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Published: Mar 12, 2020 License: BSD-3-Clause Imports: 11 Imported by: 11



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WebRTC for Golang.

Current Status:

As of October 2019, this repository is not actively maintained. The project for which it was developed is now using pion/webrtc instead.


To immediately see some action, try the chat demo from two machines (or one...)

  • git clone https://github.com/keroserene/go-webrtc
  • cd go-webrtc
  • go run demo/chat/chat.go

Type "start" in one of the Peers, and copy the session descriptions. (This is the "copy-paste" signalling channel). If ICE negotiation succeeds, a really janky chat session should begin.

To write Go code which requires WebRTC functionality:

import "github.com/keroserene/go-webrtc/"

And then you can do things like webrtc.NewPeerConnection(...).

If you've never used WebRTC before, there is already plenty of information online along with javascript examples, but for the Go code here, take a look within demo/* for real usage examples which show how to prepare a PeerConnection and set up the necessary callbacks and signaling.

Also, here are the GoDocs.

  • GCC 5+
  • TODO:
Package naming

The package name is webrtc, even though the repo name is go-webrtc. (This may be slightly contrary to Go convention, unless we consider the suffix to really begin at the last dash. Reasons:

  • Dashes aren't allowed in package names
  • Including the word "go" in a Go package name seems redundant
  • Just calling this repo webrtc wouldn't make sense either.
  • Also you can rename imported packages to whatever you like.

(e.g. import "foo" "github.com/keroserene/go-webrtc")


Latest tested native webrtc archive: 88f5d9180eae78a6162cccd78850ff416eb82483

There are currently two ways to build gowebrtc: the easy way, and the hard way.

The hard way is to build from scratch, which involves Google's depot_tools and chromium stuff, gclient syncing, which takes a couple hours, and possibly many more if you run into problems... along with writing a custom ninja file and concatenating archives correctly and such.

See webrtc.org native-code dev.

The easy way is to use the pre-built archive I've provided in lib/.

Once the archive is ready, cgo takes care of everything, and building is as easy as go build or go install.

TODO(keroserene): More information / provide a real build script to automate the hard way so it becomes the easy way. (See Issue #23)



Package webrtc/data contains the go wrapper for the Peer-to-Peer Data API portion of WebRTC spec.

See: https://w3c.github.io/webrtc-pc/#idl-def-RTCDataChannel

Package webrtc is a golang wrapper on native code WebRTC.

For consistency with the browser-based WebRTCs, the interface here is based loosely on: w3c.github.io/webrtc-pc

The main goal of this project is to present a golang WebRTC package in the most idiomatic and simple-to-use way.

However, to provide a better experience for users of this package, there are differences inherent in the interface written here and the original native code WebRTC - from the golang requirement of Capitalized identifiers for public interfaces, to the replacement of certain callbacks with goroutines.

Note that building the necessary libwebrtc static library is excessively complicated, which is why the necessary platform-specific archives will be provided in lib/. This also mitigates the possibility that future commits on native libwebrtc will break go-webrtc, because the interface with the native code, through the intermediate CGO layer, is relatively fragile.

Due to other external goals of the developers, this package will only be focused on DataChannels. However, extending this package to allow video/audio media streams and related functionality, to be a "complete" WebRTC suite, is entirely possible and will likely happen in the long term. (Issue #7) This will however have implications for the archives that need to be built and linked.

Please share any improvements or concerns as issues or pull requests on github.



This section is empty.


