# What the client sees when something is wrong


--- validation: three fields wrong at once ---
$ curl -i -X POST 'localhost:8080/api/books' -H 'Content-Type: application/json' -d '{"title":"","author":"Someone","isbn":"123","price":-1}'
HTTP 400
{"detail":"Invalid request content.","instance":"/api/books","status":400,"title":"Bad Request","errors":{"isbn":"must be 13 digits starting with 978 or 979","price":"must be greater than or equal to 0.00","title":"must not be blank"}}


--- duplicate ISBN on create ---
$ curl -i -X POST 'localhost:8080/api/books' -H 'Content-Type: application/json' -d '{"title":"Java Concurrency in Practice","author":"Brian Goetz","isbn":"9780321349606","price":39.99}'
HTTP 409
{"detail":"A book with that ISBN already exists","instance":"/api/books","status":409,"title":"Conflict"}


--- duplicate ISBN on update (book 2 takes book 1's ISBN) ---
$ curl -i -X PUT 'localhost:8080/api/books/2' -H 'Content-Type: application/json' -d '{"title":"Java Concurrency in Practice","author":"Brian Goetz","isbn":"9780134685991","price":39.99}'
HTTP 409
{"detail":"A book with that ISBN already exists","instance":"/api/books/2","status":409,"title":"Conflict"}


--- the message MySQL itself produced for the duplicate ---
Duplicate entry '9780134685991' for key 'book.uk_book_isbn'

--- unknown id ---
$ curl -i -X GET 'localhost:8080/api/books/99'
HTTP 404
{"detail":"Book 99 not found","instance":"/api/books/99","status":404,"title":"Not Found"}

$ curl -i -X DELETE 'localhost:8080/api/books/99'
HTTP 404
{"detail":"Book 99 not found","instance":"/api/books/99","status":404,"title":"Not Found"}


--- the id is not a number ---
$ curl -i -X GET 'localhost:8080/api/books/abc'
HTTP 400
{"detail":"Failed to convert 'id' with value: 'abc'","instance":"/api/books/abc","status":400,"title":"Bad Request"}


--- the body is not JSON ---
$ curl -i -X POST 'localhost:8080/api/books' -H 'Content-Type: application/json' -d '{not json'
HTTP 400
{"detail":"Failed to read request","instance":"/api/books","status":400,"title":"Bad Request"}