Method write

lib/requests.js:427–500

* Writes a batch request

(encoder, streamId)

  * Writes a batch request
  */
  write(encoder, streamId) {
    //v2: <type><n><query_1>...<query_n><consistency>
    //v3: <type><n><query_1>...<query_n><consistency><flags>[<serial_consistency>][<timestamp>]
    //dseV1+: similar to v3/v4, flags is an int instead of a byte
    if (!this.queries || !(this.queries.length > 0)) {
      throw new TypeError(util.format('Invalid queries provided %s', this.queries));
    }
    const frameWriter = new FrameWriter(types.opcodes.batch);
    let headerFlags = this.options.isQueryTracing() ? types.frameFlags.tracing : 0;
    if (this.options.getCustomPayload()) {
      //The body may contain the custom payload
      headerFlags |= types.frameFlags.customPayload;
      frameWriter.writeCustomPayload(this.options.getCustomPayload());
    }
    frameWriter.writeByte(this.type);
    frameWriter.writeShort(this.queries.length);
    const self = this;
    this.queries.forEach(function eachQuery(item, i) {
      const hints = self.hints[i];
      const params = item.params || utils.emptyArray;
      let getParamType;
      if (item.queryId) {
        // Contains prepared queries
        frameWriter.writeByte(1);
        frameWriter.writeShortBytes(item.queryId);
        getParamType = i => item.meta.columns[i].type;
      }
      else {
        // Contains string queries
        frameWriter.writeByte(0);
        frameWriter.writeLString(item.query);
        getParamType = hints ? (i => hints[i]) : (() => null);
      }

      frameWriter.writeShort(params.length);
      params.forEach((param, index) => frameWriter.writeBytes(encoder.encode(param, getParamType(index))));
    }, this);

    frameWriter.writeShort(this.options.getConsistency());

    if (types.protocolVersion.supportsTimestamp(encoder.protocolVersion)) {
      // Batch flags
      let flags = this.options.getSerialConsistency() ? batchFlag.withSerialConsistency : 0;
      const timestamp = this.timestamp;
      flags |= timestamp !== null && timestamp !== undefined ? batchFlag.withDefaultTimestamp : 0;

      flags |= this.options.getKeyspace() && types.protocolVersion.supportsKeyspaceInRequest(encoder.protocolVersion)
        ? batchFlag.withKeyspace : 0;

      if (types.protocolVersion.uses4BytesQueryFlags(encoder.protocolVersion)) {
        frameWriter.writeInt(flags);
      }
      else {
        frameWriter.writeByte(flags);
      }

      if (flags & batchFlag.withSerialConsistency) {
        frameWriter.writeShort(this.options.getSerialConsistency());