Fetch image from internet, modify and insert to database in python

Question

I'm trying to save images from one webpage to the database of another.

Here is a cut down version of the code:

POSTER_SIZE = (200, 310)

LargePoster = urllib2.urlopen(PosterURL).read()
SmallPoster = LargePoster.resize(POSTER_SIZE, Image.ANTIALIAS)

conn = MySQLdb.connect(DB_HOST, DB_USER, DB_PASS, DB_NAME, charset='utf8')
cur = conn()
cur.execute("UPDATE `table` SET `poster`=%s WHERE `id`=%d", (SmallPoster, ID))
cur.close()

Note: I do NOT want to keep the aspect ratio, so do not suggest Image.thumbnail() unless it can stretch it.

As you can see, I retrieve the image using urlopen() and read() but it returns a string. I need this string to be of class Image so I can manipulate it using PIL/Pillow and then later have it output as a string so I can send it to the database.

I know for a fact that all the images are compressed using JPEG.

Updated code for Peter

LargePosterString = urllib2.urlopen(MovieMeta['poster']).read()
LargePosterImage = Image.open(StringIO(LargePosterString))

SmallPosterImage = LargePosterImage.resize(POSTER_SIZE, Image.ANTIALIAS)
SmallPosterString = StringIO()

Format = 'JPEG'
SmallPosterImage.save(SmallPosterString.getvalue(), Format)

Steen Schütt · Accepted Answer · 2014-01-15 20:24:53Z

2

The docs suggest various ways, of which the simplest is probably to make your string into a thing that looks like a file:

from PIL import Image
from StringIO import StringIO

LargeData = urllib2.urlopen(PosterURL).read()

# read data from string
LargePoster = Image.open(StringIO(LargeData))

# After editing the image, turn it back into a string
# for saving in the database:
result = StringIO()
format = 'JPEG' # or whatever you want
SmallPoster.save(result, format)
SmallPosterString = result.getvalue()

edited Jan 15, 2014 at 20:24

Steen Schütt

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answered Jan 15, 2014 at 17:58

Peter Westlake

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4 Comments

Steen Schütt Over a year ago

This is a one-time script, so basically any working approach will do. StringIO seems like a good idea. How do I turn my modified image into a string again so I can import it to the database? Can I just use str()?

Peter Westlake Over a year ago

You can use another StringIO. I've edited the answer to show it.

Steen Schütt Over a year ago

Okay, so your edited answer is a bit off, but by trial and error I managed to correct it myself. Thank you for your answer, it was very helpful :)

Peter Westlake Over a year ago

That'll teach me not to edit in a hurry! Thanks for correcting it.

Mike McMahon · Accepted Answer · 2014-01-15 18:02:40Z

1

So yes you are receiving a string, but have you looked at the string contents? What you have is likely a binary string containing the file contents. Which you should be pretty easily reconstructed into an image. In fact you could probably put that string (as long as it is treated as binary) directly into a blob object or similar and then reconstruct it in whatever is rendering the image.

Check out the parser class as part of the PIL ImageClass

This should be able to reconstruct an image from a stream. As long as your bytes are valid image bytes (JPEG should start with the JFIF identifier).

import ImageFile
fp = open("lena.pgm", "rb")
p = ImageFile.Parser()
while 1:
    s = fp.read(1024)
    if not s:
        break
    p.feed(s)

im = p.close()
im.save("copy.jpg")

With this example it is fair enough to assume you can just use the parser and pass it your "String"

answered Jan 15, 2014 at 18:02

Mike McMahon

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2 Comments

Steen Schütt Over a year ago

I have accepted Peter's answer because it was both shorter, simpler and didn't require any disk activity, but thank you for a working alternative :)

Mike McMahon Over a year ago

@TimeSheep this does not require disk activity either. This was a short example of how the parser works. Instead create p = ImageFile.Parser() and p.feed(your_web_string) should do the trick.

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