Feature/encrypted files

README.md

@@ -306,6 +306,14 @@ Effectively implemented as:
 return dosDateTimeToDate(this.lastModFileDate, this.lastModFileTime);
 ```
 
+#### isEncrypted()
+
+Effectively implemented as:
+
+```js
+return this.generalPurposeBitFlag & 0x001;
+```
+
 ### Class: RandomAccessReader
 
 This class is meant to be subclassed by clients and instantiated for the `fromRandomAccessReader()` function.
@@ -408,8 +416,9 @@ By extension the following zip file fields are ignored by this library and not p
 
 ### No Encryption Support
 
-Currently, the presence of encryption is not even checked,
-and encrypted zip files will cause undefined behavior.
+This library is using zlib to unzip, and as [zlib doesn't support encryption](http://www.zlib.net/zlib_faq.html#faq38), neither does yauzl.
+When trying to read an encrypted file using `openReadStream`, its callback will be called with an error.
+Yauzl does emit `entry` events for encrypted files though, in case you need to be aware of their existence. You can call `entry.isEncrypted()` to find out if an emitted entry is encrypted.
 
 ### Local File Headers Are Ignored
 

index.js

@@ -275,6 +275,7 @@ ZipFile.prototype.readEntry = function() {
       // 46 - File name
       var isUtf8 = entry.generalPurposeBitFlag & 0x800
       entry.fileName = bufferToString(buffer, 0, entry.fileNameLength, isUtf8);
+      var isEncrypted = entry.isEncrypted();
 
       // 46+n - Extra field
       var fileCommentStart = entry.fileNameLength + entry.extraFieldLength;
@@ -375,7 +376,7 @@ ZipFile.prototype.readEntry = function() {
       }
 
       // validate file size
-      if (entry.compressionMethod === 0) {
+      if (entry.compressionMethod === 0 && !isEncrypted) {
         if (entry.compressedSize !== entry.uncompressedSize) {
           var msg = "compressed/uncompressed size mismatch for stored file: " + entry.compressedSize + " != " + entry.uncompressedSize;
           return emitErrorAndAutoClose(self, new Error(msg));
@@ -439,6 +440,11 @@ ZipFile.prototype.openReadStream = function(entry, callback) {
       } else {
         return callback(new Error("unsupported compression method: " + entry.compressionMethod));
       }
+
+      if (entry.isEncrypted()) {
+        return callback(new Error("File is encrypted, and cannot be read"));
+      }
+
       var fileDataStart = localFileHeaderEnd;
       var fileDataEnd = fileDataStart + entry.compressedSize;
       if (entry.compressedSize !== 0) {
@@ -490,6 +496,9 @@ function Entry() {
 Entry.prototype.getLastModDate = function() {
   return dosDateTimeToDate(this.lastModFileDate, this.lastModFileTime);
 };
+Entry.prototype.isEncrypted = function() {
+  return this.generalPurposeBitFlag & 0x001;
+};
 
 function dosDateTimeToDate(date, time) {
   var day = date & 0x1f; // 1-31

test/test.js

@@ -65,17 +65,27 @@ listZipFiles(path.join(__dirname, "success")).forEach(function(zipfilePath) {
           if (timestamp > new Date()) throw new Error(messagePrefix + "timestamp in the future: " + timestamp);
           var fileNameKey = entry.fileName.replace(/\/$/, "");
           var expectedContents = expectedArchiveContents[fileNameKey];
-          if (expectedContents == null) {
-            throw new Error(messagePrefix + "not supposed to exist");
-          }
           delete expectedArchiveContents[fileNameKey];
           if (entry.fileName !== fileNameKey) {
             // directory
+            if (expectedContents == null) {
+              throw new Error(messagePrefix + "not supposed to exist");
+            }
+
             console.log(messagePrefix + "pass");
+
             zipfile.readEntry();
           } else {
             zipfile.openReadStream(entry, function(err, readStream) {
-              if (err) throw err;
+              if (err) {
+                if (expectedContents == null) {
+                  console.log(messagePrefix + "pass");
+                  // Expected error. Skip to next file
+                  return zipfile.readEntry();
+                } else {
+                  throw err;
+                }
+              }
               var buffers = [];
               readStream.on("data", function(data) {
                 buffers.push(data);