Feature/ap 34 introduce faucet service

package.json

@@ -7,7 +7,7 @@
   "scripts": {
     "build": "tsc",
     "format": "prettier --write \"src/**/*.ts\"",
-    "start": "export NODE_ENV=dev-local; export MONGODB_HOST=localhost; ts-node -r tsconfig-paths/register src/main.ts",
+    "start": "export NODE_ENV=dev-local; export MONGODB_HOST=localhost; export FAUCET_SECRET=s3cr3t; ts-node -r tsconfig-paths/register src/main.ts",
     "start:dev": "nodemon",
     "start:debug": "nodemon --config nodemon-debug.json",
     "start:provided-env": "node dist/main.js",

src/app.module.ts

@@ -6,6 +6,7 @@ import { ContactsModule } from './contacts/contacts.module'
 import { BlockchainModule } from './blockchain/blockchain.module'
 import { TerminusModule } from '@nestjs/terminus'
 import { TerminusOptionsService } from './health/terminus-options.service'
+import { FaucetModule } from './faucet/faucet.module'
 
 @Module({
   imports: [
@@ -14,6 +15,7 @@ import { TerminusOptionsService } from './health/terminus-options.service'
     MessagingModule,
     ContactsModule,
     BlockchainModule,
+  FaucetModule,
     TerminusModule.forRootAsync({
       useClass: TerminusOptionsService,
     }),

src/faucet/faucet.auth.guard.ts

@@ -0,0 +1,32 @@
+import {
+  Injectable,
+  CanActivate,
+  ExecutionContext,
+  Inject,
+} from '@nestjs/common'
+import { Observable } from 'rxjs'
+import { ConfigService } from '../config/config.service'
+
+@Injectable()
+export class FaucetAuthGuard implements CanActivate {
+  constructor(
+    @Inject('ConfigService') private readonly configService: ConfigService
+  ) {}
+
+  public canActivate(
+    context: ExecutionContext
+  ): boolean | Promise<boolean> | Observable<boolean> {
+    const faucetSecret = this.configService.get('FAUCET_SECRET')
+    if (!faucetSecret) {
+      console.log(
+        'No faucet secret defined. Is environment variable $FAUCET_SECRET defined?'
+      )
+      return false
+    }
+
+    const request = context.switchToHttp().getRequest()
+    const authorizationHeaderValue = request.headers.authorization
+
+    return faucetSecret === authorizationHeaderValue
+  }
+}

src/faucet/faucet.controller.ts

@@ -0,0 +1,43 @@
+import { Blockchain, Identity } from '@kiltprotocol/prototype-sdk'
+import {
+  Controller,
+  Get,
+  Inject,
+  UseGuards,
+  Param,
+  Query,
+} from '@nestjs/common'
+import { BlockchainService } from '../blockchain/interfaces/blockchain.interfaces'
+import { FaucetAuthGuard } from './faucet.auth.guard'
+
+@Controller('faucet')
+export class FaucetController {
+  constructor(
+    @Inject('BlockchainService')
+    private readonly blockchainService: BlockchainService
+  ) {}
+
+  /**
+   * Transfer a certain amount of Kilt to an account.
+   *
+   * Call with curl:
+   *
+   *   curl -X GET -H "Authorization: {FAUCET_SECRET}" \
+   *        "http://{services-url}/faucet/transfer?receiverAddress={adress}&amount={amount}"
+   *
+   * @param receiverAddress address of the receiver account
+   * @param amount the amount of Kilt to tranfer
+   */
+  @Get('transfer')
+  @UseGuards(FaucetAuthGuard)
+  public async transfer(
+    @Query('receiverAddress') receiverAddress: string,
+    @Query('amount') amount: number
+  ): Promise<void> {
+    const blockchain: Blockchain = await this.blockchainService.connect()
+    const alice = Identity.buildFromURI('//Alice')
+
+    console.log(`Transferring ${amount} tokens to ${receiverAddress}`)
+    await blockchain.makeTransfer(alice, receiverAddress, amount)
+  }
+}

src/faucet/faucet.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common'
+import { FaucetController } from './faucet.controller'
+
+@Module({
+  imports: [],
+  controllers: [FaucetController],
+  providers: [],
+})
+export class FaucetModule {}