feat: ✨ implement larc caching (#148)

apps/api/src/routes/v1/rest/larc/+endpoint.ts

@@ -1,11 +1,11 @@
+import { PrismaClient } from "@libs/db";
 import { createHandler } from "@libs/lambda";
-import { load } from "cheerio";
-import { fetch } from "cross-fetch";
 import { ZodError } from "zod";
 
-import { fmtBldg, fmtDays, fmtTime, quarterToLarcSuffix } from "./lib";
 import { QuerySchema } from "./schema";
 
+const prisma = new PrismaClient();
+
 export const GET = createHandler(async (event, context, res) => {
   const headers = event.headers;
   const requestId = context.awsRequestId;
@@ -14,55 +14,11 @@ export const GET = createHandler(async (event, context, res) => {
   try {
     const { year, quarter } = QuerySchema.parse(query);
 
-    // SS10wk does not have LARC sessions apparently
-    if (quarter === "Summer10wk") return res.createOKResult([], headers, requestId);
-
-    // TODO: move this code to its own scraper, and rewrite this route to fetch
-    // data from the DB.
-
-    const html = await fetch(
-      `https://enroll.larc.uci.edu/${year}${quarterToLarcSuffix(quarter)}`,
-    ).then((response) => response.text());
-
-    const $ = load(html);
-
-    const larcSections = $(".tutorial-group")
-      .toArray()
-      .map((card) => {
-        const match = $(card)
-          .find(".card-header")
-          .text()
-          .trim()
-          .match(
-            /(?<courseNumber>[^()]*)( \(same as (?<sameAs>.*)\))? - (.*) \((?<courseName>.*)\)/,
-          );
-
-        const sections = $(card)
-          .find(".list-group")
-          .toArray()
-          .map((group) => {
-            const rows = $(group).find(".col-lg-4");
-
-            const [days, time] = $(rows[0])
-              .find(".col")
-              .map((_, col) => $(col).text().trim());
-
-            const [instructor, building] = $(rows[1])
-              .find(".col")
-              .map((_, col) => $(col).text().trim());
-
-            return {
-              days: fmtDays(days),
-              time: fmtTime(time),
-              instructor,
-              bldg: fmtBldg(building),
-            };
-          });
-
-        return { courseInfo: { ...match?.groups }, sections };
-      });
-
-    return res.createOKResult(larcSections, headers, requestId);
+    return res.createOKResult(
+      (await prisma.larcTerm.findFirst({ where: { year, quarter } }))?.courses ?? [],
+      headers,
+      requestId,
+    );
   } catch (e) {
     if (e instanceof ZodError) {
       const messages = e.issues.map((issue) => issue.message);

libs/db/prisma/schema.prisma

@@ -181,6 +181,15 @@ model Instructor {
   courses            Json     @default("[]")
 }
 
+model LarcTerm {
+  year    String
+  quarter Quarter
+  courses Json
+
+  @@id([year, quarter])
+  @@unique([year, quarter], name: "idx")
+}
+
 model Major {
   id              String           @id
   degreeId        String

services/larc-scraper/build.mjs

@@ -0,0 +1,72 @@
+import { chmod, copyFile, mkdir, rm } from "node:fs/promises";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { build } from "esbuild";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+/**
+ * @see https://github.com/evanw/esbuild/issues/1921#issuecomment-1623640043
+ */
+// language=JavaScript
+const js = `
+  import topLevelModule from "node:module";
+  import topLevelUrl from "node:url";
+  import topLevelPath from "node:path";
+
+  const require = topLevelModule.createRequire(import.meta.url);
+  const __filename = topLevelUrl.fileURLToPath(import.meta.url);
+  const __dirname = topLevelPath.dirname(__filename);
+`;
+
+async function buildApp() {
+  const options = {
+    entryPoints: { index: "src/index.ts" },
+    outdir: "dist",
+    outExtension: { ".js": ".mjs" },
+    bundle: true,
+    minify: true,
+    format: "esm",
+    platform: "node",
+    target: "node20",
+    logLevel: "info",
+    banner: { js },
+    plugins: [
+      {
+        name: "clean",
+        setup(build) {
+          build.onStart(async () => {
+            await rm(join(__dirname, "dist/"), { recursive: true, force: true });
+            await mkdir(join(__dirname, "dist/"));
+          });
+        },
+      },
+      {
+        name: "copy",
+        setup(build) {
+          build.onEnd(async () => {
+            await copyFile(
+              join(
+                __dirname,
+                "../../libs/db/node_modules/prisma/libquery_engine-linux-arm64-openssl-3.0.x.so.node",
+              ),
+              join(__dirname, "dist/libquery_engine-linux-arm64-openssl-3.0.x.so.node"),
+            );
+            await copyFile(
+              join(__dirname, "../../libs/db/prisma/schema.prisma"),
+              join(__dirname, "dist/schema.prisma"),
+            );
+            await chmod(
+              join(__dirname, "dist/libquery_engine-linux-arm64-openssl-3.0.x.so.node"),
+              0o755,
+            );
+          });
+        },
+      },
+    ],
+  };
+  await build(options);
+}
+
+buildApp().then();

