MM-16224: Adds new API endpoint + (App & Client & Store) to retrieve the difference between the set of channel members and given group members. (#11186)

api4/channel.go

@@ -4,7 +4,9 @@
 package api4
 
 import (
+	"encoding/json"
 	"net/http"
+	"strings"
 
 	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
@@ -37,6 +39,7 @@ func (api *API) InitChannel() {
 	api.BaseRoutes.Channel.Handle("/stats", api.ApiSessionRequired(getChannelStats)).Methods("GET")
 	api.BaseRoutes.Channel.Handle("/pinned", api.ApiSessionRequired(getPinnedPosts)).Methods("GET")
 	api.BaseRoutes.Channel.Handle("/timezones", api.ApiSessionRequired(getChannelMembersTimezones)).Methods("GET")
+	api.BaseRoutes.Channel.Handle("/members_minus_group_members", api.ApiSessionRequired(channelMembersMinusGroupMembers)).Methods("GET")
 	api.BaseRoutes.ChannelForUser.Handle("/unread", api.ApiSessionRequired(getChannelUnread)).Methods("GET")
 
 	api.BaseRoutes.ChannelByName.Handle("", api.ApiSessionRequired(getChannelByName)).Methods("GET")
@@ -1295,3 +1298,53 @@ func updateChannelScheme(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	ReturnStatusOK(w)
 }
+
+func channelMembersMinusGroupMembers(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireChannelId()
+	if c.Err != nil {
+		return
+	}
+
+	groupIDsParam := groupIDsQueryParamRegex.ReplaceAllString(c.Params.GroupIDs, "")
+
+	if len(groupIDsParam) < 26 {
+		c.SetInvalidParam("group_ids")
+		return
+	}
+
+	groupIDs := []string{}
+	for _, gid := range strings.Split(c.Params.GroupIDs, ",") {
+		if len(gid) != 26 {
+			c.SetInvalidParam("group_ids")
+			return
+		}
+		groupIDs = append(groupIDs, gid)
+	}
+
+	if !c.App.SessionHasPermissionTo(c.App.Session, model.PERMISSION_MANAGE_SYSTEM) {
+		c.SetPermissionError(model.PERMISSION_MANAGE_SYSTEM)
+		return
+	}
+
+	users, totalCount, err := c.App.ChannelMembersMinusGroupMembers(
+		c.Params.ChannelId,
+		groupIDs,
+		c.Params.Page,
+		c.Params.PerPage,
+	)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	b, marshalErr := json.Marshal(&model.UsersWithGroupsAndCount{
+		Users: users,
+		Count: totalCount,
+	})
+	if marshalErr != nil {
+		c.Err = model.NewAppError("Api4.channelMembersMinusGroupMembers", "api.marshal_error", nil, marshalErr.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Write(b)
+}