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#!/usr/bin/env python3
import argparse
import concurrent.futures
import json
import re
import sys
import time
from dataclasses import dataclass, asdict
from typing import Dict, List, Optional, Tuple
import requests
from xml.etree import ElementTree as ET
BASE_URL = "https://courses.illinois.edu/cisapp/explorer/catalog"
@dataclass
class CourseRecord:
index: str
name: Optional[str]
description: Optional[str]
prerequisites: Optional[str]
def parse_xml(content: bytes) -> ET.Element:
try:
return ET.fromstring(content)
except ET.ParseError as exc:
raise RuntimeError(f"Failed to parse XML: {exc}")
def fetch(session: requests.Session, url: str) -> bytes:
resp = session.get(url, timeout=30)
if resp.status_code != 200:
raise RuntimeError(f"GET {url} -> {resp.status_code}")
return resp.content
def get_subject_ids(session: requests.Session, year: str, term: str) -> List[str]:
url = f"{BASE_URL}/{year}/{term}.xml"
root = parse_xml(fetch(session, url))
subjects = []
for node in root.findall(".//subject"):
node_id = node.attrib.get("id")
if node_id:
subjects.append(node_id)
return subjects
def get_course_numbers_for_subject(session: requests.Session, year: str, term: str, subject: str) -> List[str]:
url = f"{BASE_URL}/{year}/{term}/{subject}.xml"
root = parse_xml(fetch(session, url))
courses = []
for node in root.findall(".//course"):
node_id = node.attrib.get("id")
if node_id:
courses.append(node_id)
return courses
def extract_prerequisite_text(root: ET.Element) -> Optional[str]:
# Prefer explicitly labeled prerequisite elements if present
for tag in ["prerequisites", "prerequisite", "Prerequisites", "Prerequisite"]:
found = root.find(f".//{tag}")
if found is not None and (found.text and found.text.strip()):
return found.text.strip()
# Fallback: courseSectionInformation often contains "Prerequisite:" free text
csi = root.find(".//courseSectionInformation")
if csi is not None and csi.text:
text = csi.text.strip()
match = re.search(r"Prerequisite[s]?:\s*(.*)$", text, flags=re.IGNORECASE | re.DOTALL)
if match:
return match.group(1).strip()
# As a last resort, scan description for a Prerequisite sentence
desc = root.find(".//description")
if desc is not None and desc.text:
text = desc.text.strip()
match = re.search(r"Prerequisite[s]?:\s*(.*)$", text, flags=re.IGNORECASE | re.DOTALL)
if match:
return match.group(1).strip()
return None
def get_course_details(session: requests.Session, year: str, term: str, subject: str, course_number: str) -> CourseRecord:
url = f"{BASE_URL}/{year}/{term}/{subject}/{course_number}.xml"
root = parse_xml(fetch(session, url))
# Title/name may be in <label> or <title>
name = None
label_node = root.find(".//label")
if label_node is not None and label_node.text:
name = label_node.text.strip()
else:
title_node = root.find(".//title")
if title_node is not None and title_node.text:
name = title_node.text.strip()
description = None
desc_node = root.find(".//description")
if desc_node is not None and desc_node.text:
description = desc_node.text.strip()
prerequisites_text = extract_prerequisite_text(root)
return CourseRecord(
index=f"{subject} {course_number}",
name=name,
description=description,
prerequisites=prerequisites_text,
)
def try_year_term(session: requests.Session, year: str, term: str) -> bool:
url = f"{BASE_URL}/{year}/{term}.xml"
resp = session.get(url, timeout=15)
return resp.status_code == 200
def detect_default_year_term(session: requests.Session) -> Tuple[str, str]:
# Try a few common combinations in likely order
current_year = time.gmtime().tm_year
candidate_terms = ["fall", "summer", "spring", "winter"]
candidates: List[Tuple[str, str]] = []
# Current year candidates first
for term in candidate_terms:
candidates.append((str(current_year), term))
# Then previous year
for term in candidate_terms:
candidates.append((str(current_year - 1), term))
for year, term in candidates:
if try_year_term(session, year, term):
return year, term
# Fallback to a known historical term
return "2024", "fall"
def main() -> int:
parser = argparse.ArgumentParser(description="Fetch UIUC course catalog into JSON")
parser.add_argument("--year", default=None, help="Catalog year, e.g. 2025")
parser.add_argument("--term", default=None, help="Term, e.g. fall|spring|summer|winter")
parser.add_argument("--subject", default=None, help="Limit to a single subject (e.g., CS)")
parser.add_argument("--max-workers", type=int, default=12, help="Max concurrent requests")
parser.add_argument("--output", default="data/courses.json", help="Output JSON path")
parser.add_argument("--sleep", type=float, default=0.0, help="Optional per-request sleep seconds")
args = parser.parse_args()
session = requests.Session()
session.headers.update({"Accept": "application/xml, text/xml;q=0.9, */*;q=0.8", "User-Agent": "uiuc-course-scraper/1.0"})
year = args.year
term = args.term
if not year or not term:
year, term = detect_default_year_term(session)
print(f"[info] Using detected catalog: {year} {term}")
else:
print(f"[info] Using catalog: {year} {term}")
try:
subject_ids = [args.subject] if args.subject else get_subject_ids(session, year, term)
except Exception as exc:
print(f"[error] Failed to get subjects for {year} {term}: {exc}")
return 1
print(f"[info] Found {len(subject_ids)} subject(s)")
all_course_records: List[CourseRecord] = []
def process_subject(subject_id: str) -> List[CourseRecord]:
try:
if args.sleep:
time.sleep(args.sleep)
course_numbers = get_course_numbers_for_subject(session, year, term, subject_id)
except Exception as exc_subj:
print(f"[warn] Failed to list courses for {subject_id}: {exc_subj}")
return []
subject_records: List[CourseRecord] = []
for course_number in course_numbers:
try:
if args.sleep:
time.sleep(args.sleep)
record = get_course_details(session, year, term, subject_id, course_number)
subject_records.append(record)
except Exception as exc_course:
print(f"[warn] Failed details for {subject_id} {course_number}: {exc_course}")
continue
return subject_records
with concurrent.futures.ThreadPoolExecutor(max_workers=args.max_workers) as executor:
future_to_subject: Dict[concurrent.futures.Future, str] = {}
for subject_id in subject_ids:
future = executor.submit(process_subject, subject_id)
future_to_subject[future] = subject_id
for future in concurrent.futures.as_completed(future_to_subject):
subject_id = future_to_subject[future]
try:
subject_records = future.result()
all_course_records.extend(subject_records)
print(f"[info] {subject_id}: {len(subject_records)} course(s)")
except Exception as exc:
print(f"[warn] Subject {subject_id} failed: {exc}")
# Sort deterministically
all_course_records.sort(key=lambda r: (r.index.split()[0], int(re.sub(r"[^0-9]", "", r.index.split()[1])) if len(r.index.split()) > 1 and re.search(r"\d", r.index.split()[1]) else r.index))
# Serialize to JSON array of objects
output_path = args.output
output_dir = output_path.rsplit("/", 1)[0] if "/" in output_path else "."
try:
import os
os.makedirs(output_dir, exist_ok=True)
except Exception:
pass
with open(output_path, "w", encoding="utf-8") as f:
json.dump([asdict(r) for r in all_course_records], f, ensure_ascii=False, indent=2)
print(f"[done] Wrote {len(all_course_records)} courses -> {output_path}")
return 0
if __name__ == "__main__":
sys.exit(main())
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