Suppose you are in an area (or a country) behind a firewall, and you want to access a web page outside that firewall.In theory, a proxy would be a simple solution: just route your requests through the proxy server to make the website think a user is located wherever the proxy is located.However, in practice, finding a good proxy with useful options and good performance can be tricky and often requires a monthly subscription for access.This requires creating an account and adding funds to it, usually with a credit card - and this significantly raises the fixed costs of using a proxy.One solution is to set up 21 as a bitcoin-payable HTTP proxy, with (say) 1 cent in bitcoin charged per request.This would both compensate the proxy provider and reduce the up-front cost for the proxy user, as no account setup would be needed.The provider doesn't manage accounts and the user doesn't have a password to remember.Moreover, as a portable device with a virtualizable IP, requests from 21 are less likely to be blocked - which is potentially quite useful for a low-volume (<10000 requests per day) proxy server used by a few of your friends abroad.

Let's see how to set one up.You will need the following first: If you've got all the prerequisites, you are ready to go.You will need to install the requests library: First, we will set up a simple example server running locally.This will be used to test out the proxy that you are about to write.To set up the example server open a terminal.If you use a 21 Bitcoin Computer, ssh into it: Create a file called example-server-for-http-proxy.py Fill it with the following code (also downloadable here): , = () () " () .: ": " :.(=,bitcoin asking for id=) This example-server-for-http-proxy.py has two endpoints (/ and /AmIBehindProxy).bitcoin kaufen amazonThese endpoints will be used to debug your proxy locally and confirm that it's working as advertised before trying to connect to a real remote server like stanford.edu.bitcoin api python

Let's start the server to test it out: Leave the current terminal open and open up another one.If you use a 21 Bitcoin Computer, SSH into it: Use the command line curl utility to request the URL http://[::1]:5000/ from this example server as follows: It should display Hello, World!.Now, try curling the other endpoint of this example server: It should display I didn't see any evidence of a proxy.java card bitcoinAll the example server is doing is looking for the standard X-Forwarded-For header in the HTTP request to see if it was indeed a proxy that routed your request.ostatni bitcoinWe will use this to debug the proxy server below.how to use bitcoin fogLeave the current terminal open and open up a third one.If you use a 21 Bitcoin Computer, SSH into it: Create a file called proxy.py Fill it with the following code (also downloadable here): , , = () = = (, ) (, ={: () () (:h = (.)h.(,

,=5) (..,..,.. (=) (..,..,.. (=) (..,) e: .: e (=) = (r.. (r.=) The proxy is now running on port 9000 of your computer, and the destination server from the earlier step is running on port 5000.Note: our proxy looks a lot like our original server, and that's normal!They are both web (HTTP) servers based on the Flask web microframework.But the proxy is a little more elaborate.First, the proxy uses bitcoin.The Payment class is a blueprint designed to makes it very simple to use micropayments with our server endpoints.It is applied here as a decorator: @payment.required(3000), which means that every call to this endpoint will require a payment of 3000 satoshis.Your 21 wallet is used as the payout address for all the money collected by the proxy.Second, the @app.route part is slightly different than the corresponding Python decorator on the example server.It catches requests made to the destination server and routes them to the destination server if a micropayment has been embedded in the request.

The catch_all function performs the following operations: Now we're going to put the pieces together.To set up the client, open a fourth terminal.If you have a 21 Bitcoin Computer, SSH into it: Create a file called client-for-http-proxy.py in a new directory.Fill it with the following code (also downloadable here): = = = {: } = = () ()(\ \ )r = .(=+ )(r.)()()r = .(=+ , =)(r.)()r = .(=,: Finally, let's run the client: To recap, what we did here was: The bitcoin portion of this is based on the 21 Bitcoin Library's BitTransferRequests class, essentially a bitcoin-powered wrapper around the standard Python3 requests library.Thus, when the proxy returns a 402 Payment Required error, the library automatically handles the micropayment and passes through the full HTTP response object unscathed.In the sample code above we only used r.text, but you could try r.headers and r.status_code.They would be the same between the proxied and direct connection.

After you've done this, you can run 21 log to see the various changes to your buffer.This proxy is fairly limited in what in can do and highly insecure!However, it's a great experiment to explore the power of bitcoin micropayments with existing tools and protocols.Here are some ideas on what to build next: Make this example high performance by replacing the simple Flask proxy server with a proper deployment on the underlying hardware.See this and this for some first steps.Many websites that are behind services like Cloudflare will reject requests from proxies.For educational purposes, see if you can increase the number of websites you can connect to via the proxy by removing the "X-Forwarded-For" headers, changing the "User-Agent" strings, and doing similar things to the outbound request.Modify this code to create a paying proxy which would pay for bitcoin-payable resources on your behalf when you request them.Modify this code to create a reverse proxy, which you can put in front of any existing HTTP-accessible resource to create a bitcoin paywall.