Re: [Py4j-users] Question about Python bytearray and Java byte[]

[Alex G. <ale...@ne...>]

14.10.2012 22:25, kur...@co... kirjoitti:
> Hello all,
>
> First off I want to say thanks to the developers of this project.  We 
> are a python shop using py4j to work with a vendor that provides us 
> .class and .so library interfaces.  For our Mac and Windows developers 
> we use the py4j package to talk to the .class driver otherwise we use 
> Python's ctypes to interact with their native unix .so library.
>
> So my question relates to bytearrays in Python.  I have a 
> straightforward Gateway java class attached below that interacts with 
> our vendor's code.  In red I've highlighted where my issues are.  On 
> the python side I'm doing this:
>
>     code = gateway.ttsRequestBuffer(self.server_ip, self.server_port, 
> text, self.voice, fmt, bFirst, bAll)
>
>     buf = self.gw.ttsGetBufferData() if (code == 
> driver_h.TTS_RESULT_SUCCESS) else None
>
>
> buf is a Python bytearray.  The Java Gateway is returning byte[] which 
> in this case is the binary of a short .wav clip. Attached are two 
> files, each one is the hexdump of the short .wav file.  The unix one 
> is generated by using Python's ctype library and the Java uses py4j to 
> talk to our vendor's library.
>
>
> Java using py4j:
>
> 00000000  52 49 46 46 00 1c 02 00  57 41 56 45 66 6d 74 20 
>  |RIFF....WAVEfmt |
>
> 00000010  12 00 00 00 01 00 01 00  40 1f 00 00 80 3e 00 00 
>  |........@....>..|
>
>
> Unix using ctypes:
>
> 00000000  52 49 46 46 da 1c 02 00  57 41 56 45 66 6d 74 20 
>  |RIFF....WAVEfmt |
>
> 00000010  12 00 00 00 01 00 01 00  40 1f 00 00 80 3e 00 00 
>  |........@....>..|
>
>
> These are the first 32 bytes of the files.  This occurs throughout and 
> doesn't seem to be random, take a look at the file differences between 
> the two attachments, it's very strange. And I did test 
> writeToTempfile() to verify it wasn't on the Java side.  The problem 
> definitely is between returning the byte[] buffer on the Java side and 
> the reading of that bytearray on Python side.
>
> We would love to get this working so our Mac and Windows developers 
> can work with our vendor's library.
>
> Any ideas would be helpful,
> Thanks!
> Kurt
>
This problem was caused by the unicode-based serialization of bytes in 
the latest release and has been fixed in development. See here: 
https://github.com/bartdag/py4j/issues/91
>
> *******************************
>
>
> import java.lang.String;
>
> import java.io.IOException;
>
>
> import py4j.GatewayServer;
>
> import voiceware.libttsapi;  // This is our vendors library
>
>
> class Gateway
>
> {
>
> private libttsapi m_ttsapi;
>
>
> /* Default c'tor create libttsapi instance used by our gateway to
>
>      * communicate with our python app */
>
> public Gateway()
>
>     {
>
>         m_ttsapi = new libttsapi();
>
>     }
>
> /* python client will call this and get socket error if gateway not up */
>
> public boolean get_gw_status()
>
>     {
>
> return true;
>
>     }
>
>
> /* server status port is default to 7777 */
>
> public int ttsRequestStatus(String ipaddr, int status_port)
>
>     {
>
> int rc;
>
> try
>
>         {
>
>             rc = m_ttsapi.ttsRequestStatus(ipaddr, status_port);
>
>         }
>
> catch (IOException e)
>
>         {
>
>             rc = -9;
>
>         }
>
> return rc;
>
>     }
>
>
> /* request to generate buffer from tts server */
>
> public int ttsRequestBuffer(String ipaddr, int port, String text, int 
> speakerId,
>
> int bufformat, int reqfirst, int oneframe)
>
>     {
>
> int rc;
>
> try
>
>         {
>
>             rc = m_ttsapi.ttsRequestBuffer(ipaddr, port, text, speakerId,
>
>   bufformat, reqfirst, oneframe);
>
>         }
>
> catch (IOException e)
>
>         {
>
>             rc = -9;
>
>         }
>
> return rc;
>
>     }
>
>
> /* Typically after if ttsRequestBuffer() successfull to get buffer 
> contents */
>
> public byte[] ttsGetBufferData()
>
>     {
>
> return m_ttsapi.szVoiceData;
>
>     }
>
>
> /* main entry point for Gateway */
>
> public static void main(String[] args)
>
>     {
>
> GatewayServer gatewayServer = new GatewayServer(new Gateway());
>
> gatewayServer.start();
>
>     }
>
> }
>
>
>
>
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