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Now each time I save the picture which is plotted by 'matplotlib' on hard disk and then upload it to field.binary() filed;

I want to know whether I could save the picture into field.binary() filed when it was plotted immediately.

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Author Best Answer

hi Axel, thanks for your reply; I have made some try according to your advice but still failed; my main code is as below:

....

picture=fields.binary()

....

plt.figure(figsize=(8.2, 6))

plt.bar(xTem, aa, width=0.35, facecolor='lightskyblue', edgecolor='white', label='aa') xTem = [x + 0.35 for x in xTem] plt.bar(xTem, Aa, width=0.35, facecolor='yellowgreen', edgecolor='white', label='Aa')

plt.savefig('d:\a1.png')

pic_data = open('d:\a1.png', 'rb').read()

self.write({'picture': base64.encodestring(pic_data)})


These code run well, but I  should save it to hard disk first and then upload; 


how shall I "save it into the binary fields"?

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that's because you are saving it to the disk and it's not needed, savefig could handle a file like object as states http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.savefig

you could do:

try:

from cStringIO import StringIO

except ImportError:

from StringIO import StringIO

pic_data = StringIO()

plt.savefig(pic_data)

self.write({'picture': base64.encodestring(pic_data.getvalue())})

Author

thanks a lot; it is very useful.

Author

but some time I get error as below(not each time, and i don;t know whether it has relationship with the new code.):

Traceback (most recent call last):

File "D:\programs\anaconda2\lib\SocketServer.py", line 596, in process_request_thread

self.finish_request(request, client_address)

File "D:\programs\anaconda2\lib\SocketServer.py", line 331, in finish_request

self.RequestHandlerClass(request, client_address, self)

File "D:\programs\anaconda2\lib\SocketServer.py", line 654, in __init__

self.finish()

File "D:\programs\anaconda2\lib\SocketServer.py", line 713, in finish

self.wfile.close()

File "D:\programs\anaconda2\lib\socket.py", line 283, in close

self.flush()

File "D:\programs\anaconda2\lib\socket.py", line 307, in flush

self._sock.sendall(view[write_offset:write_offset+buffer_size])

error: [Errno 10053]

Best Answer

Hi @vx2008

just get the image value data as a base64 encoded string to save it into the binary fields and you will be ok

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