6 files changed, 67 insertions, 25 deletions
diff --git a/common.go b/common.go
index 310da86..2d73189 100644
--- a/common.go
+++ b/common.go
@@ -30,10 +30,10 @@ func readLimitedLine(br *bufio.Reader, length int) ([]byte, error) {
 	}
 }
 
-func getInt(m *Message, param string) (int64, error) {
+func getInt(m *Message, param string, fallback int64) (int64, error) {
 	p := m.Param(param)
 	if p == "" {
-		return 0, nil
+		return fallback, nil
 	}
 	n, err := strconv.ParseUint(p, 10, 63)
 	if err != nil || (n != 0 && p[0] == '0') || (n == 0 && len(p) != 1) {
diff --git a/message.go b/message.go
index fdb16b3..ccd455f 100644
--- a/message.go
+++ b/message.go
@@ -114,22 +114,14 @@ func (msg *Message) TryComputeLength() bool {
 	return true
 }
 
-// SetLength sets the length header parameter to n.
-func (msg *Message) SetLength(n int64) {
-	if n == 0 {
-		msg.SetParam("length", "")
-	} else {
-		setInt(msg, "length", n)
-	}
+// Intent retrieves the message header intent.
+func (msg *Message) Intent() string {
+	return msg.Header.Intent
 }
 
-// Length gets the length header parameter (or 0 if it's not set or invalid).
-func (msg *Message) Length() int64 {
-	n, err := getInt(msg, "length")
-	if err != nil {
-		return 0
-	}
-	return n
+// SetIntent sets the message header intent.
+func (msg *Message) SetIntent(s string) {
+	msg.Header.Intent = s
 }
 
 // Param retrieves a header parameter. It performs no value validation.
@@ -147,19 +139,29 @@ func (msg *Message) SetParam(key, value string) {
 	}
 }
 
-// Intent retrieves the message header intent.
-func (msg *Message) Intent() string {
-	return msg.Header.Intent
+// Length gets the length header parameter (or 0 if it's not set or invalid).
+func (msg *Message) Length() int64 {
+	n, err := getInt(msg, "length", 0)
+	if err != nil {
+		return 0
+	}
+	return n
 }
 
-// SetIntent sets the message header intent.
-func (msg *Message) SetIntent(s string) {
-	msg.Header.Intent = s
+// SetLength sets the length header parameter to n.
+//
+// If negative or zero, the parameter is unset.
+func (msg *Message) SetLength(n int64) {
+	if n <= 0 {
+		msg.SetParam("length", "")
+	} else {
+		setInt(msg, "length", n)
+	}
 }
 
 // Validate validates the message header parameter value format (length).
 func (msg *Message) Validate() error {
-	_, err := getInt(msg, "length")
+	_, err := getInt(msg, "length", 0)
 	return err
 }
 
diff --git a/message_test.go b/message_test.go
index 6955fc3..1a73fa5 100644
--- a/message_test.go
+++ b/message_test.go
@@ -92,7 +92,7 @@ func TestParse(t *testing.T) {
 			}
 		} else if !msgEqual(msg, tst.m) {
 			t.Errorf("\nexpected: %+v\ngot:      %+v", tst.m, msg)
-		} else if l := msg.Length(); tst.v == nil && l != int64(len(tst.b)) {
+		} else if l := msg.Length(); tst.v == nil && (l != int64(len(tst.b)) && !(l < 0 == (len(tst.b) == 0))) {
 			t.Errorf("%+v: expected length %d, got %d", tst.m, len(tst.b), l)
 		} else if err = msg.Validate(); !errorEqual(err, tst.v) {
 			t.Errorf("%+v: expected validation error %+v, got %+v (%s)", msg, tst.v, err, err)
diff --git a/request.go b/request.go
index 0fb27a2..44bae56 100644
--- a/request.go
+++ b/request.go
@@ -219,6 +219,26 @@ func (r *Request) SetSelect(selector, query string) error {
 	return setSelect(&r.Message, "select", selector, query)
 }
 
+// Length gets the length request parameter (or 0 if not set or invalid).
+func (r *Request) Length() int64 {
+	n, err := getInt(&r.Message, "length", 0)
+	if err != nil {
+		return 0
+	}
+	return n
+}
+
+// SetLength sets the length request parameter to n.
+//
+// If n is negative or zero, the parameter is unset.
+func (r *Request) SetLength(n int64) {
+	if n <= 0 {
+		r.SetParam("length", "")
+	} else {
+		setInt(&r.Message, "length", n)
+	}
+}
+
 // Validate validates the request header intent and parameter value format
 // (length, name, type, if_modified, select)
 func (r *Request) Validate() error {
diff --git a/response.go b/response.go
index 3ecb961..4c3f753 100644
--- a/response.go
+++ b/response.go
@@ -224,6 +224,26 @@ func (r *Response) SetSelect(selector, query string) error {
 	return setSelect(&r.Message, "select", selector, query)
 }
 
+// Length gets the length response parameter (or -1 if it's not set or invalid).
+func (r *Response) Length() int64 {
+	n, err := getInt(&r.Message, "length", -1)
+	if err != nil {
+		return -1
+	}
+	return n
+}
+
+// SetLength sets the length response parameter to n.
+//
+// If negative, the parameter is unset.
+func (r *Response) SetLength(n int64) {
+	if n < 0 {
+		r.SetParam("length", "")
+	} else {
+		setInt(&r.Message, "length", n)
+	}
+}
+
 // Validate validates the response intent and header parameter value format
 // (length, name, type, time, modified, location, reason, select)
 func (r *Response) Validate() error {
diff --git a/server.go b/server.go
index 26301ab..c8491fc 100644
--- a/server.go
+++ b/server.go
@@ -139,7 +139,7 @@ func (srv *Server) HandleConn(conn net.Conn) {
 	req.Body = io.LimitReader(req.Body, req.Length())
 
 	if srv.Validate {
-		if err != nil {
+		if err := req.Validate(); err != nil {
 			panic(err)
 		}
 	}