# All files / microservices/server server-nats.ts

89.74% Statements 35/39
75% Branches 9/12
87.5% Functions 14/16
91.67% Lines 33/36

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    1x

    1x

    1x

    1x

    11x
    11x
    11x

    11x

    2x
    2x
    2x

    2x
    2x

    3x
    3x
    1x

    1x

    3x
    3x

    1x
    1x

    3x
    1x

    2x
    2x

    2x
    1x

    1x
    1x

    1x

    3x
    1x

    2x

     import { Observable } from 'rxjs';
    import {
      CONNECT_EVENT,
      ERROR_EVENT,
      NATS_DEFAULT_URL,
      NO_PATTERN_MESSAGE,
    } from '../constants';
    import { Client } from '../external/nats-client.interface';
    import { CustomTransportStrategy, PacketId } from '../interfaces';
    import {
      MicroserviceOptions,
      NatsOptions,
    } from '../interfaces/microservice-configuration.interface';
    import { ReadPacket } from '../interfaces/packet.interface';
    import { Server } from './server';

    let natsPackage: any = {};

    export class ServerNats extends Server implements CustomTransportStrategy {
      private readonly url: string;
      private natsClient: Client;

      constructor(private readonly options: MicroserviceOptions['options']) {
        super();
        this.url =
          this.getOptionsProp<NatsOptions>(this.options, 'url') || NATS_DEFAULT_URL;

        natsPackage = this.loadPackage('nats', ServerNats.name);
      }

      public listen(callback: () => void) {
        this.natsClient = this.createNatsClient();
        this.handleError(this.natsClient);
        this.start(callback);
      }

      public start(callback?: () => void) {
        this.bindEvents(this.natsClient);
        this.natsClient.on(CONNECT_EVENT, callback);
      }

      public bindEvents(client: Client) {
        const queue = this.getOptionsProp<NatsOptions>(this.options, 'queue');
        const subscribe = (channel: string) => {
          Iif (queue) {
            return client.subscribe(
              channel,
              { queue },
              this.getMessageHandler(channel, client).bind(this),
            );
          }
          client.subscribe(
            channel,
            this.getMessageHandler(channel, client).bind(this),
          );
        };
        const registeredPatterns = Object.keys(this.messageHandlers);
        registeredPatterns.forEach(channel => subscribe(channel));
      }

      public close() {
        this.natsClient && this.natsClient.close();
        this.natsClient = null;
      }

      public createNatsClient(): Client {
        const options = this.options || ({} as NatsOptions);
        return natsPackage.connect({
          ...options,
          url: this.url,
          json: true,
        });
      }

      public getMessageHandler(channel: string, client: Client) {
        return async (buffer, replyTo: string) =>
          this.handleMessage(channel, buffer, client, replyTo);
      }

      public async handleMessage(
        channel: string,
        message: ReadPacket & PacketId,
        client: Client,
        replyTo: string,
      ) {
        const publish = this.getPublisher(client, replyTo, message.id);
        const status = 'error';

        if (!this.messageHandlers[channel]) {
          return publish({ id: message.id, status, err: NO_PATTERN_MESSAGE });
        }
        const handler = this.messageHandlers[channel];
        const response$ = this.transformToObservable(
          await handler(message.data),
        ) as Observable<any>;
        response$ && this.send(response$, publish);
      }

      public getPublisher(publisher: Client, replyTo: string, id: string) {
        return response =>
          publisher.publish(
            replyTo,
            Object.assign(response, {
              id,
            }),
          );
      }

      public handleError(stream) {
        stream.on(ERROR_EVENT, err => this.logger.error(err));
      }
    }