constraint.StringLength

Constraint: StringLength

Description

Check that a string has a minimum and maximum 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

strlen

Fields

Field	Type	Description
Minimum	int	the minimum length
Maximum	int	the maximum length (only checked if this value is > 0)
ExclusiveMin	bool	if set to true, specifies the minimum value is exclusive
ExclusiveMax	bool	if set to true, specifies the maximum value is exclusive
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)
Message	string	the violation message to be used if the constraint fails. If empty, the default message is used
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.StringLength{
                        Minimum: 2,
                        Maximum: 5,
                    },
                },
            },
        },
    }

    ok, violations, _ := validator.ValidateString(`{"foo": "a"}`)
    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)
    }

    ok, violations, _ = validator.ValidateString(`{"foo": "aa"}`)
    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)
    }

    ok, violations, _ = validator.ValidateString(`{"foo": "aaaaaa"}`)
    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:"&strlen{Min:2, Max:5}"`
}

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

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

    ok, violations, _ := validator.ValidateStringInto(`{"foo": "a"}`, 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)
    }

    ok, violations, _ = validator.ValidateStringInto(`{"foo": "aa"}`, 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)
    }

    ok, violations, _ = validator.ValidateStringInto(`{"foo": "aaaaaa"}`, 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