Implement v4 endpoints for OAuth (#6040)

* Implement POST /oauth/apps endpoint for APIv4

* Implement GET /oauth/apps endpoint for APIv4

* Implement GET /oauth/apps/{app_id} and /oauth/apps/{app_id}/info endpoints for APIv4

* Refactor API version independent oauth endpoints

* Implement DELETE /oauth/apps/{app_id} endpoint for APIv4

* Implement /oauth/apps/{app_id}/regen_secret endpoint for APIv4

* Implement GET /user/{user_id}/oauth/apps/authorized endpoint for APIv4

* Implement POST /oauth/deauthorize endpoint

utils/api.go

@@ -5,7 +5,10 @@ package utils
 
 import (
 	"net/http"
+	"net/url"
 	"strings"
+
+	"github.com/mattermost/platform/model"
 )
 
 type OriginCheckerProc func(*http.Request) bool
@@ -22,3 +25,28 @@ func GetOriginChecker(r *http.Request) OriginCheckerProc {
 
 	return nil
 }
+
+func RenderWebError(err *model.AppError, w http.ResponseWriter, r *http.Request) {
+	T, _ := GetTranslationsAndLocale(w, r)
+
+	title := T("api.templates.error.title", map[string]interface{}{"SiteName": ClientCfg["SiteName"]})
+	message := err.Message
+	details := err.DetailedError
+	link := "/"
+	linkMessage := T("api.templates.error.link")
+
+	status := http.StatusTemporaryRedirect
+	if err.StatusCode != http.StatusInternalServerError {
+		status = err.StatusCode
+	}
+
+	http.Redirect(
+		w,
+		r,
+		"/error?title="+url.QueryEscape(title)+
+			"&message="+url.QueryEscape(message)+
+			"&details="+url.QueryEscape(details)+
+			"&link="+url.QueryEscape(link)+
+			"&linkmessage="+url.QueryEscape(linkMessage),
+		status)
+}