Documentation
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Overview ¶
Package validation defines the validation contract.
There is no reflection and there are no struct tags: every request type implements Validate and returns the errors per field. It is more verbose than `binding:"required"`, and deliberately so -- the message is written by whoever knows the domain, and the CLI generates the method skeleton along with the struct.
Index ¶
- func Confirmed(e Errors, field, value, confirmation string)
- func Email(e Errors, field, value string)
- func MaxLen(e Errors, field, value string, n int)
- func MinLen(e Errors, field, value string, n int)
- func NotZero[T comparable](e Errors, field string, value T)
- func Required(e Errors, field, value string)
- type Errors
- type Validatable
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Confirmed ¶ added in v0.19.0
Confirmed rejects a value its confirmation field does not repeat.
It is what a "confirm your password" box is for, and the message goes on the confirmation rather than on the field itself: a form that reports "password does not match" next to the first box tells the person to change the one they meant, and they change it, and the form fails again.
An empty confirmation is reported here rather than by Required, so the field gets one message instead of two saying the same thing.
func Email ¶
Email checks the shape only. Deliverability is proven by sending mail, never by a regular expression.
Whitespace is rejected rather than trimmed: an address with a space in it is almost always a paste accident, and silently trimming input hides the mistake from the person who made it.
func MinLen ¶
MinLen counts runes, not bytes: a limit measured in bytes rejects valid input in any language that needs more than one byte per character.
func NotZero ¶ added in v0.10.0
func NotZero[T comparable](e Errors, field string, value T)
NotZero reports a value that was never filled in.
It is Required for everything that is not text. Required takes a string and the generator used to hand it a literal "" for an int, a date or an amount -- so every required field of those types failed validation with "is required" no matter what was sent, and the generated create endpoint could not be used at all. Found by audit.
A time.Time is asked rather than compared: a parsed "0001-01-01T00:00:00Z" carries a location the zero value does not, so == says they differ when they do not.
Bool has no meaningful zero to reject -- false is an answer, not an absence -- and the specification refuses `required` on a bool for that reason.
Types ¶
type Errors ¶
Errors maps a field to its messages. It serializes straight into the HTMX partial that re-renders the form with inline errors.
func (Errors) Add ¶
Add appends a message to a field. It is a no-op on a nil map, so a caller that forgot to initialize the map does not panic in the middle of a request.
func (Errors) Error ¶
Error renders the errors with fields in a stable order, so that logs and golden files do not change between runs.
func (Errors) First ¶ added in v0.11.1
First returns one message, for a view that shows a single line.
A form that lists every error next to its field uses the map directly. One that shows a banner needs one sentence, and picking it at the call site means every template does it slightly differently.
The field order is not stable -- a map has none -- so this is for the case where any of them answers the question "what is wrong". When which field failed matters, read the map.
type Validatable ¶
type Validatable interface {
Validate() Errors
}
Validatable is implemented by every request type.
Source Files