02-binding

Parameter Binding Example

This example demonstrates automatic parameter binding from different sources.

Features

• JSON body binding with validation
• URI parameter binding
• Query parameter binding
• Combined URI and JSON binding
• Custom validation

Running

go run main.go

Testing

Create User (JSON Binding)

curl -X POST http://localhost:8080/users \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice",
    "email": "alice@example.com",
    "password": "secret123",
    "age": 25
  }'

Update User (URI + JSON Binding)

curl -X PUT http://localhost:8080/users/1 \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice_updated",
    "email": "alice.new@example.com"
  }'

Query Users (Query Parameters)

curl "http://localhost:8080/users?page=1&page_size=10&keyword=alice"

Get User by ID

curl http://localhost:8080/users/1

Validation Test

# Valid request
curl -X POST http://localhost:8080/validate \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice",
    "email": "alice@example.com",
    "password": "secret123",
    "age": 25
  }'

# Invalid: reserved username
curl -X POST http://localhost:8080/validate \
  -H "Content-Type: application/json" \
  -d '{
    "username": "admin",
    "email": "admin@example.com",
    "password": "secret123",
    "age": 25
  }'

# Invalid: email format
curl -X POST http://localhost:8080/validate \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice",
    "email": "invalid-email",
    "password": "secret123",
    "age": 25
  }'

# Invalid: password too short
curl -X POST http://localhost:8080/validate \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice",
    "email": "alice@example.com",
    "password": "123",
    "age": 25
  }'

Validation Tags

Fox uses github.com/go-playground/validator/v10 for validation:

• required: Field must not be empty
• email: Must be a valid email address
• min, max: String length or numeric value range
• gte, lte: Greater/less than or equal
• gt, lt: Greater/less than
• omitempty: Skip validation if empty

For more validation tags, see: https://github.com/go-playground/validator