# HTTP proxy service with libp2p

This examples shows how to create a simple HTTP proxy service with libp2p:


```
                                                                                                                 XXX
                                                                                                               XX  XXXXXX
                                                                                                              X         XX
                                                                                                    XXXXXXX  XX          XX XXXXXXXXXX
                    +---------------------+                  +---------------------+              XXX      XXX            XXX        XXX
 HTTP Request       |                     |                  |                     |             XX                                    XX
+------------------->                     |  libp2p stream   |                     |  HTTP       X                                      X
                    |    Local peer       <------------------>   Remote peer       <------------->     HTTP SERVER - THE INTERNET      XX
<-------------------+                     |                  |                     | Req & Resp   XX                                   X
    HTTP Response   |   libp2p host       |                  |    libp2p host      |               XXXX XXXX XXXXXXXXXXXXXXXXXXXX   XXXX
                    +---------------------+                  +---------------------+                                            XXXXX

```

In order to proxy an HTTP request, we create a local peer which listens on `localhost:9900`. HTTP requests performed to that address are tunneled via a libp2p stream to a remote peer, which then performs the HTTP requests and sends the response back to the local peer, which relays it
to the user.

Note that this is a very simple approach to a proxy, and does not perform any header management, nor supports HTTPS. The `proxy.go` code is thoroughly commeted, detailing what is happening in every step.

## Build

From `go-libp2p` base folder:

```
> make deps
> go build ./examples/echo
```

## Usage

First run the "remote" peer as follows. It will print a local peer address. If you would like to run this on a separate machine, please replace the IP accordingly:

```sh
$ ./http-proxy
Proxy server is ready
libp2p-peer addresses:
/ip4/127.0.0.1/tcp/12000/ipfs/QmddTrQXhA9AkCpXPTkcY7e22NK73TwkUms3a44DhTKJTD
```

The run the local peer, indicating that it will need to forward http requests to the remote peer as follows:

```
$ ./http-proxy -d /ip4/127.0.0.1/tcp/12000/ipfs/QmddTrQXhA9AkCpXPTkcY7e22NK73TwkUms3a44DhTKJTD
Proxy server is ready
libp2p-peer addresses:
/ip4/127.0.0.1/tcp/12001/ipfs/Qmaa2AYTha1UqcFVX97p9R1UP7vbzDLY7bqWsZw1135QvN
proxy listening on  127.0.0.1:9900
```

As you can see, the proxy prints the listening address `127.0.0.1:9900`. You can now use this address as proxy, for example with `curl`:

```
$ curl -x "127.0.0.1:9900" "http://ipfs.io/ipfs/QmfUX75pGRBRDnjeoMkQzuQczuCup2aYbeLxz5NzeSu9G6"
it works!

```