Optimal Proxy Chooser

I am back to outdo myself at presenting another pointless bash script which has the potential to be a disgrace to the programming community. Maybe this will serve as documentation on how one can get carried away while writing code.

People who access the interwebs behind a proxy-server will know the pain when things get slow and you have no clue which proxy-server will work out and helplessly refer to the stars' alignment to choose a server. When KGP had one of its We bring you internet from the 90s moments, I had decided that there has got to be a way to choose a proxy based on the bandwidth all the proxies were offering. Either there isn't any popular service to do that or my googling skills need serious refinement. So I set out to implement a poor man's method of choosing an optimal proxy-server from a multitude of choices and set that as the System-Wide Proxy. The script is only for Linux.

I have tested this on Ubuntu 14.04 (I know it's not the linuxest of OSes out there, but it rocks my boat). Identifying the optimal proxy-server should work on any Linux distro. Setting the system proxy is specific to Ubuntu.

I used curl to download a test file (I chose a random file of 3MB. Replace the url based on your preferences - be sure to test that the download is working throught curl before using it) and got the request time. Choosing the minimum request time among the options, I selected the optimal server. I haven't got the faintest of ideas whether this is theoretically the optimal server, but I guess it works for a naive implementation.

Let's call this proxychooser.sh

minind=0 #index for the optimal server
min="100000.000" #minimum of the request times

#Storing the proxy servers' addresses in an array.
#Bonus points if the you extract the addresses from a config file.
proxies=(
"http://144.16.192.213:8080"
"http://144.16.192.216:8080"
"http://144.16.192.217:8080"
"http://144.16.192.218:8080"
"http://144.16.192.245:8080"
"http://144.16.192.247:8080"
"http://10.3.100.211:8080"
"http://10.3.100.212:8080")

#Looping over the array
for (( c=0; c<${#proxies[@]}; c++ ))
do
    var=$(curl --no-sessionid -x "${proxies[c]}"  -o ./proxyfile.pdf -s -w %{time_total}\\n http://www.cred.be/download/download.php?file=sites/default/files/CredCrunch15.pdf)
    #var is the request time (string)
    # -x is used to give the proxy to be used
    # proxyfile is the downloaded dummy
    # replace the url with one of your choice
    echo ${proxies[c]} $var
    #note that all values are in strings. So using bc for comparisions
    # output is "1" for true and "0" for false
    var2=$(echo "$min > $var" | bc)

    # request time is 0.000 when it is not successful
    if [ "$var" != "0.000" ]&&[ "$var2" == "1" ];
    then
        #saving the current minimum
        min=$var
        minind=$c
    fi
done

if [ "$min" == "0.000" ];
then
    echo "Possible network problems, no connection"
    return 0
fi

echo "Best proxy is ----" ${proxies[minind]}


#------Insert Ubuntu specific code below--------

This gets the optimal proxy server.

I have toiled over an hour googling to find a generic method to set the System-Wide Http Proxy on Linux which doesn't involve a restart. Using the enivronment variable http_proxy with export doesn't work at all as it is restricted to that shell/session. Editing files like /etc/environment didn't solve anything even when the network-manager is restarted. So I had to go with the Ubuntu specific approach, apologies to all the pure Linuxers out there if you feel let down.

A cool dude helped me on stackexchange regarding setting the System-Wide Proxy on Ubuntu. Add the following to the end of the above script proxychooser.sh. I have got to admit that I don't fully understand how the following works, will have to dig into Ubuntu's documentation sometime.

If you feel this is overkill, you can always manually set your proxy through GUI after getting the optimal server.

source ./bus.sh
proxies3=(
"144.16.192.213"
"144.16.192.216"
"144.16.192.217"
"144.16.192.218"
"144.16.192.245"
"144.16.192.247"
"10.3.100.211"
"10.3.100.212")

HTTP_PROXY_HOST=${proxies3[minind]}
HTTP_PROXY_PORT=8080
HTTPS_PROXY_HOST=${proxies3[minind]}
HTTPS_PROXY_PORT=8080

gsettings set org.gnome.system.proxy.http host "$HTTP_PROXY_HOST"
gsettings set org.gnome.system.proxy.http port "$HTTP_PROXY_PORT"
gsettings set org.gnome.system.proxy.https host "$HTTPS_PROXY_HOST"
gsettings set org.gnome.system.proxy.https port "$HTTPS_PROXY_PORT"

sudo sed -i.bak '/http[s]::proxy/Id' /etc/apt/apt.conf
sudo tee -a /etc/apt/apt.conf <<EOF
Acquire::http::proxy "http://$HTTP_PROXY_HOST:$HTTP_PROXY_PORT/";
Acquire::https::proxy "http://$HTTPS_PROXY_HOST:$HTTPS_PROXY_PORT/";
EOF

sudo sed -i.bak '/http[s]_proxy/Id' /etc/environment
sudo tee -a /etc/environment <<EOF
http_proxy="http://$HTTP_PROXY_HOST:$HTTP_PROXY_PORT/"
https_proxy="http://$HTTPS_PROXY_HOST:$HTTPS_PROXY_PORT/"
EOF

Save a file bus.sh alongside proxychooser.sh. I got this from stackexchange

#!/bin/bash

# Remember to run this script using the command "source ./filename.sh"

# Search these processes for the session variable 
# (they are run as the current user and have the DBUS session variable set)
compatiblePrograms=( nautilus kdeinit kded4 pulseaudio trackerd )

# Attempt to get a program pid
for index in ${compatiblePrograms[@]}; do
    PID=$(pidof -s ${index})
    if [[ "${PID}" != "" ]]; then
        break
    fi
done
if [[ "${PID}" == "" ]]; then
    echo "Could not detect active login session"
    return 1
fi

QUERY_ENVIRON="$(tr '\0' '\n' < /proc/${PID}/environ | grep "DBUS_SESSION_BUS_ADDRESS" | cut -d "=" -f 2-)"
if [[ "${QUERY_ENVIRON}" != "" ]]; then
    export DBUS_SESSION_BUS_ADDRESS="${QUERY_ENVIRON}"
    echo "Connected to session:"
    echo "DBUS_SESSION_BUS_ADDRESS=${DBUS_SESSION_BUS_ADDRESS}"
else
    echo "Could not find dbus session ID in user environment."
    return 1
fi

return 0

Make sure both the scripts are executable by sudo chmod +x scriptname.sh and run the proxychooser.sh whenever you feel a need to change the proxy.

Here are the gists for the working scripts. proxychooser.sh and bus.sh

I am counting on this post's popularity in KGP being minimal. A Game-Theoretic analysis(or common sense) would deduce that the chosen optimal server might no longer be optimal if the majority of the users opt for that server. Don't disappoint me junta. Be sure to expect some detailed posts on Game Theory in the future. Thanks.

Please point out any gaping mistakes or suggest anything that might improve the approach.