File.ReadAllTextAsync and File.WriteAllTextAsync to perform non-blocking file I/O operations.
Use JsonSerializer.Deserialize<T> and JsonSerializer.Serialize from the System.Text.Json namespace.
Create a JsonSerializerOptions object and set WriteIndented = true to format the output.

Good luck trying the exercise! If you’re unsure how to proceed, check the “Solution” tab above.

Get hints

Make sure to use the generic version of the deserializer: JsonSerializer.Deserialize<InventoryItem>(jsonString).
Because Deserialize can technically return null, you can use the null-conditional operator or a standard if check before adding quantityToAdd to the stock quantity.
Pass your configured JsonSerializerOptions instance as the second argument to JsonSerializer.Serialize() to ensure the output is indented.
Don't forget to await your utility method call and your file read operations in Program.cs.