docs/grpc: add C# docs
This commit is contained in:
Brett Cawley
Olaoluwa Osuntokun
parent
f069276970
commit
9d213948ba
226
docs/grpc/c#.md
Normal file
226
docs/grpc/c#.md
Normal file
|
|
@ -0,0 +1,226 @@
|
|||
# How to write a C# gRPC client for the Lightning Network Daemon
|
||||
|
||||
This section enumerates what you need to do to write a client that communicates with `lnd` in C#.
|
||||
|
||||
|
||||
### Prerequisites
|
||||
|
||||
* .Net Core [SDK](https://dotnet.microsoft.com/download)
|
||||
* If using Windows, a unix terminal such as [Cygwin](https://www.cygwin.com/)
|
||||
|
||||
|
||||
### Setup and Installation
|
||||
|
||||
`lnd` uses the `gRPC` protocol for communication with clients like `lncli`.
|
||||
|
||||
`gRPC` is based on protocol buffers, and as such, you will need to compile the `lnd` proto file in C# before you can use it to communicate with `lnd`.
|
||||
|
||||
This assumes you are using a Windows machine, but it applies equally to Mac and Linux.
|
||||
|
||||
Create a new `.net core` console application called `lndclient` at your root directory (On Windows : `C:/`), and install `Grpc.Tools` (1.17.0 at time of writing)
|
||||
|
||||
```bash
|
||||
mkdir lndclient
|
||||
cd lndclient
|
||||
dotnet new console
|
||||
dotnet add package Grpc.Tools --version 1.17.0
|
||||
```
|
||||
|
||||
* Create the necessary folder structure, and then fetch the lnd [rpc.proto](https://github.com/lightningnetwork/lnd/blob/master/lnrpc/rpc.proto) file:
|
||||
```bash
|
||||
mkdir Grpc
|
||||
curl -o Grpc/rpc.proto -s https://raw.githubusercontent.com/lightningnetwork/lnd/master/lnrpc/rpc.proto
|
||||
```
|
||||
|
||||
* Copy Google's [annotations.proto](https://github.com/googleapis/googleapis/blob/master/google/api/annotations.proto) to the correct folder:
|
||||
```bash
|
||||
mkdir Grpc/google
|
||||
mkdir Grpc/google/api
|
||||
curl -o Grpc/google/api/annotations.proto -s https://raw.githubusercontent.com/googleapis/googleapis/master/google/api/annotations.proto
|
||||
```
|
||||
|
||||
* Copy Google's [http.proto](https://github.com/googleapis/googleapis/blob/master/google/api/http.proto) to the correct folder:
|
||||
```bash
|
||||
curl -o Grpc/google/api/http.proto -s https://raw.githubusercontent.com/googleapis/googleapis/master/google/api/http.proto
|
||||
```
|
||||
|
||||
* Copy Google's [descriptor.proto](https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/descriptor.proto) to the correct folder:
|
||||
```bash
|
||||
mkdir Grpc/google/protobuf
|
||||
curl -o Grpc/google/protobuf/descriptor.proto -s https://raw.githubusercontent.com/protocolbuffers/protobuf/master/src/google/protobuf/descriptor.proto
|
||||
```
|
||||
|
||||
* Compile the proto file using `protoc.exe` from nuget package `Grpc.Tools` (possibly replace "YOUR_USER", version "1.17.0", or your OS in both paths):
|
||||
```bash
|
||||
# linux + mac nuget package location: ~/.nuget/packages
|
||||
cd Grpc
|
||||
C:/Users/<YOUR_USER>/.nuget/packages/grpc.tools/1.17.0/tools/windows_x64/protoc.exe --csharp_out . --grpc_out . rpc.proto --plugin=protoc-gen-grpc=C:/Users/<YOUR_USER>/.nuget/packages/grpc.tools/1.17.0/tools/windows_x64/grpc_csharp_plugin.exe
|
||||
```
|
||||
|
||||
|
||||
After following these steps, two files `Rpc.cs` and `RpcGrpc.cs` will be generated in the `Grpc` folder in your project.
