Rename server => modules

modules/middleware/fetchPackage.js

@@ -0,0 +1,153 @@
+const semver = require("semver");
+
+const addLeadingSlash = require("../utils/addLeadingSlash");
+const createPackageURL = require("../utils/createPackageURL");
+const createSearch = require("../utils/createSearch");
+const getNpmPackageInfo = require("../utils/getNpmPackageInfo");
+const incrementCounter = require("../utils/incrementCounter");
+
+function tagRedirect(req, res) {
+  const version = req.packageInfo["dist-tags"][req.packageVersion];
+
+  // Cache tag redirects for 1 minute.
+  res
+    .set({
+      "Cache-Control": "public, max-age=60",
+      "Cache-Tag": "redirect,tag-redirect"
+    })
+    .redirect(
+      302,
+      createPackageURL(req.packageName, version, req.filename, req.search)
+    );
+}
+
+function semverRedirect(req, res) {
+  const maxVersion = semver.maxSatisfying(
+    Object.keys(req.packageInfo.versions),
+    req.packageVersion
+  );
+
+  if (maxVersion) {
+    // Cache semver redirects for 1 minute.
+    res
+      .set({
+        "Cache-Control": "public, max-age=60",
+        "Cache-Tag": "redirect,semver-redirect"
+      })
+      .redirect(
+        302,
+        createPackageURL(req.packageName, maxVersion, req.filename, req.search)
+      );
+  } else {
+    res
+      .status(404)
+      .type("text")
+      .send(`Cannot find package ${req.packageSpec}`);
+  }
+}
+
+function filenameRedirect(req, res) {
+  let filename;
+  if (req.query.module != null) {
+    // See https://github.com/rollup/rollup/wiki/pkg.module
+    filename =
+      req.packageConfig.module ||
+      req.packageConfig["jsnext:main"] ||
+      "/index.js";
+  } else if (
+    req.query.main &&
+    req.packageConfig[req.query.main] &&
+    typeof req.packageConfig[req.query.main] === "string"
+  ) {
+    // Deprecated, see #63
+    filename = req.packageConfig[req.query.main];
+
+    // Count which packages are using this so we can warn them when we
+    // remove this functionality.
+    incrementCounter(
+      "package-json-custom-main",
+      req.packageSpec + "?main=" + req.query.main,
+      1
+    );
+  } else if (
+    req.packageConfig.unpkg &&
+    typeof req.packageConfig.unpkg === "string"
+  ) {
+    filename = req.packageConfig.unpkg;
+  } else if (
+    req.packageConfig.browser &&
+    typeof req.packageConfig.browser === "string"
+  ) {
+    // Deprecated, see #63
+    filename = req.packageConfig.browser;
+
+    // Count which packages are using this so we can warn them when we
+    // remove this functionality.
+    incrementCounter("package-json-browser-fallback", req.packageSpec, 1);
+  } else {
+    filename = req.packageConfig.main || "/index.js";
+  }
+
+  // Redirect to the exact filename so relative imports
+  // and URLs resolve correctly.
+  // TODO: increase the max-age?
+  res
+    .set({
+      "Cache-Control": "public,max-age=60",
+      "Cache-Tag": "redirect,filename-redirect"
+    })
+    .redirect(
+      302,
+      createPackageURL(
+        req.packageName,
+        req.packageVersion,
+        addLeadingSlash(filename),
+        createSearch(req.query)
+      )
+    );
+}
+
+/**
+ * Fetch the package metadata and tarball from npm. Redirect to the exact
+ * version if the request targets a tag or uses a semver version, or to the
+ * exact filename if the request omits the filename.
+ */
+function fetchPackage(req, res, next) {
+  getNpmPackageInfo(req.packageName).then(
+    packageInfo => {
+      if (packageInfo == null || packageInfo.versions == null) {
+        return res
+          .status(404)
+          .type("text")
+          .send(`Cannot find package "${req.packageName}"`);
+      }
+
+      req.packageInfo = packageInfo;
+      req.packageConfig = req.packageInfo.versions[req.packageVersion];
+
+      if (!req.packageConfig) {
+        if (req.packageVersion in req.packageInfo["dist-tags"]) {
+          return tagRedirect(req, res);
+        } else {
+          return semverRedirect(req, res);
+        }
+      }
+
+      if (!req.filename) {
+        return filenameRedirect(req, res);
+      }
+
+      next();
+    },
+    error => {
+      console.error(error);
+
+      return res
+        .status(500)
+        .type("text")
+        .send(`Cannot get info for package "${req.packageName}"`);
+    }
+  );
+}
+
+module.exports = fetchPackage;