generate a qr code in pyramid view, return it without writing to disk

Question

I have a pyramid view that needs to generate a qr code and return it as an image to the user. I want to avoid storing the image, I want to just generate it, send it and forget about it.

The first thing I tried was something like this:

oRet = StringIO.StringIO()
oQR  = pyqrcode.create('yo mamma')
oQR.svg(oRet, scale=8)
return Response(body = oRet.read(), content_type="image/svg")

But this generates an svg file that can't be opened.

Looking a little closer:

oRet = StringIO.StringIO()
oQR  = pyqrcode.create('yo mamma')

oQR.eps(oRet, scale=8)  
with open('test.eps','w') as f: # cant display image in file
    f.write(oRet.read())

with open('test2.eps','w') as f:  # image file works fine
    oQR.eps(f, scale=8)

oQR.svg(oRet, scale=8) 
with open('test.svg','w') as f:  # cant display image in file
    f.write(oRet.read())

with open('test2.svg','w') as f:  # image file works fine
    oQR.svg(f, scale=8)

oQR.png(oRet) 
with open('test.png','w') as f:  # cant display image
    f.write(oRet.read())

with open('test2.png','w') as f:  #works
    oQR.png(f)   # works

with open('test3.png','w') as f:
    f.write(oQR.png_as_base64_str()) #doesn't work

So my question is: How do I return a newly generated qr code as a pyramid response without storing it on disk? I don't mind too much what format the image is in

Answer 1

we have a winner:

oRet = StringIO.StringIO()
oQR  = pyqrcode.create('yo mamma')
oQR.png(oRet, scale=8)

oResp =  Response(body = oRet.getvalue(), content_type="image/png",content_disposition='attachment; filename="yummy.png"')
return oResp

The trick was to use oRet.getvalue() instead or oRet.read()