Method getPreviewData

server/controllers/ChartController.js:981–1017

(chart, projectId, user, noSource)

  }

  getPreviewData(chart, projectId, user, noSource) {
    return this.chartCache.findLast(user.id, chart.id)
      .then((cache) => {
        if (noSource === "true") {
          return new Promise((resolve) => resolve(cache));
        }

        return this.connectionController.findById(chart.connection_id);
      })
      .then((connection) => {
        if (noSource === "true") {
          return new Promise((resolve) => resolve(connection));
        }

        const source = findSourceForConnection(connection);
        if (source?.backend?.runChartQuery) {
          assertSourceServerEnabled(source);
          return source.backend.runChartQuery({ connection, query: chart.query });
        }

        return new Promise((resolve, reject) => reject("The connection type is not supported"));
      })
      .then((data) => {
        const previewData = data;
        if (noSource !== "true" && user) {
          // cache, but do it async
          this.chartCache.create(user.id, chart.id, data);
        } else if (noSource) {
          return new Promise((resolve) => resolve(previewData.data));
        }

        return new Promise((resolve) => resolve(data));
      })
      .catch((error) => {
        return new Promise((resolve, reject) => reject(error));
      });
  }

  previewChart(chart, projectId, user, noSource) {
    return this.getPreviewData(chart, projectId, user, noSource)