cb109 · September 25, 2024 08:02 · Feb 12, 2021 · Feb 12, 2021 · Feb 12, 2021 · Feb 12, 2021
diff --git a/template.html b/template.html
@@ -1,7 +1,7 @@
 <!-- To make the AutocompleteSelect work we need to include some CSS and javascript -->
-{{ select_workspace_form.media }}
+{{ autocomplete_form.media }}
 
 <form id="mycustommodel_form">
-  {{ select_workspace_form }}
+  {{ autocomplete_form }}
   <button type="submit">Submit</button>
 </form>
diff --git a/views.py b/views.py
@@ -1,19 +1,38 @@
+from typing import Callable
+from typing import Iterable
+
+from django.http import JsonResponse
+
 from myproject.myapp.forms import MyCustomModelForm
 from myproject.myapp.models import MyCustomModel
 from myproject.myapp.utils import search
 
 
+def make_autocomplete_response(
+    queryset: Iterable, instance_to_text_func: Callable
+) -> JsonResponse:
+    return JsonResponse(
+        {
+            "results": [
+                {"id": instance.id, "text": instance_to_text_func(instance)}
+                for instance in queryset
+            ],
+            "pagination": {"more": False},
+        }
+    )
+
+
 def search_mycustommodel(request):
     term = request.GET.get("term", "")
-    candidates = search(Workspace.objects, term, ["name"]).order_by(
+    candidates = search(MyCustomModel.objects, term, ["name"]).order_by(
         "name",
     )
     return make_autocomplete_response(
-        workspace_candidates, lambda workspace: workspace.name
+        candidates, lambda instance: instance.name
     )
 
 
-def template(request, pk):
+def template(request, pk: int):
     instance = MyCustomModel.objects.get(pk=pk)
     autocomplete_form = MyCustomModelForm(
         initial={"mycustommodel": instance},

diff --git a/views.py b/views.py
@@ -1,3 +1,4 @@
+from myproject.myapp.forms import MyCustomModelForm
 from myproject.myapp.models import MyCustomModel
 from myproject.myapp.utils import search
 
@@ -14,7 +15,7 @@ def search_mycustommodel(request):
 
 def template(request, pk):
     instance = MyCustomModel.objects.get(pk=pk)
-    autocomplete_form = SelectWorkspaceForm(
+    autocomplete_form = MyCustomModelForm(
         initial={"mycustommodel": instance},
     )
     return render_to_response(

diff --git a/forms.py b/forms.py
@@ -0,0 +1,74 @@
+from typing import Iterable
+from typing import Optional
+
+from django.contrib import admin
+from django.contrib.admin.widgets import AutocompleteSelect
+from django.forms import ModelChoiceField
+
+from myproject.myapp.models import MyCustomModel
+
+
+class CustomUrlAutocompleteSelect(AutocompleteSelect):
+    """URL is not based on url_name implicitly, instead passed in as a kwarg."""
+
+    def __init__(self, *args, **kwargs):
+        self.url = kwargs.pop("url")
+        super().__init__(*args, **kwargs)
+
+    def get_url(self):
+        return self.url
+
+
+def build_modelchoicefield(
+    autocomplete_url: str,
+    model: type,
+    fieldname: str,
+    queryset: Iterable,
+    label: Optional[str] = None,
+    required: bool = False,
+) -> ModelChoiceField:
+    # FIXME:
+    #   Our shenanigans to use the AutocompleteSelect outside of the
+    #   admin have a little drawback here: The queryset that we pass
+    #   will be used to check for a valid selection, but it is not
+    #   what the API returns, so it will not affect what we see in
+    #   the dropdown, unfortunately. It will however be respected
+    #   when we submit the form and display an error 'invalid
+    #   selection'.
+    options = {
+        "queryset": queryset,
+        "widget": CustomUrlAutocompleteSelect(
+            model._meta.get_field(fieldname).remote_field,
+            admin.site,
+            url=autocomplete_url,
+        ),
+        "required": required,
+    }
+    if label:
+        options["label"] = label
+    return ModelChoiceField(**options)
+
+
+
+class MyCustomModelForm(forms.ModelForm):
+    """Note: Make sure to include {{ form.media }} in the template."""
+
+    class Meta:
+        model = MyCustomModel
+        fields = ("id",)
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self.fields["id"] = build_modelchoicefield(
+            autocomplete_url="/autocomplete/mycustommodel",
+            model=MyCustomModel,
+            fieldname="id",
+            queryset=MyCustomModel.objects.all(),
+            required=False,
+        )
+
+        # HACK: Rename field to use a less generic input name in html,
+        #   otherwise the selet would have name="id".
+        self.fields["mycustommodel"] = self.fields["id"]
+        del self.fields["id"]
diff --git a/template.html b/template.html
@@ -0,0 +1,7 @@
+<!-- To make the AutocompleteSelect work we need to include some CSS and javascript -->
+{{ select_workspace_form.media }}
+
+<form id="mycustommodel_form">
+  {{ select_workspace_form }}
+  <button type="submit">Submit</button>
+</form>
diff --git a/urls.py b/urls.py
@@ -0,0 +1,10 @@
+...
+
+urlpatterns = [
+    ...
+    url(
+        r"^autocomplete/mycustommodel$",
+        myproject.myapp.views.search_mycustommodel,
+    ),
+    ...
+]
diff --git a/views.py b/views.py
@@ -0,0 +1,23 @@
+from myproject.myapp.models import MyCustomModel
+from myproject.myapp.utils import search
+
+
+def search_mycustommodel(request):
+    term = request.GET.get("term", "")
+    candidates = search(Workspace.objects, term, ["name"]).order_by(
+        "name",
+    )
+    return make_autocomplete_response(
+        workspace_candidates, lambda workspace: workspace.name
+    )
+
+
+def template(request, pk):
+    instance = MyCustomModel.objects.get(pk=pk)
+    autocomplete_form = SelectWorkspaceForm(
+        initial={"mycustommodel": instance},
+    )
+    return render_to_response(
+        "myapp/template.html", {"autocomplete_form": autocomplete_form}
+    )
+