Allow custom importers.

src/extract.js

@@ -95,7 +95,7 @@ export function extract(rendered, { compileOptions = {}, extractOptions = {} } =
   .then(({ compiledFiles, orderedFiles }) => {
     const parsedDeclarations = parseFiles(compiledFiles);
     const extractions = processFiles(orderedFiles, compiledFiles, parsedDeclarations, pluggable);
-    const importer = makeImporter(extractions, includedFiles, includedPaths);
+    const importer = makeImporter(extractions, includedFiles, includedPaths, compileOptions.importer);
     const extractionCompileOptions = makeExtractionCompileOptions(compileOptions, entryFilename, extractions, importer);
 
     return sass.renderAsync(extractionCompileOptions)
@@ -117,7 +117,7 @@ export function extractSync(rendered, { compileOptions = {}, extractOptions = {}
   const { compiledFiles, orderedFiles } = loadCompiledFilesSync(includedFiles, entryFilename, compileOptions.data);
   const parsedDeclarations = parseFiles(compiledFiles);
   const extractions = processFiles(orderedFiles, compiledFiles, parsedDeclarations, pluggable);
-  const importer = makeSyncImporter(extractions, includedFiles, includedPaths);
+  const importer = makeSyncImporter(extractions, includedFiles, includedPaths, compileOptions.importer);
   const extractionCompileOptions = makeExtractionCompileOptions(compileOptions, entryFilename, extractions, importer);
 
   sass.renderSync(extractionCompileOptions);

src/importer.js

@@ -1,3 +1,4 @@
+import Promise from 'bluebird';
 import path from 'path';
 import { normalizePath, makeAbsolute } from './util';
 
@@ -15,9 +16,14 @@ function findImportedPath(url, prev, includedFilesMap, includedPaths) {
   }
 
   for(let i = 0; i < candidateFromPaths.length; i++) {
-    // Get normalize absolute candidate from path
+    let candidatePath;
     let candidateFromPath = normalizePath(makeAbsolute(candidateFromPaths[i]));
-    let candidatePath = path.posix.join(candidateFromPath, url);
+    if (path.isAbsolute(url)) {
+      candidatePath = normalizePath(url);
+    } else {
+      // Get normalize absolute candidate from path
+      candidatePath = path.posix.join(candidateFromPath, url);
+    }
 
     if(includedFilesMap[candidatePath]) {
       return candidatePath;
@@ -26,7 +32,12 @@ function findImportedPath(url, prev, includedFilesMap, includedPaths) {
       let indexOfBasename = url.lastIndexOf(urlBasename);
       let partialUrl = `${url.substring(0, indexOfBasename)}_${urlBasename}`;
 
-      candidatePath = path.posix.join(candidateFromPath, partialUrl);
+      if (path.isAbsolute(partialUrl)) {
+        candidatePath = normalizePath(partialUrl);
+      } else {
+        candidatePath = path.posix.join(candidateFromPath, partialUrl);
+      }
+
       if(includedFilesMap[candidatePath]) {
         return candidatePath;
       }
@@ -76,13 +87,45 @@ function getIncludedFilesMap(includedFiles) {
  * Create an importer that will resolve @import directives with the injected
  * data found in provided extractions object
  */
-export function makeImporter(extractions, includedFiles, includedPaths) {
+export function makeImporter(extractions, includedFiles, includedPaths, customImporter) {
   const includedFilesMap = getIncludedFilesMap(includedFiles);
 
   return function(url, prev, done) {
     try {
-      const result = getImportResult(extractions, url, prev, includedFilesMap, includedPaths);
-      done(result);
+      let promise = Promise.resolve();
+      if (customImporter) {
+        promise = new Promise(resolve => {
+          if (Array.isArray(customImporter)) {
+            const promises = [];
+            customImporter.forEach(importer => {
+              const thisPromise = new Promise(res => {
+                const modifiedUrl = importer(url, prev, res);
+                if (modifiedUrl !== undefined) {
+                  res(modifiedUrl);
+                }
+              });
+              promises.push(thisPromise);
+            })
+            Promise.all(promises).then(results => {
+              resolve(results.find(item => item !== null));
+            });
+          } else {
+            const modifiedUrl = customImporter(url, prev, resolve);
+            if (modifiedUrl !== undefined) {
+              resolve(modifiedUrl);
+            }
+          }
+        });
+      }
+      promise.then(modifiedUrl => {
+        if (modifiedUrl && modifiedUrl.file) {
+          url = modifiedUrl.file;
+        }
+        const result = getImportResult(extractions, url, prev, includedFilesMap, includedPaths);
+        done(result);
+      }).catch(err => {
+        done(err);
+      });
     } catch(err) {
       done(err);
     }
@@ -93,11 +136,24 @@ export function makeImporter(extractions, includedFiles, includedPaths) {
  * Create a synchronous importer that will resolve @import directives with the injected
  * data found in provided extractions object
  */
-export function makeSyncImporter(extractions, includedFiles, includedPaths) {
+export function makeSyncImporter(extractions, includedFiles, includedPaths, customImporter) {
   const includedFilesMap = getIncludedFilesMap(includedFiles);
 
