gas-client

A client-side utility class that uses promises to call server-side Google Apps Script functions. This is a user-friendly wrapper of google.script.run.

It can also optionally be used in local development and is designed to interact with the Google Apps Script Dev Server used in the React / Google Apps Script project.

---

Installation

Install

> npm install gas-client
# or
> yarn add gas-client

import Server from 'gas-client';
const { serverFunctions } = new Server();

// We now have access to all our server functions, which return promises
serverFunctions
  .addSheet(sheetTitle)
  .then((response) => doSomething(response))
  .catch((err) => handleError(err));

Development mode

To use with Google Apps Script Dev Server, pass in a config object with allowedDevelopmentDomains indicating the localhost port you are using. This setting will be ignored in production (see below for more details).

import Server from 'gas-client';

const { serverFunctions } = new Server({
  allowedDevelopmentDomains: 'https://localhost:3000',
});

serverFunctions
  .addSheet(sheetTitle)
  .then((response) => doSomething(response))
  .catch((err) => handleError(err));

---

How to use

Using the gas-client utility class

The gas-client file lets you use promises to call and handle responses from the server, instead of using google.script.run:

// Google's client-side utility "google.script.run" works like this:
google.script.run
  .withSuccessHandler((response) => doSomething(response))
  .withFailureHandler((err) => handleError(err))
  .addSheet(sheetTitle);

// With this package we can now do this:
import Server from 'gas-client';
const { serverFunctions } = new Server();

// We now have access to all our server functions, which return promises
serverFunctions
  .addSheet(sheetTitle)
  .then((response) => doSomething(response))
  .catch((err) => handleError(err));

// Or we can use async/await syntax:
async () => {
  try {
    const response = await serverFunctions.addSheet(sheetTitle);
    doSomething(response);
  } catch (err) {
    handleError(err);
  }
};

Now we can use familiar Promises in our client-side code and have easy access to all server functions.

---

API

The config object takes: allowedDevelopmentDomains: A config to specifiy which domains are permitted for communication with Google Apps Script Webpack Dev Server development tool. This is a security setting, and if not specified, will block functionality in development.

allowedDevelopmentDomains will accept either a space-separated string of allowed subdomains, e.g. 'https://localhost:3000 https://localhost:8080' (notice no trailing slashes); or a function that takes in the requesting origin and should return true to allow communication, e.g. (origin) => /localhost:\d+$/.test(origin);

Production mode

In the normal Google Apps Script production environment, new Server() will have one available method:

• serverFunctions: an object containing all publicly exposed server functions (see example above).

Note that the allowedDevelopmentDomains configuration will be ignored in production, so the same code can and should be used for development and production.

Development mode

Development mode for the gas-client helper class will be run when:

1. the google client API cannot be found, i.e. an error is thrown with the message "ReferenceError: google is not defined", and

2. a process.env.NODE_ENV variable is set to 'development'. webpack.DefinePlugin can be set this up like this:

   plugins: [
     // ...,
     new webpack.DefinePlugin({
       'process.env': JSON.stringify({ NODE_ENV: 'development' }),
     }),
   ];

Calling new Server({ allowedDevelopmentDomains }) will create an instance with the following method in development mode:

• serverFunctions: a proxy object, used for development purposes, that mimics calling google.script.run. It will dispatch a message to the parent iframe (our custom Dev Server), which will call an app that actually interacts with the google.script.run API. Development mode will also handle the response and resolve or reject based on the response type. See the implementation for details on the event signature.