Re: [gpsd-users] Python client library modification.

[Eric]

Cuningan Re Set <address@hidden>:
> Hello all, today i am not going to call for help, today i want to share
> with you a little modification i have done on the Python Library for gpsd.
> The default library, if you call gps.next() or gps.read() it will block
> until any data arrive from the daemon, it will lock waiting for any data to
> come from the socket on the method read() of the class gpscommon on the
> file client.py (around line 86 ), the call to this method is produced from
> the method next() or read() of the class gps on the file gps.py (around
> line 310 to 330 ).
> 
> I found that if GPSd does not have any valid data from the physical GPS it
> will not transmit any data to the client more than what device it have
> connected and nothing more, you can see that connecting with #cgps, you can
> see that there is no more JSON data after the device information, but with
> #gpsmon you can see that the gps is throwing NMEA data.
> 
> What i have done is avoiding the socket locking in method read of the class
> gpscommon, to do this i have modified the gps.__init__() method to add a
> timeout argument with default to 30 seconds, this argument is passed to
> gpscommon.__init__() that passed it to gpscommon.connect() and create a
> socket with the timeout we selected or 30 seconds by default.
> 
> Now, when you call gps.next() to fill the gpsd object with data it will
> block for a maximun of the timeout you especified or 30 seconds by default,
> if failed it will return -1 that will raise and exception on the gps.next()
> method on file gps.py (around line 310)
> 
> To avoid crashing your program you can do something like:
> 
> try:
>    gpsd.next()
> except(StopIteration):
>    pass
> 
> if gpsd.waiting:
>    #If there is valid data do ...
> else:
>    #If there is not valid data do...
> 
> In attached file is the complete Python library, make full copy of your
> gps/ folder first!!.
> Untar it into /usr/lib/python2.7/dist-packages#tar -zxvf
> gps_modificado_3.14.tgz
> 
> If you can not download it from the email you can download it from my Box
> Cloud here:
> 
> https://app.box.com/s/xfanenhr94fh6pyfnmy7uedw4zc33qlf
> 
> Thanks, maybe this can help someone more.

Can you express this as a patch against the stock library?  If the timeout
argument is optional I might take it.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>