coap

package module
v1.0.2 Latest Latest
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 Go to latest Published: Mar 29, 2022 License: MIT Imports: 17 Imported by: 0

README

Constrained Application Protocol Client and Server for go

You can read more about CoAP in RFC 7252. I also did some preliminary work on SUBSCRIBE support from an early draft.

Benchmark

goos: darwin
goarch: amd64
BenchmarkQps
BenchmarkQps-8   	   96454	     12558 ns/op	     360 B/op	       9 allocs/op
PASS

Documentation

Overview

Package coap provides a CoAP client and server.

Index

Constants

View Source 
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
)

Variables

View Source 
var (
	ErrInvalidTokenLen   = errors.New("invalid token length")
	ErrOptionTooLong     = errors.New("option is too long")
	ErrOptionGapTooLarge = errors.New("option gap too large")
)

Message encoding errors.

Functions

func ListenAndServe 

func ListenAndServe(n, addr string, rh Handler) error

ListenAndServe binds to the given address and serve requests forever.

func Serve 

func Serve(listener *net.UDPConn, rh Handler) error

Serve processes incoming UDP packets on the given listener, and processes these requests forever (or until the listener is closed).

func Transmit 

func Transmit(l *net.UDPConn, a *net.UDPAddr, m Message) error

Transmit a message.

Types

type COAPCode 

type COAPCode uint8

COAPCode is the type used for both request and response codes. 

const (
	GET    COAPCode = 1
	POST   COAPCode = 2
	PUT    COAPCode = 3
	DELETE COAPCode = 4
)

Request Codes 

const (
	Created               COAPCode = 65
	Deleted               COAPCode = 66
	Valid                 COAPCode = 67
	Changed               COAPCode = 68
	Content               COAPCode = 69
	BadRequest            COAPCode = 128
	Unauthorized          COAPCode = 129
	BadOption             COAPCode = 130
	Forbidden             COAPCode = 131
	NotFound              COAPCode = 132
	MethodNotAllowed      COAPCode = 133
	NotAcceptable         COAPCode = 134
	PreconditionFailed    COAPCode = 140
	RequestEntityTooLarge COAPCode = 141
	UnsupportedMediaType  COAPCode = 143
	InternalServerError   COAPCode = 160
	NotImplemented        COAPCode = 161
	BadGateway            COAPCode = 162
	ServiceUnavailable    COAPCode = 163
	GatewayTimeout        COAPCode = 164
	ProxyingNotSupported  COAPCode = 165
)

Response Codes

func (COAPCode) String 

func (c COAPCode) String() string

type COAPType 

type COAPType uint8

COAPType represents the message type. 

const (
	// Confirmable messages require acknowledgements.
	Confirmable COAPType = 0
	// NonConfirmable messages do not require acknowledgements.
	NonConfirmable COAPType = 1
	// Acknowledgement is a message indicating a response to confirmable message.
	Acknowledgement COAPType = 2
	// Reset indicates a permanent negative acknowledgement.
	Reset COAPType = 3
)

func (COAPType) String 

func (t COAPType) String() string

type Conn 

type Conn struct {
	Busy atomic.Value
	// contains filtered or unexported fields
}

Conn is a CoAP client connection.

func Dial 

func Dial(n, addr string) (*Conn, error)

Dial connects a CoAP client.

func (*Conn) Receive 

func (c *Conn) Receive() (*Message, error)

Receive a message.

func (*Conn) Send 

func (c *Conn) Send(req Message) (*Message, error)

Send a message. Get a response if there is one.

type Handler 

type Handler interface {
	ServeCOAP(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message
}

Handler is a type that handles CoAP messages.

func FuncHandler 

func FuncHandler(f func(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message) Handler

FuncHandler builds a handler from a function.

type MediaType 

type MediaType uint16

MediaType specifies the content type of a message. 

const (
	TextPlain     MediaType = 0  // text/plain;charset=utf-8
	AppLinkFormat MediaType = 40 // application/link-format
	AppXML        MediaType = 41 // application/xml
	AppOctets     MediaType = 42 // application/octet-stream
	AppExi        MediaType = 47 // application/exi
	AppJSON       MediaType = 50 // application/json
)

