digitwin/node_modules/socks/docs/examples/javascript/connectExample.md

# socks examples

## Example for SOCKS 'connect' command

The connect command is the most common use-case for a SOCKS proxy. This establishes a direct connection to a destination host through a proxy server. The destination host only has knowledge of the proxy server connecting to it and does not know about the origin client (you).

**Origin Client (you) <-> Proxy Server <-> Destination Server**

In this example, we are connecting to a web server on port 80, and sending a very basic HTTP request to receive a response. It's worth noting that there are many socks-http-agents that can be used with the node http module (and libraries such as request.js) to make this easier. This HTTP request is used as a simple example.

The 'connect' command can be used via the SocksClient.createConnection() factory function as well as by creating a SocksClient instance and using event handlers.

### Using createConnection with async/await

Since SocksClient.createConnection returns a Promise, we can easily use async/await for flow control.

```typescript
const SocksClient = require('socks').SocksClient;

const options  = {
  proxy: {
    host: '104.131.124.203',
    port: 1081,
    type: 5
  },

  destination: {
    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
    port: 80
  },

  command: 'connect'
};

async function start() {
  try {
    const info = await SocksClient.createConnection(options);

    console.log(info.socket);
    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)

    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
    info.socket.on('data', (data) => {
      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
      /*
        HTTP/1.1 200 OK
        Access-Control-Allow-Origin: *
        Content-Type: application/json; charset=utf-8
        Date: Sun, 24 Dec 2017 03:47:51 GMT
        Content-Length: 300

        {
          "as":"AS14061 Digital Ocean, Inc.",
          "city":"Clifton",
          "country":"United States",
          "countryCode":"US",
          "isp":"Digital Ocean",
          "lat":40.8326,
          "lon":-74.1307,
          "org":"Digital Ocean",
          "query":"104.131.124.203",
          "region":"NJ",
          "regionName":"New Jersey",
          "status":"success",
          "timezone":"America/New_York",
          "zip":"07014"
        }
      */
  } catch (err) {
    // Handle errors
  }
}

start();
```

### Using createConnection with Promises

```typescript
const SocksClient = require('socks').SocksClient;

const options  = {
  proxy: {
    ipaddress: '104.131.124.203',
    port: 1081,
    type: 5
  },

  destination: {
    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
    port: 80
  },

  command: 'connect'
};

SocksClient.createConnection(options)
.then(info => {
  console.log(info.socket);
  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)

  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
  info.socket.on('data', (data) => {
    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
    /*
      HTTP/1.1 200 OK
      Access-Control-Allow-Origin: *
      Content-Type: application/json; charset=utf-8
      Date: Sun, 24 Dec 2017 03:47:51 GMT
      Content-Length: 300

      {
        "as":"AS14061 Digital Ocean, Inc.",
        "city":"Clifton",
        "country":"United States",
        "countryCode":"US",
        "isp":"Digital Ocean",
        "lat":40.8326,
        "lon":-74.1307,
        "org":"Digital Ocean",
        "query":"104.131.124.203",
        "region":"NJ",
        "regionName":"New Jersey",
        "status":"success",
        "timezone":"America/New_York",
        "zip":"07014"
      }
    */
})
.catch(err => {
  // handle errors
});
```

### Using createConnection with callbacks

SocksClient.createConnection() optionally accepts a callback function as a second parameter.

**Note:** If a callback function is provided, a Promise is still returned from the function, but the promise will always resolve regardless of if there was en error. (tldr: Do not mix callbacks and Promises).

```typescript
const SocksClient = require('socks').SocksClient;

const options  = {
  proxy: {
    ipaddress: '104.131.124.203',
    port: 1081,
    type: 5
  },

  destination: {
    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
    port: 80
  },

  command: 'connect'
};

SocksClient.createConnection(options, (err, info) => {
  if (err) {
    // handle errors
  } else {
    console.log(info.socket);
    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)

    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
    info.socket.on('data', (data) => {
      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
      /*
        HTTP/1.1 200 OK
        Access-Control-Allow-Origin: *
        Content-Type: application/json; charset=utf-8
        Date: Sun, 24 Dec 2017 03:47:51 GMT
        Content-Length: 300

        {
          "as":"AS14061 Digital Ocean, Inc.",
          "city":"Clifton",
          "country":"United States",
          "countryCode":"US",
          "isp":"Digital Ocean",
          "lat":40.8326,
          "lon":-74.1307,
          "org":"Digital Ocean",
          "query":"104.131.124.203",
          "region":"NJ",
          "regionName":"New Jersey",
          "status":"success",
          "timezone":"America/New_York",
          "zip":"07014"
        }
      */
  }
})
```

### Using event handlers

SocksClient also supports instance creation of a SocksClient. This allows for event based flow control.

```typescript
const SocksClient = require('socks').SocksClient;

const options  = {
  proxy: {
    ipaddress: '104.131.124.203',
    port: 1081,
    type: 5
  },

  destination: {
    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
    port: 80
  },

  command: 'connect'
};

const client = new SocksClient(options);

client.on('established', (info) => {
  console.log(info.socket);
  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)

  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
  info.socket.on('data', (data) => {
    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
    /*
      HTTP/1.1 200 OK
      Access-Control-Allow-Origin: *
      Content-Type: application/json; charset=utf-8
      Date: Sun, 24 Dec 2017 03:47:51 GMT
      Content-Length: 300

      {
        "as":"AS14061 Digital Ocean, Inc.",
        "city":"Clifton",
        "country":"United States",
        "countryCode":"US",
        "isp":"Digital Ocean",
        "lat":40.8326,
        "lon":-74.1307,
        "org":"Digital Ocean",
        "query":"104.131.124.203",
        "region":"NJ",
        "regionName":"New Jersey",
        "status":"success",
        "timezone":"America/New_York",
        "zip":"07014"
      }
    */
});

// Failed to establish proxy connection to destination.
client.on('error', () => {
  // Handle errors
});
```