[change] Reduce sortedm2m queries for templates #204

To remove queries generated by sortedm2m, 'formfield_for_manytomany'
is overriden such that on page loads, we can get templates using
'get_relevant_templates'. Added device/group id to identify selected
templates. Changes are made in JS to ensure templates are viewed and
changes are saved as per initial behaviour.
Ordering is not maintained.

Closes #204

Signed-off-by: DragnEmperor <[email protected]>

Author: DragnEmperor

openwisp_controller/config/admin.py

@@ -462,6 +462,13 @@ def get_fields(self, request, obj):
         fields = super().get_fields(request, obj)
         return self._error_reason_field_conditional(obj, fields)
 
+    def formfield_for_manytomany(self, db_field, request, **kwargs):
+        # setting queryset none for all requests except POST as queryset
+        # is required for the form to be valid
+        if db_field.name == 'templates' and request.method != 'POST':
+            kwargs['queryset'] = Template.objects.none()
+        return super().formfield_for_manytomany(db_field, request, **kwargs)
+
 
 class ChangeDeviceGroupForm(forms.Form):
     device_group = forms.ModelChoiceField(
@@ -1317,6 +1324,13 @@ def get_extra_context(self, pk=None):
         }
         return ctx
 
+    def formfield_for_manytomany(self, db_field, request, **kwargs):
+        # setting queryset none for all requests except POST as queryset
+        # is required for the form to be valid
+        if db_field.name == 'templates' and request.method != 'POST':
+            kwargs['queryset'] = Template.objects.none()
+        return super().formfield_for_manytomany(db_field, request, **kwargs)
+
 
 admin.site.register(Device, DeviceAdminExportable)
 admin.site.register(Template, TemplateAdmin)

openwisp_controller/config/static/config/js/relevant_templates.js

@@ -33,7 +33,8 @@ django.jQuery(function ($) {
       if (templateConfig.required) {
         inputField.prop("disabled", true);
       }
-      if (isSelected || templateConfig.required) {
+      // mark the template as selected if it is required or if it is enabled for the current device or group
+      if (isSelected || templateConfig.required || templateConfig.selected) {
         inputField.prop("checked", true);
       }
       return element;
@@ -115,6 +116,14 @@ django.jQuery(function ($) {
       var url = window._relevantTemplateUrl.replace("org_id", orgID);
       // Get relevant templates of selected org and backend
       url = url + "?backend=" + backend;
+      if (!isDeviceGroup()) {
+        var deviceID = $('input[name="config-0-device"]').val();
+        url = url + "&device=" + deviceID;
+      } else {
+        // Get the group id from the URL
+        var pathParts = window.location.pathname.split("/");
+        url = url + "&group=" + pathParts[pathParts.length - 3];
+      }
       $.get(url).done(function (data) {
         resetTemplateOptions();
         var enabledTemplates = [],
@@ -156,7 +165,8 @@ django.jQuery(function ($) {
         // Adds "li" elements for templates that are not selected
         // in the database.
         var counter =
-          selectedTemplates !== undefined ? selectedTemplates.length : 0;
+            selectedTemplates !== undefined ? selectedTemplates.length : 0,
+          deviceTemplates = [];
         Object.keys(data).forEach(function (templateId, index) {
           // corner case in which backend of template does not match
           if (!data[templateId]) {
@@ -186,6 +196,9 @@ django.jQuery(function ($) {
           if (isSelected === true) {
             enabledTemplates.push(templateId);
           }
+          if (element.children().children("input").prop("checked") === true) {
+            deviceTemplates.push(templateId);
+          }
           sortedm2mUl.append(element);
           if (!isDeviceGroup()) {
             sortedm2mPrefixUl.append(prefixElement);
@@ -194,6 +207,23 @@ django.jQuery(function ($) {
         if (firstRun === true && selectedTemplates !== undefined) {
           updateTemplateSelection(selectedTemplates);
         }
+        // this runs on first load and sets the name of hidden input field which tracks
+        // the selected templates.
+        if (selectedTemplates === undefined) {
+          if (!isDeviceGroup()) {
+            $(
+              `.has_original .field-templates .sortedm2m-container input[type="hidden"]`,
+            ).attr("name", templatesFieldName());
+            // set the initial value of the hidden input field
+            // to the selected templates
+            django._owcInitialValues[templatesFieldName()] =
+              deviceTemplates.join(",");
+          } else {
+            $(
+              `.field-templates .sortedm2m-container input[type="hidden"]`,
+            ).attr("name", templatesFieldName());
+          }
+        }
         updateTemplateHelpText();
         updateConfigTemplateField(enabledTemplates);
       });

openwisp_controller/config/views.py

@@ -15,6 +15,7 @@
 
 Organization = load_model('openwisp_users', 'Organization')
 Template = load_model('config', 'Template')
+Config = load_model('config', 'Config')
 DeviceGroup = load_model('config', 'DeviceGroup')
 OrganizationConfigSettings = load_model('config', 'OrganizationConfigSettings')
 
@@ -24,6 +25,8 @@ def get_relevant_templates(request, organization_id):
     returns default templates of specified organization
     """
     backend = request.GET.get("backend", None)
+    device_id = request.GET.get("device", None)
+    group_id = request.GET.get("group", None)
     user = request.user
     if not user.is_superuser and not user.is_manager(organization_id):
         return HttpResponse(status=403)
@@ -38,13 +41,24 @@ def get_relevant_templates(request, organization_id):
         .filter(Q(organization_id=org.pk) | Q(organization_id=None))
         .only('id', 'name', 'backend', 'default', 'required')
     )
+    # for checking which templates are enabled for given device or group
+    selected_templates = []
+    if device_id:
+        selected_templates = Config.objects.filter(device_id=device_id).values_list(
+            'templates__id', flat=True
+        )
+    if group_id:
+        selected_templates = DeviceGroup.objects.filter(
+            pk=group_id, organization_id=organization_id
+        ).values_list('templates__id', flat=True)
     relevant_templates = {}
     for template in queryset:
         relevant_templates[str(template.pk)] = dict(
             name=template.name,
             backend=template.get_backend_display(),
             default=template.default,
             required=template.required,
+            selected=template.pk in selected_templates,
         )
     return JsonResponse(relevant_templates)