implement the escaping rules

message.go

@@ -42,8 +42,8 @@ func (m *Message) parseTags() (map[string]string, error) {
 			key := m.Raw[m.parseIndex : m.parseIndex+next]
 			m.parseIndex += next + 1
 			eot := m.findNext(";", " ")
-			tags[key] = m.Raw[m.parseIndex : m.parseIndex+eot]
+			tags[key] = unescapeTag(m.Raw[m.parseIndex : m.parseIndex+eot])
-			m.parseIndex += len(tags[key]) + 1
+			m.parseIndex += len(m.Raw[m.parseIndex:m.parseIndex+eot]) + 1
 		} else if m.Raw[m.parseIndex+next] == ';' {
 			key := m.Raw[m.parseIndex : m.parseIndex+next]
 			m.parseIndex += next + 1
@@ -69,9 +69,10 @@ func (m *Message) parseCommand() (command, error) {
 	start := m.parseIndex
 	endofparse := strings.Index(m.Raw[m.parseIndex:], " ")
 	if endofparse == -1 {
-		return "", fmt.Errorf("end of string encountered while parsing command")
+		m.parseIndex = len(m.Raw) // a command with no parameters
-	}
+	} else {
 		m.parseIndex += endofparse
+	}
 	return command(m.Raw[start:m.parseIndex]), nil
 }
 
@@ -131,6 +132,45 @@ func (m *Message) findNext(bs ...string) int {
 	return r
 }
 
+func unescapeTag(s string) string {
+	sb := strings.Builder{}
+	escaping := false
+	i := 0
+	for i < len(s) {
+		if escaping {
+			if i+1 > len(s) {
+				break
+			}
+			switch s[i] {
+			case ':':
+				sb.WriteByte(';')
+			case '\\':
+				sb.WriteByte('\\')
+			case 's':
+				sb.WriteByte(' ')
+			case 'r':
+				sb.WriteByte('\r')
+			case 'n':
+				sb.WriteByte('\n')
+			default:
+				sb.WriteByte(s[i])
+			}
+			i++
+			escaping = false
+		} else if s[i] == '\\' {
+			if !escaping {
+				escaping = true
+				i++
+				continue
+			}
+		} else {
+			sb.WriteByte(s[i])
+			i++
+		}
+	}
+	return sb.String()
+}
+
 func (m *Message) ToBytes() []byte {
 	return nil
 }

message_test.go

@@ -33,6 +33,12 @@ func TestParsing(t *testing.T) {
 				Command:    PRIVMSG,
 				Parameters: []string{"#chan", "Hey what's up!"},
 			}},
+		{
+			input: `@a=b\\and\nk;c=72\s45;d=gh\:764 CAP`,
+			output: &Message{
+				Tags:    map[string]string{"a": "b\\and\nk", "c": "72 45", "d": `gh;764`},
+				Command: command("CAP"),
+			}},
 		{
 			input: `@tag1=value1;tag2;vendor1/tag3=value2;vendor2/tag4= :dan!d@localhost PRIVMSG #chan :Hey what's up!`,
 			output: &Message{
@@ -41,6 +47,18 @@ func TestParsing(t *testing.T) {
 				Command:    PRIVMSG,
 				Parameters: []string{"#chan", "Hey what's up!"},
 			}},
+		{
+			input: ":src AWAY",
+			output: &Message{
+				Source:  "src",
+				Command: AWAY,
+			}},
+		{
+			input: ":src AWAY ",
+			output: &Message{
+				Source:  "src",
+				Command: AWAY,
+			}},
 		{
 			input: `CAP REQ :sasl`,
 			output: &Message{
@@ -65,6 +83,13 @@ func TestParsing(t *testing.T) {
 				Command:    CAP,
 				Parameters: []string{"REQ", "    asdf qwer"},
 			}},
+		{
+			input: ":coolguy!ag@net\x035w\x03ork.admin PRIVMSG foo :bar baz",
+			output: &Message{
+				Source:     "coolguy!ag@net\x035w\x03ork.admin",
+				Command:    PRIVMSG,
+				Parameters: []string{"foo", "bar baz"},
+			}},
 		{
 			input: `:coolguy PRIVMSG bar :lol :) `,
 			output: &Message{
@@ -86,6 +111,57 @@ func TestParsing(t *testing.T) {
 				Command:    MODE,
 				Parameters: []string{"#tckk", "+n"},
 			}},
+		{
+			input: ":services.esper.net MODE #foo-bar +o foobar  ",
+			output: &Message{
+				Source:     "services.esper.net",
+				Command:    MODE,
+				Parameters: []string{"#foo-bar", "+o", "foobar"},
+			}},
+		{
+			input: `@tag1=value\\ntest COMMAND`,
+			output: &Message{
+				Tags:    map[string]string{"tag1": `value\ntest`},
+				Command: command("COMMAND"),
+			}},
+		{
+			input: `@tag1=value\1 COMMAND`,
+			output: &Message{
+				Tags:    map[string]string{"tag1": `value1`},
+				Command: command("COMMAND"),
+			}},
+		{
+			input: `@tag1=value\ COMMAND`,
+			output: &Message{
+				Tags:    map[string]string{"tag1": `value`},
+				Command: command("COMMAND"),
+			}},
+		{
+			input: `@tag1=1;tag2=3;tag3=4;tag1=5 COMMAND`,
+			output: &Message{
+				Tags:    map[string]string{"tag1": "5", "tag2": "3", "tag3": "4"},
+				Command: command("COMMAND"),
+			}},
+		{
+			input: `@tag1=1;tag2=3;tag3=4;tag1=5;vendor/tag2=8 COMMAND`,
+			output: &Message{
+				Tags:    map[string]string{"tag1": "5", "tag2": "3", "tag3": "4", "vendor/tag2": "8"},
+				Command: command("COMMAND"),
+			}},
+		{
+			input: `:SomeOp MODE #channel :+i`,
+			output: &Message{
+				Source:     "SomeOp",
+				Command:    MODE,
+				Parameters: []string{"#channel", "+i"},
+			}},
+		{
+			input: `:SomeOp MODE #channel +oo SomeUser :AnotherUser`,
+			output: &Message{
+				Source:     "SomeOp",
+				Command:    MODE,
+				Parameters: []string{"#channel", "+oo", "SomeUser", "AnotherUser"},
+			}},
 	}
 	for _, tc := range testcases {
 		m := &Message{Raw: tc.input}
@@ -94,6 +170,12 @@ func TestParsing(t *testing.T) {
 			t.Logf("tags: actual: %v, expected: %v", m.Tags, tc.output.Tags)
 			t.Fail()
 		}
+		for i := range tc.output.Tags {
+			if tc.output.Tags[i] != m.Tags[i] {
+				t.Logf("tags: actual: %v, expected: %v", m.Tags[i], tc.output.Tags[i])
+				t.Fail()
+			}
+		}
 		if tc.output.Source != m.Source {
 			t.Logf("source: actual: %v, expected: %v", m.Source, tc.output.Source)
 			t.Fail()
@@ -106,5 +188,11 @@ func TestParsing(t *testing.T) {
 			t.Logf("parameters: actual: %v (%d), expected: %v (%d)", m.Parameters, len(m.Parameters), tc.output.Parameters, len(tc.output.Parameters))
 			t.Fail()
 		}
+		for i := range tc.output.Parameters {
+			if tc.output.Parameters[i] != m.Parameters[i] {
+				t.Logf("parameters: actual: %v, expected: %v", m.Parameters[i], tc.output.Parameters[i])
+				t.Fail()
+			}
+		}
 	}
 }