[MM-387] Add a global welcome message field

README.md

@@ -78,6 +78,7 @@ where
     - **ActionName**: Sets the action name used by the plugin to identify which action is taken by a user.
     - **ActionSuccessfulMessage**: Message posted after the user takes this action and joins the specified channels.
     - **ChannelsAddedTo**: List of channel names the user is added to. Must be the channel handle used in the URL, in lowercase. For example, in the following URL the **channel name** value is `my-channel`: https://example.com/my-team/channels/my-channel
+- **GlobalWelcomeMessage**: The welcome message to send globally to a new user from the Welcome Bot. Adding this field will ignore the `TeamName`, `Message`, `AttachmentMessage` and `Actions` fields in the config to post a global message, irrespective of the team the user is part of.
 
 The preview of the configured messages, as well as the creation of a channel welcome message, can be done via bot commands:
 * `/welcomebot help` - Displays usage information.
@@ -179,6 +180,12 @@ To accomplish the above, you can specify the following configuration in your `co
                                 "ChannelsAddedTo": ["escalation-process", "incidents"]
                             }
                         ]
+                    },
+                    {
+                        "DelayInSeconds": 5,
+                        "GlobalWelcomeMessage": [
+                            "### Welcome {{.UserDisplayName}} to the Mattermost!",
+                        ],
                     }
                 ]
             }

server/configuration.go

@@ -25,6 +25,9 @@ type ConfigMessageAction struct {
 
 // ConfigMessage represents the message to send in channel
 type ConfigMessage struct {
+	// This message will send a global welcome message using the bot
+	GlobalWelcomeMessage []string
+
 	// This message will fire when it matches the supplied team
 	TeamName string
 

server/hooks.go

@@ -1,14 +1,52 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
+	"html/template"
+	"strings"
 	"time"
 
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/mattermost/mattermost-server/v6/plugin"
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
 )
 
+// UserHasBeenCreated is invoked after a user was created.
+func (p *Plugin) UserHasBeenCreated(c *plugin.Context, user *model.User) {
+	data := p.constructGlobalMessageTemplate(user.Id)
+	if data == nil {
+		return
+	}
+
+	for _, message := range p.getWelcomeMessages() {
+		if data.User.IsGuest() && !message.IncludeGuests {
+			continue
+		}
+
+		if len(message.GlobalWelcomeMessage) > 0 {
+			tmpMsg, _ := template.New("Response").Parse(strings.Join(message.GlobalWelcomeMessage, "\n"))
+			var message bytes.Buffer
+			err := tmpMsg.Execute(&message, data)
+			if err != nil {
+				p.API.LogError("Failed to execute message template", "Error", err.Error())
+			}
+
+			post := &model.Post{
+				Message:   message.String(),
+				UserId:    p.botUserID,
+				ChannelId: data.DirectMessage.Id,
+			}
+
+			if _, err := p.API.CreatePost(post); err != nil {
+				p.API.LogError("We could not create the response post", "UserID", post.UserId, "Error", err.Error())
+			}
+
+			return
+		}
+	}
+}
+
 // UserHasJoinedTeam is invoked after the membership has been committed to the database. If
 // actor is not nil, the user was added to the team by the actor.
 func (p *Plugin) UserHasJoinedTeam(c *plugin.Context, teamMember *model.TeamMember, actor *model.User) {
@@ -22,7 +60,7 @@ func (p *Plugin) UserHasJoinedTeam(c *plugin.Context, teamMember *model.TeamMemb
 			continue
 		}
 
-		if message.TeamName == data.Team.Name {
+		if message.TeamName == data.Team.Name && len(message.GlobalWelcomeMessage) == 0 {
 			go p.processWelcomeMessage(*data, *message)
 		}
 	}

server/message_template.go

@@ -11,3 +11,11 @@ type MessageTemplate struct {
 	DirectMessage   *model.Channel
 	UserDisplayName string
 }
+
+// GloablMessageTemplate represents all the data that can be used in the template for a welcomebot global message
+type GloablMessageTemplate struct {
+	WelcomeBot      *model.User
+	User            *model.User
+	DirectMessage   *model.Channel
+	UserDisplayName string
+}

server/welcomebot.go

@@ -45,6 +45,29 @@ func (p *Plugin) constructMessageTemplate(userID, teamID string) *MessageTemplat
 	return data
 }
 
+func (p *Plugin) constructGlobalMessageTemplate(userID string) *GloablMessageTemplate {
+	data := &GloablMessageTemplate{}
+	var err *model.AppError
+
+	if len(userID) > 0 {
+		if data.User, err = p.API.GetUser(userID); err != nil {
+			p.API.LogError("failed to query user", "user_id", userID)
+			return nil
+		}
+	}
+
+	if data.User != nil {
+		if data.DirectMessage, err = p.API.GetDirectChannel(userID, p.botUserID); err != nil {
+			p.API.LogError("failed to query direct message channel", "user_id", userID)
+			return nil
+		}
+	}
+
+	data.UserDisplayName = data.User.GetDisplayName(model.ShowNicknameFullName)
+
+	return data
+}
+
 func (p *Plugin) getSiteURL() string {
 	siteURL := "http://localhost:8065"