constraint.StringExactLength

Constraint: StringExactLength

Description

Check that a string has an exact length

Note: By default, this constraint is non-strict - if the value being checked is not a string, this constraint does not fail (unless the Strict field is set)

V8n Tag Abbreviation

strxlen

Fields

Field	Type	Description
Value	int	the exact length expected
UseRuneLen	bool	if set to true, uses the rune length (true Unicode length) to check length of string
NormalisationForm	string	is the optional unicode normalisation form to be used prior to checking length (no unicode normalisation is performed if this is empty or unknown form)
Stop	bool	when set to true, Stop prevents further validation checks on the property if this constraint fails
Strict	bool	when set to true, fails if the value being checked is not a correct type

Examples

Programmatic example...

package main

import (
    "fmt"

    "github.com/marrow16/valix"
)

func main() {
    validator := &valix.Validator{
        Properties: valix.Properties{
            "foo": {
                Type: valix.JsonString,
                Constraints: valix.Constraints{
                    &valix.StringExactLength{
                        Value:             1,
                        UseRuneLen:        true,
                        NormalisationForm: "NFC",
                    },
                },
            },
        },
    }

    // NB. "\u0063\u0327" is 'c' followed by combining cedilla
    ok, violations, _ := validator.ValidateString("{\"foo\": \"\u0063\u0327\"}")
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }

    // NB. "\u00e7" is a 'c' with cedilla
    ok, violations, _ = validator.ValidateString("{\"foo\": \"\u00e7\"}")
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }

    // NB. "\u00b8" is a cedilla (non-combining)
    ok, violations, _ = validator.ValidateString("{\"foo\": \"c\u00b8\"}")
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }
}

try on go-playground

Struct v8n tag example...

package main

import (
    "fmt"

    "github.com/marrow16/valix"
)

type MyStruct struct {
    Foo string `json:"foo" v8n:"&strxlen{Value:1, UseRuneLen:true, NormalisationForm: 'NFC'}"`
}

var validator = valix.MustCompileValidatorFor(MyStruct{}, nil)

func main() {
    my := &MyStruct{}

    // NB. "\u0063\u0327" is 'c' followed by combining cedilla
    ok, violations, _ := validator.ValidateStringInto("{\"foo\": \"\u0063\u0327\"}", my)
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }

    // NB. "\u00e7" is a 'c' with cedilla
    ok, violations, _ = validator.ValidateStringInto("{\"foo\": \"\u00e7\"}", my)
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }

    // NB. "\u00b8" is a cedilla (non-combining)
    ok, violations, _ = validator.ValidateStringInto("{\"foo\": \"c\u00b8\"}", my)
    fmt.Printf("Passed? %v\n", ok)
    for i, v := range violations {
        fmt.Printf("Violation[%d] Message: %s, Property: %s, Path: %s\n", i+1, v.Message, v.Property, v.Path)
    }
}

try on go-playground