fix: handle namespace and add proxy support

1 files changed, 57 insertions, 0 deletions

diff --git a/scripts/scrape.js b/scripts/scrape.js
new file mode 100644
index 0000000..93f6a41
--- /dev/null
+++ b/scripts/scrape.js
@@ -0,0 +1,57 @@
+import { XMLParser } from "fast-xml-parser";
+import fs from "fs/promises";
+import path from "path";
+import dns from "node:dns";
+import { ProxyAgent } from "undici";
+
+dns.setDefaultResultOrder("ipv4first");
+
+const proxy = process.env.HTTPS_PROXY || process.env.https_proxy || process.env.HTTP_PROXY || process.env.http_proxy;
+const dispatcher = proxy ? new ProxyAgent(proxy) : undefined;
+
+const [ , , YEAR = "2025", TERM = "fall" ] = process.argv;
+// UIUC's API uses XML namespaces (e.g. `<ns2:term>`). In order for the
+// returned object to have plain keys like `term` and `subject`, we instruct
+// fast-xml-parser to strip the namespace prefixes.
+const parser = new XMLParser({ ignoreAttributes: false, removeNSPrefix: true });
+const BASE = `https://courses.illinois.edu/cisapp/explorer`;
+
+async function getXML(url) {
+  const res = await fetch(url, { dispatcher });
+  if (!res.ok) throw new Error(`Request failed: ${res.status} ${url}`);
+  return parser.parse(await res.text());
+}
+
+async function scrapeSchedule(year, term) {
+  const catalog = {};
+  const termRoot = await getXML(`${BASE}/schedule/${year}/${term}.xml`);
+  const subjects = termRoot.term?.subjects?.subject;
+  if (!subjects) throw new Error(`Unexpected XML structure for ${year} ${term}`);
+  const subjHrefs = Array.isArray(subjects) ? subjects.map(s => s['@_href']) : [subjects['@_href']];
+
+  for (const subjURL of subjHrefs) {
+    const subjXML = await getXML(subjURL);
+    const courses = subjXML.subject?.courses?.course || [];
+    const courseList = Array.isArray(courses) ? courses : [courses];
+    for (const c of courseList) {
+      const courseURL = c['@_href'];
+      const courseXML = await getXML(courseURL);
+      const id = courseXML.course['@_id'];
+      const desc = courseXML.course.description ?? "";
+      const m = desc.match(/Prerequisite[s]?:\s*([^.;]*)/i);
+      if (!m) continue;
+      const prereqs = m[1]
+        .match(/[A-Z]{2,4}\s?\d{2,3}[A-Z]?/g)
+        ?.map(s => s.replace(/\s+/, "")) ?? [];
+      if (prereqs.length) catalog[id.replace(/\s+/, "")] = prereqs;
+    }
+    await new Promise(r => setTimeout(r, 300));
+  }
+  return catalog;
+}
+
+const data = await scrapeSchedule(YEAR, TERM);
+const outDir = path.resolve("data");
+await fs.mkdir(outDir, { recursive: true });
+await fs.writeFile(path.join(outDir, `catalog_${YEAR}_${TERM}.json`), JSON.stringify(data, null, 2));
+console.log(`Saved ${Object.keys(data).length} courses`);