# Connecting to Rostrum

There are various ways to connect to your rostrum server, depending on your use case.

If you want to use the server privately for your wallet, Electron Cash is a popular wallet.

If you're using electrum for development purposes, the following options are suggested based on your choice of programming langauge:

| Language | Library |
|----------|---------|
| JavaScript / TypeScript | [electrum-cash](https://www.npmjs.com/package/electrum-cash) |
| Python | [bitcoincash](https://pypi.org/project/bitcoincash) |
| Android Kotlin | [libbitcoincashkotlin](https://gitlab.com/bitcoinunlimited/libbitcoincashkotlin) |

If you want to use it from a terminal, you can use the `contrib/client.py` script from the Rostrum source code repostiory.

## Wallet: Electron Cash

```bash
# Connecting to your local server
$ electron-cash --oneserver --server=127.0.0.1:50001:t
```

Note: Some versions of Electron Cash have an issue where it won't connect to non-SSL server, even when it's localhost.


## Terminal

### Using Python over TCP

Using the `contrib/client.py` script from the Rostrum source code repostiory.

```bash
$ python3 contrib/client.py -h
usage: client.py [-h] [--port PORT] [--server SERVER] method [args ...]

positional arguments:
  method
  args

optional arguments:
  -h, --help       show this help message and exit
  --port PORT
  --server SERVER
  ```

  Example:
  ```bash
% python3 contrib/client.py blockchain.block.headers 0 1
{'id': 0, 'jsonrpc': '2.0', 'result': {'count': 1, 'hex': '0100000000000000000000000000000000000000000000000000000000000000000000003ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a29ab5f49ffff001d1dac2b7c', 'max': 2016}}
```

### Using node.js over SSL

The package [electrum-cli](https://www.npmjs.com/package/electrum-cli) is a command line tool for querying elecrum servers over a SSL connection.

Example:
```
% electrum-cli --server rostrum.nexa.ink:20002 server.version
[
  "Rostrum 6.0.0",
  "1.4"
]
```

### Using netcat over TCP

It's possible to use [ncat](https://nmap.org/ncat/) to do simple queries from
terminal. For Nexa, use port 20001. For Bitcoin Cash, use port 50001.

```bash
% (echo '{ "id": 1, "method": "server.version", "params": ["AtomicDEX", ["1.4", "2.0"]] }'; sleep 0.5) | ncat rostrum.devops.cash 20001
{"id":1,"jsonrpc":"2.0","result":["Rostrum 5.0.0","1.4.3"]}

```

## JavaScript / TypeScript: ElectrumCash library

```typescript
import { ElectrumCluster, ElectrumTransport, RequestResponse } from 'electrum-cash';

const electrum = new ElectrumCluster('client name', '1.4.2', 1, 1);
electrum.addServer('bitcoincash.network');
try {
  await electrum.ready();
} catch (e) {
  console.log('Failed to connect ', e);
}
const response = await electrum.request(
    "blockchain.block.headers", 0, 1);
await electrum.shutdown();
```

### Using Python over Web Socket (wss or ws)

Using the `contrib/websocket-client.py` script from the Rostrum source code repository.

```bash
$ python3 contrib/websocket-client.py -h
usage: _wsdump.py [-h] [-p PROXY] [-v [VERBOSE]] [-n] [-r] [-s [SUBPROTOCOLS ...]] [-o ORIGIN] [--eof-wait EOF_WAIT] [-t TEXT] [--timings] [--headers HEADERS] ws_url

WebSocket Simple Dump Tool

positional arguments:
  ws_url                websocket url. ex. ws://echo.websocket.events/

options:
  -h, --help            show this help message and exit
  -p PROXY, --proxy PROXY
                        proxy url. ex. http://127.0.0.1:8080
  -v [VERBOSE], --verbose [VERBOSE]
                        set verbose mode. If set to 1, show opcode. If set to 2, enable to trace websocket module
  -n, --nocert          Ignore invalid SSL cert
  -r, --raw             raw output
  -s [SUBPROTOCOLS ...], --subprotocols [SUBPROTOCOLS ...]
                        Set subprotocols
  -o ORIGIN, --origin ORIGIN
                        Set origin
  --eof-wait EOF_WAIT   wait time(second) after 'EOF' received.
  -t TEXT, --text TEXT  Send initial text
  --timings             Print timings in seconds
  --headers HEADERS     Set custom headers. Use ',' as separator
  ```

Example:

```bash
  % python3 contrib/websocket-client.py blockchains://electrum.nexa.org:20004 -t '{"id":0, "method":"blockchain.transaction.get", "params":[ "868d9ae77bb08def01d111f63f9e220bb24f0350379072418d08ae98db2650c3"]}'
  Press Ctrl+C to quit
  < {"id":0,"jsonrpc":"2.0","result":"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"}
  >
```