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package irc
import (
"context"
"errors"
"fmt"
"io"
"sync"
"time"
"golang.org/x/time/rate"
)
// ClientConfig is a structure used to configure a Client.
type ClientConfig struct {
// General connection information.
Nick string
Pass string
User string
Name string
// If this is set to true, the ISupport value on the client struct will be
// non-nil.
EnableISupport bool
// If this is set to true, the Tracker value on the client struct will be
// non-nil.
EnableTracker bool
// Connection settings
PingFrequency time.Duration
PingTimeout time.Duration
// SendLimit is how frequent messages can be sent. If this is zero,
// there will be no limit.
SendLimit time.Duration
// SendBurst is the number of messages which can be sent in a burst.
SendBurst int
// Handler is used for message dispatching.
Handler Handler
}
type capStatus struct {
// Requested means that this cap was requested by the user
Requested bool
// Required will be true if this cap is non-optional
Required bool
// Enabled means that this cap was accepted by the server
Enabled bool
// Available means that the server supports this cap
Available bool
}
// Client is a wrapper around irc.Conn which is designed to make common
// operations much simpler. It is safe for concurrent use.
type Client struct {
*Conn
closer io.Closer
ISupport *ISupportTracker
Tracker *Tracker
config ClientConfig
// Internal state
currentNick string
limiter *rate.Limiter
incomingPongChan chan string
errChan chan error
caps map[string]capStatus
remainingCapResponses int
connected bool
}
// NewClient creates a client given an io stream and a client config.
func NewClient(rwc io.ReadWriteCloser, config ClientConfig) *Client {
c := &Client{ //nolint:exhaustruct
Conn: NewConn(rwc),
closer: rwc,
config: config,
currentNick: config.Nick,
errChan: make(chan error, 1),
caps: make(map[string]capStatus),
}
if config.SendLimit != 0 {
if config.SendBurst == 0 {
config.SendBurst = 1
}
c.limiter = rate.NewLimiter(rate.Every(config.SendLimit), config.SendBurst)
}
if config.EnableISupport || config.EnableTracker {
c.ISupport = NewISupportTracker()
}
if config.EnableTracker {
c.Tracker = NewTracker(c.ISupport)
}
// Replace the writer writeCallback with one of our own
c.Conn.Writer.WriteCallback = c.writeCallback
return c
}
func (c *Client) writeCallback(w *Writer, line string) error {
if c.limiter != nil {
// Note that context.Background imitates the previous implementation,
// but it may be worth looking for a way to use this with a passed in
// context in the future.
err := c.limiter.Wait(context.Background())
if err != nil {
return err
}
}
_, err := w.RawWrite([]byte(line + "\r\n"))
if err != nil {
c.sendError(err)
}
return err
}
// maybeStartPingLoop will start a goroutine to send out PING messages at the
// PingFrequency in the config if the frequency is not 0.
func (c *Client) maybeStartPingLoop(wg *sync.WaitGroup, exiting chan struct{}) {
if c.config.PingFrequency <= 0 {
return
}
wg.Add(1)
c.incomingPongChan = make(chan string, 5)
go func() {
defer wg.Done()
pingHandlers := make(map[string]chan struct{})
ticker := time.NewTicker(c.config.PingFrequency)
defer ticker.Stop()
for {
select {
case <-ticker.C:
// Each time we get a tick, we send off a ping and start a
// goroutine to handle the pong.
timestamp := time.Now().Unix()
pongChan := make(chan struct{}, 1)
pingHandlers[fmt.Sprintf("%d", timestamp)] = pongChan
wg.Add(1)
go c.handlePing(timestamp, pongChan, wg, exiting)
case data := <-c.incomingPongChan:
// Make sure the pong gets routed to the correct
// goroutine.
c := pingHandlers[data]
delete(pingHandlers, data)
if c != nil {
c <- struct{}{}
}
case <-exiting:
return
}
}
}()
}
func (c *Client) handlePing(timestamp int64, pongChan chan struct{}, wg *sync.WaitGroup, exiting chan struct{}) {
defer wg.Done()
err := c.Writef("PING :%d", timestamp)
if err != nil {
c.sendError(err)
return
}
timer := time.NewTimer(c.config.PingTimeout)
defer timer.Stop()
select {
case <-timer.C:
c.sendError(errors.New("ping timeout"))
case <-pongChan:
return
case <-exiting:
return
}
}
// maybeStartCapHandshake will run a CAP LS and all the relevant CAP REQ
// commands if there are any CAPs requested.
