Implementing a Terminal Proxy

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Problem

As a Linuxer, being proficient with the terminal is an essential skill. But in the terminal, downloading and installing things can sometimes be very slow, which is frustrating. I naturally wondered whether I could add a proxy to improve the speed. I had been using Shadowsocks before, and the browser used SwitchyProxy, which achieved basic proxy-based internet access. So, is there a similar tool in the terminal? The answer is yes. Through targeted searching, I successfully solved the proxy problem in the terminal. I summarize it here and hope it can help everyone.

Tools Needed

Shadowsocks, Polipo

Shadowsocks

Download and Install Client

Install Command-line Client

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pip install shadowsocks
apt-get install shadowsocks-libev
cpan Net::Shadowsocks

For Shadowsocks configuration, you can refer to this article. I configured it a long time ago, so I will not recall it here, since I have mostly forgotten it.

Let us start directly from Polipo.

Polipo

Polipo has multiple installation methods. You can install it directly with Python’s package manager pip, or use the package manager of each operating system. I recommend the latter because I personally think it is easier to manage. Here I use Ubuntu as an example.

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apt-cache search polipo

adzapper - proxy advertisement zapper add-on
polipo - lightweight, caching web proxy
polipo-dbg - debug package for polipo

The second package is the one for beginners like us. Install it:

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sudo apt-get install polipo

After installation, it starts automatically by default.
We first need to modify its configuration file, /etc/polipo/config:

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logSyslog = true
logFile = /var/log/polipo/polipo.log
logLevel = 4 # 没有这句话的话`sudo polipo -v`会出现无法查看log文件的情况

socksParentProxy = "localhost:1080" # 这里假设shadowsocks的local port为1080
socksProxyType = socks5 # 是不是和SwitchyProxy的设置很像?

For specific configuration options, refer to the file /usr/share/doc/polipo/examples/config.sample.

After configuration, we need to restart the Polipo service. Every time the configuration file is modified, the service must be restarted to load it.

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sudo service polipo stop;
sudo service polipo start;

Or directly:

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sudo service polipo restart;

You can use:

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sudo polipo -v

to view the specific configuration items, and you can see that our previous changes have taken effect.

Testing

After configuration is complete, how do you know whether you can already access the internet through the proxy?
You can use the following commands:

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~$ curl -i http://ip.cn
当前 IP：60.xxx.xxx.x 来自：中国北京北京 xxx/电信
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~$ http_proxy=http://localhost:8123 curl -i http://ip.cn # polipo的默认端口为8123,如有需要可以自行改动
当前 IP：xxx.xxx.xxx.xx0 来自：美国加利福尼亚州洛杉矶

This counts as success.

Recently I discovered that the website ip.cn no longer works and returns a 500 error. Replacing it with ipinfo.io/ip works; this is another website that returns your public IP.
There are also other websites that provide similar IP-returning services:

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curl ifconfig.me
curl icanhazip.com
curl ipecho.net/plain
curl ifconfig.co

Ways to obtain your public IP from the browser:

Going Further

Typing such a long command, http_proxy=http://localhost:8123, every time is really not what we want. For convenience, you can type export http_proxy=http://localhost:8123 in the terminal, meaning it takes effect for all commands in that terminal. Or go one step further and add export http_proxy=http://localhost:8123 to .bashrc, so it runs automatically every time the terminal starts. If you do not want every command to go through the proxy, you can do as I did and add alias hp="http_proxy=http://localhost:8123" to .bashrc. Then every time you need a proxy, just add hp before the command.

Configure Proxy for Git

The speed of git clone is quite moving, only a few dozen KB/s. Configuring a proxy for Git is also very simple.

Add the following setting to the http items of .gitconfig files.

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[http]
proxy = <address of the proxy server>:<port of the proxy server>

You can also configure it using the following config command:

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git config --global http.proxy <address of the proxy server>:<port of the proxy server>

Connect to GitHub via SSH

Enjoy proxy-based internet access in the terminal.