@nzz/q-server/processing/rendering-info-fetcher.js

__Q__ is a system that lets journalists create visual elements for stories. It is developed by [NZZ Storytelling](https://www.nzz.ch/storytelling) and used in the [NZZ](https://www.nzz.ch) newsroom.

const querystring = require('querystring');
const fetch = require('node-fetch');
const clone = require('clone');
const deepmerge = require('deepmerge');
const Boom = require('boom');
const server = require('../server').getServer();
const deleteMetaProperties = require('../helper/meta-properties').deleteMetaProperties;

function isToolConfiguredForTarget(toolName, target, tools) {
  let endpointConfig = tools.get(`/${toolName}/endpoint`, { target: target })
  if (endpointConfig) {
    return true;
  }
  return false;
}

function getRenderingInfo(data, target, toolRuntimeConfig) {
  // we will change data in this function, so we clone it here to have be pure
  data = clone(data);
  const toolName = data.tool;

  if (!isToolConfiguredForTarget(toolName, target, server.settings.app.tools)) {
    return Promise.reject(Boom.notImplemented(`no endpoint for tool ${toolName} and target ${target}`));
  }

  const baseUrl = server.settings.app.tools.get(`/${toolName}/baseUrl`, { target: target })
  const endpoint = server.settings.app.tools.get(`/${toolName}/endpoint`, { target: target })
  let requestUrl;
  if (endpoint.hasOwnProperty('path')) {
    requestUrl = `${baseUrl}${endpoint.path}`;
  } else if (endpoint.hasOwnProperty('url')) {
    requestUrl = endpoint.url;
  } else {
    throw new Error('Endpoint has no path nor url configured');
  }

  // add _id, createdDate and updatedDate as query params to rendering info request
  let queryParams = ['_id', 'createdDate', 'updatedDate'];
  let query = {};
  for (let queryParam of queryParams) {
    if (data.hasOwnProperty(queryParam) && data[queryParam]) {
      query[queryParam] = data[queryParam];
    }
  }
  let queryString = querystring.stringify(query);

  // strip the meta properties before sending the data to the tool service
  const body = {
    item: deleteMetaProperties(data),
    toolRuntimeConfig: toolRuntimeConfig
  }

  return fetch(`${requestUrl}?${queryString}`, {
      method: 'POST',
      body: JSON.stringify(body),
      headers: {
        'Content-Type': 'application/json'
      }
    })
    .then(response => {
      if (!response.ok) {
        return response.json()
          .then(data => {
            throw Boom.create(response.status, data.message);
          })
      } else {
        return response.json();
      }
    })
    .then(renderingInfo => {
      // add stylesheets configured in tool config
      if (endpoint.stylesheets && endpoint.stylesheets.length) {
        console.log('DEPRECATION NOTICE: endpoint.stylesheets support will be removed in Q server 3.0. Use endpoint.additionalRenderingInfo.stylesheets');
        if (Array.isArray(renderingInfo.stylesheets)) {
          renderingInfo.stylesheets = renderingInfo.stylesheets.concat(endpoint.stylesheets);
        } else {
          renderingInfo.stylesheets = endpoint.stylesheets;
        }
      }     

      // add scripts configured in tool config
      if (endpoint.scripts && endpoint.scripts.length) {
        console.log('DEPRECATION NOTICE: endpoint.scripts support will be removed in Q server 3.0. Use endpoint.additionalRenderingInfo.scripts');
        renderingInfo.scripts = renderingInfo.scripts.concat(endpoint.scripts)
      }

      return renderingInfo;
    })
    .then(renderingInfo => {
      // check if the tool config has additional renderingInfo and apply it if so
      if (endpoint.additionalRenderingInfo) {
        renderingInfo = deepmerge(renderingInfo, endpoint.additionalRenderingInfo, {
          arrayMerge: (destArr, srcArr) => {
            return srcArr.concat(destArr);
          }
        });
      }
      return renderingInfo;
    })
    .then(renderingInfo => {
      // add the path to the stylesheets returned from rendering service if they have a name property
      if (renderingInfo.stylesheets !== undefined && renderingInfo.stylesheets.length > 0) {
        for (var i = 0; i < renderingInfo.stylesheets.length; i++) {
          let stylesheet = renderingInfo.stylesheets[i];
          if (stylesheet.name !== undefined) {
            stylesheet.path = `/tools/${toolName}/stylesheet/${stylesheet.name}`;
          }
        }
      }

      // add the path to the scripts returned from rendering service if they have a name property
      if (renderingInfo.scripts !== undefined && renderingInfo.scripts.length > 0) {
        for (var i = 0; i < renderingInfo.scripts.length; i++) {
          let script = renderingInfo.scripts[i];
          if (script.name !== undefined) {
            script.path = `/tools/${toolName}/script/${script.name}`;
          }
        }
      }

      return renderingInfo;
    })
}

module.exports = {
  getRenderingInfo: getRenderingInfo
}