Validate Golang request data with simple rules
GitHub - thedevsaddam/govalidator: Validate Golang request data with simple rules. Highly inspired by Laravel's request validation.







Validate golang request data with simple rules. Highly inspired by Laravel's request validation.
Installation
Install the package using
$ go get github.com/thedevsaddam/govalidator
// or
$ go get gopkg.in/thedevsaddam/govalidator.v1
Usage
To use the package import it in your *.go code
import "github.com/thedevsaddam/govalidator"
// or
import "gopkg.in/thedevsaddam/govalidator.v1"
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"},
		"phone":    []string{"digits:ফোন নাম্বার অবশ্যই ১১ নম্বারের হতে 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 pass the rules
	}
	v := govalidator.New(opts)
	e := v.Validate()
	err := map[string]interface{}{"validationError": e}
	w.Header().Set("Content-type", "application/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
{
    "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 is required",
            "The email field must be a valid email address"
        ],
        "phone": [
            "ফোন নাম্বার অবশ্যই ১১ নম্বারের হতে হবে"
        ],
        "username": [
            "আপনাকে অবশ্যই ইউজারনেম দিতে হবে",
            "ইউজারনেম অবশ্যই ৩-৮ অক্ষর হতে হবে"
        ],
        "web": [
            "The web field format is invalid"
        ]
    }
}
More examples
Validate file

Validate file

Validate application/json or text/plain as raw body

Validate JSON to simple struct
Validate JSON to map
Validate JSON to nested struct
Validate using custom rule

Validate struct directly

Validate Struct

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_space The field under validation may have alpha-numeric characters, as well as dashes, underscores and space.
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. Moreover, both bounds can be omitted to create an unbounded minimum (e.g: numeric_between:,65) or an unbounded maximum (e.g: numeric_between:-1,).
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
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)
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)
email The field under validation must have a valid email.
float The field under validation must have a valid float number.
mac_address The field under validation must have be a valid Mac Address.
min:numeric The field under validation must have a min length of characters for string, items length for slice/map, value for integer or float.
e.g: min:3 may contains characters minimum length of 3 like "john", "jane", "jane321" but not "mr", "xy"
max:numeric The field under validation must have a max length of characters for string, items length for slice/map, value for integer or float.
e.g: max:6 may contains characters maximum length of 6 like "john doe", "jane doe" but not "john", "jane"
len:numeric The field under validation must have an exact length of characters, exact integer or float value, exact size of map/slice.
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:regular 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. 3) Zero length of map, slice. 4) Zero value for integer or float
size:integer The field under validation validate a file size only in form-data (see example)
ext:jpg,png The field under validation validate a file extension (see example)
mime:image/jpg,image/png The field under validation validate a file mime type (see example)
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,
}
Contribution
If you are interested to make the package better please send pull requests or create an issue so that others can fix.
Read the contribution guide here
Contributors

Jun Kimura
Steve HIll
ErickSkrauch
Sakib Sami
Rip
Jose Nazario

See all contributors
See benchmarks
Read API documentation
License
The govalidator is an open-source software licensed under the MIT License.
