Enable SEE for external library

* Add DSN key
* Add PRAGMA execution
* Add SEE for external libsqlite3 library

Closes mattn#162
Closes mattn#487

Author: gjrtimmer

driver/config.go

@@ -466,6 +466,9 @@ type Config struct {
 	// Database
 	Database string
 
+	// Encryption Key
+	Key string
+
 	// Mode of the SQLite database
 	Mode Mode
 
@@ -603,6 +606,10 @@ func (cfg *Config) FormatDSN() string {
 	var buf bytes.Buffer
 
 	params := url.Values{}
+	if len(cfg.Key) > 0 {
+		params.Set("key", cfg.Key)
+	}
+
 	if len(cfg.Cache.String()) > 0 {
 		params.Set("cache", cfg.Cache.String())
 	}
@@ -759,6 +766,22 @@ func (cfg *Config) createConnection() (driver.Conn, error) {
 		return nil, errors.New("sqlite succeeded without returning a database")
 	}
 
+	// Create basic connection
+	conn := &SQLiteConn{
+		cfg:    cfg,
+		db:     db,
+		tz:     cfg.TimeZone,
+		txlock: cfg.TransactionLock.Value(),
+	}
+
+	// Handle Encryption key before anything else
+	if len(cfg.Key) > 0 {
+		if err := conn.PRAGMA(PRAGMA_SEE_KEY, cfg.Key); err != nil {
+			C.sqlite3_close_v2(db)
+			return nil, err
+		}
+	}
+
 	// Set SQLITE Busy Timeout Handler
 	if cfg.BusyTimeout > 0 {
 		rv = C.sqlite3_busy_timeout(db, C.int(cfg.BusyTimeout))
@@ -771,14 +794,6 @@ func (cfg *Config) createConnection() (driver.Conn, error) {
 		}
 	}
 
-	// Create basic connection
-	conn := &SQLiteConn{
-		cfg:    cfg,
-		db:     db,
-		tz:     cfg.TimeZone,
-		txlock: cfg.TransactionLock.Value(),
-	}
-
 	// At this point we have the following
 	// - database pointer
 	// - basic connection
@@ -1021,6 +1036,11 @@ func ParseDSN(dsn string) (cfg *Config, err error) {
 			dsn = dsn[:pos]
 		}
 
+		// Parse encryption key
+		if val := params.Get("key"); val != "" {
+			cfg.Key = val
+		}
+
 		// Parse Autentication
 		if val := params.Get("user"); val != "" {
 			cfg.Authentication.Username = val

driver/connection.go

@@ -50,6 +50,12 @@ type SQLiteConn struct {
 func (c *SQLiteConn) PRAGMA(name, value string) error {
 	stmt := fmt.Sprintf("PRAGMA %s = %s;", name, value)
 
+	// Use switch for future modifications to PRAGMA's
+	switch name {
+	case PRAGMA_SEE_KEY, PRAGMA_SEE_REKEY:
+		stmt = fmt.Sprintf("PRAGMA %s = '%s'", name, strings.Replace(value, "'", "''", -1))
+	}
+
 	cs := C.CString(stmt)
 	rv := C.sqlite3_exec(c.db, cs, nil, nil, nil)
 	C.free(unsafe.Pointer(cs))

driver/libsqlite_see.go

@@ -0,0 +1,14 @@
+// Copyright (C) 2018 The Go-SQLite3 Authors.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build libsqlite3
+// +build sqlite_see
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_HAS_CODEC=1
+*/
+import "C"

driver/pragma.go

@@ -8,7 +8,6 @@
 package sqlite3
 
 const (
-	PRAGMA_SSE_KEY                 = "key"
 	PRAGMA_AUTO_VACUUM             = "auto_vacuum"
 	PRAGMA_CASE_SENSITIVE_LIKE     = "case_sensitive_like"
 	PRAGMA_DEFER_FOREIGN_KEYS      = "defer_foreign_keys"
@@ -18,6 +17,8 @@ const (
 	PRAGMA_LOCKING_MODE            = "locking_mode"
 	PRAGMA_QUERY_ONLY              = "query_only"
 	PRAGMA_RECURSIVE_TRIGGERS      = "recursive_triggers"
+	PRAGMA_SEE_KEY                 = "key"
+	PRAGMA_SEE_REKEY               = "rekey"
 	PRAGMA_SECURE_DELETE           = "secure_delete"
 	PRAGMA_SYNCHRONOUS             = "synchronous"
 	PRAGMA_WRITABLE_SCHEMA         = "writable_schema"