The AI Pasted Text into SQL

An AI assistant wrote a product search for this shop: /products/search?q=te finds every product whose name contains te. It built the SQL by joining strings with +:

const word = req.query.q || "";
const rows = db.prepare("SELECT name, price FROM products WHERE name LIKE '%" + word + "%'").all() as ProductRow[];

The + pastes the visitor's text into the SQL itself. A quote in that text ends the SQL string early, and the rest runs as SQL: Ana's breaks the query, and x' UNION SELECT name, email FROM customers -- answers every customer's name and email, as if they were products. This is SQL injection. TypeScript can't catch it: to the compiler, the AI's SQL is just a string like any other.

The fix is a placeholder: write ? in the SQL and pass the value beside it, to .all(...). Here it is on another table:

const rows = db.prepare("SELECT name FROM customers WHERE city = ?").all(city) as CustomerRow[];

The SQL text stays the same whatever the visitor types, and the database only compares the value, quotes and all. Your code must give these answers:

GET /products/search?q=te     →  200  [{"name": "Notebook", "price": 7}, {"name": "Teapot", "price": 22}]
GET /products/search?q=MUG    →  200  [{"name": "Mug", "price": 12}]
GET /products/search?q=Ana's  →  200  []
GET /products/search?q=x' UNION SELECT name, email FROM customers --  →  200  []
GET /products/search          →  200  [{"name": "Mug", "price": 12}, {"name": "Notebook", "price": 7}, … all 8 products]

Your task: rewrite the handler of GET /products/search. Read q (default ""), build the pattern %word% as a string, run the query with LIKE ? and the pattern as its value, typed as ProductRow[], and answer the rows as JSON.

Assignment
Follow the Coding Tutorial to rewrite the search route with a placeholder.

Hint
The % signs go into the value, not into the SQL: the SQL only says LIKE ?. Pass pattern to .all(...) and add as ProductRow[]: it gives an array with one object per row, ready for res.json.