most basic middleware function

lib/middleware.js

@@ -0,0 +1,31 @@
+'use strict';
+
+module.exports = function (le) {
+  return function () {
+    var prefix = le.acmeChallengePrefix; // /.well-known/acme-challenge/:token
+
+    return function (req, res, next) {
+      if (0 !== req.url.indexOf(prefix)) {
+        next();
+        return;
+      }
+
+      var key = req.url.slice(prefix.length);
+      var hostname = req.hostname || (req.headers.host || '').toLowerCase().replace(/:*/, '');
+
+      // TODO tpl copy?
+      le.challenger.getAsync(le, hostname, key).then(function (token) {
+        if (!token) {
+          res.status = 404;
+          res.send("Error: These aren't the tokens you're looking for. Move along.");
+          return;
+        }
+
+        res.send(token);
+      }, function (/*err*/) {
+        res.status = 404;
+        res.send("Error: These aren't the tokens you're looking for. Move along.");
+      });
+    };
+  };
+};