fix(route): update backend URL handling for internal Docker network

[MODSetter]

Description

Motivation and Context

FIX #

Screenshots

API Changes

• This PR includes API changes

Change Type

• Bug fix
• New feature
• Performance improvement
• Refactoring
• Documentation
• Dependency/Build system
• Breaking change
• Other (specify):

Testing Performed

• Tested locally
• Manual/QA verification

Checklist

• Follows project coding standards and conventions
• Documentation updated as needed
• Dependencies updated as needed
• No lint/build errors or new warnings
• All relevant tests are passing

High-level PR Summary

This PR fixes a backend URL resolution issue for server-to-server communication within Docker containers. The route handler now prioritizes FASTAPI_BACKEND_INTERNAL_URL for internal Docker network communication (e.g., http://backend:8000) over the browser-facing URL, preventing 503 errors during authenticated Zero queries when the zero-cache system invokes this route server-side.

⏱️ Estimated Review Time: 5-15 minutes

💡 Review Order Suggestion

Order	File Path
1	surfsense_web/app/api/zero/query/route.ts

Summary by CodeRabbit

• Chores
  • Updated the Zero query API route configuration to optimize backend communication by prioritizing internal network paths for server-to-server requests, improving performance and reliability.

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Project	Deployment	Actions	Updated (UTC)
surf-sense-frontend	Ready	Preview, Comment	Jun 2, 2026 1:35am

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: f1b4176a-c7d2-4305-bdf1-949291bbfbc0

📥 Commits

Reviewing files that changed from the base of the PR and between abea00d and 97de041.

📒 Files selected for processing (1)

• surfsense_web/app/api/zero/query/route.ts

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📝 Walkthrough

Walkthrough

The zero query API route's backend URL is now derived from an internal FastAPI backend environment variable with fallbacks to external URL and a default localhost endpoint, and the URL is normalized by removing trailing slashes.

Changes

Zero Query Internal Backend Routing

Layer / File(s)	Summary
Backend URL configuration with internal Docker routing surfsense_web/app/api/zero/query/route.ts	The backendURL constant now derives from process.env.FASTAPI_BACKEND_INTERNAL_URL with fallbacks to BACKEND_URL and a default of http://localhost:8000, with trailing slash normalization applied.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• MODSetter/SurfSense#1289: Directly modifies the same backendURL constant in the zero query route to add internal Docker-to-FastAPI routing via environment variables.

Poem

🐰 Through Docker's hidden lanes we roam,
The backend found a closer home—
No slashes trailing in the night,
Internal routes shine clean and bright! ✨

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docker-hot-patch

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