jamescun / Legit

Legit is an input validation framework for Go. Legit differs from existing frameworks by constructing validation from types and interfaces, preferring custom validators to complex struct tags.

go get -u github.com/jamescun/legit

Included validators:

• Email
• UUID
• UUID3
• UUID4
• UUID5
• Credit Card
• Lowercase
• Uppercase
• No whitespace
• Printable characters
• Alpha
• Alphanumeric
• Numeric
• ASCII
• Positive number
• Negative number

Example

package main

import (
	"fmt"
	"net/http"

	"github.com/jamescun/legit"
)

type User struct {
	Email legit.Email    `json:"email"`
	Age   legit.Positive `json:"age"`
}

func Handler(w http.ResponseWriter, r *http.Request) {
	var user User
	err := legit.ParseRequestAndValidate(r, &user)
	if err != nil {
		fmt.Fprintln(w, "invalid user:", err)
		return
	}
}

Custom Example

package main

import (
	"fmt"
	"regexp"
	"errors"
	"encoding/json"

	"github.com/jamescun/legit"
)

type Name string

// very simplistic regexp for human name validation
var expName = regexp.MustCompile(`[a-zA-Z\ ]{1,64}`)

// attach Validate() method to our custom name type, satisfying the legit.Object interface,
// defining our custom name validation.
func (n Name) Validate() error {
	if !expName.MatchString(string(n)) {
		return errors.New("invalid name")
	}

	return nil
}

type User struct {
	Email legit.Email `json:"email"`
	Name  Name        `json:"name"`
}

func main() {
	body := []byte(`{"email": "[email protected]", "name": "John Doe"}`)
	
	var user User
	json.Unmarshal(body, &user)

	err := legit.Validate(user)
	if err != nil {
		fmt.Println("invalid user!", err)
	}
}