horizoncd/horizon

// Copyright © 2023 Horizoncd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
package generator
 
import (
    "bytes"
    "encoding/base64"
    "strconv"
    "strings"
    "time"
 
    "github.com/google/uuid"
    "k8s.io/apimachinery/pkg/util/rand"
)
 
// ref: https://github.blog/2021-04-05-behind-githubs-new-authentication-token-formats/
const (
    HorizonAppUserToServerAccessTokenPrefix = "hu_"
    OauthAPPAccessTokenPrefix               = "ho_"
    AccessTokenPrefix                       = "ha_"
    RefreshTokenPrefix                      = "hr_"
)
 
func NewAuthorizeGenerator() CodeGenerator {
    return &authorizationCodeGenerator{}
}
 
func NewHorizonAppUserToServerAccessGenerator() CodeGenerator {
    return &basicTokenGenerator{prefix: HorizonAppUserToServerAccessTokenPrefix}
}
 
func NewOauthAccessGenerator() CodeGenerator {
    return &basicTokenGenerator{prefix: OauthAPPAccessTokenPrefix}
}
 
func NewGeneralAccessTokenGenerator() CodeGenerator {
    return &basicTokenGenerator{prefix: AccessTokenPrefix}
}
 
func NewRefreshTokenGenerator() CodeGenerator {
    return &basicTokenGenerator{prefix: RefreshTokenPrefix}
}
 
type authorizationCodeGenerator struct{}
 
type basicTokenGenerator struct {
    prefix string
}
 
func (g *authorizationCodeGenerator) Generate(info *CodeGenerateInfo) string {
    buf := bytes.NewBufferString(info.Token.ClientID)
    buf.WriteString(strconv.Itoa(int(info.Token.UserID)))
    token := uuid.NewMD5(uuid.Must(uuid.NewRandom()), buf.Bytes())
    code := base64.URLEncoding.EncodeToString([]byte(token.String()))
    code = strings.ToUpper(strings.TrimRight(code, "="))
    return code
}
 
func (g *basicTokenGenerator) Generate(info *CodeGenerateInfo) string {
    clientID := func(info *CodeGenerateInfo) string {
        if info.Token.ClientID != "" {
            return info.Token.ClientID
        }
        return rand.String(20)
    }(info)
    buf := bytes.NewBufferString(clientID)
    buf.WriteString(strconv.Itoa(int(info.Token.UserID)))
    buf.WriteString(strconv.FormatInt(time.Now().UnixNano(), 10))
    access := base64.URLEncoding.EncodeToString([]byte(uuid.NewMD5(uuid.Must(uuid.NewRandom()), buf.Bytes()).String()))
    return g.prefix + strings.ToUpper(strings.TrimRight(access, "="))
}