Add server/events/slack/slack_client.go

server/events/slack/slack_client.go

@@ -0,0 +1,52 @@
+package slack
+
+import (
+	"errors"
+
+	"github.com/nlopes/slack"
+)
+
+type Client interface {
+	PostMessage(text string) (string, error)
+}
+
+type ConcreteClient struct {
+	client  *slack.Client
+	channel string
+}
+
+func NewClient(slackToken string, channelName string) (*ConcreteClient, error) {
+	slackClient := slack.New(slackToken)
+
+	if _, err := slackClient.AuthTest(); err != nil {
+		return nil, err
+	}
+
+	// https://api.slack.com/faq
+	// 'How do I find a channel's ID if I only have its #name?'
+	// says need to look through all channels and match the name
+	channels, err := slackClient.GetChannels(true)
+	if err != nil {
+		return nil, err
+	}
+	for _, c := range channels {
+		if c.Name == channelName {
+			// channel exists, no errors
+			return &ConcreteClient{
+				client:  slackClient,
+				channel: channelName,
+			}, nil
+		}
+	}
+
+	return nil, errors.New("channel_not_found")
+}
+
+func (s *ConcreteClient) PostMessage(text string) (string, error) {
+	params := slack.NewPostMessageParameters()
+	params.AsUser = true
+	params.EscapeText = false
+
+	_, timestamp, err := s.client.PostMessage(s.channel, text, params)
+	return timestamp, err
+}