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package participant
import (
"context"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"net/http"
"strings"
"time"
"github.com/johnandersen777/socialweb-computer-kcp/internal/atproto/market"
"github.com/johnandersen777/socialweb-computer-kcp/internal/atproto/xrpc"
"github.com/johnandersen777/socialweb-computer-kcp/internal/contract/pds"
"github.com/johnandersen777/socialweb-computer-kcp/internal/kit/ttlcache"
)
const (
ServiceAuthLifetime = 5 * time.Minute
ServiceAuthRefreshMargin = 30 * time.Second
)
type PDSServiceAuth struct {
Open func(ctx context.Context) (pds.ServiceAuth, error)
DID string
Lifetime time.Duration
}
var _ xrpc.Minter = PDSServiceAuth{}
func (a PDSServiceAuth) ServiceAuth(ctx context.Context, audience, lxm string) (string, error) {
if a.Open == nil || a.DID == "" {
return "", errors.New("participant: the PDS service-auth handle names no account")
}
minter, err := a.Open(ctx)
if err != nil {
return "", err
}
lifetime := a.Lifetime
if lifetime <= 0 {
lifetime = ServiceAuthLifetime
}
return minter.ServiceAuth(ctx, a.DID, audience, lxm, time.Now().Add(lifetime))
}
type SessionServiceAuth struct {
Endpoint string
HTTP *http.Client
Auth xrpc.Auth
Lifetime time.Duration
}
var _ xrpc.Minter = SessionServiceAuth{}
func (m SessionServiceAuth) ServiceAuth(ctx context.Context, audience, lxm string) (string, error) {
if strings.TrimSpace(m.Endpoint) == "" {
return "", errors.New("participant: the session service-auth has no PDS URL")
}
lifetime := m.Lifetime
if lifetime <= 0 {
lifetime = ServiceAuthLifetime
}
client := &xrpc.Client{Host: m.Endpoint, HTTP: m.HTTP, Auth: m.Auth}
return xrpc.GetServiceAuth(ctx, client, audience, lxm, time.Now().Add(lifetime))
}
type Tokens struct {
minter xrpc.Minter
timeout time.Duration
cache *ttlcache.Cache[string, string]
}
func NewTokens(minter xrpc.Minter, timeout time.Duration) *Tokens {
return &Tokens{minter: minter, timeout: timeout, cache: ttlcache.New[string, string](ttlcache.Options{})}
}
func (t *Tokens) Token(ctx context.Context, host, lxm string) (string, error) {
if t == nil || t.minter == nil {
return "", errors.New("participant: no service-auth minter is configured")
}
aud := market.ServiceDIDForHost(host)
return t.cache.GetOrLoad(ctx, aud+"\x00"+lxm, func(ctx context.Context) (string, time.Duration, error) {
requested := time.Now().Add(ServiceAuthLifetime)
callCtx := ctx
if t.timeout > 0 {
var cancel context.CancelFunc
callCtx, cancel = context.WithTimeout(ctx, t.timeout)
defer cancel()
}
token, err := t.minter.ServiceAuth(callCtx, aud, lxm)
if err != nil {
return "", 0, fmt.Errorf("getServiceAuth %s: %w", aud, err)
}
ttl := time.Until(CacheExpiry(token, requested))
if ttl <= 0 {
ttl = -1
}
return token, ttl, nil
})
}
func (t *Tokens) Invalidate(host, lxm string) {
if t == nil {
return
}
t.cache.Delete(market.ServiceDIDForHost(host) + "\x00" + lxm)
}
func (t *Tokens) Source(host, lxm string) xrpc.Source[string] {
return tokenSource{tokens: t, host: host, lxm: lxm}
}
type tokenSource struct {
tokens *Tokens
host string
lxm string
}
func (s tokenSource) Get(ctx context.Context) (string, error) {
return s.tokens.Token(ctx, s.host, s.lxm)
}
func (s tokenSource) Invalidate() {
s.tokens.Invalidate(s.host, s.lxm)
}
func CacheExpiry(token string, requested time.Time) time.Time {
fallback := requested.Add(-ServiceAuthRefreshMargin)
parts := strings.Split(token, ".")
if len(parts) < 2 {
return fallback
}
payload, err := base64.RawURLEncoding.DecodeString(parts[1])
if err != nil {
return fallback
}
var claims struct {
Exp int64 `json:"exp"`
}
if json.Unmarshal(payload, &claims) != nil || claims.Exp == 0 {
return fallback
}
expires := time.Unix(claims.Exp, 0).Add(-ServiceAuthRefreshMargin)
if expires.After(requested) {
return fallback
}
return expires
}
