# Xander
[](https://hex.pm/packages/xander)
Elixir client for Cardano's Ouroboros networking protocol. This library can be used to build Elixir applications that connect to a Cardano node using the Node-to-Client protocol.
⚠️ This project is under active development. See [Xogmios](https://github.com/wowica/xogmios) for a more stable solution to connect to a Cardano node through [Ogmios](https://ogmios.dev/).
## Mini-Protocols currently supported by this library:
- [x] Tx Submission
- [x] Local State Query
- get_epoch_number
- get_current_era
- get_current_block_height
- get_current_tip
- [ ] Chain-Sync
## Quickstart
Below is an example of how to connect to a Cardano node and run a query that returns the current tip of the ledger, similar to a `cardano-cli query tip` command.
```elixir
$ iex
> Mix.install([{:xander, "~> 0.2.0"}])
> # Must be a valid Unix socket path
> # to a fully synced Cardano node
> socket_path = "/path/to/cardano-node.socket"
> config = Xander.Config.default_config!(socket_path)
[
network: :mainnet,
path: [socket_path: "/tmp/cardano-node.socket"],
port: 0,
type: :socket
]
> {:ok, pid} = Xander.Query.start_link(config)
{:ok, #PID<0.207.0>}
> Xander.Query.run(pid, :get_current_tip)
{:ok,
{147911158, "b2a4f78539559866281d6089143fa4c99db90b7efc4cf7787777f927967f0c8a"}}
```
For a more detailed description of different ways to use this library, read the following sections:
<details>
<summary><i>Running Queries via Docker</i></summary>
## Running Queries via Docker
In order to run queries via Docker, you need to build the image first:
```
docker build -t xander .
```
With the image built, you can now connect to either a local Cardano node via a UNIX socket or to a node at Demeter.run.
#### 1. Connecting via a local UNIX socket
This assumes you have access to a fully synced Cardano node.
🚨 **Note:** Socket files mapped via socat/ssh tunnels **DO NOT WORK** when using containers on OS X.
Run the previously built Docker image with the `-v` argument, which mounts the path of your local socket path to
the container's default socket path (`/tmp/cardano-node.socket`):
```
docker run --rm \
-v /your/local/node.socket:/tmp/cardano-node.socket \
xander elixir run_queries.exs
```
#### 2. Connecting to a node at Demeter.run
The demo application can connect to a Cardano node at [Demeter.run](https://demeter.run/) 🪄
First, create a Node on Demeter and grab the Node's URL.
Then, run the Docker image with the `DEMETER_URL` environment variable set to your Node's URL:
```bash
docker run --rm \
-e DEMETER_URL=https://your-node-at.demeter.run \
xander elixir run_with_demeter.exs
```
</details>
<details>
<summary><i>Running Queries with native Elixir install</i></summary>
## Running Queries with native Elixir install
For those with Elixir already installed, simply run the commands below:
```
# Must set a local unix socket
elixir run_queries.exs
# Must set a Demeter URL
elixir run_queries_with_demeter.exs
```
More information on connection below:
#### a) Connecting via local UNIX socket
Run the following command using your own Cardano node's socket path:
```bash
CARDANO_NODE_PATH=/your/cardano/node.socket elixir run_queries.exs
```
##### Setting up Unix socket mapping (optional when no direct access to Cardano node)
This is useful if you want to run the application on a server different from your Cardano node.
🚨 **Note:** Socket files mapped via socat/ssh tunnels **DO NOT WORK** when using containers on OS X.
1. Run socat on the remote server with the following command:
```bash
socat TCP-LISTEN:3002,reuseaddr,fork UNIX-CONNECT:/home/cardano_node/socket/node.socket
```
2. Run socat on the local machine with the following command:
```bash
socat UNIX-LISTEN:/tmp/cardano_node.socket,reuseaddr,fork TCP:localhost:3002
```
3. Start an SSH tunnel from the local machine to the remote server with the following command:
```bash
ssh -N -L 3002:localhost:3002 user@remote-server-ip
```
4. Run the example script:
```bash
CARDANO_NODE_PATH=/tmp/cardano_node.socket elixir run.exs
```
#### b) Connecting via Demeter.run
To connect to a node at Demeter.run, set `DEMETER_URL` to your Node Demeter URL.
```bash
DEMETER_URL=https://your-node-at.demeter.run elixir run_with_demeter.exs
```
</details>
<details>
<summary><i>Submitting Transactions</i></summary>
## Submitting Transactions
⚠️ This project does not provide off-chain transaction functionality such as building and signing of transactions.
In order to submit transactions via Xander, you can either run the `submit_tx.exs` script directly or use Docker.
## Running the script
This assumes you have Elixir installed. In order to run the script directly, follow the steps below:
1. Get ahold of the CBOR hex of a valid signed transaction (not covered by this library)
2. Populate the environment variable `CARDANO_NODE_SOCKET_PATH` with a socket file for a fully synced Cardano node.
3. Ensure the `Config.default_config!` function call matches the network being used:
- `Config.default_config!(socket_path)` defaults to Mainnet
- `Config.default_config!(socket_path, :preview)` for Preview network
4. Run `elixir submit_tx.exs <transaction-CBOR-hex>` providing the CBOR hex as its single argument.
A successful submission should return the transaction ID. This ID can be used to check the status of the transaction on any Cardano blockchain explorer.
## Using Docker
This assumes you have Docker installed. No Elixir installation is required.
1. First, build the image:
```
docker build -t xander .
```
2. Ensure the `Config.default_config!` function inside the `submit_tx.exs` file matches the network being used:
- `Config.default_config!(socket_path)` defaults to Mainnet
- `Config.default_config!(socket_path, :preview)` for Preview network
3. Get ahold of the CBOR hex of a valid signed transaction (not covered by this library)
Run the previously built Docker image with the `-v` argument, which mounts the path of your local socket path to
the container's default socket path (`/tmp/cardano-node-preview.socket`):
```
docker run --rm \
-v /your/local/preview-node.socket:/tmp/cardano-node-preview.socket \
xander elixir submit_tx.exs <transaction-CBOR-hex>
```
A successful submission should return the transaction ID. This ID can be used to check the status of the transaction on any Cardano blockchain explorer.
</details>
