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package config
import (
"crypto/rand"
"encoding/json"
"errors"
"fmt"
"os"
"path/filepath"
"reflect"
"github.com/kyren223/eko/pkg/assert"
)
type Cache struct {
// Key is a server URL like "eko.kyren.codes" and value is the base 16 hash
TosHashes map[string]string `json:"tos_hashes"`
DeviceID string `json:"device_id"`
}
func DefaultCache() Cache {
return Cache{
TosHashes: map[string]string{},
DeviceID: "",
}
}
func VerifyAndFixCache(cache *Cache) error {
if cache.DeviceID == "" {
cache.DeviceID = GenerateDeviceID()
}
return nil
}
func GenerateDeviceID() string {
// Generate a random 32-byte device ID
// Gurantees uniqueness, so it's not reverseable and it is annonymized
// For legal reasons: this may still be logged on the server, so associated with an IP address
deviceId := [32]byte{}
_, err := rand.Read(deviceId[:])
assert.NoError(err, "random never fails")
return fmt.Sprintf("%x", deviceId)
}
var (
cache = Cache{}
CacheDir string
CacheFile string
)
func LoadCache() error {
userCacheDir, err := os.UserCacheDir()
if err != nil {
return err
}
CacheDir = filepath.Join(userCacheDir, "eko")
err = os.MkdirAll(CacheDir, 0o750)
if err != nil {
return err
}
CacheFile = filepath.Join(CacheDir, "cache.json")
contents, err := os.ReadFile(CacheFile) // #nosec 304
if errors.Is(err, os.ErrNotExist) {
cache = DefaultCache()
return writeCache()
}
if err != nil {
return err
}
var rawMap map[string]json.RawMessage
if err := json.Unmarshal(contents, &rawMap); err != nil {
return err
}
defaultVal := reflect.ValueOf(DefaultCache())
finalCache := reflect.New(defaultVal.Type()).Elem()
finalCache.Set(defaultVal)
for i := 0; i < defaultVal.NumField(); i++ {
field := defaultVal.Type().Field(i)
jsonTag := field.Tag.Get("json")
if jsonTag == "" {
jsonTag = field.Name
}
rawValue, found := rawMap[jsonTag]
fieldValue := finalCache.Field(i)
if !found || !fieldValue.CanAddr() {
continue
}
err := json.Unmarshal(rawValue, fieldValue.Addr().Interface())
if err != nil {
return fmt.Errorf("error unmarshaling field %s: %w", field.Name, err)
}
}
cache = finalCache.Interface().(Cache)
err = VerifyAndFixCache(&cache)
if err != nil {
return err
}
return writeCache()
}
func writeCache() error {
b, err := json.MarshalIndent(cache, "", " ")
if err != nil {
return err
}
return os.WriteFile(CacheFile, b, 0o600)
}
func ReadCache() Cache {
return cache
}
func UseCache(f func(cache *Cache)) error {
f(&cache)
return writeCache()
}
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