Add support read hook and implement webAPI based read hook

[hellais]

Based on discussion and feedback from @AidasK in #42

[hellais]

I can't run the unittests locally so I am hoping this will kick off the travis unittest.

[AidasK]

test FlowFile functions should get extension FAILED - fails, because you have deleted getExtension method. It should not be hard to launch tests locally, you only need to install npm. Please ask if you have any serious questions.

[hellais]

I believe the above error is now fixed. What is the status on getting this merged into upstream?

[evilaliv3]

@AidasK can you provide us a feedback for the possibility to merge it and for a tentative release schedule?

[AidasK]

Is read defined?

[evilaliv3]

yes it has the default you suggested:

      read: webAPIFileRead,

that is:

 /**
  * Default read function using the webAPI
  *
  * @function webAPIFileRead(chunk, startByte, endByte, fileType)
  *
  */
 function webAPIFileRead(chunk, startByte, endByte, fileType) {
   var function_name = (chunk.fileObj.file.slice ? 'slice' :
     (chunk.fileObj.file.mozSlice ? 'mozSlice' :
       (chunk.fileObj.file.webkitSlice ? 'webkitSlice' :
         'slice')));
   chunk.readFinished(chunk.fileObj.file[function_name](startByte, endByte, fileType));
 }

[AidasK]

read -> var read ?

[evilaliv3]

an other time this is a code pattern (https://github.com/shichuan/javascript-patterns/blob/master/general-patterns/single-var-pattern.html) but given that you do not use it in other parts of the code i will change it.

[AidasK]

Sorry, haven't noticed comma in line above. I just try to follow google style guide and to be consistent.

[AidasK]

Could you also update documentation? It would be great to have an example, how you are using this for compression and encryption. Thanks!

[AidasK]

comma might cause a fata error for IE browsers

[evilaliv3]

k, i'm removing it.

[evilaliv3]

this has been integrated a lot of time ago by means of a different pull request.