Problems outputting an image over http using Python

Question

I'm trying to load an image file from my local disk and output it over http when the script is accessed on my webserver via cgi.

For example I want http://example.com/getimage.py?imageid=foo to return the corresponding image. Just opening the file and printing imgfile.read() after the appropriate content headers, however, causes the image to be scrambled. Clearly the output isn't right, but I have no idea why.

What would be the best way to do this, using the built-in modules of 2.6?

Edit:

The code essentially boils down to:

imgFile=open(fileName,"rb")
print "Content-type: image/jpeg"
print
print imgFile.read()
imgFile.close()

It outputs an image, just one that seems to be random data.

Community · Accepted Answer · 2017-05-23 11:56:10Z

3

~~You probably have to open() your image files in binary mode:~~

~~imgfile = open("%s.png" % imageid, "rb") print imgfile.read()~~

On Windows, you need to explicitly make stdout binary:

import sys
if sys.platform == "win32":
    import os, msvcrt
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)

You also might want to use CR+LF pairs between headers (see RFC 2616 section 6):

imgFile = open(fileName, "rb")
sys.stdout.write("Content-type: image/jpeg\r\n")
sys.stdout.write("\r\n")
sys.stdout.write(imgFile.read())
imgFile.close()

edited May 23, 2017 at 11:56

CommunityBot

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answered Nov 14, 2010 at 8:16

Frédéric Hamidi

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4 Comments

Kal Zekdor Over a year ago

No, I did that from the start. Also of note is that I can read the image and write it to another file with no problem, only outputting it causes the issue.

Frédéric Hamidi Over a year ago

@Kal, I see. Does that work better if you call sys.stdout.write() instead of print? Are you running Windows?

Frédéric Hamidi Over a year ago

@Kal, if you're running Windows, there are additional hoops to jump through, but if you're on Linux that should work fine as it is.

Kal Zekdor Over a year ago

On windows, yes, using IIS 7.

PaulMcG · Accepted Answer · 2010-11-14 08:50:37Z

0

Python comes with its own HTTP module, SimpleHTTPServer - why not check out SimpleHTTPServer.py in the /Lib directory of your Python installation, and see how it is done there?

answered Nov 14, 2010 at 8:50

PaulMcG

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