Files
gluetun/internal/storage/read.go
2024-03-21 17:02:11 +00:00

115 lines
3.2 KiB
Go

package storage
import (
"encoding/json"
"fmt"
"io"
"os"
"github.com/qdm12/gluetun/internal/constants/providers"
"github.com/qdm12/gluetun/internal/models"
"golang.org/x/text/cases"
"golang.org/x/text/language"
)
// readFromFile reads the servers from server.json.
// It only reads servers that have the same version as the hardcoded servers version
// to avoid JSON decoding errors.
func (s *Storage) readFromFile(filepath string, hardcodedVersions map[string]uint16) (
servers models.AllServers, err error) {
file, err := os.Open(filepath)
if os.IsNotExist(err) {
return servers, nil
} else if err != nil {
return servers, err
}
b, err := io.ReadAll(file)
if err != nil {
return servers, err
}
if err := file.Close(); err != nil {
return servers, err
}
return s.extractServersFromBytes(b, hardcodedVersions)
}
func (s *Storage) extractServersFromBytes(b []byte, hardcodedVersions map[string]uint16) (
servers models.AllServers, err error) {
rawMessages := make(map[string]json.RawMessage)
if err := json.Unmarshal(b, &rawMessages); err != nil {
return servers, fmt.Errorf("decoding servers: %w", err)
}
// Note schema version is at map key "version" as number
allProviders := providers.All()
servers.ProviderToServers = make(map[string]models.Servers, len(allProviders))
titleCaser := cases.Title(language.English)
for _, provider := range allProviders {
hardcodedVersion, ok := hardcodedVersions[provider]
if !ok {
panicOnProviderMissingHardcoded(provider)
}
rawMessage, ok := rawMessages[provider]
if !ok {
// If the provider is not found in the data bytes, just don't set it in
// the providers map. That way the hardcoded servers will override them.
// This is user provided and could come from different sources in the
// future (e.g. a file or API request).
continue
}
mergedServers, versionsMatch, err := s.readServers(provider,
hardcodedVersion, rawMessage, titleCaser)
if err != nil {
return models.AllServers{}, err
} else if !versionsMatch {
// mergedServers is the empty struct in this case, so don't set the key
// in the providerToServers map.
continue
}
servers.ProviderToServers[provider] = mergedServers
}
return servers, nil
}
func (s *Storage) readServers(provider string, hardcodedVersion uint16,
rawMessage json.RawMessage, titleCaser cases.Caser) (servers models.Servers,
versionsMatch bool, err error) {
provider = titleCaser.String(provider)
var versionObject struct {
Version uint16 `json:"version"`
}
err = json.Unmarshal(rawMessage, &versionObject)
if err != nil {
return servers, false, fmt.Errorf("decoding servers version for provider %s: %w",
provider, err)
}
persistedVersion := versionObject.Version
versionsMatch = hardcodedVersion == persistedVersion
if !versionsMatch {
s.logger.Info(fmt.Sprintf(
"%s servers from file discarded because they have "+
"version %d and hardcoded servers have version %d",
provider, persistedVersion, hardcodedVersion))
return servers, versionsMatch, nil
}
err = json.Unmarshal(rawMessage, &servers)
if err != nil {
return servers, false, fmt.Errorf("decoding servers for provider %s: %w",
provider, err)
}
return servers, versionsMatch, nil
}