If you changed to another WIFI ssid, you can use this script to automatically switch your proxy setting

auto_switch_proxy.sh

#!/bin/bash

##############
##
##
## Switch your proxy setting based on your SSID
##
## Author: Gcuafy <gcaufy@gmail.com>
## Install:
##    $ alias ap='source ~/whaterveryourcodeis/auto_switch_proxy.sh'
##    $ alias apc='~/whaterveryourcodeis/auto_switch_proxy.sh'
## Usage:
##    $ apc -e # Modify the proxy setting
##    $ apc -l # List the proxy setting
##    $ apc -c # Check the current proxy setting
##    $ ap     # Auto switch the proxy setting. if it's not set for the SSID, then use the default one
##
##

# proxy setting file
CONFIG_FILE=~/.auto_switch_proxy.ini
CONFIG_ENV_FILE=~/.auto_switch_proxy.env

error() {
    printf "\e[31m[✘]\e[0m ${1}\n"
}

success() {
    printf "\e[32m[✔]\e[0m ${1}\n"
}

# If the file does not exsit, generate a default file.
check_config() {
  if [ ! -f $CONFIG_FILE ]; then
    cat > "$CONFIG_FILE" << EOF
[default]
http_proxy=1
https_proxy=2
no_proxy=3
EOF
fi
}

# Get MacOS SSID
get_mac_ssid() {
  /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I | awk '/ SSID/ {print substr($0, index($0, $2))}'
}

# Parse the .ini file
get_setting() {
    cat <<EOF | python
try:
  import ConfigParser as cp
except ImportError:
  import configparser as cp
config = cp.ConfigParser()
config.read('$CONFIG_FILE')

name = '$1'
if not config.has_section(name):
  name = 'default'

print('AUTO_SWITCH_SECTION=%s\nhttp_proxy=%s\nhttps_proxy=%s\nno_proxy=%s'%(name, config.get(name, 'http_proxy') if config.has_option(name, 'http_proxy') else '', config.get(name, 'https_proxy') if config.has_option(name, 'https_proxy') else '', config.get(name, 'no_proxy') if config.has_option(name, 'no_proxy') else ''))
EOF
}

edit_config() {
  vi $CONFIG_FILE
}

list_config() {
  cat $CONFIG_FILE
}

current_config() {
  echo '============CURRENT ENVIRONMENT VARIABLES=========='
  cat $CONFIG_ENV_FILE | grep -v AUTO_SWITCH_SECTION
}

main() {
  ssid=`get_mac_ssid`
  if [ x"$ssid" == "x" ]; then
    error "Can not find WIFI SSID, Make sure it is MacOS."
    exit
  fi

  success "SSID: $ssid"
  env=`get_setting $ssid`

  echo "$env" > $CONFIG_ENV_FILE

  source "$CONFIG_ENV_FILE"

  if [ x"$AUTO_SWITCH_SECTION" == "x" ]; then
    error "Error to load your config file: $CONFIG_FILE, try to remove it and run again."
    exit
  fi

  success "Using: [$AUTO_SWITCH_SECTION]"
  echo '============================'
  cat "$CONFIG_ENV_FILE" | grep -v AUTO_SWITCH_SECTION
}

# Main
(return 0 2>/dev/null) && sourced=1 || sourced=0

if [ "$sourced" == "0" ] && [ "1" == "$#" ]; then
  if [ 'list' == $1 ] || [ '-l' == $1 ]; then
    list_config
  elif [ 'edit' == $1 ] || [ '-e' == $1 ]; then
    edit_config
  elif [ 'current' == $1 ] || [ '-c' == $1 ]; then
    current_config
  fi
else
  check_config
  main
fi