View Source
var (
	INFO  *log.Logger
	WARN  *log.Logger
	ERROR *log.Logger
	TRACE *log.Logger
View Source
var DCMap = NewCGOMap()
View Source
var PCMap = NewCGOMap()
View Source
var SdpTypes = []string{"offer", "pranswer", "answer", "rollback"}

TODO: Turn into Enum.


func CgoSdpToGoString

func CgoSdpToGoString(sdp C.CGO_sdp) string

func EnumToStringSafe

func EnumToStringSafe(value int, valueStrings []string) string

Return a string value for an integer enum from a mapping array or the integer string if the integer it outside the expected range.

func MaxPacketLifeTime

func MaxPacketLifeTime(maxPacketLifeTime int) func(*DataChannelInit)

MaxPacketLifeTime configures a DataChannels 'maxRetransmitTime' option.

func MaxRetransmits

func MaxRetransmits(maxRetransmits int) func(*DataChannelInit)

MaxRetransmits configures a DataChannels 'maxRetransmits' option.

func Negotiated

func Negotiated(negotiated bool) func(*DataChannelInit)

Negotiated configures a DataChannels 'negotiated' option.

func Ordered

func Ordered(ordered bool) func(*DataChannelInit)

Ordered configures a DataChannels 'ordered' option.

func SetLoggingVerbosity

func SetLoggingVerbosity(level int)

Logging verbosity level, from 0 (nothing) upwards.


type BundlePolicy

type BundlePolicy int
const (
	BundlePolicyBalanced BundlePolicy = iota

These "Enum" consts must match order in: peerconnectioninterface.h There doesn't seem to be a way to have a named container for enums in go, and the idiomatic way seems to be just prefixes.

func (BundlePolicy) String

func (p BundlePolicy) String() string

type CGOMap

type CGOMap struct {
	// contains filtered or unexported fields

func NewCGOMap

func NewCGOMap() CGOMap

func (*CGOMap) Delete

func (m *CGOMap) Delete(index int)

func (*CGOMap) Get

func (m *CGOMap) Get(index int) interface{}

func (*CGOMap) Set

func (m *CGOMap) Set(p interface{}) int

type Configuration

type Configuration struct {
	IceServers []IceServer
	// [ED] RtcpMuxPolicy        RtcpMuxPolicy
	PeerIdentity string // Target peer identity


func NewConfiguration

func NewConfiguration(options ...ConfigurationOption) *Configuration

Create a new Configuration with default values according to spec. Accepts any number of |IceServer|s. Returns nil if there's an error.

func (*Configuration) AddIceServer

func (config *Configuration) AddIceServer(params ...string) error

type ConfigurationOption

type ConfigurationOption func(c *Configuration) error

Used in Configuration's variadic functional constructor

func OptionBundlePolicy

func OptionBundlePolicy(policy BundlePolicy) ConfigurationOption

func OptionIceServer

func OptionIceServer(params ...string) ConfigurationOption

func OptionIceTransportPolicy

func OptionIceTransportPolicy(policy IceTransportPolicy) ConfigurationOption

type DataChannel

type DataChannel struct {
	BufferedAmountLowThreshold int
	BinaryType                 string

	// Event Handlers
	OnOpen              func()
	OnClose             func()
	OnMessage           func([]byte) // byte slice.
	OnBufferedAmountLow func()
	// contains filtered or unexported fields

OnError - is not implemented because the underlying Send always returns true as specified for SCTP, there is no reasonable exposure of other specific errors from the native code, and OnClose already covers the bases.

func NewDataChannel

func NewDataChannel(o unsafe.Pointer) *DataChannel

Create a Go Channel struct, and prepare internal CGO references / observers. The most reasonable place for this to be created is from PeerConnection, which is not available in the subpackage.

func (*DataChannel) BufferedAmount

func (c *DataChannel) BufferedAmount() int

func (*DataChannel) Close

func (c *DataChannel) Close() error

func (*DataChannel) ID

func (c *DataChannel) ID() int

func (*DataChannel) Label

func (c *DataChannel) Label() string

func (*DataChannel) MaxPacketLifeTime

func (c *DataChannel) MaxPacketLifeTime() uint

func (*DataChannel) MaxRetransmits

func (c *DataChannel) MaxRetransmits() uint

func (*DataChannel) Negotiated

func (c *DataChannel) Negotiated() bool

func (*DataChannel) Ordered

func (c *DataChannel) Ordered() bool

func (*DataChannel) Protocol

func (c *DataChannel) Protocol() string

func (*DataChannel) ReadyState

func (c *DataChannel) ReadyState() DataState

func (*DataChannel) Send

func (c *DataChannel) Send(data []byte)

