feat: add GRPC wrapper classes for lnd & loop

app/src/api/grpc.ts

@@ -0,0 +1,39 @@
+import { grpc } from '@improbable-eng/grpc-web';
+import { ProtobufMessage } from '@improbable-eng/grpc-web/dist/typings/message';
+import { Metadata } from '@improbable-eng/grpc-web/dist/typings/metadata';
+import { UnaryMethodDefinition } from '@improbable-eng/grpc-web/dist/typings/service';
+import { DEV_HOST } from 'config';
+
+/**
+ * Executes a single GRPC request and returns a promise which will resolve with the response
+ * @param methodDescriptor the GRPC method to call on the service
+ * @param request The GRPC request message to send
+ * @param metadata headers to include with the request
+ */
+export const grpcRequest = <TReq extends ProtobufMessage, TRes extends ProtobufMessage>(
+  methodDescriptor: UnaryMethodDefinition<TReq, TRes>,
+  request: TReq,
+  metadata?: Metadata.ConstructorArg,
+): Promise<TRes> => {
+  return new Promise((resolve, reject) => {
+    grpc.unary(methodDescriptor, {
+      host: DEV_HOST,
+      request,
+      metadata,
+      onEnd: ({ status, statusMessage, headers, message, trailers }) => {
+        console.log(
+          `GRPC Request: ${methodDescriptor.service.serviceName}.${methodDescriptor.methodName}`,
+        );
+        console.log(' - status', status, statusMessage);
+        console.log(' - headers', headers);
+        if (status === grpc.Code.OK && message) {
+          resolve(message as TRes);
+          console.log(' - message', message.toObject());
+        } else {
+          reject(new Error(statusMessage));
+        }
+        console.log(' - trailers', trailers);
+      },
+    });
+  });
+};

app/src/api/lnd.ts

@@ -0,0 +1,45 @@
+import { GetInfoResponse, ListChannelsRequest } from 'types/generated/lnd_pb';
+import { Lightning } from 'types/generated/lnd_pb_service';
+import { Channel, NodeInfo } from 'types/state';
+import { DEV_MACAROON } from 'config';
+import { grpcRequest } from './grpc';
+
+/**
+ * An API wrapper to communicate with the LND node via GRPC
+ */
+class LndApi {
+  private _meta = {
+    'X-Grpc-Backend': 'lnd',
+    macaroon: DEV_MACAROON,
+  };
+
+  /**
+   * call the LND `GetInfo` RPC and return the response
+   */
+  async getInfo(): Promise<NodeInfo> {
+    const res = await grpcRequest(Lightning.GetInfo, new GetInfoResponse(), this._meta);
+    return res.toObject();
+  }
+
+  /**
+   * call the LND `ListChannels` RPC and return the response
+   */
+  async listChannels(): Promise<Channel[]> {
+    const res = await grpcRequest(
+      Lightning.ListChannels,
+      new ListChannelsRequest(),
+      this._meta,
+    );
+    return res.toObject().channelsList.map(c => ({
+      chanId: c.chanId,
+      remotePubkey: c.remotePubkey,
+      capacity: c.capacity,
+      localBalance: c.localBalance,
+      remoteBalance: c.remoteBalance,
+      uptime: c.uptime,
+      active: c.active,
+    }));
+  }
+}
+
+export default LndApi;

app/src/api/loop.ts

@@ -0,0 +1,26 @@
+import { ListSwapsRequest, ListSwapsResponse } from 'types/generated/loop_pb';
+import { SwapClient } from 'types/generated/loop_pb_service';
+import { grpcRequest } from './grpc';
+
+/**
+ * An API wrapper to communicate with the Loop daemon via GRPC
+ */
+class LoopApi {
+  private _meta = {
+    'X-Grpc-Backend': 'loop',
+  };
+
+  /**
+   * call the LND `ListSwaps` RPC and return the response
+   */
+  async listSwaps(): Promise<ListSwapsResponse.AsObject> {
+    const res = await grpcRequest(
+      SwapClient.ListSwaps,
+      new ListSwapsRequest(),
+      this._meta,
+    );
+    return res.toObject();
+  }
+}
+
+export default LoopApi;