issue-#4

add documentation

baked_in.go

@@ -3,16 +3,14 @@ package validator
 import (
 	"log"
 	"reflect"
-	"regexp"
 	"strconv"
 )
 
-var bakedInValidators = map[string]ValidationFunc{
+var BakedInValidators = map[string]ValidationFunc{
 	"required": required,
 	"len":      length,
 	"min":      min,
 	"max":      max,
-	"regex":    regex,
 }
 
 func required(field interface{}, param string) bool {
@@ -151,27 +149,6 @@ func max(field interface{}, param string) bool {
 	}
 }
 
-// regex is the builtin validation function that checks
-// whether the string variable matches a regular expression
-func regex(field interface{}, param string) bool {
-
-	s, ok := field.(string)
-	if !ok {
-		log.Fatalf("Bad field type %s\n", field)
-	}
-
-	re, err := regexp.Compile(param)
-	if err != nil {
-		log.Fatalf("Bad regex param %s\n", param)
-	}
-
-	if !re.MatchString(s) {
-		return false
-	}
-
-	return true
-}
-
 // asInt retuns the parameter as a int64
 // or panics if it can't convert
 func asInt(param string) int64 {

doc.go

@@ -1,24 +1,186 @@
-// Package validator implements value validations
+/*
-//
+Package validator implements value validations for structs and individual fields based on tags.
-// The MIT License (MIT)
+
-//
+Built In Validator
-// Copyright (c) 2015 Dean Karn
+
-//
+The package contains a built in Validator instance for use,
-// Permission is hereby granted, free of charge, to any person obtaining a copy
+but you may also create a new instance if needed.
-// of this software and associated documentation files (the "Software"), to deal
+
-// in the Software without restriction, including without limitation the rights
+	// built in
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	errs := validator.ValidateStruct(//your struct)
-// copies of the Software, and to permit persons to whom the Software is
+	errs := validator.ValidateFieldByTag(field, "omitempty,min=1,max=10")
-// furnished to do so, subject to the following conditions:
+
-//
+	// new
-// The above copyright notice and this permission notice shall be included in all
+	newValidator = validator.New("struct tag name", validator.BakedInFunctions)
-// copies or substantial portions of the Software.
+
-//
+A simple example usage:
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	type UserDetail {
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+		Details string `validate:"-"`
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	}
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	type User struct {
-// SOFTWARE.
+		Name         string     `validate:"required,max=60"`
+		PreferedName string     `validate:"omitempty,max=60"`
+		Sub          UserDetail
+	}
+
+	user := &User {
+		Name: "",
+	}
+
+	// errs will contain a hierarchical list of errors
+	// using the StructValidationErrors struct
+	// or nil if no errors exist
+	errs := validator.ValidateStruct(user)
+
+	// in this case 1 error Name is required
+	errs.Struct will be "User"
+	errs.StructErrors will be empty <-- fields that were structs
+	errs.Errors will have 1 error of type FieldValidationError
+
+Error Handling
+
+The error can be used like so
+
+	fieldErr, _ := errs["Name"]
+	fieldErr.Field    // "Name"
+	fieldErr.ErrorTag // "required"
+
+Both StructValidationErrors and FieldValidationError implement the Error interface but it's
+intended use is for development + debugging, not a production error message.
+
+	fieldErr.Error() // Field validation for "Name" failed on the "required" tag
+	errs.Error()
+	// Struct: User
+	// Field validation for "Name" failed on the "required" tag
+
+Why not a better error message? because this library intends for you to handle your own error messages
+
+Why should I handle my own errors? Many reasons, for me building and internationalized application
+I needed to know the field and what validation failed so that I could provide an error in the users specific language.
+
+	if fieldErr.Field == "Name" {
+		switch fieldErr.ErrorTag
+		case "required":
+			return "Translated string based on field + error"
+		default:
+		return "Translated string based on field"
+	}
+
+The hierarchical structure is hard to work with sometimes.. Agreed Flatten function to the rescue!
+Flatten will return a map of FieldValidationError's but the field name will be namespaced.
+
+	// if UserDetail Details field failed validation
+	Field will be "Sub.Details"
+
+	// for Name
+	Field will be "Name"
+
+Custom Functions
+
+Custom functions can be added
+
+	//Structure
+	func customFunc(field interface{}, param string) bool {
+
+		if whatever {
+			return false
+		}
+
+		return true
+	}
+
+	validator.AddFunction("custom tag name", customFunc)
+	// NOTE: using the same tag name as an existing function
+	//       will overwrite the existing one
+
+Custom Tag Name
+
+A custom tag name can be set to avoid conficts, or just have a shorter name
+
+	validator.SetTag("valid")
+
+Multiple Validators
+
+Multiple validators on a field will process in the order defined
+
+	type Test struct {
+		Field `validate:"max=10,min=1"`
+	}
+
+	// max will be checked then min
+
+Bad Validator definitions are not handled by the library
+
+	type Test struct {
+		Field `validate:"min=10,max=0"`
+	}
+
+	// this definition of min max will never validate
+
+Baked In Validators
+
+Here is a list of the current built in validators:
+
+	-
+		Tells the validation to skip this struct field; this is particularily
+		handy in ignoring embedded structs from being validated. (Usage: -)
+
+	omitempty
+		Allows conitional validation, for example if a field is not set with
+		a value (Determined by the required validator) then other validation
+		such as min or max won't run, but if a value is set validation will run.
+		(Usage: omitempty)
+	len
+		For numbers, max will ensure that the value is
+		equal to the parameter given. For strings, it checks that
+		the string length is exactly that number of characters. For slices,
+		arrays, and maps, validates the number of items. (Usage: len=10)
+	max
+		For numbers, max will ensure that the value is
+		less than or equal to the parameter given. For strings, it checks
+		that the string length is at most that number of characters. For
+		slices, arrays, and maps, validates the number of items. (Usage: max=10)
+	min
+		For numbers, min will ensure that the value is
+		greater or equal to the parameter given. For strings, it checks that
+		the string length is at least that number of characters. For slices,
+		arrays, and maps, validates the number of items. (Usage: min=10)
+
+	required
+		This validates that the value is not the data types default value.
+		For numbers ensures value is not zero. For strings ensures value is
+		not "". For slices, arrays, and maps, ensures the length is not zero.
+		(Usage: required)
+
+Validator notes:
+
+	regex
+		a regex validator won't be added because commas and = signs can be part of
+		a regex which conflict with the validation definitions, although workarounds
+		can be made, they take away from using pure regex's. Furthermore it's quick
+		and dirty but the regex's become harder to maintain and are not reusable, so
+		it's as much as a programming philosiphy as anything.
+
+		In place of this new validator functions should be created; a regex can be
+		used within the validator function and even be precompiled for better efficiency.
+
+		And the best reason, you can sumit a pull request and we can keep on adding to the
+		validation library of this package!
+
+Panics
+
+This package panics when bad input is provided, this is by design, bad code like that should not make it to production.
+
+	type Test struct {
+		TestField string `validate:"nonexistantfunction=1"`
+	}
+
+	t := &Test{
+		TestField: "Test"
+	}
+
+	validator.ValidateStruct(t) // this will panic
+*/
 package validator

