Break middleware out into separate files

server/middleware/serveFile.js

@@ -0,0 +1,45 @@
+const path = require('path')
+const { getPackageInfo } = require('./RegistryUtils')
+const { generateMetadata } = require('./MetadataUtils')
+const { generateDirectoryIndexHTML } = require('./IndexUtils')
+const { sendFile } = require('./ResponseUtils')
+
+/**
+ * Send the file, JSON metadata, or HTML directory listing.
+ */
+function serveFile(registryURL, autoIndex, maximumDepth) {
+  return function (req, res, next) {
+    // TODO: change query param from "json" => "meta"
+    if (req.query.json != null) {
+      generateMetadata(req.packageDir, req.file, req.stats, maximumDepth, function (error, metadata) {
+        if (metadata) {
+          res.set('Cache-Control', 'public, max-age=31536000').send(metadata)
+        } else {
+          res.status(500).send(`Cannot generate JSON metadata for ${req.packageSpec}${req.filename}`)
+        }
+      })
+    } else if (req.stats.isFile()) {
+      // TODO: use res.sendFile instead of our own custom function?
+      sendFile(res, path.join(req.packageDir, req.file), req.stats, 31536000)
+    } else if (autoIndex && req.stats.isDirectory()) {
+      // TODO: re-use packageInfo from fetchPackage middleware
+      getPackageInfo(registryURL, req.packageName, function (error, packageInfo) {
+        if (error) {
+          res.status(500).send(`Cannot generate index page for ${req.packageSpec}${req.filename}`)
+        } else {
+          generateDirectoryIndexHTML(packageInfo, req.packageVersion, req.packageDir, req.file, function (error, html) {
+            if (html) {
+              res.send(html)
+            } else {
+              res.status(500).send(`Cannot generate index page for ${req.packageSpec}${req.filename}`)
+            }
+          })
+        }
+      })
+    } else {
+      res.status(403).send(`Cannot serve ${req.packageSpec}${req.filename}; it's not a req.file`)
+    }
+  }
+}
+
+module.exports = serveFile