go-validator

---

A Fast Validator for struct filed using tag, highly inspired by automatically recovery theory.

There are numerous validators for golang, but almost of them lack of automatically recovery from error. It's very easy to find errors during run-time. But if we wanna our process is to be sure running in safe mode to keep our service perfect available, it definitely require self-recovery ability, especially when wrong setting or arguments can be delivered by user, or other programs...

quick start

import (
    "github.com/jekkay/govalidator"
    "encoding/json"
    "fmt"
    "testing"
}

type Range struct {
    A int32   `json:"a" min:"10" max:"100" default:"50"`
    B int32   `json:"b" min:"20" max:"90" default:"80"`
    C *uint64 `json:"c" min:"30" max:"90" req:"true" default:"60"`
    D string  `json:"d" min:"1" max:"10" req:"true" in:"hello,world,jekkay" regex:"^[a-d]+$" default:"jekkay"`
}

func TestValidObject2(t *testing.T) {
	r := new(Range)
	r.A = 120
	r.B = 130

	if e := govalidator.ValidObject(r, false); e != nil {
		fmt.Println(e)
	}
	govalidator.ValidObject(r, true)
	bs, _ := json.MarshalIndent(r, "", "  ")
	fmt.Println(string(bs))
}

output is

[
`A` at most 100, current is 120
`B` at most 90, current is 130 
`C` is empty
`D` is empty
]
{
  "a": 100,
  "b": 90,
  "c": 60,
  "d": "jekkay"
}

ValidObjectfunction will check struct filed whether is valid, it will return all errors found. Set parameter `fix` to true if you wanna auto fix struct filed. It's very helpful to make sure the value in custom range, and set default value if necessary.

it's available for the nested struct as well, see test file for more: validator_test.go.

Function

function	parameters	description
ValidObject	obj:ptr, a pointer to struct object fix: boolean, indicate whether auto adjust value	auto fix error value
Validate	obj:ptr, a pointer to struct object	validate object error, return the first one
Validates	obj:ptr, a pointer to struct object	validate object error, return all errors

Auto Fix Value

Set parameter `fix` to true, ValidObjectfunction will do some adjustment.

• if the filed is number(int, uint...), logic like this:

   if currentValue < min {
       if currentValue == 0 {
            currentValue = defalut
       } else {
            currentValue = min
       }
   }
   if currentValue > max {
       currentValue = max
   }
     

if there is no default tag set, min will be used as default value instead.

• if the field is string(string), logic like this

  if len(str) < min || len(str) > max 
       || dismatch(str, regex) || !in(str, options) {
      str = default
  }

• if the field is pointer, logic like this:

  if ptr == nil && required{
    ptr = new(type)
  }
  if ptr != nil {
     check(*ptr) --> logic go above
  }

Tags

Tags are used to describe the constraint of the field.

Tag	description	require
default	default value	√
min	the minimum length of the string, or the minimum value of number	×
max	the maximum length of the string , or the maximum value of number	×
req	require value	×
regex	regular expression	×
in	value options	×

Number Range Constraint:

Tag	Field Type	description
min	Int, Int8,Int16,Int32,Int64 Uint,Uint8,Uint16,Uint32,Uint64	minimum value
max	Int, Int8,Int16,Int32,Int64 Uint,Uint8,Uint16,Uint32,Uint64	Maximum value
default	Int, Int8,Int16,Int32,Int64 Uint,Uint8,Uint16,Uint32,Uint64	defalut value

Field Type	min	max	default
Uint	0	2^32 -1	0
Uint8	0	2^8 -1	0
Uint16	0	2^16 -1	0
Uint32	0	2^32 -1	0
Uint64	0	2^64 -1	0

Field Type	min	max	default
Int	-2^31	2^31 -1	0
Int8	-2^7	2^7 -1	0
Int16	-2^15	2^15 -1	0
Int32	-2^31	2^31 -1	0
Int64	-2^63	2^63 -1	0

Field Type	min	max	default	precision
Float32	-3.4e38	3.4e38	0	7
Float64	-1.7e308	1.7e308	0	16

Tags decorate description:

Field Type	min	max	default	req	in	regex
(number) Int8,Uint8, Int16,Uint16 ... Int64,Uint64	√	√	√	×	×	×
string	√	√	√	√	√	√
ptr -> number	√	√	√	√	×	×
ptr -> string	√	√	√	√	√	√
ptr -> struct	×	×	×	√	×	×

Author

• Jekkay Hu
• Blog: http://www.easysb.cn
• Email: jekkay#qqvips.cn