Enable Tag Merging

CHANGELOG.rst

@@ -10,6 +10,7 @@ Changelog
   We believe that this should not cause a noticable performance change, and the number of queries involved should not change.
 * Add Django 5.0 support (no code changes were needed, but now we test this release).
 * Add Python 3.12 support
+* Added functionality for tag merging
 
 5.0.1 (2023-10-26)
 ~~~~~~~~~~~~~~~~~~

docs/admin.rst

@@ -39,3 +39,19 @@ method to the :class:`~django.contrib.admin.ModelAdmin`, using
 
         def tag_list(self, obj):
             return u", ".join(o.name for o in obj.tags.all())
+
+
+Merging tags in the admin
+=======================
+
+Functionality has been added to the admin app to allow for tag "merging".
+Really what is happening is a "find and replace" where the selected tags are being used.
+
+To merge your tags follow these steps:
+
+1. Navigate to the Tags page inside of the Taggit app
+2. Select the tags that you want to merge
+3. Use the dropdown action list and select `Merge selected tags` and then click `Go`
+4. This will redirect you onto a new page where you can insert the new tag name.
+5. Click `Merge Tags`
+6. This will redirect you back to the tag list

taggit/admin.py

@@ -1,7 +1,12 @@
 from django.contrib import admin
+from django.db import transaction
+from django.shortcuts import redirect, render
+from django.urls import path
 
 from taggit.models import Tag, TaggedItem
 
+from .forms import MergeTagsForm
+
 
 class TaggedItemInline(admin.StackedInline):
     model = TaggedItem
@@ -14,3 +19,66 @@ class TagAdmin(admin.ModelAdmin):
     ordering = ["name", "slug"]
     search_fields = ["name"]
     prepopulated_fields = {"slug": ["name"]}
+    actions = ["render_tag_form"]
+
+    def get_urls(self):
+        urls = super().get_urls()
+        custom_urls = [
+            path(
+                "merge-tags/",
+                self.admin_site.admin_view(self.merge_tags_view),
+                name="merge_tags",
+            ),
+        ]
+        return custom_urls + urls
+
+    @admin.action(description="Merge selected tags")
+    def render_tag_form(self, request, queryset):
+        selected = request.POST.getlist(admin.helpers.ACTION_CHECKBOX_NAME)
+        if not selected:
+            self.message_user(request, "Please select at least one tag.")
+            return redirect(request.get_full_path())
+
+        selected_tag_ids = ",".join(selected)
+        redirect_url = (
+            f"{request.get_full_path()}merge-tags/?selected_tags={selected_tag_ids}"
+        )
+
+        return redirect(redirect_url)
+
+    def merge_tags_view(self, request):
+        if request.method == "GET":
+            selected_tag_ids = request.GET.get("selected_tags", "").split(",")
+
+            # store selected_tag_ids in session data until they are merged
+            request.session["selected_tag_ids"] = selected_tag_ids
+        else:
+            selected_tag_ids = request.session.get("selected_tag_ids", [])
+
+        if request.method == "POST":
+            form = MergeTagsForm(request.POST)
+            if form.is_valid():
+                new_tag_name = form.cleaned_data["new_tag_name"]
+                new_tag, created = Tag.objects.get_or_create(name=new_tag_name)
+                with transaction.atomic():
+                    for tag_id in selected_tag_ids:
+                        tag = Tag.objects.get(id=tag_id)
+                        tagged_items = TaggedItem.objects.filter(tag=tag)
+                        for tagged_item in tagged_items:
+                            tagged_item.tag = new_tag
+                            tagged_item.save()
+                        # tag.delete()  #this will delete the selected tags after merge
+
+                # clear the selected_tag_ids from session after merge is complete
+                request.session.pop("selected_tag_ids", None)
+                return redirect("..")
+            else:
+                print(f"Form errors: {form.errors}")
+                self.message_user(request, "Form is invalid.", level="error")
+
+        context = {
+            "form": MergeTagsForm(),
+            "selected_tag_ids": selected_tag_ids,
+        }
+
+        return render(request, "admin/taggit/merge_tags_form.html", context)

taggit/forms.py

@@ -52,3 +52,11 @@ def has_changed(self, initial_value, data_value):
         initial_value.sort()
 
         return initial_value != data_value
+
+
+class MergeTagsForm(forms.Form):
+    new_tag_name = forms.CharField(
+        label="New Tag Name",
+        max_length=255,
+        widget=forms.TextInput(attrs={"id": "id_new_tag_name"}),
+    )

taggit/templates/admin/taggit/merge_tags_form.html

@@ -0,0 +1,29 @@
+<div id="mergeTagsModal">
+  <div>
+    <div>
+      <div>
+        <form
+          id="merge-tags-form"
+          method="post"
+          action="{% url 'admin:merge_tags' %}"
+        >
+          {% csrf_token %} {% for field in form %}
+          <div>
+            {{ field.label_tag }} {{ field }} {% if field.errors %}
+            <ul class="errorlist">
+              {% for error in field.errors %}
+              <li>{{ error }}</li>
+              {% endfor %}
+            </ul>
+            {% endif %}
+          </div>
+          {% endfor %}
+
+          <div>
+            <button type="submit" class="btn btn-primary">Merge Tags</button>
+          </div>
+        </form>
+      </div>
+    </div>
+  </div>
+</div>