Doc and lint cleanups

client.go

@@ -5,19 +5,24 @@ import (
 	"time"
 )
 
-const RESPONSE_TIMEOUT = time.Second * 2
-
-const RESPONSE_RANDOM_FACTOR = 1.5
-
-const MAX_RETRANSMIT = 4
+const (
+	// ResponseTimeout is the amount of time to wait for a
+	// response.
+	ResponseTimeout = time.Second * 2
+	// ResponseRandomFactor is a multiplier for response backoff.
+	ResponseRandomFactor = 1.5
+	// MaxRetransmit is the maximum number of times a message will
+	// be retransmitted.
+	MaxRetransmit = 4
+)
 
-// A CoAP client connection.
+// Conn is a CoAP client connection.
 type Conn struct {
 	conn *net.UDPConn
 	buf  []byte
 }
 
-// Get a CoAP client.
+// Dial connects a CoAP client.
 func Dial(n, addr string) (*Conn, error) {
 	uaddr, err := net.ResolveUDPAddr(n, addr)
 	if err != nil {
@@ -32,7 +37,7 @@ func Dial(n, addr string) (*Conn, error) {
 	return &Conn{s, make([]byte, maxPktLen)}, nil
 }
 
-// Duration a message.  Get a response if there is one.
+// Send a message.  Get a response if there is one.
 func (c *Conn) Send(req Message) (*Message, error) {
 	err := Transmit(c.conn, nil, req)
 	if err == nil {

message.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 )
 
+// COAPType represents the message type.
 type COAPType uint8
 
 const (
@@ -37,6 +38,7 @@ func (t COAPType) String() string {
 	return typeNames[t]
 }
 
+// COAPCode is the type used for both request and response codes.
 type COAPCode uint8
 
 // Request Codes
@@ -114,10 +116,11 @@ func (c COAPCode) String() string {
 	return codeNames[c]
 }
 
-var InvalidTokenLen = errors.New("Invalid token length")
-var OptionTooLong = errors.New("Option is too long")
-var OptionGapTooLarge = errors.New("Option gap too large")
+var ErrInvalidTokenLen = errors.New("invalid token length")
+var ErrOptionTooLong = errors.New("option is too long")
+var ErrOptionGapTooLarge = errors.New("option gap too large")
 
+// OptionID identifies an option in a message.
 type OptionID uint8
 
 /*
@@ -162,6 +165,7 @@ const (
 	Size1         = OptionID(60)
 )
 
+// MediaType specifies the content type of a message.
 type MediaType byte
 
 const (
@@ -224,7 +228,7 @@ func (o option) toBytes() []byte {
 	case uint32:
 		v = i
 	default:
-		panic(fmt.Errorf("Invalid type for option %x: %T (%v)",
+		panic(fmt.Errorf("invalid type for option %x: %T (%v)",
 			o.ID, o.Value, o.Value))
 	}
 
@@ -258,7 +262,7 @@ func (o options) Minus(oid OptionID) options {
 	return rv
 }
 
-// A CoAP message.
+// Message is a CoAP message.
 type Message struct {
 	Type      COAPType
 	Code      COAPCode
@@ -269,12 +273,12 @@ type Message struct {
 	opts options
 }
 
-// Return True if this message is confirmable.
+// IsConfirmable returns true if this message is confirmable.
 func (m Message) IsConfirmable() bool {
 	return m.Type == Confirmable
 }
 
-// Get all the values for the given option.
+// Options gets all the values for the given option.
 func (m Message) Options(o OptionID) []interface{} {
 	var rv []interface{}
 
@@ -287,7 +291,7 @@ func (m Message) Options(o OptionID) []interface{} {
 	return rv
 }
 
-// Get the first value for the given option ID.
+// Option gets the first value for the given option ID.
 func (m Message) Option(o OptionID) interface{} {
 	for _, v := range m.opts {
 		if o == v.ID {
@@ -305,46 +309,46 @@ func (m Message) optionStrings(o OptionID) []string {
 	return rv
 }
 
-// Get the Path set on this message if any.
+// Path gets the Path set on this message if any.
 func (m Message) Path() []string {
 	return m.optionStrings(URIPath)
 }
 
-// Get a path as a / separated string.
+// PathString gets a path as a / separated string.
 func (m Message) PathString() string {
 	return strings.Join(m.Path(), "/")
 }
 
-// Set a path by a / separated string.
+// SetPathString sets a path by a / separated string.
 func (m *Message) SetPathString(s string) {
 	for s[0] == '/' {
 		s = s[1:]
 	}
 	m.SetPath(strings.Split(s, "/"))
 }
 
-// Update or add a LocationPath attribute on this message.
+// SetPath updates or adds a LocationPath attribute on this message.
 func (m *Message) SetPath(s []string) {
 	m.RemoveOption(URIPath)
 	for _, p := range s {
 		m.AddOption(URIPath, p)
 	}
 }
 
