validate

Install MAGE-X build tool for development:

# Install MAGE-X for development and building
go install github.com/mrz1836/mage-x/cmd/magex@latest
magex update:install

This project uses goreleaser for streamlined binary and library deployment to GitHub. To get started, install it via:

brew install goreleaser

The release process is defined in the .goreleaser.yml configuration file.

Then create and push a new Git tag using:

magex version:bump bump=patch push=true branch=master

This process ensures consistent, repeatable releases with properly versioned artifacts and citation metadata.

View all build commands

magex help

All workflows are driven by modular configuration in .github/env/ — no YAML editing required.

View all workflows and the control center →

To update all dependencies (Go modules, linters, and related tools), run:

magex deps:update

This command ensures all dependencies are brought up to date in a single step, including Go modules and any managed tools. It is the recommended way to keep your development environment and CI in sync with the latest versions.

package main

import (
    "fmt"
    "log"

    "github.com/mrz1836/go-validate"
)

type User struct {
    Name     string `validation:"min_length=2 max_length=50"`
    Email    string `validation:"format=email"`
    Age      uint   `validation:"min=18 max=120"`
    Username string `validation:"min_length=3 max_length=20"`
}

func main() {
    // Initialize validations (required)
    validate.InitValidations()

    user := User{
        Name:     "John Doe",
        Email:    "john@example.com",
        Age:      25,
        Username: "johndoe",
    }

    // Validate the struct
    isValid, errors := validate.IsValid(user)
    if !isValid {
        for _, err := range errors {
            fmt.Printf("Validation error: %s\n", err.Error())
        }
    } else {
        fmt.Println("User is valid!")
    }
}

package main

import (
    "fmt"

    "github.com/mrz1836/go-validate"
)

type RegistrationForm struct {
    Email                string `validation:"format=email"`
    Password             string `validation:"min_length=8"`
    PasswordConfirmation string `validation:"compare=Password"`
    TermsAccepted        bool   // No validation needed
}

func main() {
    validate.InitValidations()

    form := RegistrationForm{
        Email:                "user@domain.com",
        Password:             "SecurePass123",
        PasswordConfirmation: "SecurePass123", // Must match Password field
        TermsAccepted:        true,
    }

    isValid, errors := validate.IsValid(form)
    if !isValid {
        fmt.Println("Registration form has errors:")
        for _, err := range errors {
            fmt.Printf("- %s\n", err.Error())
        }
    } else {
        fmt.Println("Registration form is valid!")
    }
}

package main

import (
    "fmt"

    "github.com/mrz1836/go-validate"
)

type Product struct {
    SKU         string  `validation:"format=regexp:^[A-Z]{2,3}[0-9]{4,6}$"`
    Name        string  `validation:"min_length=1 max_length=100"`
    Price       float64 `validation:"min=0.01"`
    Description string  `validation:"max_length=500"`
}

func main() {
    validate.InitValidations()

    product := Product{
        SKU:         "AB12345",  // Must match pattern: 2-3 uppercase letters + 4-6 digits
        Name:        "Wireless Headphones",
        Price:       99.99,
        Description: "High-quality wireless headphones with noise cancellation",
    }

    isValid, errors := validate.IsValid(product)
    if !isValid {
        fmt.Println("Product validation failed:")
        for _, err := range errors {
            fmt.Printf("- %s\n", err.Error())
        }
    } else {
        fmt.Println("Product is valid!")
    }
}

package main

import (
    "fmt"

    "github.com/mrz1836/go-validate"
)

type Contact struct {
    Name        string
    Email       string
    Phone       string
    Website     string
    CountryCode string
}

func (c *Contact) Validate() (bool, []validate.ValidationError) {
    var errors []validate.ValidationError

    // Email validation with MX record check
    if valid, err := validate.IsValidEmail(c.Email, true); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "Email",
            Message: err.Error(),
        })
    }

    // Phone number validation (US/Canada/Mexico)
    if valid, err := validate.IsValidPhoneNumber(c.Phone, c.CountryCode); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "Phone",
            Message: err.Error(),
        })
    }

    // Website host validation
    if c.Website != "" && !validate.IsValidHost(c.Website) {
        errors = append(errors, validate.ValidationError{
            Key:     "Website",
            Message: "is not a valid host or IP address",
        })
    }

    return len(errors) == 0, errors
}

func main() {
    contact := Contact{
        Name:        "Jane Smith",
        Email:       "jane@protonmail.com",
        Phone:       "555-123-4567",
        Website:     "janesmith.dev",
        CountryCode: "1", // USA/Canada
    }

    isValid, errors := contact.Validate()
    if !isValid {
        fmt.Println("Contact validation failed:")
        for _, err := range errors {
            fmt.Printf("- %s\n", err.Error())
        }
    } else {
        fmt.Println("Contact is valid!")
    }
}

package main

import (
    "fmt"
    "reflect"
    "strings"

    "github.com/mrz1836/go-validate"
)

// Custom validation for allowed colors
type colorValidation struct {
    validate.Validation
    allowedColors []string
}

func (c *colorValidation) Validate(value interface{}, _ reflect.Value) *validate.ValidationError {
    strValue, ok := value.(string)
    if !ok {
        return &validate.ValidationError{
            Key:     c.FieldName(),
            Message: "must be a string",
        }
    }

    // Check if color is in allowed list
    for _, color := range c.allowedColors {
        if strings.EqualFold(strValue, color) {
            return nil // Valid
        }
    }

    return &validate.ValidationError{
        Key:     c.FieldName(),
        Message: fmt.Sprintf("must be one of: %s", strings.Join(c.allowedColors, ", ")),
    }
}

