Re-use registry HTTP agent for package info requests

server/utils/fetchNpmPackageInfo.js

@@ -0,0 +1,47 @@
+const url = require("url");
+const https = require("https");
+
+const config = require("../config");
+const bufferStream = require("./bufferStream");
+const agent = require("./registryAgent");
+
+function parseJSON(res) {
+  return bufferStream(res).then(JSON.parse);
+}
+
+function fetchNpmPackageInfo(packageName) {
+  return new Promise((resolve, reject) => {
+    const encodedPackageName =
+      packageName.charAt(0) === "@"
+        ? `@${encodeURIComponent(packageName.substring(1))}`
+        : encodeURIComponent(packageName);
+
+    const infoURL = `${config.registryURL}/${encodedPackageName}`;
+
+    console.log(
+      `info: Fetching package info for ${packageName} from ${infoURL}`
+    );
+
+    const { hostname, pathname } = url.parse(infoURL);
+    const options = {
+      agent: agent,
+      hostname: hostname,
+      path: pathname,
+      headers: {
+        Accept: "application/json"
+      }
+    };
+
+    https
+      .get(options, res => {
+        if (res.statusCode === 200) {
+          resolve(parseJSON(res));
+        } else {
+          reject(res);
+        }
+      })
+      .on("error", reject);
+  });
+}
+
+module.exports = fetchNpmPackageInfo;