password

package
v0.1.3 Latest Latest
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Published: Jan 13, 2021 License: MIT Imports: 5 Imported by: 4

Documentation

Overview

Package password provides a library for generating high-entropy random password strings via the crypto/rand package.

res, err := Generate(64, 10, 10, false, false)
if err != nil  {
  log.Fatal(err)
}
log.Printf(res)

Most functions are safe for concurrent use.

Index

Examples

Constants

View Source
const (
	// LowerLetters is the list of lowercase letters.
	LowerLetters = "abcdefghijklmnopqrstuvwxyz"

	// UpperLetters is the list of uppercase letters.
	UpperLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

	// Digits is the list of permitted digits.
	Digits = "0123456789"

	// Symbols is the list of symbols.
	Symbols = "~!@#$%^&*()_+`-={}|[]\\:\"<>?,./"
)

Variables

View Source
var (
	// ErrExceedsTotalLength is the error returned with the number of digits and
	// symbols is greater than the total length.
	ErrExceedsTotalLength = errors.New("number of digits and symbols must be less than total length")

	// ErrLettersExceedsAvailable is the error returned with the number of letters
	// exceeds the number of available letters and repeats are not allowed.
	ErrLettersExceedsAvailable = errors.New("number of letters exceeds available letters and repeats are not allowed")

	// ErrDigitsExceedsAvailable is the error returned with the number of digits
	// exceeds the number of available digits and repeats are not allowed.
	ErrDigitsExceedsAvailable = errors.New("number of digits exceeds available digits and repeats are not allowed")

	// ErrSymbolsExceedsAvailable is the error returned with the number of symbols
	// exceeds the number of available symbols and repeats are not allowed.
	ErrSymbolsExceedsAvailable = errors.New("number of symbols exceeds available symbols and repeats are not allowed")
)

Functions

func Generate

func Generate(length, numDigits, numSymbols int, noUpper, allowRepeat bool) (string, error)

Generate is the package shortcut for Generator.Generate.

Example
package main

import (
	"log"

	"github.com/admpub/go-password/password"
)

func main() {
	res, err := password.Generate(64, 10, 10, false, false)
	if err != nil {
		log.Fatal(err)
	}
	log.Print(res)
}
Output:

func MustGenerate

func MustGenerate(length, numDigits, numSymbols int, noUpper, allowRepeat bool) string

MustGenerate is the package shortcut for Generator.MustGenerate.

Example
package main

import (
	"log"

	"github.com/admpub/go-password/password"
)

func main() {
	// Will panic on error
	res := password.MustGenerate(64, 10, 10, false, false)
	log.Print(res)
}
Output:

func NewMockGenerator added in v0.1.3

func NewMockGenerator(result string, err error) *mockGenerator

NewMockGenerator creates a new generator that satisfies the PasswordGenerator interface. If an error is provided, the error is returned. If a result if provided, the result is always returned, regardless of what parameters are passed into the Generate or MustGenerate methods.

This function is most useful for tests where you want to have predicable results for a transitive resource that depends on go-password.

Example (Testing)
package main

import (
	"fmt"

	"github.com/admpub/go-password/password"
)

func main() {
	// Accept a password.PasswordGenerator interface instead of a
	// password.Generator struct.
	f := func(g password.PasswordGenerator) string {
		// These values don't matter
		return g.MustGenerate(1, 2, 3, false, false)
	}

	// In tests
	gen := password.NewMockGenerator("canned-response", nil)

	fmt.Print(f(gen))
}
Output:

canned-response

Types

type Generator added in v0.1.1

type Generator struct {
	// contains filtered or unexported fields
}

Generator is the stateful generator which can be used to customize the list of letters, digits, and/or symbols.

func NewGenerator added in v0.1.1

func NewGenerator(i *GeneratorInput) (*Generator, error)

NewGenerator creates a new Generator from the specified configuration. If no input is given, all the default values are used. This function is safe for concurrent use.

Example (Custom)
package main

import (
	"log"

	"github.com/admpub/go-password/password"
)

func main() {
	// Customize the list of symbols.
	gen, err := password.NewGenerator(&password.GeneratorInput{
		Symbols: "!@#$%^()",
	})
	if err != nil {
		log.Fatal(err)
	}

	_ = gen // gen.Generate(...)
}
Output:

Example (Nil)
package main

import (
	"log"

	"github.com/admpub/go-password/password"
)

func main() {
	// This is exactly the same as calling "Generate" directly. It will use all
	// the default values.
	gen, err := password.NewGenerator(nil)
	if err != nil {
		log.Fatal(err)
	}

	_ = gen // gen.Generate(...)
}
Output:

func (*Generator) Generate added in v0.1.1

func (g *Generator) Generate(length, numDigits, numSymbols int, noUpper, allowRepeat bool) (string, error)

Generate generates a password with the given requirements. length is the total number of characters in the password. numDigits is the number of digits to include in the result. numSymbols is the number of symbols to include in the result. noUpper excludes uppercase letters from the results. allowRepeat allows characters to repeat.

The algorithm is fast, but it's not designed to be performant; it favors entropy over speed. This function is safe for concurrent use.

Example
package main

import (
	"log"

	"github.com/admpub/go-password/password"
)

func main() {
	gen, err := password.NewGenerator(nil)
	if err != nil {
		log.Fatal(err)
	}

	res, err := gen.Generate(64, 10, 10, false, false)
	if err != nil {
		log.Fatal(err)
	}
	log.Print(res)
}
Output:

func (*Generator) MustGenerate added in v0.1.1

func (g *Generator) MustGenerate(length, numDigits, numSymbols int, noUpper, allowRepeat bool) string

MustGenerate is the same as Generate, but panics on error.

type GeneratorInput added in v0.1.1

type GeneratorInput struct {
	LowerLetters string
	UpperLetters string
	Digits       string
	Symbols      string
	Reader       io.Reader // rand.Reader by default
}

GeneratorInput is used as input to the NewGenerator function.

type PasswordGenerator added in v0.1.3

type PasswordGenerator interface {
	Generate(int, int, int, bool, bool) (string, error)
	MustGenerate(int, int, int, bool, bool) string
}

PasswordGenerator is an interface that implements the Generate function. This is useful for testing where you can pass this interface instead of a real password generator to mock responses for predicability.

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