Since os.popen is deprecated and replaced by subprocess.Popen, how can I convert this code:
os.popen('swfdump /tmp/filename.swf -d')
to use subprocess.Popen properly? I tried:
subprocess.Popen("swfdump /tmp/filename.swf -d")
subprocess.Popen("swfdump %s -d" % (filename))
but it doesn’t seem to work correctly. What is the right way to use subprocess.Popen with commands and variables like this?
You know, I ran into the same issue when switching from os.popen to subprocess.popen. The big difference is how subprocess.popen expects commands. Instead of passing the entire command as a single string, you need to split it into a list of individual elements. So, the code:
subprocess.popen("swfdump /tmp/filename.swf -d")
Should be written like this:
subprocess.popen(["swfdump", "/tmp/filename.swf", "-d"])
This way, Python can properly handle each part of the command separately. Also, if you’re looking to capture the output, you can add stdout=subprocess.PIPE to capture and then read from it:
proc = subprocess.popen(["swfdump", "/tmp/filename.swf", "-d"], stdout=subprocess.PIPE)
output = proc.communicate()[0]
That’s the basic approach to avoid confusion and to make sure everything works smoothly.
I definitely feel you on this. When I swapped out os.popen for subprocess.popen, I noticed passing the command as a string doesn’t work unless you set shell=True. But honestly, it’s better to avoid using shell=True if you can, as it opens up potential security issues. So, here’s what you can do:
subprocess.popen(["swfdump", filename, "-d"])
This way, you’re passing the command as a list, which is much safer. However, if you really need to pass a single string for some reason, you can use:
subprocess.popen(f"swfdump {filename} -d", shell=True)
But as I said, using shell=True can be risky, especially if the filename can be manipulated. So, whenever possible, go for the list-based approach. It’s cleaner and avoids potential issues.
Yeah, switching over from os.popen to subprocess.popen made me double-check how I structure my commands. The key takeaway for me was to avoid passing the full command as a single string without using shell=True, like so:
subprocess.popen(["swfdump", filename, "-d"])
It’s way safer since it avoids the risk of shell injection. If you need to capture the command’s output, you can use stdout=subprocess.PIPE like this:
proc = subprocess.popen(["swfdump", filename, "-d"], stdout=subprocess.PIPE)
output = proc.communicate()[0]
This ensures you get the output correctly, and it’s much more robust than os.popen. You’re definitely on the right track, just keep that in mind!