Enhancement: hook to populate UI with default values on entity creation

[sglebs]

Is your feature request related to a problem? Please describe.

Currently the UI to add an entity does not populate it with default values.

#327 does not solve it. The UI still opens with blank values.

Describe the solution you'd like

I was expecting before_create from #327 to do this, but it seems to run AFTER the SAVE button is clicked. The UI is opened blank, still. Maybe we need another hook, before_ui_opens or something like that?

Describe alternatives you've considered

I have overriden before_create but it is only run AFTER. Same with before_edit

Additional context

In before_create I have put logic to honor SQLALchemy's default values:

    async def before_create(self, request: Request, data: Dict[str, Any], knowledge_ingestion_profile: Any) -> None:
        # We basically want to honor all columns with default values defined by SQLAlchemy
        if knowledge_ingestion_profile.requests_per_second is None:
            knowledge_ingestion_profile.requests_per_second = KnowledgeIngestionProfile.requests_per_second.default.arg
        if knowledge_ingestion_profile.verify_ssl is None:
            knowledge_ingestion_profile.verify_ssl = KnowledgeIngestionProfile.verify_ssl.default.arg
        if knowledge_ingestion_profile.http_headers is None or len(knowledge_ingestion_profile.http_headers.strip()) <= 0:
            knowledge_ingestion_profile.http_headers = KnowledgeIngestionProfile.http_headers.default.arg
      ...
      ...

Unfortunately it does not run soon enough to populate the UI when the user clicks "New "

[sglebs]

Note: I have had this need for a long time. See #287 . Unfortunately #327 did not solve it for me, as it runs "too late" :-(

[hasansezertasan]

I think we need an attribute called default in the BaseField class.

I just checked the templates, and saw these lines...

starlette-admin/starlette_admin/templates/create.html

Lines 29 to 40 in 2540c51

	<div class="card-body border-bottom py-3">
	{% block create_form %}
	{% for field in model.get_fields_list(request, 'CREATE' | ra) %}
	<div class="mb-3">
	{% with action=('CREATE'| ra), data=(None if not obj else obj[field.name]), error=errors.get(field.name, None) if errors else None %}
	{% include field.label_template %}
	{% include field.form_template %}
	{% endwith %}
	</div>
	{% endfor %}
	{% endblock %}
	</div>

The data that input fields take is calculated inside the template (see obj[field.name]), so overriding before_create or before_edit won't work. We need to move that functionality from Jinja2 to Python and call it from Jinja2, it'll make it easier to override. Otherwise, you would have to override +10 template files.

[jowilf]

I think we need an attribute called default in the BaseField class.

Yes, and read the default value from the column definition (SQLAlchemy), Field(mongoengine)...

[hasansezertasan]

I think we need an attribute called default in the BaseField class.

Yes, and read the default value from the column definition (SQLAlchemy), Field(mongoengine)...

Yep, that's what I'm talking about. Do you have a work in progress about this? If not, I may try to implement some stuff (I missed your reviews 😂, they are teaching!).

[jowilf]

Yep, that's what I'm talking about. Do you have a work in progress about this? If not, I may try to implement some stuff (I missed your reviews 😂, they are teaching!).

I'm glad you are learning from my reviews. Feel free to submit a PR for this. Thanks