From 571e646543a2c1d20518399f62de37d76fe1be28 Mon Sep 17 00:00:00 2001
From: Nick Lockwood <nicklockwood@fb.com>
Date: Thu, 7 Jan 2016 04:00:15 -0800
Subject: [PATCH] Improved null url handling

Summary:
public
Attempting to load an undefined URL via XMLHttpRequest produced a confusing error deep within the network layer. This diff improves the networking stack to catch such errors earlier, and also adds a helpful error in the JS layer.

Fixes https://github.com/facebook/react-native/issues/4558

Reviewed By: javache

Differential Revision: D2811080

fb-gh-sync-id: 1837427e1080a0308f2c4f9a8a42bce2e041fb48
---
 Libraries/Network/RCTNetworking.m       | 4 ++++
 Libraries/Network/XMLHttpRequestBase.js | 3 +++
 React/Base/RCTUtils.m                   | 6 +++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Libraries/Network/RCTNetworking.m b/Libraries/Network/RCTNetworking.m
index 0c5aeaecd..6bbea21b1 100644
--- a/Libraries/Network/RCTNetworking.m
+++ b/Libraries/Network/RCTNetworking.m
@@ -136,6 +136,10 @@ RCT_EXPORT_MODULE()
 
 - (id<RCTURLRequestHandler>)handlerForRequest:(NSURLRequest *)request
 {
+  if (!request.URL) {
+    return nil;
+  }
+
   if (!_handlers) {
 
     // get handlers
diff --git a/Libraries/Network/XMLHttpRequestBase.js b/Libraries/Network/XMLHttpRequestBase.js
index 6c7bb8b48..4cdc42472 100644
--- a/Libraries/Network/XMLHttpRequestBase.js
+++ b/Libraries/Network/XMLHttpRequestBase.js
@@ -179,6 +179,9 @@ class XMLHttpRequestBase {
       // async is default
       throw new Error('Synchronous http requests are not supported');
     }
+    if (!url) {
+      throw new Error('Cannot load an empty url');
+    }
     this._reset();
     this._method = method;
     this._url = url;
diff --git a/React/Base/RCTUtils.m b/React/Base/RCTUtils.m
index 48e1fea08..e6ebdb806 100644
--- a/React/Base/RCTUtils.m
+++ b/React/Base/RCTUtils.m
@@ -494,7 +494,11 @@ NSString *RCTBundlePathForURL(NSURL *URL)
     // Not a bundle-relative file
     return nil;
   }
-  return [path substringFromIndex:bundlePath.length + 1];
+  path = [path substringFromIndex:bundlePath.length];
+  if ([path hasPrefix:@"/"]) {
+    path = [path substringFromIndex:1];
+  }
+  return path;
 }
 
 BOOL RCTIsXCAssetURL(NSURL *imageURL)