Errors

Zinc uses normal Go error returns for handler failure flow.

At a glance

app.Get("/users/{id}", func(c *zinc.Context) error {
  user, err := findUser(c.Param("id"))
  if err != nil {
    return zinc.ErrNotFound.WithMessage("user not found")
  }
  return c.JSON(user)
})

Return errors from handlers and middleware. Let one app-level error handler decide how errors become HTTP responses.

Returning errors

app.Get("/users/{id}", func(c *zinc.Context) error {
  return zinc.ErrNotFound
})

If the returned error is an HTTPError, Zinc writes the associated status and message.

Structured HTTP errors

Build more specific errors with WithMessage, WithCause, WithMeta, and WithHeader.

return zinc.ErrBadRequest.
  WithMessage("invalid user payload").
  WithCause(err).
  WithMeta("field", "email")

Predefined errors

Zinc ships a broad set of predefined HTTP errors, including:

• ErrBadRequest
• ErrUnauthorized
• ErrForbidden
• ErrNotFound
• ErrMethodNotAllowed
• ErrUnprocessableEntity
• ErrInternalServerError

You can also create your own with NewError(code).

Abort helpers

For explicit short-circuiting inside handlers or middleware:

• AbortWithStatus(code)
• AbortWithJSON(code, value)
• Fail(err)

Example:

func requireAuth(c *zinc.Context) error {
  if c.GetHeader("Authorization") == "" {
    return c.AbortWithStatus(zinc.StatusUnauthorized)
  }
  return c.Next()
}

Custom error handlers

Override Zinc’s default error writer with Config.ErrorHandler.

app := zinc.NewWithConfig(zinc.Config{
  ErrorHandler: func(c *zinc.Context, err error) {
    _ = c.Status(zinc.StatusInternalServerError).JSON(zinc.Map{
      "error": err.Error(),
    })
  },
})

That gives you one place to standardize API error envelopes.

See also

• Your First Route for a small returned-error example.
• Configuration for Config.ErrorHandler.
• Errors API for predefined HTTP errors.