Sample code for Python networking and threading
In the threading directory are two programs to demonstrate the use
of threading in Python. The program threadHello.py shows how to
create a set of threads that print a message and their thread ID.
python threadHello.py -n [number]
The program threadShared.py shows how to use shared memory with
threads. Each thread has a shared variable i that is NOT protected
with semaphores, and another one that is properly protected and
accessed through a thread-safe object.
python threadShared.py -n [number]
In the download directory are two programs that demonstrate using
the Python Requests library. The program download.py downloads a set
of URLs, located in urls.txt, and stores them in a directory called
downloads.
python download.py -i [input file] -d [download directory]
The program threadedDownload.py creates a separate thread to
download each URL in parallel:
python download.py -i [input file] -d [download directory]
The code in the download-accelerator directory is for a lab
download
accelerator
where students write a script that downloads a file in parallel. The
file experiments.py calls the downloadAccelerator.py script to
download files of several different sizes using a variable number of
threads.
python experiments.py
The file plot.py uses the data collected with the experiments to
create a series of boxplots showing the distribution of the download
time versus the number of threads, one for each file.
python plot.py
The code in the echo-server directory shows how to use the
lower-level Python sockets library as well as how to create a server
based on polling. The program echo-server.py uses server.py to create
a basic echo server:
python echoserver.py -p [port]
The program echo-client.py uses client.py to create a basic echo client:
python echoclient.py -s [server] -p [port]
This version of the echo server can handle only one client at a time.
The program echoserver-poll.py uses poller.py to show how a server
can use the poll() system call to multiplex handling multiple clients
while using a single thread of control.
Note that because the server is so simple, this code does not do many other things a polling server should do, such as using non-blocking I/O, timing out idle sockets, and using a separate receive cache for each client.