Factor out getTunnelOption()

request.js

@@ -133,6 +133,32 @@ function constructProxyHeaderWhiteList(headers, proxyHeaderWhiteList) {
     }, {})
 }
 
+function getTunnelOption(self, options) {
+  // Tunnel HTTPS by default, or if a previous request in the redirect chain
+  // was tunneled.  Allow the user to override this setting.
+
+  // If self.tunnel is already set (because this is a redirect), use the
+  // existing value.
+  if (typeof self.tunnel !== 'undefined') {
+    return self.tunnel
+  }
+
+  // If options.tunnel is set (the user specified a value), use it.
+  if (typeof options.tunnel !== 'undefined') {
+    return options.tunnel
+  }
+
+  // If the destination is HTTPS, tunnel.
+  if (self.uri.protocol === 'https:') {
+    return true
+  }
+
+  // Otherwise, leave tunnel unset, because if a later request in the redirect
+  // chain is HTTPS then that request (and any subsequent ones) should be
+  // tunneled.
+  return undefined
+}
+
 function constructTunnelOptions(request) {
   var proxy = request.proxy
 
@@ -377,24 +403,7 @@ Request.prototype.init = function (options) {
     self.proxy = getProxyFromURI(self.uri)
   }
 
-  // Goals:
-  //  - Tunnel HTTPS by default, or if a previous request in the redirect chain
-  //    was tunneled
-  //  - Allow the user to override this setting
-  // Implementation:
-  //  - If this is a redirect, self.tunnel may be set -> don't do anything.
-  //  - If options.tunnel is set, use it.
-  //  - Otherwise, tunnel if the destination is HTTPS, but don't set
-  //    tunnel=false if it's not, because if a later rquest in the redirect
-  //    chain is HTTPS then that request (and any subsequent ones) should be
-  //    tunneled.
-  if (typeof self.tunnel === 'undefined') {
-    if (typeof options.tunnel !== 'undefined') {
-      self.tunnel = options.tunnel
-    } else if (self.uri.protocol === 'https:') {
-      self.tunnel = true
-    }
-  }
+  self.tunnel = getTunnelOption(self, options)
   if (self.proxy) {
     self.setupTunnel()
   }