|
||||
|
||||
|
||||
|
||||
#### Imports and Client
|
||||
|
||||
Every time you use C# `gRPC`, you will have to import the generated rpc classes, and use `nuget` package manger to install `Grpc.Core` (1.17.0 at time of writing), `Google.Protobuf` (3.6.1), and `Google.Api.CommonProtos` (1.4.0).
|
||||
|
||||
```bash
|
||||
# from project root, install packages using nuget
|
||||
cd ../
|
||||
dotnet add package Grpc.Core --version 1.17.0
|
||||
dotnet add package Google.Protobuf --version 3.6.1
|
||||
dotnet add package Google.Api.CommonProtos --version 1.4.0
|
||||
```
|
||||
|
||||
After installing these, use the code below to set up a channel and client to connect to your `lnd` node:
|
||||
|
||||
```c#
|
||||
|
||||
using System.Collections.Generic;
|
||||
using System.IO;
|
||||
using System.Threading.Tasks;
|
||||
using Grpc.Core;
|
||||
using Lnrpc;
|
||||
...
|
||||
|
||||
// Due to updated ECDSA generated tls.cert we need to let gprc know that
|
||||
// we need to use that cipher suite otherwise there will be a handshake
|
||||
// error when we communicate with the lnd rpc server.
|
||||
System.Environment.SetEnvironmentVariable("GRPC_SSL_CIPHER_SUITES", "HIGH+ECDSA");
|
||||
|
||||
// Lnd cert is at AppData/Local/Lnd/tls.cert on Windows
|
||||
// ~/.lnd/tls.cert on Linux and ~/Library/Application Support/Lnd/tls.cert on Mac
|
||||
var cert = File.ReadAllText(<Tls_Cert_Location>);
|
||||
|
||||
var sslCreds = new SslCredentials(cert);
|
||||
var channel = new Grpc.Core.Channel("localhost:10009", sslCreds);
|
||||
var client = new Lnrpc.Lightning.LightningClient(channel);
|
||||
|
||||
```
|
||||
|
||||
### Examples
|
||||
|
||||
Let's walk through some examples of C# `gRPC` clients. These examples assume that you have at least two `lnd` nodes running, the RPC location of one of which is at the default `localhost:10009`, with an open channel between the two nodes.
|
||||
|
||||
#### Simple RPC
|
||||
|
||||
```c#
|
||||
// Retrieve and display the wallet balance
|
||||
// Use "WalletBalanceAsync" if in async context
|
||||
var response = client.WalletBalance(new WalletBalanceRequest());
|
||||
Console.WriteLine(response);
|
||||
```
|
||||
|
||||
#### Response-streaming RPC
|
||||
|
||||
```c#
|
||||
var request = new InvoiceSubscription();
|
||||
using (var call = client.SubscribeInvoices(request))
|
||||
{
|
||||
while (await call.ResponseStream.MoveNext())
|
||||
{
|
||||
var invoice = call.ResponseStream.Current;
|
||||
Console.WriteLine(invoice.ToString());
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Now, create an invoice for your node at `localhost:10009` and send a payment to it from another node.
|
||||
```bash
|
||||
$ lncli addinvoice --amt=100
|
||||
{
|
||||
"r_hash": <R_HASH>,
|
||||
"pay_req": <PAY_REQ>
|
||||
}
|
||||
$ lncli sendpayment --pay_req=<PAY_REQ>
|
||||
```
|
||||
|
||||
Your console should now display the details of the recently satisfied invoice.
