parse

Documentation

Overview

Package parse provides parsing functionality for converting similar looking values into others with validation.

Index

• func Parse(src, dst any, options ...Option) error
• type InvalidParseError
  • func (e InvalidParseError) Error() string
• type Option
  • func WithDisallowUnknownFields() Option
  • func WithRenameFunc(f RenameFunc) Option
• type ParseError
  • func (e ParseError) Error() string
  • func (e ParseError) Path() string
  • func (e ParseError) Unwrap() error
• type Parser
• type RenameFunc
• type UnconvertableTypeError
  • func (e UnconvertableTypeError) Error() string
• type UnknownFieldError
  • func (e UnknownFieldError) Error() string

Examples

• Parse

Functions

func Parse

func Parse(src, dst any, options ...Option) error

Parse attempts to copy data from src into dst. If dst implements the Parser interface, Parse simply calls dst.Parse(src). Otherwise, it uses reflection to assign fields or elements to dst. To succeed, dst must be a non-nil pointer to a settable value.

The function supports struct-to-struct, map-to-struct, and slice-to-slice copying, as well as direct conversions between basic types (including []byte to string). If src is nil, no assignment is performed. If dst is not a valid pointer, an InvalidParseError is returned. If a type conversion is not possible, an UnconvertableTypeError is returned.

Successfully parsed value is already validated and can be used safely.

Any errors encountered during parsing are wrapped in a ParseError.

Parse also accepts options. See Option.

Example

package main

import (
	"fmt"

	"github.com/metafates/schema/parse"
	"github.com/metafates/schema/required"
)

func main() {
	type User struct {
		Name    required.Any[string] `json:"such_tags_are_ignored_by_default"`
		Comment string
		Age     int
	}

	var user1, user2 User

	parse.Parse(map[string]any{
		"Name":         "john",
		"Comment":      "lorem ipsum",
		"Age":          99,
		"UnknownField": "this field will be ignored",
	}, &user1)

	parse.Parse(struct {
		Name, Comment string
		Age           uint8 // types will be converted
	}{
		Name:    "jane",
		Comment: "dolor sit",
		Age:     55,
	}, &user2)

	fmt.Printf("user1: name=%q comment=%q age=%v\n", user1.Name.Get(), user1.Comment, user1.Age)
	fmt.Printf("user2: name=%q comment=%q age=%v\n", user2.Name.Get(), user2.Comment, user2.Age)

}

Output:

user1: name="john" comment="lorem ipsum" age=99
user2: name="jane" comment="dolor sit" age=55

Types

type InvalidParseError

type InvalidParseError struct {
	Type reflect.Type
}

InvalidParseError describes an invalid argument passed to Parse. The argument to Parse must be a non-nil pointer.

func (InvalidParseError) Error

func (e InvalidParseError) Error() string

type Option

type Option func(cfg *config)

Option modifies the parsing logic.

func WithDisallowUnknownFields

func WithDisallowUnknownFields() Option

WithDisallowUnknownFields is an option that will return an error if unknown field is supplied.

func WithRenameFunc

func WithRenameFunc(f RenameFunc) Option

WithRenameFunc is an option that will rename src fields/keys during parsing before matching with dst fields.

type ParseError

type ParseError struct {
	Msg   string
	Inner error
	// contains filtered or unexported fields
}

func (ParseError) Error

func (e ParseError) Error() string

func (ParseError) Path

func (e ParseError) Path() string

Path returns the path to the value which raised this error.

func (ParseError) Unwrap

func (e ParseError) Unwrap() error

type Parser

type Parser interface {
	Parse(v any) error
}

type RenameFunc

type RenameFunc func(string) string

type UnconvertableTypeError

type UnconvertableTypeError struct {
	Target, Original string
}

func (UnconvertableTypeError) Error

func (e UnconvertableTypeError) Error() string

type UnknownFieldError

type UnknownFieldError struct {
	Name string
}

func (UnknownFieldError) Error

func (e UnknownFieldError) Error() string