I am resizing images client side before sending them to my flask app.
The resized image, which is drawn into a canvas to be resized, is sent via a POST request.
In my app the image is decoded via base64:
def resize_image(item):
content = item.split(';')[1]
image_encoded = content.split(',')[1]
body = base64.decodestring(image_encoded.encode('utf-8'))
return body
The imagedata is stored as type String in the body variable. I can save the data to my local machine and it works:
filename = 'some_image.jpg'
with open(filename, 'wb') as f:
print "written"
f.write(body)
What I need is to upload the resized image to AWS3. On one point I need to read() the image contents, but until the image is saved somewhere as a file it is still a String, so it fails:
file_data = request.values['a']
imagedata = resize_image(file_data)
s3 = boto.connect_s3(app.config['MY_AWS_ID'], app.config['MY_AWS_SECRET'], host='s3.eu-central-1.amazonaws.com')
bucket_name = 'my_bucket'
bucket = s3.get_bucket(bucket_name)
k = Key(bucket)
# fails here
file_contents = imagedata.read()
k.key = "my_images/" + "test.png"
k.set_contents_from_string(file_contents)
Unless there is an other solution, I thought I save the image temporarily to my server (Heroku) and upload it and then delete it, how would this work? Deleting afterwards is important here!
set_contents_from_string takes a string as a parameter, you could probably just pass your image string data directly to it for upload to S3
Solution:
Delete this part:
file_contents = imagedata.read()
Use imagedata directly here:
k.set_contents_from_string(imagedata)
If you need to call .read() on your data, but don't need save file on disk use StringIO:
import StringIO
output = StringIO.StringIO()
output.write('decoded image')
output.seek(0)
output.read()
Out[1]: 'decoded image'