142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
package alps
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import (
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"encoding/json"
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"fmt"
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"reflect"
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"sync"
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imapmetadata "github.com/emersion/go-imap-metadata"
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imapclient "github.com/emersion/go-imap/client"
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"github.com/labstack/echo/v4"
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)
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// ErrNoStoreEntry is returned by Store.Get when the entry doesn't exist.
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var ErrNoStoreEntry = fmt.Errorf("alps: no such entry in store")
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// Store allows storing per-user persistent data.
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//
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// Store shouldn't be used from inside Session.DoIMAP.
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type Store interface {
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Get(key string, out interface{}) error
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Put(key string, v interface{}) error
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}
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var warnedTransientStore = false
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func newStore(session *Session, logger echo.Logger) (Store, error) {
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s, err := newIMAPStore(session)
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if err == nil {
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return s, nil
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} else if err != errIMAPMetadataUnsupported {
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return nil, err
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}
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if !warnedTransientStore {
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logger.Print("Upstream IMAP server doesn't support the METADATA extension, using transient store instead")
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warnedTransientStore = true
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}
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return newMemoryStore(), nil
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}
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type memoryStore struct {
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locker sync.RWMutex
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entries map[string]interface{}
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}
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func newMemoryStore() *memoryStore {
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return &memoryStore{entries: make(map[string]interface{})}
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}
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func (s *memoryStore) Get(key string, out interface{}) error {
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s.locker.RLock()
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defer s.locker.RUnlock()
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v, ok := s.entries[key]
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if !ok {
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return ErrNoStoreEntry
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}
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reflect.ValueOf(out).Elem().Set(reflect.ValueOf(v).Elem())
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return nil
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}
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func (s *memoryStore) Put(key string, v interface{}) error {
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s.locker.Lock()
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s.entries[key] = v
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s.locker.Unlock()
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return nil
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}
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type imapStore struct {
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session *Session
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cache *memoryStore
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}
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var errIMAPMetadataUnsupported = fmt.Errorf("alps: IMAP server doesn't support METADATA extension")
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func newIMAPStore(session *Session) (*imapStore, error) {
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err := session.DoIMAP(func(c *imapclient.Client) error {
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mc := imapmetadata.NewClient(c)
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ok, err := mc.SupportMetadata()
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if err != nil {
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return fmt.Errorf("alps: failed to check for IMAP METADATA support: %v", err)
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}
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if !ok {
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return errIMAPMetadataUnsupported
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}
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return nil
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})
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if err != nil {
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return nil, err
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}
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return &imapStore{session, newMemoryStore()}, nil
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}
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func (s *imapStore) key(key string) string {
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return "/private/vendor/alps/" + key
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}
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func (s *imapStore) Get(key string, out interface{}) error {
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if err := s.cache.Get(key, out); err != ErrNoStoreEntry {
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return err
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}
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var entries map[string]string
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err := s.session.DoIMAP(func(c *imapclient.Client) error {
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mc := imapmetadata.NewClient(c)
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var err error
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entries, err = mc.GetMetadata("", []string{s.key(key)}, nil)
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return err
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})
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if err != nil {
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return fmt.Errorf("alps: failed to fetch IMAP store entry %q: %v", key, err)
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}
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v, ok := entries[s.key(key)]
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if !ok {
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return ErrNoStoreEntry
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}
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if err := json.Unmarshal([]byte(v), out); err != nil {
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return fmt.Errorf("alps: failed to unmarshal IMAP store entry %q: %v", key, err)
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}
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return s.cache.Put(key, out)
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}
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func (s *imapStore) Put(key string, v interface{}) error {
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b, err := json.Marshal(v)
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if err != nil {
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return fmt.Errorf("alps: failed to marshal IMAP store entry %q: %v", key, err)
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}
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entries := map[string]string{
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s.key(key): string(b),
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}
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err = s.session.DoIMAP(func(c *imapclient.Client) error {
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mc := imapmetadata.NewClient(c)
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return mc.SetMetadata("", entries)
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})
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if err != nil {
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return fmt.Errorf("alps: failed to put IMAP store entry %q: %v", key, err)
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}
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return s.cache.Put(key, v)
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}
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