Content types.

type Message 

type Message struct {
	Type      COAPType
	Code      COAPCode
	MessageID uint16

	Token, Payload []byte
	// contains filtered or unexported fields
}

Message is a CoAP message.

func ParseMessage 

func ParseMessage(data []byte) (Message, error)

ParseMessage extracts the Message from the given input.

func Receive 

func Receive(l *net.UDPConn, buf []byte) (Message, error)

Receive a message.

func (*Message) AddOption 

func (m *Message) AddOption(opID OptionID, val interface{})

AddOption adds an option.

func (Message) IsConfirmable 

func (m Message) IsConfirmable() bool

IsConfirmable returns true if this message is confirmable.

func (*Message) MarshalBinary 

func (m *Message) MarshalBinary() ([]byte, error)

MarshalBinary produces the binary form of this Message.

func (Message) Option 

func (m Message) Option(o OptionID) interface{}

Option gets the first value for the given option ID.

func (Message) Options 

func (m Message) Options(o OptionID) []interface{}

Options gets all the values for the given option.

func (Message) Path 

func (m Message) Path() []string

Path gets the Path set on this message if any.

func (Message) PathString 

func (m Message) PathString() string

PathString gets a path as a / separated string.

func (*Message) RemoveOption 

func (m *Message) RemoveOption(opID OptionID)

RemoveOption removes all references to an option

func (*Message) SetOption 

func (m *Message) SetOption(opID OptionID, val interface{})

SetOption sets an option, discarding any previous value

func (*Message) SetPath 

func (m *Message) SetPath(s []string)

SetPath updates or adds a URIPath attribute on this message.

func (*Message) SetPathString 

func (m *Message) SetPathString(s string)

SetPathString sets a path by a / separated string.

func (*Message) UnmarshalBinary 

func (m *Message) UnmarshalBinary(data []byte) error

UnmarshalBinary parses the given binary slice as a Message.

type OptionID 

type OptionID uint8

OptionID identifies an option in a message. 

const (
	IfMatch       OptionID = 1
	URIHost       OptionID = 3
	ETag          OptionID = 4
	IfNoneMatch   OptionID = 5
	Observe       OptionID = 6
	URIPort       OptionID = 7
	LocationPath  OptionID = 8
	URIPath       OptionID = 11
	ContentFormat OptionID = 12
	MaxAge        OptionID = 14
	URIQuery      OptionID = 15
	Accept        OptionID = 17
	LocationQuery OptionID = 20
	ProxyURI      OptionID = 35
	ProxyScheme   OptionID = 39
	Size1         OptionID = 60
)

Option IDs.

type ServeMux 

type ServeMux struct {
	// contains filtered or unexported fields
}

ServeMux provides mappings from a common endpoint to handlers by request path.

func NewServeMux 

func NewServeMux() *ServeMux

NewServeMux creates a new ServeMux.

func (*ServeMux) Handle 

func (mux *ServeMux) Handle(pattern string, handler Handler)

Handle configures a handler for the given path.

func (*ServeMux) HandleFunc 

func (mux *ServeMux) HandleFunc(pattern string,
	f func(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message)

HandleFunc configures a handler for the given path.

func (*ServeMux) ServeCOAP 

func (mux *ServeMux) ServeCOAP(l *net.UDPConn, a *net.UDPAddr, m *Message) *Message

ServeCOAP handles a single COAP message. The message arrives from the given listener having originated from the given UDPAddr.

type TcpMessage 

type TcpMessage struct {
	Message
}

TcpMessage is a CoAP Message that can encode itself for TCP transport.

func Decode 

func Decode(r io.Reader) (*TcpMessage, error)

Decode reads a single message from its input.

func (*TcpMessage) MarshalBinary 

func (m *TcpMessage) MarshalBinary() ([]byte, error)

func (*TcpMessage) UnmarshalBinary 

func (m *TcpMessage) UnmarshalBinary(data []byte) error

Source Files

View all Source files

Directories

Path Synopsis
example
client
obsclient
obsserver
server

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