   return function(url, prev) {
     try {
+      if (customImporter) {
+        let modifiedUrl;
+        if (Array.isArray(customImporter)) {
+          customImporter.forEach(importer => {
+            modifiedUrl = modifiedUrl || importer(url, prev);
+          })
+        } else {
+          modifiedUrl = customImporter(url, prev);
+        }
+        if (modifiedUrl && modifiedUrl.file) {
+          url = modifiedUrl.file;
+        }
+      }
       const result = getImportResult(extractions, url, prev, includedFilesMap, includedPaths);
       return result;
     } catch(err) {

test/include.js

@@ -6,6 +6,7 @@ const { normalizePath } = require('../src/util');
 const includeRootFile = path.join(__dirname, 'sass', 'include', 'root.scss');
 const includeRoot2File = path.join(__dirname, 'sass', 'include', 'root2.scss');
 const includeRoot3File = path.join(__dirname, 'sass', 'include', 'root3.scss');
+const includeRoot4File = path.join(__dirname, 'sass', 'include', 'root4.scss');
 const includeSubFile = path.join(__dirname, 'sass', 'include', 'sub', 'included.scss');
 const includeSubFile2 = path.join(__dirname, 'sass', 'include', 'sub', 'included2.scss');
 const includeSubDir = path.join(__dirname, 'sass', 'include', 'sub');
@@ -266,4 +267,64 @@ describe('include', () => {
       });
     });
   });
+
+  describe('custom importer', () => {
+    const getNewUrl = url => url === 'foo' ? './included.scss' : url;
+
+    describe('sync', () => {
+      it('should extract all variables', () => {
+        const rendered = renderSync({ file: includeRoot4File, includePaths: [includeSubDir], importer: url => ({ file: getNewUrl(url) }) });
+        verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+      });
+    });
+
+    describe('async', () => {
+      it('should extract all variables', () => {
+        return render({ file: includeRoot4File, includePaths: [includeSubDir], importer: (url, prev, done) => { done({ file: getNewUrl(url) }); } })
+        .then(rendered => {
+          verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+        });
+      });
+    });
+  });
+
+  describe('array of custom importers', () => {
+    const getNewUrl = url => url === 'foo' ? './included.scss' : url;
+
+    describe('sync', () => {
+      it('should extract all variables', () => {
+        const rendered = renderSync({ file: includeRoot4File, includePaths: [includeSubDir], importer: [() => null, url => ({ file: getNewUrl(url) })] });
+        verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+      });
+    });
+
+    describe('async', () => {
+      it('should extract all variables', () => {
+        return render({ file: includeRoot4File, includePaths: [includeSubDir], importer: [(url, prev, done) => { done(null); }, (url, prev, done) => { done({ file: getNewUrl(url) }); }] })
+        .then(rendered => {
+          verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+        });
+      });
+    });
+  });
+
+  describe('absolute include path', () => {
+    const getNewUrl = url => url === 'foo' ? path.join(__dirname, 'sass', 'include', 'sub', 'included.scss') : url;
+
+    describe('sync', () => {
+      it('should extract all variables', () => {
+        const rendered = renderSync({ file: includeRoot4File, importer: url => ({ file: getNewUrl(url) }) });
+        verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+      });
+    });
+
+    describe('async', () => {
+      it('should extract all variables', () => {
+        return render({ file: includeRoot4File, importer: (url, prev, done) => { done({ file: getNewUrl(url) }); } })
+        .then(rendered => {
+          verifyFunctions(rendered, includeRoot4File, SUB_INCLUDED_COLOR, SUB_INCLUDED2_COLOR, includeSubFile,  includeSubFile2);
+        });
+      });
+    });
+  });
 });

test/sass/include/root4.scss

@@ -0,0 +1,2 @@
+@import 'foo';
+$color: $includedColor;