-// Remove all references to an option
-func (m *Message) RemoveOption(opId OptionID) {
-	m.opts = m.opts.Minus(opId)
+// RemoveOption removes all references to an option
+func (m *Message) RemoveOption(opID OptionID) {
+	m.opts = m.opts.Minus(opID)
 }
 
-// Add an option.
-func (m *Message) AddOption(opId OptionID, val interface{}) {
-	m.opts = append(m.opts, option{opId, val})
+// AddOption adds an option.
+func (m *Message) AddOption(opID OptionID, val interface{}) {
+	m.opts = append(m.opts, option{opID, val})
 }
 
-// Set an option, discarding any previous value
-func (m *Message) SetOption(opId OptionID, val interface{}) {
-	m.RemoveOption(opId)
-	m.AddOption(opId, val)
+// SetOption sets an option, discarding any previous value
+func (m *Message) SetOption(opID OptionID, val interface{}) {
+	m.RemoveOption(opID)
+	m.AddOption(opID, val)
 }
 
 func (m *Message) encode() ([]byte, error) {
@@ -402,7 +406,7 @@ func (m *Message) encode() ([]byte, error) {
 			buf.Write([]byte{byte(int(o.ID)-prev)<<4 | byte(len(b))})
 		}
 		if int(o.ID)-prev > 15 {
-			return nil, OptionGapTooLarge
+			return nil, ErrOptionGapTooLarge
 		}
 
 		buf.Write(b)
@@ -420,17 +424,17 @@ func (m *Message) encode() ([]byte, error) {
 
 func parseMessage(data []byte) (rv Message, err error) {
 	if len(data) < 6 {
-		return rv, errors.New("Short packet")
+		return rv, errors.New("short packet")
 	}
 
 	if data[0]>>6 != 1 {
-		return rv, errors.New("Invalid version")
+		return rv, errors.New("invalid version")
 	}
 
 	rv.Type = COAPType((data[0] >> 4) & 0x3)
 	tokenLen := int(data[0] & 0xf)
 	if tokenLen > 8 {
-		return rv, InvalidTokenLen
+		return rv, ErrInvalidTokenLen
 	}
 
 	rv.Code = COAPCode(data[1])
@@ -451,7 +455,7 @@ func parseMessage(data []byte) (rv Message, err error) {
 			b = b[1:]
 		}
 		if len(b) < l {
-			return rv, errors.New("Truncated")
+			return rv, errors.New("truncated")
 		}
 		var opval interface{} = b[:l]
 		switch oid {

message_test.go

@@ -50,7 +50,7 @@ func TestEncodeMessageLargeOptionGap(t *testing.T) {
 	req.AddOption(ProxyURI, "u")
 
 	_, err := req.encode()
-	if err != OptionGapTooLarge {
+	if err != ErrOptionGapTooLarge {
 		t.Fatalf("Expected 'option gap too large', got: %v", err)
 	}
 }

server.go

@@ -1,4 +1,4 @@
-// CoAP Client and Server in Go
+// Package coap provides a CoAP client and server.
 package coap
 
 import (
@@ -9,7 +9,7 @@ import (
 
 const maxPktLen = 1500
 
-// Handle CoAP messages.
+// Handler is a type that handles CoAP messages.
 type Handler interface {
 	// Handle the message and optionally return a response message.
 	ServeCOAP(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message
@@ -21,7 +21,7 @@ func (f funcHandler) ServeCOAP(l *net.UDPConn, a *net.UDPAddr, m *Message) *Mess
 	return f(l, a, m)
 }
 
-// Build a handler from a function.
+// FuncHandler builds a handler from a function.
 func FuncHandler(f func(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message) Handler {
 	return funcHandler(f)
 }
@@ -59,7 +59,7 @@ func Transmit(l *net.UDPConn, a *net.UDPAddr, m Message) error {
 
 // Receive a message.
 func Receive(l *net.UDPConn, buf []byte) (Message, error) {
-	l.SetReadDeadline(time.Now().Add(RESPONSE_TIMEOUT))
+	l.SetReadDeadline(time.Now().Add(ResponseTimeout))
 
 	nr, _, err := l.ReadFromUDP(buf)
 	if err != nil {
@@ -68,7 +68,7 @@ func Receive(l *net.UDPConn, buf []byte) (Message, error) {
 	return parseMessage(buf[:nr])
 }
 
-// Bind to the given address and serve requests forever.
+// ListenAndServe binds to the given address and serve requests forever.
 func ListenAndServe(n, addr string, rh Handler) error {
 	uaddr, err := net.ResolveUDPAddr(n, addr)
 	if err != nil {