func (c *Client) maybeStartCapHandshake() error {
if len(c.caps) == 0 {
return nil
}
err := c.Write("CAP LS")
if err != nil {
return err
}
c.remainingCapResponses = 1 // We count the CAP LS response as a normal response
for key, cap := range c.caps {
if cap.Requested {
err = c.Writef("CAP REQ :%s", key)
if err != nil {
return err
}
c.remainingCapResponses++
}
}
return nil
}
// CapRequest allows you to request IRCv3 capabilities from the server during
// the handshake. The behavior is undefined if this is called before the
// handshake completes so it is recommended that this be called before Run. If
// the CAP is marked as required, the client will exit if that CAP could not be
// negotiated during the handshake.
func (c *Client) CapRequest(capName string, required bool) {
capStatus := c.caps[capName]
capStatus.Requested = true
capStatus.Required = capStatus.Required || required
c.caps[capName] = capStatus
}
// CapEnabled allows you to check if a CAP is enabled for this connection. Note
// that it will not be populated until after the CAP handshake is done, so it is
// recommended to wait to check this until after a message like 001.
func (c *Client) CapEnabled(capName string) bool {
return c.caps[capName].Enabled
}
// CapAvailable allows you to check if a CAP is available on this server. Note
// that it will not be populated until after the CAP handshake is done, so it is
// recommended to wait to check this until after a message like 001.
func (c *Client) CapAvailable(capName string) bool {
return c.caps[capName].Available
}
func (c *Client) sendError(err error) {
select {
case c.errChan <- err:
default:
}
}
func (c *Client) startReadLoop(wg *sync.WaitGroup, exiting chan struct{}) {
wg.Add(1)
go func() {
defer wg.Done()
for {
select {
case <-exiting:
return
default:
m, err := c.ReadMessage()
if err != nil {
c.sendError(err)
break
}
if f, ok := clientFilters[m.Command]; ok {
f(c, m)
}
if c.ISupport != nil {
_ = c.ISupport.Handle(m)
}
if c.Tracker != nil {
_ = c.Tracker.Handle(m)
}
if c.config.Handler != nil {
c.config.Handler.Handle(c, m)
}
}
}
}()
}
// Run starts the main loop for this IRC connection. Note that it may break in
// strange and unexpected ways if it is called again before the first connection
// exits.
func (c *Client) Run() error {
return c.RunContext(context.Background())
}
// RunContext is the same as Run but a context.Context can be passed in for
// cancelation.
func (c *Client) RunContext(ctx context.Context) error {
// exiting is used by the main goroutine here to ensure any sub-goroutines
// get closed when exiting.
exiting := make(chan struct{})
var wg sync.WaitGroup
c.maybeStartPingLoop(&wg, exiting)
if c.config.Pass != "" {
err := c.Writef("PASS :%s", c.config.Pass)
if err != nil {
return err
}
}
err := c.maybeStartCapHandshake()
if err != nil {
return err
}
// This feels wrong because it results in CAP LS, CAP REQ, NICK, USER, CAP
// END, but it works and lets us keep the code a bit simpler.
err = c.Writef("NICK :%s", c.config.Nick)
if err != nil {
return err
}
err = c.Writef("USER %s 0 * :%s", c.config.User, c.config.Name)
if err != nil {
return err
}
// Now that the handshake is pretty much done, we can start listening for
// messages.
c.startReadLoop(&wg, exiting)
// Wait for an error from any goroutine or for the context to time out, then
// signal we're exiting and wait for the goroutines to exit.
select {
case err = <-c.errChan:
case <-ctx.Done():
}
close(exiting)
c.closer.Close()
wg.Wait()
return err
}
// CurrentNick returns what the nick of the client is known to be at this point
// in time.
func (c *Client) CurrentNick() string {
return c.currentNick
}
// FromChannel takes a Message representing a PRIVMSG and returns if that
// message came from a channel or directly from a user.
func (c *Client) FromChannel(m *Message) bool {
if len(m.Params) < 1 {
return false
}
// The first param is the target, so if this doesn't match the current nick,
// the message came from a channel.
return m.Params[0] != c.currentNick
}
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