forked from shomali11/slacker
/
slacker.go
181 lines (151 loc) · 4.81 KB
/
slacker.go
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package slacker
import (
"context"
"errors"
"fmt"
"strings"
"github.com/nlopes/slack"
"github.com/shomali11/proper"
)
const (
space = " "
dash = "-"
newLine = "\n"
invalidToken = "invalid token"
helpCommand = "help"
directChannelMarker = "D"
userMentionFormat = "<@%s>"
codeMessageFormat = "`%s`"
boldMessageFormat = "*%s*"
italicMessageFormat = "_%s_"
slackBotUser = "USLACKBOT"
)
// NewClient creates a new client using the Slack API
func NewClient(token string) *Slacker {
client := slack.New(token)
slacker := &Slacker{
Client: client,
RTM: client.NewRTM(),
}
return slacker
}
// Slacker contains the Slack API, botCommands, and handlers
type Slacker struct {
Client *slack.Client
RTM *slack.RTM
botCommands []*BotCommand
initHandler func()
errorHandler func(err string)
helpHandler func(request Request, response ResponseWriter)
defaultMessageHandler func(request Request, response ResponseWriter)
defaultEventHandler func(interface{})
}
// Init handle the event when the bot is first connected
func (s *Slacker) Init(initHandler func()) {
s.initHandler = initHandler
}
// Err handle when errors are encountered
func (s *Slacker) Err(errorHandler func(err string)) {
s.errorHandler = errorHandler
}
// DefaultCommand handle messages when none of the commands are matched
func (s *Slacker) DefaultCommand(defaultMessageHandler func(request Request, response ResponseWriter)) {
s.defaultMessageHandler = defaultMessageHandler
}
// DefaultEvent handle events when an unknown event is seen
func (s *Slacker) DefaultEvent(defaultEventHandler func(interface{})) {
s.defaultEventHandler = defaultEventHandler
}
// Help handle the help message, it will use the default if not set
func (s *Slacker) Help(helpHandler func(request Request, response ResponseWriter)) {
s.helpHandler = helpHandler
}
// Command define a new command and append it to the list of existing commands
func (s *Slacker) Command(usage string, description string, handler func(request Request, response ResponseWriter)) {
s.botCommands = append(s.botCommands, NewBotCommand(usage, description, handler))
}
// Listen receives events from Slack and each is handled as needed
func (s *Slacker) Listen() error {
s.prependHelpHandle()
go s.RTM.ManageConnection()
for msg := range s.RTM.IncomingEvents {
switch event := msg.Data.(type) {
case *slack.ConnectedEvent:
if s.initHandler == nil {
continue
}
go s.initHandler()
case *slack.MessageEvent:
if s.isFromBot(event) {
continue
}
if !s.isBotMentioned(event) && !s.isDirectMessage(event) {
continue
}
go s.handleMessage(event)
case *slack.RTMError:
if s.errorHandler == nil {
continue
}
go s.errorHandler(event.Error())
case *slack.InvalidAuthEvent:
return errors.New(invalidToken)
default:
if s.defaultEventHandler == nil {
continue
}
go s.defaultEventHandler(event)
}
}
return nil
}
func (s *Slacker) sendMessage(text string, channel string) {
s.RTM.SendMessage(s.RTM.NewOutgoingMessage(text, channel))
}
func (s *Slacker) isFromBot(event *slack.MessageEvent) bool {
info := s.RTM.GetInfo()
return len(event.User) == 0 || event.User == slackBotUser || event.User == info.User.ID || len(event.BotID) > 0
}
func (s *Slacker) isBotMentioned(event *slack.MessageEvent) bool {
info := s.RTM.GetInfo()
return strings.Contains(event.Text, fmt.Sprintf(userMentionFormat, info.User.ID))
}
func (s *Slacker) isDirectMessage(event *slack.MessageEvent) bool {
return strings.HasPrefix(event.Channel, directChannelMarker)
}
func (s *Slacker) handleMessage(event *slack.MessageEvent) {
response := NewResponse(event.Channel, s.Client, s.RTM)
ctx := context.Background()
for _, cmd := range s.botCommands {
parameters, isMatch := cmd.Match(event.Text)
if !isMatch {
continue
}
cmd.Execute(NewRequest(ctx, event, parameters), response)
return
}
if s.defaultMessageHandler != nil {
s.defaultMessageHandler(NewRequest(ctx, event, &proper.Properties{}), response)
}
}
func (s *Slacker) defaultHelp(request Request, response ResponseWriter) {
helpMessage := empty
for _, command := range s.botCommands {
tokens := command.Tokenize()
for _, token := range tokens {
if token.IsParameter {
helpMessage += fmt.Sprintf(codeMessageFormat, token.Word) + space
} else {
helpMessage += fmt.Sprintf(boldMessageFormat, token.Word) + space
}
}
helpMessage += dash + space + fmt.Sprintf(italicMessageFormat, command.description) + newLine
}
response.Reply(helpMessage)
}
func (s *Slacker) prependHelpHandle() {
if s.helpHandler == nil {
s.helpHandler = s.defaultHelp
}
s.botCommands = append([]*BotCommand{NewBotCommand(helpCommand, helpCommand, s.helpHandler)}, s.botCommands...)
}