Website: don't crash server if EJS code crashes

Show the error message in the browser instead of crashing the server if
an EJS script throws an exception.

Author: strager

website/src/server.mjs

@@ -30,10 +30,17 @@ export function makeServer({ htmlRedirects, wwwRootPath }) {
         return;
 
       case "build-ejs":
+        let out = null;
+        try {
+          out = await router.renderEJSFile(
+            path.join(router.wwwRootPath, classifiedDirectory.path)
+          );
+        } catch (error) {
+          response.writeHeader(500, { "content-type": "text/plain" });
+          response.end(error.stack);
+          return;
+        }
         response.writeHeader(200, { "content-type": "text/html" });
-        let out = await router.renderEJSFile(
-          path.join(router.wwwRootPath, classifiedDirectory.path)
-        );
         response.end(out);
         return;
 

website/test/test-server.mjs

@@ -334,6 +334,19 @@ describe("server", () => {
       );
     });
   });
+
+  describe("EJS", () => {
+    it("exception causes 500 error", async () => {
+      fs.writeFileSync(
+        path.join(wwwRootPath, "index.ejs.html"),
+        "<%= variableDoesNotExist %>"
+      );
+
+      let response = await request.get("/");
+      expect(response.status).toBe(500);
+      expect(response.data).toContain("variableDoesNotExist");
+    });
+  });
 });
 
 // quick-lint-js finds bugs in JavaScript programs.