Re: OT? plpython2u

On 10/20/2016 12:52 PM, Nahum Castro wrote:
> Oh, Awesome.
>
> Thanks a lot.

FYI, I forgot to close the mem_file in the example I sent.

>
> Nahum.
>
> 2016-10-20 14:47 GMT-05:00 Adrian Klaver <adrian.klaver@aklaver.com
> <mailto:adrian.klaver@aklaver.com>>:
>
>     On 10/20/2016 12:03 PM, Nahum Castro wrote:
>
>
>
>         2016-10-20 13:06 GMT-05:00 Jonathan Rogers
>         <jrogers@socialserve.com <mailto:jrogers@socialserve.com>
>         <mailto:jrogers@socialserve.com <mailto:jrogers@socialserve.com>>>:
>
>
>             On 10/20/2016 01:14 PM, Nahum Castro wrote:
>             > Hello all.
>             >
>             > I need to process images on my database, they are stored
>         on a bytea column.
>             >
>             > The process consist on scaling and I have done this so far:
>             >
>             > CREATE OR REPLACE FUNCTION  ajustar(randstring bytea)
>             > RETURNS bytea AS
>             > $$
>             >     import PIL
>             >     from PIL import Image
>             >     basewidth = 300
>             >     img = randstring
>             >     wpercent = (basewidth/float(img.size[0]))
>             >     hsize = int((float(img.size[1])*float(wpercent)))
>             >     img = img.resize((basewidth,hsize), PIL.Image.ANTIALIAS)
>             >
>             >     return img
>             > $$
>             >   LANGUAGE 'plpython2u' VOLATILE;
>
>             As you probably know, Postgres procedural languages are
>         server-side
>             extensions and therefore have nothing to do with psycopg,
>         which is a
>             client-side library.
>
>         ​Thanks, but rather than help in plpython is how to pass the
>         variable
>         bytea from postgres to an image in python.
>
>
>             >
>             > The objective of this pl is read the bytea from the
>         database, scale,
>             > then replace the scaled image in the database, but I don't
>         know  what
>             > type use to pass to the variable img.
>
>             AFAICT, if you pass a bytea value to a plpythonu function,
>         it will
>             receive a Python str object.
>
>
>         ​That is where i get confused, what is stored in the db is in
>         bytea, how
>         I do to transform in a str?​
>
>
>     It is done for you:
>
>     https://www.postgresql.org/docs/9.5/static/plpython-data.html#AEN65498
>     <https://www.postgresql.org/docs/9.5/static/plpython-data.html#AEN65498>
>
>     "PostgreSQL bytea is converted to Python str in Python 2 and to
>     bytes in Python 3. In Python 2, the string should be treated as a
>     byte sequence without any character encoding.
>
>     When the PostgreSQL return type is bytea, the return value will be
>     converted to a string (Python 2) or bytes (Python 3) using the
>     respective Python built-ins, with the result being converted to bytea."
>
>
>     So something like this:
>
>     CREATE OR REPLACE FUNCTION public.ajustar(randstring bytea)
>      RETURNS bytea
>      LANGUAGE plpythonu
>     AS $function$
>         from io import BytesIO
>         import PIL
>         from PIL import Image
>         basewidth = 300
>         mem_file = BytesIO()
>         mem_file.write(randstring)
>         img = Image.open(mem_file)
>         wpercent = (basewidth/float(img.size[0]))
>         hsize = int((float(img.size[1])*float(wpercent)))
>         img = img.resize((basewidth,hsize), PIL.Image.ANTIALIAS)
>
>         return img
>     $function$
>
>
>     postgres@test=# select ajustar(barcode) from pict_test where
>     full_upc = '744835000544';
>                                                                  ajustar
>
----------------------------------------------------------------------------------------------------------------------------------
>
>
\x3c50494c2e496d6167652e496d61676520696d616765206d6f64653d5247422073697a653d333030783230392061742030783746393343314532333635303e
>     (1 row)
>
>
>     barcode are small png's in this case.
>
>
>
>
>
>             >
>             > This is the query.
>             > update personal set foto=ajustar(encode(foto, 'hex')::bytea);
>
>             Why are you encoding the binary data into a textual
>         representation? What
>             image format is stored in column "foto"? Depending on the
>         format, you
>             probably want to use one of these constructors in function
>         "ajustar":
>
>
>         ​Sorry I forgot, all images are in jpeg​ format.
>
>
>
>
>         http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.fromstring
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.fromstring>
>
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.fromstring
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.fromstring>>
>
>
>         http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.open
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.open>
>
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.open
>         <http://pillow.readthedocs.io/en/3.4.x/reference/Image.html?highlight=Image#PIL.Image.open>>
>
>
>         ​Again thanks.​
>         Nahum
>
>
>
>             --
>             Jonathan Rogers
>             Socialserve.com by Emphasys Software
>             jrogers@emphasys-software.com
>         <mailto:jrogers@emphasys-software.com>
>         <mailto:jrogers@emphasys-software.com
>         <mailto:jrogers@emphasys-software.com>>
>
>             --
>             Jonathan Rogers
>             Socialserve.com by Emphasys Software
>             jrogers@emphasys-software.com
>         <mailto:jrogers@emphasys-software.com>
>         <mailto:jrogers@emphasys-software.com
>         <mailto:jrogers@emphasys-software.com>>
>
>
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>
>
>
>         --
>         *Nahum Castro González*
>         Blvd. Perdigón 214, Brisas del Lago.
>         CP 37207
>         León, Guanajuato, México
>         Tel (477)1950304
>         Cel (477)1274694
>
>
>
>     --
>     Adrian Klaver
>     adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
>
>
>
>
> --
> *Nahum Castro González*
> Blvd. Perdigón 214, Brisas del Lago.
> CP 37207
> León, Guanajuato, México
> Tel (477)1950304
> Cel (477)1274694


--
Adrian Klaver
adrian.klaver@aklaver.com