From 74a190516bbe8da39400aab9f6ac8b2a2883e3ae Mon Sep 17 00:00:00 2001
From: Gary Borton <gary.borton@airbnb.com>
Date: Thu, 4 Oct 2018 12:08:11 -0700
Subject: [PATCH] [assets] Adds support for publicPath to enable serving assets
 from different locations.

---
 packages/metro-config/src/defaults/index.js    | 1 +
 packages/metro/src/Assets.js                   | 3 ++-
 packages/metro/src/DeltaBundler/Transformer.js | 1 +
 packages/metro/src/JSTransformer/worker.js     | 2 ++
 packages/metro/src/assetTransformer.js         | 1 +
 5 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/metro-config/src/defaults/index.js b/packages/metro-config/src/defaults/index.js
index 6c32cc04d6..a87563602f 100644
--- a/packages/metro-config/src/defaults/index.js
+++ b/packages/metro-config/src/defaults/index.js
@@ -79,6 +79,7 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
     postMinifyProcess: x => x,
     transformVariants: {default: {}},
     workerPath: 'metro/src/DeltaBundler/Worker',
+    publicPath: '/assets',
   },
   cacheStores: [
     new FileStore({
diff --git a/packages/metro/src/Assets.js b/packages/metro/src/Assets.js
index 5ab85a91cf..2aa89ad89f 100644
--- a/packages/metro/src/Assets.js
+++ b/packages/metro/src/Assets.js
@@ -177,8 +177,9 @@ async function getAssetData(
   localPath: string,
   assetDataPlugins: $ReadOnlyArray<string>,
   platform: ?string = null,
+  publicPath: ?string = '/assets',
 ): Promise<AssetData> {
-  let assetUrlPath = path.join('/assets', path.dirname(localPath));
+  let assetUrlPath = `${publicPath}/${path.dirname(localPath)}`;
 
   // On Windows, change backslashes to slashes to get proper URL path from file path.
   if (path.sep === '\\') {
diff --git a/packages/metro/src/DeltaBundler/Transformer.js b/packages/metro/src/DeltaBundler/Transformer.js
index 4ca88f0a6c..e1aa9200e9 100644
--- a/packages/metro/src/DeltaBundler/Transformer.js
+++ b/packages/metro/src/DeltaBundler/Transformer.js
@@ -48,6 +48,7 @@ class Transformer {
         enableBabelRCLookup: this._config.transformer.enableBabelRCLookup,
         minifierPath: this._config.transformer.minifierPath,
         optimizationSizeLimit: this._config.transformer.optimizationSizeLimit,
+        publicPath: this._config.transformer.publicPath,
       },
     };
 
diff --git a/packages/metro/src/JSTransformer/worker.js b/packages/metro/src/JSTransformer/worker.js
index aaf386319e..82bbcaf9b4 100644
--- a/packages/metro/src/JSTransformer/worker.js
+++ b/packages/metro/src/JSTransformer/worker.js
@@ -84,6 +84,7 @@ export type JsTransformerConfig = {|
   +enableBabelRCLookup: boolean,
   +minifierPath: string,
   +optimizationSizeLimit: number,
+  +publicPath: string,
 |};
 
 export type CustomTransformOptions = {[string]: mixed, __proto__: null};
@@ -179,6 +180,7 @@ class JsTransformer {
         // is used by other tooling, and this would affect it.
         inlineRequires: false,
         projectRoot: this._projectRoot,
+        publicPath: this._config.publicPath,
       },
       plugins: [],
       src: sourceCode,
diff --git a/packages/metro/src/assetTransformer.js b/packages/metro/src/assetTransformer.js
index 6892670ce3..bf5fd15f2a 100644
--- a/packages/metro/src/assetTransformer.js
+++ b/packages/metro/src/assetTransformer.js
@@ -36,6 +36,7 @@ async function transform(
     filename,
     assetDataPlugins,
     options.platform,
+    options.publicPath,
   );
 
   return {