validator.go

@@ -108,7 +108,7 @@ type Validator struct {
 
 // var bakedInValidators = map[string]ValidationFunc{}
 
-var internalValidator = NewValidator(defaultTagName, bakedInValidators)
+var internalValidator = NewValidator(defaultTagName, BakedInValidators)
 
 // NewValidator creates a new Validator instance
 // NOTE: it is not necessary to create a new validator as the internal one will do in 99.9% of cases, but the option is there.
@@ -283,10 +283,12 @@ func (v *Validator) validateFieldByNameAndTag(f interface{}, name string, tag st
 		panic("Invalid field passed to ValidateFieldWithTag")
 	}
 
+	// TODO: validate commas in regex's
 	valTags := strings.Split(tag, ",")
 
 	for _, valTag := range valTags {
 
+		// TODO: validate = in regex's
 		vals := strings.Split(valTag, "=")
 		key := strings.Trim(vals[0], " ")
 
@@ -299,8 +301,8 @@ func (v *Validator) validateFieldByNameAndTag(f interface{}, name string, tag st
 			continue
 		}
 
-		valFunc := v.validationFuncs[key]
+		valFunc, ok := v.validationFuncs[key]
-		if valFunc == nil {
+		if !ok {
 			panic(fmt.Sprintf("Undefined validation function on field %s", name))
 		}