Rene Nochebuena
328b80c060
Struct validation backed by go-playground/validator/v10 with xerrors integration and pluggable i18n message providers. What's included: - Validator interface with Struct(v any) error method - New(...Option) constructor with WithMessageProvider functional option - MessageProvider interface for i18n; DefaultMessages (EN) and SpanishMessages (ES) built in - ValidationErrors mapped to xerrors.ErrInvalidInput with field and tag context keys - InvalidValidationError (non-struct input) mapped to xerrors.ErrInternal - Full playground.ValidationErrors attached via WithError for callers needing all failures Tested-via: todo-api POC integration Reviewed-against: docs/adr/
80 lines
2.0 KiB
Go
80 lines
2.0 KiB
Go
package valid
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import (
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"errors"
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"code.nochebuena.dev/go/xerrors"
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playground "github.com/go-playground/validator/v10"
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)
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// Validator validates structs using struct tags.
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type Validator interface {
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// Struct validates v and returns a *xerrors.Err if validation fails.
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// Returns nil if v is valid.
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// Returns ErrInvalidInput for field constraint failures (first error only).
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// Returns ErrInternal if v is not a struct.
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Struct(v any) error
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}
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// Option configures a Validator.
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type Option func(*config)
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// config holds constructor configuration.
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type config struct {
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mp MessageProvider
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}
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// WithMessageProvider sets a custom MessageProvider.
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// Default: DefaultMessages (English).
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func WithMessageProvider(mp MessageProvider) Option {
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return func(c *config) {
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c.mp = mp
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}
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}
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// New returns a Validator. Without options, DefaultMessages (English) is used.
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func New(opts ...Option) Validator {
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cfg := &config{mp: DefaultMessages}
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for _, o := range opts {
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o(cfg)
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}
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return &validator{
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v: playground.New(),
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mp: cfg.mp,
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}
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}
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// validator is the concrete implementation of Validator.
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type validator struct {
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v *playground.Validate
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mp MessageProvider
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}
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// Struct implements Validator.
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//
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// Only the first validation error is surfaced. Apps needing all failures can
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// cast errors.Unwrap(err) to validator.ValidationErrors themselves.
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func (val *validator) Struct(v any) error {
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err := val.v.Struct(v)
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if err == nil {
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return nil
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}
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var invalidErr *playground.InvalidValidationError
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if errors.As(err, &invalidErr) {
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return xerrors.Wrap(xerrors.ErrInternal, "internal validation error", err)
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}
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var validationErrs playground.ValidationErrors
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if errors.As(err, &validationErrs) {
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first := validationErrs[0]
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msg := val.mp.Message(first.Field(), first.Tag(), first.Param())
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return xerrors.New(xerrors.ErrInvalidInput, msg).
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WithContext("field", first.Field()).
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WithContext("tag", first.Tag()).
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WithError(err)
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}
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return xerrors.Wrap(xerrors.ErrInternal, "internal validation error", err)
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}
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