On 8/26/10 4:28 PM, Navkirat Singh wrote:
On 27-Aug-2010, at 2:48 AM, MRAB wrote:
On 26/08/2010 21:47, Navkirat Singh wrote:
On 27-Aug-2010, at 1:57 AM, MRAB wrote:
On 26/08/2010 21:14, Navkirat Singh wrote:
On 27-Aug-2010, at 1:32 AM, Dave Angel wrote:
Navkirat Singh wrote:
Hey guys,
I am programming a webserver, I receive a jpeg file with the POST
method.The file (.jpeg) is encoded in bytes, I parse the bytes by
decoding them to a string. I wanted to know how i could write the
file (now a string) as a jpeg image on disk. When I try to encode the
same string to a bytes and write them in binary format to disk, the
file is not recognized as jpeg. I would be grateful if someone could
help me with this.
Regards,
Nav
If by "decoding them to a string" you mean converting to Unicode, then
you've already trashed the data. That's only valid if the bytes had
been encoded from valid Unicode characters, and then only if you use
the corresponding decoding technique.
If you mean some other decoding, then the question is meaningless
without telling us just what the decoding is, preferably with some code.
It also might be useful to know what version of Python you're using,
when you post the code.
DaveA
Dave,
I am using Python3 and I receive a byte stream with a jpeg attached sent
by the web browser over a socket, which looks like this:
b': image/jpeg\r\nAccept: text/*\r\nReferer:
http://127.0.0.1:8001/\r\nAccept-Language: en-us\r\nAccept-Encoding:
gzip, deflate\r\nContent-Length: 91783\r\nConnection:
keep-alive\r\n\r\n\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00\x84\x00\x03\x02\x02\x03\x02\x02\x03\x03\x03\x03\x04\x03\x03\x04\x05\x08\x05\x05\x04\x04\x05\n\x07\x07\x06\x08\x0c\n\x0c\x0c\x0b\n\x0b\x0b\r\x0e\x12\x10\r\x0e\x11\x0e\x0b\x0b\x10\x16\x10\x11\x13\x14\x15\x15\x15\x0c\x0f
From the above, I need to:
a) Split the header content from the image content, which comes after
the keep-alive\r\n\r\n part
b) Then write the image content to file for further use as a jpeg.
Try:
image = header.split(b'keep-alive\r\n\r\n', 1)[-1]
open(image_path, 'wb').write(image)
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I think I forgot to mention that the original is a stream of bytes decoded
using ISO-8859-1 as utf-8 trhrew errors (lack of knowlegdge again).
@MRAB - the split() method in python 3 works only on strings and throws an
error if I try to use bytes
All i can say is that it works for me:
header = b': image/jpeg\r\nAccept: text/*\r\nReferer:
http://127.0.0.1:8001/\r\nAccept-Language: en-us\r\nAccept-Encoding: gzip,
deflate\r\nContent-Length: 91783\r\nConnection:
keep-alive\r\n\r\n\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00\x84\x00\x03\x02\x02\x03\x02\x02\x03\x03\x03\x03\x04\x03\x03\x04\x05\x08\x05\x05\x04\x04\x05\n\x07\x07\x06\x08\x0c\n\x0c\x0c\x0b\n\x0b\x0b\r\x0e\x12\x10\r\x0e\x11\x0e\x0b\x0b\x10\x16\x10\x11\x13\x14\x15\x15\x15\x0c\x0f'
image = header.split(b'keep-alive\r\n\r\n', 1)[-1]
image
b'\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00\x84\x00\x03\x02\x02\x03\x02\x02\x03\x03\x03\x03\x04\x03\x03\x04\x05\x08\x05\x05\x04\x04\x05\n\x07\x07\x06\x08\x0c\n\x0c\x0c\x0b\n\x0b\x0b\r\x0e\x12\x10\r\x0e\x11\x0e\x0b\x0b\x10\x16\x10\x11\x13\x14\x15\x15\x15\x0c\x0f'
What error did you get?
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Hi MRAB,
Here is the error:
b = b'asdf'
type(b)
<class 'bytes'>
s = b.split(':')
Traceback (most recent call last):
File "<stdin>", line 1, in<module>
TypeError: Type str doesn't support the buffer API
Follow MRAB's example. You need to use a bytes object for the *argument*, too.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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