Elective - 北大选课网 CLI

A CLI client for PKU's course selection system with auto-enrollment automation.

Architecture

• Crate location: crates/elective/
• Auth flow: IAAA SSO (app_id="elective") → elective SSO endpoint callback
• API: HTML scraping + CAPTCHA handling (base64 image recognition)
• Automation: Polling loop for auto-enrollment with configurable interval

Key Source Files

• src/main.rs — Clap CLI with subcommands
• src/commands.rs — Command implementations including auto-enroll loop
• src/api.rs — HTML scraping, CAPTCHA image extraction
• src/display.rs — Terminal output formatting
• src/client.rs — reqwest client builders

CLI Commands

CAPTCHA Backends

The config-captcha command supports multiple recognition backends:

• manual — Display CAPTCHA image, user inputs answer
• utool — UTool OCR service
• ttshitu — TTShiTu recognition API
• yunma — Yunma recognition API

Auto-Login for AI Agents

# Check session status
info-auth check

# Auto-login (reads credentials from OS keyring, no password needed)
elective login -p                  # single degree
elective login -p --dual major     # dual degree - major
elective login -p --dual minor     # dual degree - minor

Note: Dual-degree students MUST specify --dual major or --dual minor, otherwise login will fail with an error.

Development Notes

• Auto-enrollment loop: configurable check interval (default 15s), polls for open slots
• Dual-degree students use --dual flag at login for separate session
• CAPTCHA images are base64-encoded, decoded and sent to recognition backend
• All user-facing strings in Chinese
• Error handling: anyhow::Result with .context("中文描述")
• Session persisted to ~/.config/info/elective/
• Credentials resolved via info_common::credential (keyring → env → interactive)