README
¶
assert 
Dead simple 0 dependency "typed" golang validator
Motivation
Most go validators use either struct tags or a string based representation of the validation rules, and while there's nothing wrong with that, sometimes you just want to quickly validate an input and perhaps cast it to a different type from which you received it.
With assert you may also rest assured you did not typo any of the validation rules as all rules are functions, hence a bit more "typed" than something like validate:"required,min=4,max=5"
Installing
go get github.com/sindreslungaard/assert
Examples
Simple example of validating the character length of an interface and returning it as a string
package main
import "github.com/sindreslungaard/assert"
func main() {
// This can be any value, any type.
src := "some-value"
str, err := assert.Is(src).MinLen(5).MaxLen(10).String()
if err != nil {
// handle error
}
// str == "some-value"
}
Every assertion formats the input to a type it prefers to test on before executing, so you can do number assertions on string values and so on
num, err := assert.Is("55").MinNum(50).Int()
num, err := assert.Is(55).MinNum(50).Int()
// Both of these are OK
Example validation for a http form POST request
func mySignupHandler(c *gin.Context) {
username, err := assert.Is(c.PostForm("username")).MinLen(3).MaxLen(20).AlphaNumeric().String()
if err != nil {
// let the user know
}
password, err := assert.Is(c.PostForm("password")).MinLen(8)
if err != nil {
// let the user know
}
}
We can recude the number of error checks with assert.First
func mySignupHandler(c *gin.Context) {
username, err1 := assert.Is(c.PostForm("username")).MinLen(3).MaxLen(20).AlphaNumeric().String()
email, err2 := assert.Is(c.PostForm("email")).Email().String()
password, err3 := assert.Is(c.PostForm("password")).MinLen(8).String()
err := assert.First(err1, err2, err3)
if err != nil {
// let the user know
}
}
Available validations
| Validation | Argument type | Description |
|---|---|---|
| NotEmpty | Checks if the input (formatted to string) is equal to "" | |
| MinLen | int | Checks if the length of input (formatted to string) is greater than or equal to the argument |
| MaxLen | int | Checks if the length of input (formatted to string) is less than or equal to the argument |
| MinNum | int | Checks if the value of input (formatted to int) is greater than or equal to the argument |
| MaxNum | int | Checks if the value of input (formatted to int) is less than or equal to the argument |
| Regex | string | Checks if the input (formatted to string) matches the provided regex pattern |
| Checks if the input (formatted to string) is a valid email | ||
| Alpha | Checks if the input (formatted to string) only contains a-z and A-Z | |
| AlphaNumeric | Checks if the input (formatted to string) only contains a-z, A-Z and 0-9 |
Available type cast assertions
Type casts should always be last in your assertion chain, they are what executes all assertions in the chain and returns any errors or the input converted to the new type.
| Type | Description |
|---|---|
| String | Formats the input as a string using fmt.Sprintf |
| Int | Formats the input as an int using fmt.Sprintf -> strconv.Atoi |
| Float64 | Formats the input as a float64 using fmt.Sprintf -> strconv.ParseFloat with 64 bit precision |
Documentation
¶
Index ¶
- func First(e ...error) error
- type AssertFunc
- type Assertion
- func (a *Assertion) Alpha() *Assertion
- func (a *Assertion) AlphaNumeric() *Assertion
- func (a *Assertion) Email() *Assertion
- func (a *Assertion) Float64() (float64, error)
- func (a *Assertion) Int() (int, error)
- func (a *Assertion) MaxLen(val int) *Assertion
- func (a *Assertion) MaxNum(val int) *Assertion
- func (a *Assertion) MinLen(val int) *Assertion
- func (a *Assertion) MinNum(val int) *Assertion
- func (a *Assertion) NotEmpty() *Assertion
- func (a *Assertion) Regex(val string) *Assertion
- func (a *Assertion) String() (string, error)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type AssertFunc ¶
type AssertFunc func(interface{}) error
type Assertion ¶
type Assertion struct {
// contains filtered or unexported fields
}
func (*Assertion) Alpha ¶
Alpha asserts that the source (formatted as string) only containes letters a-z and A-Z
func (*Assertion) AlphaNumeric ¶
AlphaNumeric asserts that the source (formatted as string) only containes characters a-z, A-Z and 0-9
func (*Assertion) Email ¶
Email asserts that the source (formatted as string) matches an email pattern
func (*Assertion) Float64 ¶
Float runs all assertions and returns the source as a float64 and errors if any
func (*Assertion) MaxLen ¶
MaxLen asserts that the character length of the source (formatted as string) is less than or equal to the value
func (*Assertion) MaxNum ¶
MaxNum asserts that the value of the source (formatted as int) is greater than or equal to the value
func (*Assertion) MinLen ¶
MinLen asserts that the character length of the source (formatted as string) is greater than or equal to the value
func (*Assertion) MinNum ¶
MinNum asserts that the value of the source (formatted as int) is less than or equal to the value
func (*Assertion) NotEmpty ¶
NotEmpty asserts that the string representation of the source is not equal to ""
Source Files