- fixed validation-guide

docs/guide/validation.md

@@ -8,76 +8,161 @@ sidebar_position: 5
 
 Fiber can make _great_ use of the validator package to ensure correct validation of data to store.
 
-* [Official validator Github page \(Installation, use, examples..\).](https://github.com/go-playground/validator)
+- [Official validator Github page \(Installation, use, examples..\).](https://github.com/go-playground/validator)
 
 You can find the detailed descriptions of the _validations_ used in the fields contained on the structs below:
 
-* [Detailed docs](https://pkg.go.dev/github.com/go-playground/validator?tab=doc)
+- [Detailed docs](https://pkg.go.dev/github.com/go-playground/validator?tab=doc)
 
 ```go title="Validation Example"
-type Job struct{
-    Type          string `validate:"required,min=3,max=32"`
-    Salary        int    `validate:"required,number"`
-}
+package main
+
+import (
+	"fmt"
+	"log"
+	"strings"
+
+	"github.com/go-playground/validator/v10"
+	"github.com/gofiber/fiber/v2"
+)
+
+type (
+	User struct {
+		Name string `validate:"required,min=5,max=20"` // Required field, min 5 char long max 20
+		Age  int    `validate:"required,teener"`       // Required field, and client needs to implement our 'teener' tag format which we'll see later
+	}
+
+	ErrorResponse struct {
+		Error       bool
+		FailedField string
+		Tag         string
+		Value       interface{}
+	}
+
+	XValidator struct {
+		validator *validator.Validate
+	}
+
+	GlobalErrorHandlerResp struct {
+		Success bool   `json:"success"`
+		Message string `json:"message"`
+	}
+)
+
+// This is the validator instance
+// for more information see: https://github.com/go-playground/validator
+var validate = validator.New()
 
-type User struct{
-    Name          string  `validate:"required,min=3,max=32"`
-    // use `*bool` here otherwise the validation will fail for `false` values
-    // Ref: https://github.com/go-playground/validator/issues/319#issuecomment-339222389
-    IsActive      *bool   `validate:"required"`
-    Email         string  `validate:"required,email,min=6,max=32"`
-    Job           Job     `validate:"dive"`
-}
+func (v XValidator) Validate(data interface{}) []ErrorResponse {
+	validationErrors := []ErrorResponse{}
+
+	errs := validate.Struct(data)
+	if errs != nil {
+		for _, err := range errs.(validator.ValidationErrors) {
+			// In this case data object is actually holding the User struct
+			var elem ErrorResponse
 
-type ErrorResponse struct {
-    FailedField string
-    Tag         string
-    Value       string
+			elem.FailedField = err.Field() // Export struct field name
+			elem.Tag = err.Tag()           // Export struct tag
+			elem.Value = err.Value()       // Export field value
+			elem.Error = true
+
+			validationErrors = append(validationErrors, elem)
+		}
+	}
+
+	return validationErrors
 }
 
-var validate = validator.New()
-func ValidateStruct(user User) []*ErrorResponse {
-    var errors []*ErrorResponse
-    err := validate.Struct(user)
-    if err != nil {
-        for _, err := range err.(validator.ValidationErrors) {
-            var element ErrorResponse
-            element.FailedField = err.StructNamespace()
-            element.Tag = err.Tag()
-            element.Value = err.Param()
-            errors = append(errors, &element)
-        }
-    }
-    return errors
+func main() {
+	myValidator := &XValidator{
+		validator: validate,
+	}
+
+	app := fiber.New(fiber.Config{
+		// Global custom error handler
+		ErrorHandler: func(c *fiber.Ctx, err error) error {
+			return c.Status(fiber.StatusBadRequest).JSON(GlobalErrorHandlerResp{
+				Success: false,
+				Message: err.Error(),
+			})
+		},
+	})
+
+	// Custom struct validation tag format
+	myValidator.validator.RegisterValidation("teener", func(fl validator.FieldLevel) bool {
+		// User.Age needs to fit our needs, 12-18 years old.
+		return fl.Field().Int() >= 12 && fl.Field().Int() <= 18
+	})
+
+	app.Get("/", func(c *fiber.Ctx) error {
+		user := &User{
+			Name: c.Query("name"),
+			Age:  c.QueryInt("age"),
+		}
+
+		// Validation
+		if errs := myValidator.Validate(user); len(errs) > 0 && errs[0].Error {
+			errMsgs := make([]string, 0)
+
+			for _, err := range errs {
+				errMsgs = append(errMsgs, fmt.Sprintf(
+					"[%s]: '%v' | Needs to implement '%s'",
+					err.FailedField,
+					err.Value,
+					err.Tag,
+				))
+			}
+
+			return &fiber.Error{
+				Code:    fiber.ErrBadRequest.Code,
+				Message: strings.Join(errMsgs, " and "),
+			}
+		}
+
+		// Logic, validated with success
+		return c.SendString("Hello, World!")
+	})
+
+	log.Fatal(app.Listen(":3000"))
 }
 
-func AddUser(c *fiber.Ctx) error {
-    //Connect to database
+/**
+OUTPUT
 
-    user := new(User)
+[1]
+Request:
 
-    if err := c.BodyParser(user); err != nil {
-        return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
-            "message": err.Error(),
-        })
-
-    }
+GET http://127.0.0.1:3000/
 
-    errors := ValidateStruct(*user)
-    if errors != nil {
-       return c.Status(fiber.StatusBadRequest).JSON(errors)
-
-    }
+Response:
 
-    //Do something else here
+{"success":false,"message":"[Name]: '' | Needs to implement 'required' and [Age]: '0' | Needs to implement 'required'"}
 
-    //Return user
-   return c.JSON(user)
-}
+[2]
+Request:
+
+GET http://127.0.0.1:3000/?name=efdal&age=9
+
+Response:
+{"success":false,"message":"[Age]: '9' | Needs to implement 'teener'"}
+
+[3]
+Request:
+
+GET http://127.0.0.1:3000/?name=efdal&age=
+
+Response:
+{"success":false,"message":"[Age]: '0' | Needs to implement 'required'"}
+
+[4]
+Request:
+
+GET http://127.0.0.1:3000/?name=efdal&age=18
+
+Response:
+Hello, World!
 
-// Running a test with the following curl commands
-// curl -X POST -H "Content-Type: application/json" --data "{\"name\":\"john\",\"isactive\":\"True\"}" http://localhost:8080/register/user
+**/
 
-// Results in
-// [{"FailedField":"User.Email","Tag":"required","Value":""},{"FailedField":"User.Job.Salary","Tag":"required","Value":""},{"FailedField":"User.Job.Type","Tag":"required","Value":""}]⏎
 ```