Feat: Support URL params for pre-filling Trigger and Backfill forms

[anshuksi282-ksolves]

closes: #54800

Description

This PR restores and enhances the ability to pre-populate the Trigger DAG and Backfill forms via URL query parameters in the Airflow 3.0 UI. This feature existed in Airflow 2.x and is useful for sharing pre-configured run links.

Key Changes:

1. URL Param Parsing:

   • Implemented using the useSearchParams hook (replacing manual parsing logic from stale PRs).
   • Added a utility getTriggerConf to handle both JSON strings (?conf={"a":1}) and Key-Value pairs (?a=1).

2. Form Updates:

   • Trigger Form: Supports run_id, logical_date, note, and conf.
   • Backfill Form: Supports from_date, to_date, max_active_runs, reprocess_behavior, and run_backwards.
   • Config Form: Automatically expands the "Advanced Options" accordion if configuration data is present in the URL.

3. Code Quality:

   • Optimized RunBackfillForm.tsx logic to keep the file size strictly under the 250-line linting limit.
   • Ensured consistent naming conventions for backfill parameters (from_date / to_date) to match the API and UI components.

4. Documentation:

   • Updated docs/core-concepts/params.rst to document the supported URL parameters and examples.

How to reproduce / Test

You can test this by running the UI and navigating to any DAG (e.g., tutorial) using the following URLs:

1. Trigger Single Run (JSON Config):
The modal should open, fields should be filled, and the JSON editor should show the config.
http://localhost:8080/dags/tutorial/trigger/single?run_id=test_run_01&note=Testing_Note&conf={"environment":"dev","debug":true}

2. Trigger Single Run (Key-Value Config):
The "Advanced Options" should open and show {"foo": "bar"}.
http://localhost:8080/dags/tutorial/trigger/single?foo=bar&retry=3

3. Backfill Form:
The Backfill form should open with dates, max runs, and the "Run Backwards" checkbox pre-selected.
http://localhost:8080/dags/tutorial/trigger/backfill?from_date=2024-01-01T00:00:00&to_date=2024-01-05T00:00:00&max_active_runs=5&run_backwards=true

---

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[jscheffl]

PR Looks clear and good for me.

I tried but the trigger form was not opening. Don't know if I mis-understood but I needed to click the "trigger" button to open the form pre-populated. Otherwise working fine. I'd expected it is oepning pre-populated when calling with a prepared/pre-filled URL.

[jscheffl]

Can you maybe add a chapter header?

[anshuksi282-ksolves]

Hi @jscheffl Agreed. I have added a new section header "Pre-populating Trigger Form via URL" to clearly separate this topic in the documentation.

[jscheffl]

The term "now" is a bit relative... especially if you might read the same text in 10 years if the feature still exists.

Suggested change

	The trigger form now supports two different ways of providing ``conf`` values. The available input methods are summarized in the table below:
	The trigger form supports two different ways of providing ``conf`` values. The available input methods are summarized in the table below:

[anshuksi282-ksolves]

The term "now" is a bit relative... especially if you might read the same text in 10 years if the feature still exists.

Good point. I have updated the text to remove the word "now" as suggested.

[anshuksi282-ksolves]

PR Looks clear and good for me.

I tried but the trigger form was not opening. Don't know if I mis-understood but I needed to click the "trigger" button to open the form pre-populated. Otherwise working fine. I'd expected it is oepning pre-populated when calling with a prepared/pre-filled URL.

Hi @jscheffl Thanks for catching that! You are correct, I missed wiring the URL state to the modal visibility logic in the initial commit.

I have pushed a fix in the latest commit (Overview.tsx) where I check for the mode parameter in the URL. Now, if the URL contains /trigger/single or /trigger/backfill, the modal will open automatically with the pre-populated values.