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| import { fromEvent } from 'rxjs';
import { takeUntil } from 'rxjs/operators';
import { CANCEL_EVENT, GRPC_DEFAULT_URL } from '../constants';
import { InvalidGrpcPackageException } from '../exceptions/errors/invalid-grpc-package.exception';
import { InvalidProtoDefinitionException } from '../exceptions/errors/invalid-proto-definition.exception';
import { CustomTransportStrategy } from '../interfaces';
import {
GrpcOptions,
MicroserviceOptions,
} from '../interfaces/microservice-configuration.interface';
import { Server } from './server';
let grpcPackage: any = {};
let grpcProtoLoaderPackage: any = {};
export class ServerGrpc extends Server implements CustomTransportStrategy {
private readonly url: string;
private grpcClient: any;
constructor(private readonly options: MicroserviceOptions['options']) {
super();
this.url =
this.getOptionsProp<GrpcOptions>(options, 'url') || GRPC_DEFAULT_URL;
grpcPackage = this.loadPackage('grpc', ServerGrpc.name);
grpcProtoLoaderPackage = this.loadPackage(
'@grpc/proto-loader',
ServerGrpc.name,
);
}
public async listen(callback: () => void) {
this.grpcClient = this.createClient();
await this.start(callback);
}
public async start(callback?: () => void) {
await this.bindEvents();
this.grpcClient.start();
callback();
}
public async bindEvents() {
const grpcContext = this.loadProto();
const packageName = this.getOptionsProp<GrpcOptions>(
this.options,
'package',
);
const grpcPkg = this.lookupPackage(grpcContext, packageName);
if (!grpcPkg) {
const invalidPackageError = new InvalidGrpcPackageException();
this.logger.error(invalidPackageError.message, invalidPackageError.stack);
throw invalidPackageError;
}
for (const name of this.getServiceNames(grpcPkg)) {
this.grpcClient.addService(
grpcPkg[name].service,
await this.createService(grpcPkg[name], name),
);
}
}
public getServiceNames(grpcPkg: any) {
return Object.keys(grpcPkg).filter(name => grpcPkg[name].service);
}
public async createService(grpcService: any, name: string) {
const service = {};
// tslint:disable-next-line:forin
for (const methodName in grpcService.prototype) {
const methodHandler = this.messageHandlers[
this.createPattern(name, methodName)
];
if (!methodHandler) {
continue;
}
service[methodName] = await this.createServiceMethod(
methodHandler,
grpcService.prototype[methodName],
);
}
return service;
}
public createPattern(service: string, methodName: string): string {
return JSON.stringify({
service,
rpc: methodName,
});
}
public createServiceMethod(
methodHandler: Function,
protoNativeHandler: any,
): Function {
return protoNativeHandler.responseStream
? this.createStreamServiceMethod(methodHandler)
: this.createUnaryServiceMethod(methodHandler);
}
public createUnaryServiceMethod(methodHandler): Function {
return async (call, callback) => {
const handler = methodHandler(call.request, call.metadata);
this.transformToObservable(await handler).subscribe(
data => callback(null, data),
err => callback(err),
);
};
}
public createStreamServiceMethod(methodHandler): Function {
return async (call, callback) => {
const handler = methodHandler(call.request, call.metadata);
const result$ = this.transformToObservable(await handler);
await result$
.pipe(takeUntil(fromEvent(call, CANCEL_EVENT)))
.forEach(data => call.write(data));
call.end();
};
}
public close() {
this.grpcClient && this.grpcClient.forceShutdown();
this.grpcClient = null;
}
public deserialize(obj): any {
try {
return JSON.parse(obj);
} catch (e) {
return obj;
}
}
public createClient(): any {
const server = new grpcPackage.Server();
const credentials = this.getOptionsProp<GrpcOptions>(
this.options,
'credentials',
);
server.bind(
this.url,
credentials || grpcPackage.ServerCredentials.createInsecure(),
);
return server;
}
public lookupPackage(root: any, packageName: string) {
/** Reference: https://github.com/kondi/rxjs-grpc */
let pkg = root;
for (const name of packageName.split(/\./)) {
pkg = pkg[name];
}
return pkg;
}
public loadProto(): any {
try {
const file = this.getOptionsProp<GrpcOptions>(this.options, 'protoPath');
const loader = this.getOptionsProp<GrpcOptions>(this.options, 'loader');
const packageDefinition = grpcProtoLoaderPackage.loadSync(file, loader);
const packageObject = grpcPackage.loadPackageDefinition(
packageDefinition,
);
return packageObject;
} catch (err) {
const invalidProtoError = new InvalidProtoDefinitionException();
const message =
err && err.message ? err.message : invalidProtoError.message;
this.logger.error(message, invalidProtoError.stack);
throw invalidProtoError;
}
}
}
|