Exception Handling

Art Admin uses typed exceptions with global middleware that automatically converts them to standard JSON responses.

Exception Types

Exception	HTTP Status	Usage
BadRequestException	400	Parameter error, business rule violation
UnauthorizedException	401	Not logged in, Token expired
ForbiddenException	403	No permission
NotFoundException	404	Resource not found
InternalServerException	500	Internal error

Usage

public async Task<UserDto> GetUserAsync(long id)
{
    var user = await _db.SysUsers.FindAsync(id);
    if (user == null)
        throw new NotFoundException("User not found");

    if (user.Status != 1)
        throw new BadRequestException("User is disabled");

    return new UserDto { ... };
}

Coding Style

Single-line if without braces:

// ✅ Correct
if (user == null)
    throw new NotFoundException("User not found");

// ❌ Wrong
if (user == null) {
    throw new NotFoundException("User not found");
}

Response Format

The global exception middleware catches all typed exceptions and returns:

{
  "code": 404,
  "msg": "User not found"
}

Successful Response

Normal returns are automatically wrapped:

{
  "code": 200,
  "data": { ... }
}

Frontend Integration

The frontend HTTP client (src/utils/http) has global ElMessage.error interception. Do not add duplicate error messages in catch blocks — just restore state:

try {
  await fetchSaveUser(formData);
} catch (e) {
  // ❌ Don't do this — duplicate toast
  // ElMessage.error('Save failed');

  // ✅ Just restore state
  loading.value = false;
}