Send a message over a DataChannel in binary mode.

func (*DataChannel) SendText

func (c *DataChannel) SendText(text string)

SendText sends a message over the DataChannel in text mode.

type DataChannelInit

type DataChannelInit struct {
	Ordered           bool
	MaxPacketLifeTime int
	MaxRetransmits    int
	Protocol          string
	Negotiated        bool
	ID                int

type DataState

type DataState int
const (
	DataStateConnecting DataState = iota

func (DataState) String

func (s DataState) String() string

type IceCandidate

type IceCandidate struct {
	Candidate     string `json:"candidate"`
	SdpMid        string `json:"sdpMid"`
	SdpMLineIndex int    `json:"sdpMLineIndex"`

func DeserializeIceCandidate

func DeserializeIceCandidate(msg string) *IceCandidate

Deserialize a received json string into an IceCandidate, if possible.

func (*IceCandidate) Serialize

func (candidate *IceCandidate) Serialize() string

Serialize an IceCandidate into a JSON string.

type IceCandidateType

type IceCandidateType int
const (
	IceCandidateTypeHost IceCandidateType = iota

func (IceCandidateType) String

func (t IceCandidateType) String() string

type IceConnectionState

type IceConnectionState int
const (
	IceConnectionStateNew IceConnectionState = iota

func (IceConnectionState) String

func (s IceConnectionState) String() string

type IceCredentialType

type IceCredentialType int

type IceGatheringState

type IceGatheringState int
const (
	IceGatheringStateNew IceGatheringState = iota

func (IceGatheringState) String

func (s IceGatheringState) String() string

type IceProtocol

type IceProtocol int
const (
	IceProtocolUPD IceProtocol = iota

func (IceProtocol) String

func (p IceProtocol) String() string

type IceServer

type IceServer struct {
	Urls       []string // The only "required" element.
	Username   string
	Credential string

func NewIceServer

func NewIceServer(params ...string) (*IceServer, error)

Create a new IceServer object. Expects anywhere from one to three strings, in this order: - comma-separated list of urls. - username - credential TODO: For the ED version, may need to support CredentialType.

type IceTcpCandidateType

type IceTcpCandidateType int
const (
	IceTcpCandidateTypeActive IceTcpCandidateType = iota

func (IceTcpCandidateType) String

func (t IceTcpCandidateType) String() string

type IceTransportPolicy

type IceTransportPolicy int
const (
	IceTransportPolicyNone IceTransportPolicy = iota


func (IceTransportPolicy) String

func (p IceTransportPolicy) String() string

type PeerConnection

type PeerConnection struct {

	// Event handlers
	OnNegotiationNeeded        func()
	OnIceCandidate             func(IceCandidate)
	OnIceCandidateError        func()
	OnSignalingStateChange     func(SignalingState)
	OnIceConnectionStateChange func(IceConnectionState)
	OnIceGatheringStateChange  func(IceGatheringState)
	OnConnectionStateChange    func(PeerConnectionState)
	OnDataChannel              func(*DataChannel)
	// contains filtered or unexported fields
WebRTC PeerConnection

This is the main container of WebRTC functionality - from handling the ICE negotiation to setting up Data Channels.

See: https://w3c.github.io/webrtc-pc/#idl-def-RTCPeerConnection

func NewPeerConnection

func NewPeerConnection(config *Configuration) (*PeerConnection, error)
Construct a WebRTC PeerConnection.

For a successful connection, provide at least one ICE server (stun or turn) in the |Configuration| struct.

func (*PeerConnection) AddIceCandidate

func (pc *PeerConnection) AddIceCandidate(ic IceCandidate) error

func (*PeerConnection) Close

func (pc *PeerConnection) Close() error

func (*PeerConnection) ConnectionState

func (pc *PeerConnection) ConnectionState() PeerConnectionState

readonly connectionState

func (*PeerConnection) CreateAnswer

func (pc *PeerConnection) CreateAnswer() (*SessionDescription, error)

CreateAnswer prepares an SDP "answer" message. This should only happen in response to an offer received and set as the remote description. Once generated, this answer should then be set as the local description and sent back over the signaling channel to the remote peer.

