feat: header authorization uplink

- define auth type basic or bearer;
- assigns the header get process.env var NPM_TOKEN;
- assigns the header get process.env by set name;
- assigns the header raw token;

src/lib/storage/up-storage.js

@@ -227,6 +227,46 @@ class ProxyStorage {
     headers[acceptEncoding] = headers[acceptEncoding] || 'gzip';
     // registry.npmjs.org will only return search result if user-agent include string 'npm'
     headers[userAgent] = headers[userAgent] || `npm (${this.userAgent})`;
+
+    // copy headers to normalize keys
+    let copyHeaders = {};
+    Object.keys(headers).map((value) => {
+      copyHeaders[value.toLowerCase()] = headers[value];
+    });
+
+    if (!copyHeaders['authorization']) {
+      let token = null;
+      // define authorization token to use in the Authorization Header
+      if (this.config.auth.token) {
+        token = this.config.auth.token;
+      } else if (this.config.auth.token_env) {
+        // get NPM_TOKEN http://blog.npmjs.org/post/118393368555/deploying-with-npm-private-modules
+        // or get other variable export in env
+        if (this.config.auth.token_env === true) {
+          token = process.env.NPM_TOKEN;
+        } else {
+          token = process.env[this.config.auth.token_env];
+        }
+      }
+
+      if (token) {
+        // define type Auth allow basic and bearer
+        const type = this.config.auth.type;
+        switch (type.toLowerCase()) {
+          case 'basic':
+            headers['Authorization'] = `Basic ${token}`;
+            break;
+          case 'bearer':
+            headers['Authorization'] = `Bearer ${token}`;
+            break;
+          default:
+            throw new Error(`Auth type '${type}' not allowed.`);
+        }
+      }
+    }
+
+    copyHeaders = null;
+
     return headers;
   }