refreshing.go RawHistoryFolder

1package provider
2
3import (
4	"context"
5	"sync"
6)
7
8// TokenRefresher is a callback that checks whether the current token
9// is still valid and returns a fresh one if needed. The returned
10// string is the new access token; if empty the old one is still fine.
11// An error means refresh failed (network down, refresh token expired,
12// etc.) — the caller should proceed with the stale token and let the
13// API return 401 naturally.
14type TokenRefresher func(ctx context.Context) (newToken string, err error)
15
16// RefreshingClient wraps a Client and calls a TokenRefresher before
17// every Stream call. When the refresher returns a new token, a fresh
18// underlying client is built via the factory function.
19type RefreshingClient struct {
20	mu      sync.Mutex
21	inner   Client
22	refresh TokenRefresher
23	factory func(token string) Client
24}
25
26// NewRefreshingClient wraps inner with automatic token refresh.
27// refreshFn is called before each Stream; if it returns a non-empty
28// token the factory rebuilds the underlying client with the new token.
29func NewRefreshingClient(inner Client, refreshFn TokenRefresher, factory func(token string) Client) *RefreshingClient {
30	return &RefreshingClient{
31		inner:   inner,
32		refresh: refreshFn,
33		factory: factory,
34	}
35}
36
37func (c *RefreshingClient) Name() string {
38	c.mu.Lock()
39	defer c.mu.Unlock()
40	return c.inner.Name()
41}
42
43func (c *RefreshingClient) Stream(ctx context.Context, req Request) (<-chan Event, error) {
44	if c.refresh != nil {
45		if newToken, err := c.refresh(ctx); err == nil && newToken != "" {
46			c.mu.Lock()
47			c.inner = c.factory(newToken)
48			c.mu.Unlock()
49		}
50		// On refresh error: proceed with the current client.
51		// The stale token will 401 and the user sees a clear error.
52	}
53	c.mu.Lock()
54	inner := c.inner
55	c.mu.Unlock()
56	return inner.Stream(ctx, req)
57}