// Builder function for the custom validation
func colorValidationBuilder(colors string, _ reflect.Kind) (validate.Interface, error) {
    allowedColors := strings.Split(colors, ",")
    for i, color := range allowedColors {
        allowedColors[i] = strings.TrimSpace(color)
    }

    return &colorValidation{
        allowedColors: allowedColors,
    }, nil
}

type Car struct {
    Make  string `validation:"min_length=1"`
    Model string `validation:"min_length=1"`
    Year  int    `validation:"min=1900 max=2024"`
    Color string `validation:"color=red,blue,green,black,white,silver"`
}

func main() {
    // Register our custom validation
    validate.AddValidation("color", colorValidationBuilder)
    validate.InitValidations()

    car := Car{
        Make:  "Toyota",
        Model: "Camry",
        Year:  2023,
        Color: "blue", // Must be one of the allowed colors
    }

    isValid, errors := validate.IsValid(car)
    if !isValid {
        fmt.Println("Car validation failed:")
        for _, err := range errors {
            fmt.Printf("- %s\n", err.Error())
        }
    } else {
        fmt.Println("Car is valid!")
    }
}

package main

import (
    "fmt"

    "github.com/mrz1836/go-validate"
)

type OrderStatus string

const (
    StatusPending   OrderStatus = "pending"
    StatusShipped   OrderStatus = "shipped"
    StatusDelivered OrderStatus = "delivered"
    StatusCancelled OrderStatus = "cancelled"
)

type Order struct {
    ID       string
    Status   string
    Priority string
}

func (o *Order) Validate() (bool, []validate.ValidationError) {
    var errors []validate.ValidationError

    // Validate order status using enum validation
    allowedStatuses := []string{"pending", "shipped", "delivered", "cancelled"}
    if valid, err := validate.IsValidEnum(o.Status, &allowedStatuses, false); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "Status",
            Message: err.Error(),
        })
    }

    // Validate priority with empty allowed
    allowedPriorities := []string{"low", "medium", "high", "urgent"}
    if valid, err := validate.IsValidEnum(o.Priority, &allowedPriorities, true); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "Priority",
            Message: err.Error(),
        })
    }

    return len(errors) == 0, errors
}

func main() {
    order := Order{
        ID:       "ORD-12345",
        Status:   "shipped",    // Valid status
        Priority: "",           // Empty allowed for priority
    }

    isValid, errors := order.Validate()
    if !isValid {
        fmt.Println("Order validation failed:")
        for _, err := range errors {
            fmt.Printf("- %s\n", err.Error())
        }
    } else {
        fmt.Println("Order is valid!")
    }
}

package main

import (
    "fmt"

    "github.com/mrz1836/go-validate"
)

// Customer model with comprehensive validation
type Customer struct {
    // Basic info with struct tags
    FirstName string `validation:"min_length=2 max_length=50"`
    LastName  string `validation:"min_length=2 max_length=50"`
    Email     string `validation:"format=email"`
    Age       uint8  `validation:"min=18 max=120"`

    // Address info
    Address string `validation:"min_length=10 max_length=200"`
    City    string `validation:"min_length=2 max_length=50"`
    State   string `validation:"min_length=2 max_length=2"` // US state codes
    ZipCode string `validation:"format=regexp:^[0-9]{5}(-[0-9]{4})?$"`

    // Contact info (validated separately)
    Phone               string `json:"phone"`
    SocialSecurityNumber string `json:"-"`

    // Account info
    AccountType    string  `validation:"min_length=1"`
    InitialBalance float64 `validation:"min=0"`
}

// Custom validation method that combines struct tags with utility functions
func (c *Customer) Validate() (bool, []validate.ValidationError) {
    // First run struct tag validations
    _, errors := validate.IsValid(*c)

    // Add phone number validation
    if valid, err := validate.IsValidPhoneNumber(c.Phone, "1"); !valid && c.Phone != "" {
        errors = append(errors, validate.ValidationError{
            Key:     "Phone",
            Message: err.Error(),
        })
    }

    // Add SSN validation
    if valid, err := validate.IsValidSocial(c.SocialSecurityNumber); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "SocialSecurityNumber",
            Message: err.Error(),
        })
    }

    // Add account type enum validation
    allowedTypes := []string{"checking", "savings", "business", "premium"}
    if valid, err := validate.IsValidEnum(c.AccountType, &allowedTypes, false); !valid {
        errors = append(errors, validate.ValidationError{
            Key:     "AccountType",
            Message: err.Error(),
        })
    }

    return len(errors) == 0, errors
}

func main() {
    validate.InitValidations()

    customer := Customer{
        FirstName:            "Alice",
        LastName:             "Johnson",
        Email:                "alice.johnson@email.com",
        Age:                  28,
        Address:              "123 Main Street, Apt 4B",
        City:                 "New York",
        State:                "NY",
        ZipCode:              "10001",
        Phone:                "555-123-4567",
        SocialSecurityNumber: "123-45-6789", // This will fail validation (blacklisted)
        AccountType:          "checking",
        InitialBalance:       1000.00,
    }

    isValid, errors := customer.Validate()
    if !isValid {
        fmt.Printf("Customer validation failed with %d errors:\n", len(errors))
        for i, err := range errors {
            fmt.Printf("%d. %s\n", i+1, err.Error())
        }
    } else {
        fmt.Println("Customer validation passed! Ready to save to database.")
    }
}