Learning STEM: Launching Tor
This tutorial helps you launch Tor programmatically as a process. That means you don’t have to manually click Tor icon to launch the browser. But since our aim is to do everything programmatically, don’t expect any GUI.
Dependencies
Let’s dive straight into an example:
from stem.process import launch_tor
tor_path = "<path to your Tor binary>"
#Or the path to Tor.exe for windows users
tor = launch_tor(tor_cmd= tor_path)
tor.terminate()
Here we launched Tor, and then terminated it. But it feels like magic, we never got to know when it started or ended. Let’s change that with a parameter called init_msg_handler
from stem.process import launch_tor
tor_path = "<path to your Tor binary>"
#Or the path to Tor.exe for windows users
tor = launch_tor(tor_cmd=tor_path, init_msg_handler=print)
tor.terminate()
init_msg_handler lets us mention the function that will handle all the messages regarding Tor’s initialization. Here print is just python’s print() function. We can put any user defined function in its place.
torrc
torrc is the configuration file that tor uses while launching. If you don’t write one explicitly, stem looks for a torrc in a default location (for me it was ‘/var/tmp/dist/tor/etc/tor/torrc’). If that doesn’t work, it creates a default torrc for you. Here’s what a sample torrc looks like. You can mention a custom torrc by using torrc_path parameter in launch_tor().
take_ownership
Let’s say you run the following code:
from stem.process import launch_tor
tor_path = "<path to your Tor binary>"
#Or the path to Tor.exe for windows users
tor = launch_tor(tor_cmd=tor_path, init_msg_handler=print)
print(omega)
tor.terminate()
and end up getting an error before you can terminate the tor process. Since tor is a seperate process, it’ll keep on running in the background until you explicitely terminate it (you can check there will be a tor process running). take_ownership binds tor process with the calling python script and aborts it if the calling python process terminates.
Try using take_ownership parameter, but before that, end the tor process manually.
There’s another method used for launching Tor - launch_tor_with_config. It basically is used when you want to write some specific tor configurations. We’ll look at them more closely in the next tutorial.
Full API can be found here