gv

Overview ¶

Package gv (gorilla-validator) provides HTTP request validation middleware for Gorilla Mux.

It simplifies the process of validating and extracting data from various HTTP request sources, including URL parameters, query strings, form data, JSON, and XML.

Features ¶

• Easy to use middleware for Gorilla Mux
• Supports multiple data sources: URL parameters, query strings, form data, JSON, and XML
• Type-safe access to validated data
• Leverages go-playground/validator for validation rules
• Automatic HTTP 400 responses for invalid requests

Example ¶

Here's an example demonstrating how to use gorilla-validator with different data sources:

package main

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

	"github.com/gorilla/mux"
	gv "github.com/iamolegga/gorilla-validator"
)

func main() {
	router := mux.NewRouter()

	// URL parameters validation example
	// Define the schema for URL parameters
	type Params struct {
		ID int `schema:"id" validate:"required,gt=0"`
	}

	router.HandleFunc("/users/{id}", func(w http.ResponseWriter, r *http.Request) {
		// Get validated URL parameters
		params := gv.Validated[*Params](r, gv.Params)
	}).Methods("GET").Use(gv.Validate(Params{}, gv.Params))

	// Query parameters validation example
	// Define the schema for query parameters
	type Query struct {
		Page  int    `schema:"page" validate:"omitempty,gte=1"`
		Limit int    `schema:"limit" validate:"omitempty,gte=1,lte=100"`
		Sort  string `schema:"sort" validate:"omitempty,oneof=name email date"`
	}

	router.HandleFunc("/users", func(w http.ResponseWriter, r *http.Request) {
		// Get validated query parameters
		query := gv.Validated[*Query](r, gv.Query)
	}).Methods("GET").Use(gv.Validate(Query{}, gv.Query))

	// JSON body validation example
	// Define the schema for JSON body
	type BodyJSON struct {
		Name     string `json:"name" schema:"name" validate:"required,min=2"`
		Email    string `json:"email" schema:"email" validate:"required,email"`
		Password string `json:"password" schema:"password" validate:"required,min=8"`
	}

	router.HandleFunc("/users", func(w http.ResponseWriter, r *http.Request) {
		// Get validated JSON body
		data := gv.Validated[*BodyJSON](r, gv.JSON)
	}).Methods("POST").Use(gv.Validate(BodyJSON{}, gv.JSON))

	// Form data validation example
	// Define the schema for form data
	type BodyForm struct {
		Email    string `schema:"email" validate:"required,email"`
		Password string `schema:"password" validate:"required"`
		Remember bool   `schema:"remember"`
	}

	router.HandleFunc("/login", func(w http.ResponseWriter, r *http.Request) {
		// Get validated form data
		loginData := gv.Validated[*BodyForm](r, gv.Form)
	}).Methods("POST").Use(gv.Validate(BodyForm{}, gv.Form))

	// Multiple validators example
	// Define schemas for URL parameters and JSON body
	type MultiParams struct {
		ID int `schema:"id" validate:"required,gt=0"`
	}

	type MultiBody struct {
		Name  *string `json:"name" schema:"name" validate:"omitempty,min=2"`
		Email *string `json:"email" schema:"email" validate:"omitempty,email"`
	}

	router.HandleFunc("/users/{id}", func(w http.ResponseWriter, r *http.Request) {
		// Get validated URL parameters and JSON body
		params := gv.Validated[*MultiParams](r, gv.Params)
		updateData := gv.Validated[*MultiBody](r, gv.JSON)
	}).Methods("PATCH").
		Use(gv.Validate(MultiParams{}, gv.Params)).
		Use(gv.Validate(MultiBody{}, gv.JSON))

	http.ListenAndServe(":8080", router)
}

Validation Rules ¶

Validation rules are defined using struct tags with the go-playground/validator syntax. For a complete list of available validation rules, see: https://github.com/go-playground/validator

Sources ¶

The library supports the following sources for validation:

• gv.Params: URL parameters from Gorilla Mux
• gv.Query: Query string parameters
• gv.Form: Form data from POST requests
• gv.JSON: JSON request body
• gv.XML: XML request body

Error Handling ¶

By default, the middleware will automatically respond with HTTP 400 (Bad Request) when validation fails. This behavior can be customized by using the `gv.ErrorHandler` function:

gv.ErrorHandler(func(err error) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "Invalid request: "+err.Error(), http.StatusBadRequest)
	}
})