|
||||
|
||||
#### Bidirectional-streaming RPC
|
||||
|
||||
```c#
|
||||
using (var call = client.SendPayment())
|
||||
{
|
||||
var responseReaderTask = Task.Run(async () =>
|
||||
{
|
||||
while (await call.ResponseStream.MoveNext())
|
||||
{
|
||||
var payment = call.ResponseStream.Current;
|
||||
Console.WriteLine(payment.ToString());
|
||||
}
|
||||
});
|
||||
|
||||
foreach (SendRequest sendRequest in SendPayment())
|
||||
{
|
||||
await call.RequestStream.WriteAsync(sendRequest);
|
||||
}
|
||||
await call.RequestStream.CompleteAsync();
|
||||
await responseReaderTask;
|
||||
}
|
||||
|
||||
|
||||
IEnumerable<SendRequest> SendPayment()
|
||||
{
|
||||
while (true)
|
||||
{
|
||||
SendRequest req = new SendRequest() {
|
||||
DestString = <DEST_PUB_KEY>,
|
||||
Amt = 100,
|
||||
PaymentHashString = <R_HASH>,
|
||||
FinalCltvDelta = 144
|
||||
};
|
||||
yield return req;
|
||||
System.Threading.Thread.Sleep(2000);
|
||||
}
|
||||
}
|
||||
```
|
||||
This example will send a payment of 100 satoshis every 2 seconds.
|
||||
|
||||
#### Using Macaroons
|
||||
|
||||
To authenticate using macaroons you need to include the macaroon in the metadata of the request.
|
||||
|
||||
```c#
|
||||
// Lnd admin macaroon is at <LND_DIR>/data/chain/bitcoin/simnet/admin.macaroon on Windows
|
||||
// ~/.lnd/data/chain/bitcoin/simnet/admin.macaroon on Linux and ~/Library/Application Support/Lnd/data/chain/bitcoin/simnet/admin.macaroon on Mac
|
||||
byte[] macaroonBytes = File.ReadAllBytes("<LND_DIR>/data/chain/bitcoin/simnet/admin.macaroon");
|
||||
var macaroon = BitConverter.ToString(macaroonBytes).Replace("-", ""); // hex format stripped of "-" chars
|
||||
```
|
||||
|
||||
The simplest approach to use the macaroon is to include the metadata in each request as shown below.
|
||||
|
||||
```c#
|
||||
client.GetInfo(new GetInfoRequest(), new Metadata() { new Metadata.Entry("macaroon", macaroon) });
|
||||
```
|
||||
|
||||
However, this can get tiresome to do for each request, so to avoid explicitly including the macaroon we can update the credentials to include it automatically.
|
||||
|
||||
```c#
|
||||
// build ssl credentials using the cert the same as before
|
||||
var sslCreds = new SslCredentials(cert);
|
||||
|
||||
// combine the cert credentials and the macaroon auth credentials using interceptors
|
||||
// so every call is properly encrypted and authenticated
|
||||
Task AddMacaroon(AuthInterceptorContext context, Metadata metadata)
|
||||
{
|
||||
metadata.Add(new Metadata.Entry("macaroon", macaroon));
|
||||
return Task.CompletedTask;
|
||||
}
|
||||
var macaroonInterceptor = new AsyncAuthInterceptor(AddMacaroon);
|
||||
var combinedCreds = ChannelCredentials.Create(sslCreds, CallCredentials.FromInterceptor(macaroonInterceptor));
|
||||
|
||||
// finally pass in the combined credentials when creating a channel
|
||||
var channel = new Grpc.Core.Channel("localhost:10009", combinedCreds);
|
||||
var client = new Lnrpc.Lightning.LightningClient(channel);
|
||||
|
||||
// now every call will be made with the macaroon already included
|
||||
client.GetInfo(new GetInfoRequest());
|
||||
```
|
||||
|
||||
|
||||
### Conclusion
|
||||
|
||||
With the above, you should have all the `lnd` related `gRPC` dependencies installed locally in your project. In order to get up to speed with `protobuf` usage from C#, see [this official `protobuf` tutorial for C#](https://developers.google.com/protocol-buffers/docs/csharptutorial). Additionally, [this official gRPC resource](http://www.grpc.io/docs/tutorials/basic/csharp.html) provides more details around how to drive `gRPC` from C#.
|
||||
Loading…
Reference in New Issue
Block a user