govalidator

#govalidator

#gorequest

#golang validation

#validation package golang

#go validation package

#github.com/thedevsaddam/govalidator

Package govalidator

Validate golang request data with simple rules. Highly inspired by Laravel's request validation.

Installation

Install the package using
go $ go get github.com/thedevsaddam/govalidator

Usage

To use the package import it in your *.go code
import "github.com/thedevsaddam/govalidator"

Example

Validate form-data, x-www-form-urlencoded and query params


package main

import (
    "encoding/json"
    "fmt"
    "net/http"

    "github.com/thedevsaddam/govalidator"
)

func handler(w http.ResponseWriter, r *http.Request) {
    rules := govalidator.MapData{
        "username": []string{"required", "between:3,8"},
        "email":    []string{"required", "min:4", "max:20", "email"},
        "web":      []string{"url"},
        "phone":    []string{"digits:11"},
        "agree":    []string{"bool"},
        "dob":      []string{"date"},
    }

    messages := govalidator.MapData{
        "username": []string{"required:আপনাকে অবশ্যই ইউজারনেম দিতে হবে", "between:ইউজারনেম অবশ্যই ৩-৮ অক্ষর হতে হবে।"},
        "zip":      []string{"numeric:জিপ কোড অবশ্যই নাম্বার হবে"},
    }

    opts := govalidator.Options{
        Request:         r,        // request object
        Rules:           rules,    // rules map
        Messages:        messages, // custom message map (Optional)
        RequiredDefault: true,     // all the field to be required
    }
    v := govalidator.New(opts)
    e := v.Validate()
    err := map[string]interface{}{"validationError": e}
    w.Header().Set("Content-type", "applciation/json")
    json.NewEncoder(w).Encode(err)
}

func main() {
    http.HandleFunc("/", handler)
    fmt.Println("Listening on port: 9000")
    http.ListenAndServe(":9000", nil)
}

Send request to the server using curl or postman: curl GET "http://localhost:9000?web=&phone=&zip=&dob=&agree="

Response
json { "validationError": { "agree": [ "The agree may only contain boolean value, string or int 0, 1" ], "dob": [ "The dob field must be a valid date format. e.g: yyyy-mm-dd, yyyy/mm/dd etc" ], "email": [ "The email field must be minimum 4 char" ], "phone": [ "The phone field must be 11 digits" ], "web": [ "The web field format is invalid" ] } }

More examples

Validation Rules

alpha The field under validation must be entirely alphabetic characters.
alpha_dash The field under validation may have alpha-numeric characters, as well as dashes and underscores.
alpha_num The field under validation must be entirely alpha-numeric characters.
between:numeric,numeric The field under validation check the length of characters/ length of array, slice, map/ range between two integer or float number etc.
numeric The field under validation must be entirely numeric characters.
numeric_between:numeric,numeric The field under validation must be a numeric value between the range. e.g: numeric_between:18,65 may contains numeric value like 35, 55 . You can also pass float value to check
bool The field under validation must be able to be cast as a boolean. Accepted input are true, false, 1, 0, "1" and "0".
credit_card The field under validation must have a valid credit card number. Accepted cards are Visa, MasterCard, American Express, Diners Club, Discover and JCB card
coordinate The field under validation must have a value of valid coordinate.
css_color The field under validation must have a value of valid CSS color. Accepted colors are hex, rgb, rgba, hsl, hsla like #909, #00aaff, rgb(255,122,122)
date The field under validation must have a valid date of format yyyy-mm-dd or yyyy/mm/dd.
date:dd-mm-yyyy The field under validation must have a valid date of format dd-mm-yyyy.
digits:int The field under validation must be numeric and must have an exact length of value.
digits_between:int,int The field under validation must be numeric and must have length between the range. e.g: digits_between:3,5 may contains digits like 2323, 12435
email The field under validation must have a valid email.
float The field under validation must have a valid float number.
in:foo,bar The field under validation must have one of the values. e.g: in:admin,manager,user must contain the values (admin or manager or user)
min:int The field under validation must have a min length of characters. e.g: min:3 may contains characters minimum length of 3 like "john", "jane", "jane321" but not "mr", "xy"
max:int The field under validation must have a max length of characters. e.g: max:6 may contains characters maximum length of 6 like "john doe", "jane doe" but not "john", "jane"
not_in:foo,bar The field under validation must have one value except foo,bar. e.g: not_in:admin,manager,user must not contain the values (admin or manager or user)
len:int The field under validation must have an exact length of characters. e.g: len:4 may contains characters exact length of 4 like Food, Mood, Good
ip The field under validation must be a valid IP address.
ip_v4 The field under validation must be a valid IP V4 address.
ip_v6 The field under validation must be a valid IP V6 address.
json The field under validation must be a valid JSON string.
lat The field under validation must be a valid latitude.
lon The field under validation must be a valid longitude.
regex:regurlar expression The field under validation validate against the regex. e.g: regex:^[a-zA-Z]+$ validate the letters.
required The field under validation must be present in the input data and not empty. A field is considered "empty" if one of the following conditions are true: 1) The value is null. 2)The value is an empty string.
url The field under validation must be a valid URL.
uuid The field under validation must be a valid UUID.
uuid_v3 The field under validation must be a valid UUID V3.
uuid_v4 The field under validation must be a valid UUID V4.
uuid_v5 The field under validation must be a valid UUID V5.

Add Custom Rules

func init() {
    // simple example
    govalidator.AddCustomRule("must_john", func(field string, rule string, message string, value interface{}) error {
        val := value.(string)
        if val != "john" || val != "John" {
            return fmt.Errorf("The %s field must be John or john", field)
        }
        return nil
    })

    // custom rules to take fixed length word.
    // e.g: word:5 will throw error if the field does not contain exact 5 word
    govalidator.AddCustomRule("word", func(field string, rule string, message string, value interface{}) error {
        valSlice := strings.Fields(value.(string))
        l, _ := strconv.Atoi(strings.TrimPrefix(rule, "word:")) //handle other error
        if len(valSlice) != l {
            return fmt.Errorf("The %s field must be %d word", field, l)
        }
        return nil
    })

}

Note: Array, map, slice can be validated by adding custom rules.

Custom Message/ Localization

If you need to translate validation message you can pass messages as options.

messages := govalidator.MapData{
    "username": []string{"required:You must provide username", "between:The username field must be between 3 to 8 chars"},
    "zip":      []string{"numeric:Please provide zip field as numeric"},
}

opts := govalidator.Options{
    Messages:        messages,
}