feat(preprocessor): Allow preprocessor to handle binary files (#3054)

lib/preprocessor.js

@@ -98,12 +98,7 @@ function createPreprocessor (config, basePath, injector) {
         var preprocessorNames = []
         for (var i = 0; i < patterns.length; i++) {
           if (mm(file.originalPath, patterns[i], {dot: true})) {
-            if (thisFileIsBinary) {
-              log.warn('Ignoring preprocessing (%s) %s because it is a binary file.',
-                config[patterns[i]].join(', '), file.originalPath)
-            } else {
-              preprocessorNames = combineLists(preprocessorNames, config[patterns[i]])
-            }
+            preprocessorNames = combineLists(preprocessorNames, config[patterns[i]])
           }
         }
 
@@ -125,7 +120,12 @@ function createPreprocessor (config, basePath, injector) {
           }
 
           instances[name] = p
-          preprocessors.push(p)
+          if (!thisFileIsBinary || p.handleBinaryFiles) {
+            preprocessors.push(p)
+          } else {
+            log.warn('Ignored preprocessing %s because %s has handleBinaryFiles=false.',
+              file.originalPath, name)
+          }
         })
 
         nextPreprocessor(null, thisFileIsBinary ? buffer : buffer.toString())

test/unit/preprocessor.spec.js

@@ -272,7 +272,7 @@ describe('preprocessor', () => {
       thirdCallback('error')
     })
 
-    it('should tbrow after 3 retries', (done) => {
+    it('should throw after 3 retries', (done) => {
       var injector = new di.Injector([{}, emitterSetting])
 
       var pp = m.createPreprocessor({'**/*.js': []}, null, injector)
@@ -288,7 +288,7 @@ describe('preprocessor', () => {
     })
   })
 
-  it('should not preprocess binary files', (done) => {
+  it('should not preprocess binary files by default', (done) => {
     var fakePreprocessor = sinon.spy((content, file, done) => {
       done(null, content)
     })
@@ -310,6 +310,29 @@ describe('preprocessor', () => {
     })
   })
 
+  it('should preprocess binary files if handleBinaryFiles=true', (done) => {
+    const fakePreprocessor = sinon.spy((content, file, done) => {
+      done(null, content)
+    })
+    fakePreprocessor.handleBinaryFiles = true
+
+    var injector = new di.Injector([{
+      'preprocessor:fake': ['factory', function () { return fakePreprocessor }]
+    }, emitterSetting])
+
+    pp = m.createPreprocessor({'**/*': ['fake']}, null, injector)
+
+    const file = {originalPath: '/some/photo.png', path: 'path'}
+
+    pp(file, (err) => {
+      if (err) throw err
+
+      expect(fakePreprocessor).to.have.been.calledOnce
+      expect(file.content).to.be.an.instanceof(Buffer)
+      done()
+    })
+  })
+
   it('should not preprocess binary files with capital letters in extension', (done) => {
     var fakePreprocessor = sinon.spy((content, file, done) => {
       done(null, content)