services/larc-scraper/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "@services/larc-scraper",
+  "version": "0.0.0",
+  "private": true,
+  "description": "Automated scraper for LARC sections",
+  "license": "MIT",
+  "type": "module",
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "scripts": {
+    "build": "node build.mjs"
+  },
+  "dependencies": {
+    "@libs/db": "workspace:^",
+    "@libs/uc-irvine-lib": "workspace:^",
+    "@libs/utils": "workspace:^",
+    "cheerio": "1.0.0-rc.12",
+    "cross-fetch": "4.0.0"
+  },
+  "devDependencies": {
+    "@peterportal-api/types": "workspace:^",
+    "esbuild": "0.20.1"
+  }
+}

services/larc-scraper/src/index.ts

@@ -0,0 +1,69 @@
+import { PrismaClient } from "@libs/db";
+import { LarcResponse, Quarter } from "@peterportal-api/types";
+import { load } from "cheerio";
+import { fetch } from "cross-fetch";
+
+import { fmtBldg, fmtDays, fmtTime, quarterToLarcSuffix } from "./lib";
+
+const EARLIEST_YEAR = 2019;
+
+const prisma = new PrismaClient();
+
+export const sleep = async (duration: number) =>
+  new Promise((resolve) => setTimeout(resolve, duration));
+
+export const handler = async () => {
+  const data: Array<{ year: string; quarter: Quarter; courses: LarcResponse }> = [];
+  const quarters = ["Fall", "Winter", "Spring", "Summer1", "Summer2"] as const;
+  for (let year = EARLIEST_YEAR; year < new Date().getFullYear() + 2; ++year) {
+    for (const quarter of quarters) {
+      console.log(`Scraping ${year} ${quarter}`);
+      const html = await fetch(
+        `https://enroll.larc.uci.edu/${year}${quarterToLarcSuffix(quarter)}`,
+      ).then((response) => response.text());
+
+      const $ = load(html);
+
+      const courses = $(".tutorial-group")
+        .toArray()
+        .map((card) => {
+          const match = $(card)
+            .find(".card-header")
+            .text()
+            .trim()
+            .match(
+              /(?<courseNumber>[^()]*)( \(same as (?<sameAs>.*)\))? - (.*) \((?<courseName>.*)\)/,
+            );
+
+          const sections = $(card)
+            .find(".list-group")
+            .toArray()
+            .map((group) => {
+              const rows = $(group).find(".col-lg-4");
+
+              const [days, time] = $(rows[0])
+                .find(".col")
+                .map((_, col) => $(col).text().trim());
+
+              const [instructor, building] = $(rows[1])
+                .find(".col")
+                .map((_, col) => $(col).text().trim());
+
+              return {
+                days: fmtDays(days),
+                time: fmtTime(time),
+                instructor,
+                bldg: fmtBldg(building),
+              };
+            });
+
+          return { courseInfo: { ...match?.groups }, sections };
+        });
+      data.push({ year: year.toString(), quarter, courses: (courses as LarcResponse) ?? [] });
+      await sleep(1000);
+    }
+  }
+  await prisma.$transaction([prisma.larcTerm.deleteMany({}), prisma.larcTerm.createMany({ data })]);
+};
+
+handler().then();

tools/cdk/src/constructs/LarcScraper.ts

@@ -0,0 +1,42 @@
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { Duration } from "aws-cdk-lib";
+import { Rule, RuleTargetInput, Schedule } from "aws-cdk-lib/aws-events";
+import { LambdaFunction } from "aws-cdk-lib/aws-events-targets";
+import { Architecture, Code, Function, Runtime } from "aws-cdk-lib/aws-lambda";
+import { Construct } from "constructs";
+
+export class LarcScraper extends Construct {
+  constructor(scope: Construct, id: string) {
+    super(scope, id);
+
+    const ruleName = `${id}-rule`;
+
+    const rule = new Rule(this, ruleName, {
+      ruleName,
+      schedule: Schedule.rate(Duration.days(1)),
+    });
+
+    const functionName = `${id}-function`;
+
+    rule.addTarget(
+      new LambdaFunction(
+        new Function(this, functionName, {
+          architecture: Architecture.ARM_64,
+          code: Code.fromAsset(
+            join(dirname(fileURLToPath(import.meta.url)), "../../../../services/larc-scraper/dist"),
+          ),
+          functionName,
+          handler: "index.handler",
+          timeout: Duration.seconds(15),
+          runtime: Runtime.NODEJS_20_X,
+          memorySize: 512,
+        }),
+        {
+          event: RuleTargetInput.fromObject({ body: "{}" }),
+        },
+      ),
+    );
+  }
+}

tools/cdk/src/stacks/services.ts

@@ -4,6 +4,7 @@ import { SubnetType, Vpc } from "aws-cdk-lib/aws-ec2";
 import type { Construct } from "constructs";
 
 import { CalendarScraper } from "../constructs/CalendarScraper";
+import { LarcScraper } from "../constructs/LarcScraper";
 import { WebsocProxy } from "../constructs/WebsocProxy";
 import { WebsocScraperV2 } from "../constructs/WebsocScraperV2";
 
@@ -30,6 +31,8 @@ export class ServicesStack extends Stack {
 
     new CalendarScraper(this, `${id}-calendar-scraper`);
 
+    new LarcScraper(this, `${id}-larc-scraper`);
+
     new WebsocProxy(this, `${id}-websoc-proxy`);
 
     new WebsocScraperV2(this, `${id}-websoc-scraper-v2`, vpc);