Google Apps Script

Google Apps Script

Developer(s)	Google
Initial release	August 19, 2009[1]
Development status	Active
Written in	JavaScript
Operating system	Cross-platform
Type	Web application framework, Scripting language
Website	script.google.com

Google Apps Script is a cloud based scripting language for light-weight application development in the Google Apps platform. It is based on JavaScript 1.6 with some portions of 1.7 and 1.8 and provides subset of ECMAScript 5 API,^[2] however instead of running on the client, it gets executed in the Google Cloud. According to Google, Google Apps Script "provides easy ways to automate tasks across Google products and third party services.".^[3] Apps Script is also the tool that powers the add-ons for Google Docs, Sheets & Forms.^[4]

Benefits

1. Based on JavaScript; easy to learn.
2. Cloud based debugger for debugging App Scripts in the web browser.
3. It can be used to create simple tools for an organization's internal consumption.
4. It can be used to perform simple system administration tasks.
5. Community-based support model.

Limitations

1. Processing limitations: as a cloud-based service, Google Apps Script limits the time that a user's script may run, as well as limiting access to Google services.
2. Currently Google Apps Store does not allow connection to internal (behind-the-firewall) corporate databases, which is key to building business apps. Similarly, lack of other connectivity, such as LDAP connectivity, limits the level to which GAS can be used in the enterprise.
3. Due to the cloud nature of Google Apps script, functions related to date and time will produce results that seems to be incorrect due to the data changing timezones. Using Date/Time objects and functions without very precise declaration and thorough testing may result in inaccurate results.^[5]

Example

The following code demonstrate use of Google Apps Script UI Services and DocList Services to display contents of a Google Drive folder in Tree format.

Notice the use of JavaScript and the use of Google Web Toolkit widgets (Google also introduced the HTML Service in June 2012, as an alternative to GWT widgets. It lets you serve web pages that can interact with server-side Apps Script functions).

function doGet(e) {   
  var app = UiApp.createApplication();
  var scrollPanel = app.createScrollPanel(); // Scroll Panel is a Google Web Toolkit Widget
  tree = app.createTree(); // Tree is a Google Web Toolkit Widget
  tree.addItem(buildTree(app, "Enterprise 2.0 - Saqib"));
  scrollPanel.add(tree);  
  scrollPanel.setHeight("500");
  app.add(scrollPanel);
  return app;
}
 
function buildTree(a, searchTerm) {
  var tree = a.createTreeItem(); // TreeItem is Google Web Toolkit Widget
  tree.setText(searchTerm);

  // Use of the Google Apps Script DocList Service to retrieve the collections.
  var folders = DocsList.getFolder(searchTerm).getFolders(); 
  for (var i = 0; i < folders.length; i++) {
    tree.addItem(buildTree(a, folders[i].getName())).setState(true, true);
  }

  var files = DocsList.getFolder(searchTerm).getFiles();
  for (var i = 0; i < files.length; i++) {    
    if (files[i].getType() == "document") {
      urlBase = "https://docs.google.com/document/edit?id=";
      iconHTML = "https://docs.google.com/images/doclist/icon_7_document_list.png";
    } 
    else if (files[i].getType() == "spreadsheet") {      
      urlBase = "https://spreadsheets.google.com/ccc?key=";
      iconHTML = "https://docs.google.com/images/doclist/icon_7_spreadsheet_list.png";
    }
    else if (files[i].getType() == "presentation") {       
      urlBase = "https://docs.google.com/present/edit?id=";
      iconHTML = "https://docs.google.com/images/doclist/icon_7_presentation_list.png";
    }
    else if (files[i].getType() == "drawing") {       
      urlBase = "https://docs.google.com/drawings/edit?id=";
      iconHTML = "https://docs.google.com/images/doclist/icon_7_drawing_list.png";       
    }
    else {
      urlBase = "https://docs.google.com/fileview?id=";
      iconHTML = "https://docs.google.com/images/doclist/icon_7_generic_list.png";    
    }    
     
    var image = a.createImage(iconHTML);
    var fileLabel = a.createAnchor(files[i].getName(), urlBase+ files[i].getId());     
    var fileLabelPanel = a.createHorizontalPanel();
    fileLabelPanel.add(image);
    fileLabelPanel.add(fileLabel);     
    tree.addItem(fileLabelPanel).setState(true, true);
  }   
  return tree;   
}

Embedding HTML in GAS with a GWT Widget:^[6]

function doGet() {
  var app = UiApp.createApplication();
  app.add(app.createHTML("<b>Hello World!</b>"));
  return app;
}

Add-ons

In March 2014, Google introduced add-ons for Docs and Sheets (soon followed by Forms). The add-on stores let users add extra features to Google editors, such as mail-merging, workflows, diagrams builders,... All add-ons are either 100% built with Google Apps Script or simply use Apps Script to display a UI in the Google editors while relying on an external backend to perform some tasks. For example, MailChimp, a mail-merging tool, has an add-on for Google Docs that communicates with MailChimp platform to send emails.

Before add-ons, it was possible to publish scripts for Google Sheets in the Script Gallery. When users installed scripts through this gallery, a copy of the Apps Script code was installed on the user's Sheet. With add-ons, the source code is not visible to the end user and everyone is using the latest version published by the developer. This new approach make it easier to support existing code and helped convince several companies, such as MailChimp or LucidChart to invest in Google Apps Script.

As part of the add-ons release, Google also introduced a UI Style Guide^[7] and CSS package to help developers built add-ons that integrate smoothly into the editors. Each add-on is also reviewed by Google before its publication and developers can benefit from advises from Googlers to provide a better user experience. It is not possible to embed ads in add-ons but it is possible to monetize them.^[8]

See also

Google App Engine

References

1. Meyer, David (August 20, 2009). "Google Apps Script gets green light". CNet. Retrieved 26 March 2011.
2. Kienle, Holger (May–June 20102010). "It's About Time to Take JavaScript (More) Seriously". IEEE Software 27 (3): 60–62. doi:10.1109/MS.2010.76. Retrieved 25 March 2011. Check date values in: |date= (help)
3. Google Apps Script
4. Bring a little something extra to Docs and Sheets with add-ons
5. "Issue 1035: utilities.formatdate subtracts a day.". Retrieved 17 December 2012.
6. GAS HTML class documentation
7. UI Style Guide for Add-ons
8. I've started a little experiment...

External links

• Official website
• developers.google.com/apps-script/case-studies