datastore/functions/index.js

// Copyright 2016 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

'use strict';

const {Datastore} = require('@google-cloud/datastore');

// Instantiates a client
const datastore = new Datastore();

const makeErrorObj = prop => {
  return new Error(
    `${prop} not provided. Make sure you have a "${prop.toLowerCase()}" property in your request`
  );
};

/**
 * Gets a Datastore key from the kind/key pair in the request.
 *
 * @param {object} requestData Cloud Function request data.
 * @param {string} requestData.key Datastore key string.
 * @param {string} requestData.kind Datastore kind.
 * @returns {object} Datastore key object.
 */
const getKeyFromRequestData = requestData => {
  if (!requestData.key) {
    return Promise.reject(makeErrorObj('Key'));
  }

  if (!requestData.kind) {
    return Promise.reject(makeErrorObj('Kind'));
  }

  return datastore.key([requestData.kind, requestData.key]);
};

/**
 * Creates and/or updates a record.
 *
 * @example
 * gcloud functions call set --data '{"kind":"Task","key":"sampletask1","value":{"description": "Buy milk"}}'
 *
 * @param {object} req Cloud Function request context.
 * @param {object} req.body The request body.
 * @param {string} req.body.kind The Datastore kind of the data to save, e.g. "Task".
 * @param {string} req.body.key Key at which to save the data, e.g. "sampletask1".
 * @param {object} req.body.value Value to save to Cloud Datastore, e.g. {"description":"Buy milk"}
 * @param {object} res Cloud Function response context.
 */
exports.set = async (req, res) => {
  // The value contains a JSON document representing the entity we want to save
  if (!req.body.value) {
    const err = makeErrorObj('Value');
    console.error(err);
    res.status(500).send(err.message);
    return;
  }

  try {
    const key = await getKeyFromRequestData(req.body);
    const entity = {
      key: key,
      data: req.body.value,
    };

    await datastore.save(entity);
    res.status(200).send(`Entity ${key.path.join('/')} saved.`);
  } catch (err) {
    console.error(new Error(err.message)); // Add to Stackdriver Error Reporting
    res.status(500).send(err.message);
  }
};

/**
 * Retrieves a record.
 *
 * @example
 * gcloud functions call get --data '{"kind":"Task","key":"sampletask1"}'
 *
 * @param {object} req Cloud Function request context.
 * @param {object} req.body The request body.
 * @param {string} req.body.kind The Datastore kind of the data to retrieve, e.g. "Task".
 * @param {string} req.body.key Key at which to retrieve the data, e.g. "sampletask1".
 * @param {object} res Cloud Function response context.
 */
exports.get = async (req, res) => {
  try {
    const key = await getKeyFromRequestData(req.body);
    const [entity] = await datastore.get(key);

    // The get operation returns an empty dictionary for non-existent entities
    // We want to throw an error instead
    if (!entity) {
      throw new Error(`No entity found for key ${key.path.join('/')}.`);
    }

    res.status(200).send(entity);
  } catch (err) {
    console.error(new Error(err.message)); // Add to Stackdriver Error Reporting
    res.status(500).send(err.message);
  }
};

/**
 * Deletes a record.
 *
 * @example
 * gcloud functions call del --data '{"kind":"Task","key":"sampletask1"}'
 *
 * @param {object} req Cloud Function request context.
 * @param {object} req.body The request body.
 * @param {string} req.body.kind The Datastore kind of the data to delete, e.g. "Task".
 * @param {string} req.body.key Key at which to delete data, e.g. "sampletask1".
 * @param {object} res Cloud Function response context.
 */
exports.del = async (req, res) => {
  // Deletes the entity
  // The delete operation will not fail for a non-existent entity, it just
  // doesn't delete anything
  try {
    const key = await getKeyFromRequestData(req.body);
    await datastore.delete(key);
    res.status(200).send(`Entity ${key.path.join('/')} deleted.`);
  } catch (err) {
    console.error(new Error(err.message)); // Add to Stackdriver Error Reporting
    res.status(500).send(err.message);
  }
};