server/public/ -- pre-requisite changes (#23278)

* invert depdendency: filestore -> model

* markdown: nolint:misspell

* inline jsonutils within model

* push model.GetInfoForBytes -> channels/app

* push channel/utils.CompileGo* -> plugin/utils

* push plugin/scheduler -> channels/jobs/plugins

* push utils.Copy(File|Dir) -> model

* oauthproiders/gitlab -> channels/app/oauthproviders/gitlab

* decouple plugin from einterfaces.MetricsInterface

* fix TestGetInfoForFile

* Revert "Run golangci in server CI (#23240)"

This reverts commit 349e5d4573.

* add model/utils

---------

Co-authored-by: Agniva De Sarker <agnivade@yahoo.co.in>

server/channels/app/oauthproviders/gitlab/gitlab.go

@@ -0,0 +1,107 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package oauthgitlab
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/mattermost/mattermost-server/server/v8/channels/einterfaces"
+	"github.com/mattermost/mattermost-server/server/v8/model"
+)
+
+type GitLabProvider struct {
+}
+
+type GitLabUser struct {
+	Id       int64  `json:"id"`
+	Username string `json:"username"`
+	Login    string `json:"login"`
+	Email    string `json:"email"`
+	Name     string `json:"name"`
+}
+
+func init() {
+	provider := &GitLabProvider{}
+	einterfaces.RegisterOAuthProvider(model.UserAuthServiceGitlab, provider)
+}
+
+func userFromGitLabUser(glu *GitLabUser) *model.User {
+	user := &model.User{}
+	username := glu.Username
+	if username == "" {
+		username = glu.Login
+	}
+	user.Username = model.CleanUsername(username)
+	splitName := strings.Split(glu.Name, " ")
+	if len(splitName) == 2 {
+		user.FirstName = splitName[0]
+		user.LastName = splitName[1]
+	} else if len(splitName) >= 2 {
+		user.FirstName = splitName[0]
+		user.LastName = strings.Join(splitName[1:], " ")
+	} else {
+		user.FirstName = glu.Name
+	}
+	user.Email = glu.Email
+	user.Email = strings.ToLower(user.Email)
+	userId := glu.getAuthData()
+	user.AuthData = &userId
+	user.AuthService = model.UserAuthServiceGitlab
+
+	return user
+}
+
+func gitLabUserFromJSON(data io.Reader) (*GitLabUser, error) {
+	decoder := json.NewDecoder(data)
+	var glu GitLabUser
+	err := decoder.Decode(&glu)
+	if err != nil {
+		return nil, err
+	}
+	return &glu, nil
+}
+
+func (glu *GitLabUser) IsValid() error {
+	if glu.Id == 0 {
+		return errors.New("user id can't be 0")
+	}
+
+	if glu.Email == "" {
+		return errors.New("user e-mail should not be empty")
+	}
+
+	return nil
+}
+
+func (glu *GitLabUser) getAuthData() string {
+	return strconv.FormatInt(glu.Id, 10)
+}
+
+func (m *GitLabProvider) GetUserFromJSON(data io.Reader, tokenUser *model.User) (*model.User, error) {
+	glu, err := gitLabUserFromJSON(data)
+	if err != nil {
+		return nil, err
+	}
+	if err = glu.IsValid(); err != nil {
+		return nil, err
+	}
+
+	return userFromGitLabUser(glu), nil
+}
+
+func (m *GitLabProvider) GetSSOSettings(config *model.Config, service string) (*model.SSOSettings, error) {
+	return &config.GitLabSettings, nil
+}
+
+func (m *GitLabProvider) GetUserFromIdToken(idToken string) (*model.User, error) {
+	return nil, nil
+}
+
+func (m *GitLabProvider) IsSameUser(dbUser, oauthUser *model.User) bool {
+	return dbUser.AuthData == oauthUser.AuthData
+}