strgo

strgo is a helper to validate a string based on a format specification that you set before. You can use this package to validate some common string case like username, name, password, email, etc.

Getting started

Installation

You can use the go get method:

go get github.com/dalikewara/strgo

Usage

This is an example to validate a username string:

• username can only contain alphanumeric characters, underscores and periods
• its length must be greater than 2 and not more than 20
• special character must be followed by at least one alphanumeric character
• prefix and suffix cannot be a special character
• allowed special characters must be appeared once in the string

func validate(username string) error {
    return strgo.Byte(username, &strgo.ByteCondition{
        MinLength:        3,
        MaxLength:        20,
        OnlyContains:     append(strgo.AlphanumericByte, []byte{'_', '.'}...),
        MustBeFollowedBy: [2][]byte{{'_', '.'}, strgo.AlphanumericByte},
        MayContainsOnce:  []byte{'_', '.'},
    })
}
validate("johndoe") // valid
validate("john_doe") // valid
validate("john.doe") // valid
validate("johndoe123") // valid
validate("john.doe123") // valid
validate("john_doe123") // valid
validate("john_doe.123") // valid
validate("_johndoe") // not valid
validate("__johndoe") // not valid
validate(".johndoe") // not valid
validate("..johndoe") // not valid
validate("johndoe_") // not valid
validate("johndoe__") // not valid
validate("johndoe.") // not valid
validate("johndoe..") // not valid
validate("john__doe") // not valid
validate("john_.doe") // not valid
validate("john..doe") // not valid
validate("john._doe") // not valid
validate("john@doe") // not valid
validate("@johndoe") // not valid
validate("johndoe@") // not valid
validate("joh_nd_oe") // not valid
validate("joh.nd.oe") // not valid

...this is an example to validate an email string:

• email can only contain alphanumeric characters and these special characters: _.-@+
• its length must be greater than 3 and not more than 255
• special character must be followed by at least one alphanumeric character
• prefix and suffix cannot be a special character
• must contain char @ and must be appeared once in the string

func validate(email string) error {
    return strgo.Byte(email, &strgo.ByteCondition{
        MinLength:        4,
        MaxLength:        255,
        OnlyContains:     append(strgo.AlphanumericByte, []byte{'_', '.', '@', '-', '+'}...),
        MustBeFollowedBy: [2][]byte{{'_', '.', '@', '-', '+'}, strgo.AlphanumericByte},
        MustContainsOnce: []byte{'@'},
    })
}
validate("johndoe@email.com") // valid
validate("john_doe@email.com") // valid
validate("john_do.e@email.com") // valid
validate("john-doe@email.com") // valid
validate("johndoe@email") // valid
validate("johndoe123@email") // valid
validate("johndoe123@email") // valid
validate("john+doe123@email") // valid
validate("johndoe123email") // not valid
validate("johndoe123.email") // not valid
validate("john@doe123@email") // not valid
validate(".johndoe123@email") // not valid
validate("johndoe123@email.") // not valid
validate("johndoe123@") // not valid
validate("john_.doe123@email") // not valid
validate("johndoe123.@email") // not valid

...and this is an example to validate a password string:

• password can only contain alphanumeric characters and special characters: !"#$% &'()*+,-./:;<=>?@[]^_`{|}~
• its length must be greater than 5 and not more than 32
• at least contain one lower and upper case letter, one number and one special character

func validate(password string) error {
    return strgo.Byte(password, &strgo.ByteCondition{
        MinLength:                   6,
        MaxLength:                   32,
        OnlyContains:                strgo.CharsByte,
        AtLeastHaveUpperLetterCount: 1,
        AtLeastHaveLowerLetterCount: 1,
        AtLeastHaveNumberCount:      1,
        AtLeastHaveSpecialCharCount: 1,
    })
}
validate("J()hndoe123") // valid
validate("John_doe123") // valid
validate("johndoe") // not valid
validate("johndoe123") // not valid
validate("Johndoe123") // not valid

Release

Changelog

Read at CHANGELOG.md

Credits

Copyright © 2022 Dali Kewara

License

MIT License