unisono/specs/005-simple-http-auth/spec.md

Feature Specification: Simple HTTP Auth

Feature Branch: 005-simple-http-auth
Created: October 13, 2025
Status: Draft
Input: User description: "Simple HTTP Auth. I create a passphrase in the .env file, and users must enter the passphrase (without username) to get access to the SPA. The access must be preserved during session."

User Scenarios & Testing (mandatory)

User Story 1 - Accessing the SPA (Priority: P1)

A user attempts to access the Single Page Application (SPA). They are prompted to enter a passphrase. Upon entering the correct passphrase, they gain access to the SPA. This access is maintained throughout their session.

Why this priority: This is the core functionality of the feature, enabling controlled access to the application.

Independent Test: Can be fully tested by navigating to the SPA, entering a valid passphrase, and verifying access to content.

Acceptance Scenarios:

1. Given a user navigates to the SPA, When they are presented with a passphrase input, Then they can enter the correct passphrase.
2. Given a user has entered the correct passphrase, When they are redirected to the SPA content, Then their access is preserved across page navigations within the SPA.
3. Given a user has entered the correct passphrase, When they close and reopen the browser (within a reasonable session timeout), Then they are still granted access without re-entering the passphrase.

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User Story 2 - Invalid Passphrase (Priority: P2)

A user attempts to access the SPA but enters an incorrect passphrase. They should be denied access and prompted to try again.

Why this priority: Essential for security and user experience, preventing unauthorized access.

Independent Test: Can be tested by entering an incorrect passphrase and verifying that access is denied.

Acceptance Scenarios:

1. Given a user navigates to the SPA, When they enter an incorrect passphrase, Then they are shown an error message and remain on the passphrase entry screen.

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Edge Cases

• What happens when the passphrase in the .env file is missing or invalid? (Answer: Default to No Authentication - the application starts without requiring a passphrase.)
• How does the system handle multiple failed passphrase attempts? (Answer: No Rate Limiting - unlimited attempts allowed.) What defines “session” for preserving access? (Answer: Browser Session - Access is preserved only as long as the browser tab/window remains open. Closing the browser or tab will require re-entry of the passphrase.)

Requirements (mandatory)

Functional Requirements

• FR-001: The system MUST prompt users to enter a passphrase before granting access to the SPA.
• FR-002: The system MUST validate the entered passphrase against a configured passphrase.
• FR-003: The system MUST grant access to the SPA upon successful passphrase validation.
• FR-004: The system MUST deny access and provide feedback upon unsuccessful passphrase validation.
• FR-005: The system MUST preserve user access to the SPA for the duration of their session.
• FR-006: The passphrase MUST be configurable via an environment variable (e.g., .env file).
• FR-007: The authentication mechanism MUST NOT require a username.
• FR-008: The system MUST log both successful and failed authentication attempts to a text file, without sensitive data.

Key Entities (include if feature involves data)

• Passphrase: A secret string used for authentication.
• Session: A period of continuous interaction between the user and the SPA, during which access is maintained.

Out of Scope

• User management (creation, deletion, modification of users)
• Password reset or recovery functionality
• Multi-factor authentication (MFA)

Success Criteria (mandatory)

Measurable Outcomes

• SC-001: 100% of users who enter the correct passphrase gain immediate access to the SPA.
• SC-002: 0% of users who enter an incorrect passphrase gain access to the SPA.
• SC-003: User access to the SPA is maintained for the entire browser session (or defined session duration) without re-authentication.
• SC-004: The passphrase can be updated in the .env file and takes effect upon application restart.

Clarifications

Session 2025-10-13

• Q: What is the desired rate limiting behavior for multiple failed passphrase attempts? → A: No Rate Limiting
• Q: How should the system behave if the passphrase is missing or invalid in the .env file? → A: Default to No Authentication
• Q: Are there any specific performance targets (e.g., latency) for the passphrase validation process? → A: No target
• Q: What kind of logging or monitoring should be in place for authentication attempts (success/failure)? → A: Standard Logging (both successful and failed attempts, without sensitive data, to a text file)
• Q: Are there any explicit functionalities that are out-of-scope for this simple HTTP authentication (e.g., user management, password reset, multi-factor authentication)? → A: All of the above (User management, password reset, and MFA are all out-of-scope).