This method is blocking, and should occur within a separate goroutine.

func (*PeerConnection) CreateDataChannel

func (pc *PeerConnection) CreateDataChannel(label string, options ...func(*DataChannelInit)) (
	*DataChannel, error)

func (*PeerConnection) CreateOffer

func (pc *PeerConnection) CreateOffer() (*SessionDescription, error)

CreateOffer prepares an SDP "offer" message, which should be set as the local description, then sent to the remote peer over a signalling channel. This should only be called by the peer initiating the connection.

This method is blocking, and should occur within a separate goroutine.

func (*PeerConnection) DeleteDataChannel

func (pc *PeerConnection) DeleteDataChannel(dc *DataChannel)

func (*PeerConnection) Destroy

func (pc *PeerConnection) Destroy() error

func (*PeerConnection) GetConfiguration

func (pc *PeerConnection) GetConfiguration() Configuration

func (*PeerConnection) IceConnectionState

func (pc *PeerConnection) IceConnectionState() IceConnectionState

readonly iceconnectionState

func (*PeerConnection) IceGatheringState

func (pc *PeerConnection) IceGatheringState() IceGatheringState

readonly icegatheringstatee

func (*PeerConnection) LocalDescription

func (pc *PeerConnection) LocalDescription() (sdp *SessionDescription)

readonly localDescription

func (*PeerConnection) RemoteDescription

func (pc *PeerConnection) RemoteDescription() (sdp *SessionDescription)

readonly remoteDescription

func (*PeerConnection) SetConfiguration

func (pc *PeerConnection) SetConfiguration(config Configuration) error

func (*PeerConnection) SetLocalDescription

func (pc *PeerConnection) SetLocalDescription(sdp *SessionDescription) error

Set a |SessionDescription| as the local description. The description should be generated from the local peer's CreateOffer or CreateAnswer, and not be a description received over the signaling channel.

func (*PeerConnection) SetRemoteDescription

func (pc *PeerConnection) SetRemoteDescription(sdp *SessionDescription) error

Set a |SessionDescription| as the remote description. This description should be one generated by the remote peer's CreateOffer or CreateAnswer, received over the signaling channel, and not a description created locally.

If the local peer is the answerer, this must be called before CreateAnswer.

func (*PeerConnection) SignalingState

func (pc *PeerConnection) SignalingState() SignalingState

readonly signalingState

type PeerConnectionState

type PeerConnectionState int
const (
	PeerConnectionStateNew PeerConnectionState = iota

func (PeerConnectionState) String

func (s PeerConnectionState) String() string

type RtcpMuxPolicy

type RtcpMuxPolicy int

type SessionDescription

type SessionDescription struct {
	Type string `json:"type"`
	Sdp  string `json:"sdp"`
WebRTC SessionDescription

See: https://w3c.github.io/webrtc-pc/#idl-def-RTCSessionDescription

func DeserializeSessionDescription

func DeserializeSessionDescription(msg string) *SessionDescription

Deserialize a received json string into a SessionDescription, if possible.

func NewSessionDescription

func NewSessionDescription(sdpType string, serializedSDP C.CGO_sdpString) *SessionDescription

Construct a SessionDescription object from a valid msg.

func (*SessionDescription) GoStringToCgoSdp

func (desc *SessionDescription) GoStringToCgoSdp() C.CGO_sdp

func (*SessionDescription) Serialize

func (desc *SessionDescription) Serialize() string

Serialize a SessionDescription into a JSON string.

type SignalingState

type SignalingState int
const (
	SignalingStateStable SignalingState = iota

func (SignalingState) String

func (s SignalingState) String() string


Path Synopsis
* Basic webrtc demo, two local clients speaking over go, to show the most basic * usage of webrtc in Go.
* Basic webrtc demo, two local clients speaking over go, to show the most basic * usage of webrtc in Go.
* Webrtc chat demo.
* Webrtc chat demo.

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