status-im/status-go

package common

import (
    "crypto/ecdsa"
    "errors"
    "regexp"
    "strings"

    "github.com/status-im/status-go/eth-node/crypto"
    "github.com/status-im/status-go/protocol/identity/alias"
    "github.com/status-im/status-go/protocol/protobuf"
)

var ErrInvalidDisplayNameRegExp = errors.New("only letters, numbers, underscores and hyphens allowed")
var ErrInvalidDisplayNameEthSuffix = errors.New(`usernames ending with "eth" are not allowed`)
var ErrInvalidDisplayNameNotAllowed = errors.New("name is not allowed")

var DISPLAY_NAME_EXT = []string{"_eth", ".eth", "-eth"}

func RecoverKey(m *protobuf.ApplicationMetadataMessage) (*ecdsa.PublicKey, error) {
    if m.Signature == nil {
        return nil, nil
    }

    recoveredKey, err := crypto.SigToPub(
        crypto.Keccak256(m.Payload),
        m.Signature,
    )
    if err != nil {
        return nil, err
    }

    return recoveredKey, nil
}

func ValidateDisplayName(displayName *string) error {
    name := strings.TrimSpace(*displayName)
    *displayName = name

    if name == "" {
        return nil
    }

    // ^[\\w-\\s]{5,24}$ to allow spaces
    if match, _ := regexp.MatchString("^[\\w-\\s]{5,24}$", name); !match {
        return ErrInvalidDisplayNameRegExp
    }

    // .eth should not happen due to the regexp above, but let's keep it here in case the regexp is changed in the future
    for _, ext := range DISPLAY_NAME_EXT {
        if strings.HasSuffix(*displayName, ext) {
            return ErrInvalidDisplayNameEthSuffix
        }
    }

    if alias.IsAlias(name) {
        return ErrInvalidDisplayNameNotAllowed
    }

    return nil
}

// implementation referenced from https://github.com/embarklabs/embark/blob/master/packages/plugins/ens/src/index.js
func IsENSName(displayName string) bool {
    if len(displayName) == 0 {
        return false
    }

    if strings.HasSuffix(displayName, ".eth") {
        return true
    }

    return false
}