From b0aee65db26a91457a3b2b862733240071dbcae0 Mon Sep 17 00:00:00 2001
From: eqinox76 <5861557+eqinox76@users.noreply.github.com>
Date: Sat, 21 Nov 2020 08:12:41 +0100
Subject: [PATCH] Added parameters for compression (#24)

---
 connection.go | 1 +
 connector.go  | 5 +++++
 dsn.go        | 7 ++++++-
 packets.go    | 5 +++++
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/connection.go b/connection.go
index 90aec6439..1cfb5f13b 100644
--- a/connection.go
+++ b/connection.go
@@ -35,6 +35,7 @@ type mysqlConn struct {
 	sequence         uint8
 	parseTime        bool
 	reset            bool // set when the Go SQL package calls ResetSession
+	compressed       bool
 
 	// for context support (Go 1.8+)
 	watching bool
diff --git a/connector.go b/connector.go
index d567b4e4f..30c827859 100644
--- a/connector.go
+++ b/connector.go
@@ -136,6 +136,11 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 		return nil, err
 	}
 
+	// #24 compression requested by client and supported by server
+	if mc.flags&clientCompress > 0 && mc.cfg.Compress {
+		mc.compressed = true
+	}
+
 	return mc, nil
 }
 
diff --git a/dsn.go b/dsn.go
index 93f3548cb..b86cff742 100644
--- a/dsn.go
+++ b/dsn.go
@@ -58,6 +58,7 @@ type Config struct {
 	CheckConnLiveness       bool // Check connections for liveness before using them
 	ClientFoundRows         bool // Return number of matching rows instead of rows changed
 	ColumnsWithAlias        bool // Prepend table alias to column names
+	Compress                bool // #24 use compression protocol
 	InterpolateParams       bool // Interpolate placeholders into query string
 	MultiStatements         bool // Allow multiple statements in one query
 	ParseTime               bool // Parse time values to time.Time
@@ -437,7 +438,11 @@ func parseDSNParams(cfg *Config, params string) (err error) {
 
 		// Compression
 		case "compress":
-			return errors.New("compression not implemented yet")
+			var isBool bool
+			cfg.Compress, isBool = readBool(value)
+			if !isBool {
+				return errors.New("invalid bool value: " + value)
+			}
 
 		// Enable client side placeholder substitution
 		case "interpolateParams":
diff --git a/packets.go b/packets.go
index 6664e5ae5..c7e5d25e8 100644
--- a/packets.go
+++ b/packets.go
@@ -301,6 +301,11 @@ func (mc *mysqlConn) writeHandshakeResponsePacket(authResp []byte, plugin string
 		clientFlags |= clientMultiStatements
 	}
 
+	// To enable compression
+	if mc.cfg.Compress {
+		clientFlags |= clientCompress
+	}
+
 	// encode length of the auth plugin data
 	var authRespLEIBuf [9]byte
 	authRespLen := len(authResp)