largeFileCallback support

README.md

@@ -57,6 +57,15 @@ You can define local directories (globs supported) or URLs.
 
 Sets a max file size (in bytes) for inlined images. Set to `0` to disable size checking.
 
+#### largeFileCallback
+
+* Type: `function`
+* Default: undefined
+* Example: `function (file) { console.log('big file found:', file.path); return file.path }`
+* Required: `false`
+
+Allows you to act on large files and change the url if you'd like. Make sure you have `strict` set to `false` when using this.
+
 #### b64Svg
 
 * Type: `bool`

index.js

@@ -10,6 +10,7 @@ const DEFAULTS = {
   maxFileSize: 10240,
   b64Svg: false,
   strict: false,
+  largeFileCallback: undefined,
 };
 
 const loop = (cb) => {

lib/image.js

@@ -80,6 +80,11 @@ function getDataUriMapping(urls = [], options = {}) {
       const file = await resolve(url, options);
       if (file && file.mime && /image/.test(file.mime)) {
         result[url] = await getDataUri(file, options);
+      } else if (options.largeFileCallback) {
+        const largeFile = await resolve(url, {...options, maxFileSize: 0});
+        if (largeFile && largeFile.mime && /image/.test(largeFile.mime)) {
+          result[url] = await options.largeFileCallback(largeFile);
+        }
       }
 
       return result;

test/fixtures/styles/big.modified.css

@@ -0,0 +1,3 @@
+.big {
+    background-image: url('https://cdn.example.com/images/blank.gif');
+}

test/test.js

@@ -59,6 +59,14 @@ describe('postcss-image-inliner', () => {
     test('big.css', 'big.css', {maxFileSize: 1}, done);
   });
 
+  it('should trigger callback on too big images', (done) => {
+    const largeFileCallback = (file) => {
+      return file.path.replace('http://localhost:3000/', 'https://cdn.example.com/');
+    };
+
+    test('big.css', 'big.modified.css', {maxFileSize: 1, largeFileCallback}, done);
+  });
+
   it('should handle multiple background images', (done) => {
     test('multi.in.css', 'multi.out.css', {}, done);
   });