I’m working on a GWT project and need to connect it to a Google Sheets document to store and retrieve data like a simple database. The main challenge I’m facing is figuring out the right approach for this integration.
From what I understand, the standard Google API Client Library for Java might not work here because it’s designed for server-side Java applications and relies on classes like java.net.HttpURLConnection which aren’t available in GWT’s client-side environment.
I’m wondering if I should go with JSNI (JavaScript Native Interface) and use the JavaScript version of Google’s API instead. Has anyone successfully implemented something similar? What would be the most efficient way to handle authentication and data operations in this setup?
Direct JSNI integration with Google Sheets API works great if you want everything client-side. I built this last year for a data entry app - worked well once I figured out the setup. You’ll use the gapi.client JavaScript library through JSNI wrapper methods. OAuth2 implicit flow makes auth simple - users log in with Google and you get the access token right in the browser. The tricky part is handling JavaScript promises inside GWT’s callback system, but wrapper classes fix that. Performance was fine for us with ~500 rows. Just make sure you handle errors properly since client-side requests fail more often, and think about caching if you’re reading data frequently.
skip both - just use google apps script as middleware. set up a doPost/doGet function for sheet operations, then call it from gwt with requestBuilder. no oauth headaches, no server setup. worked great for my inventory tracker last month.
You’re absolutely right about the Java client library limitations in GWT. Hit the same issue two years ago building a project management dashboard. The JavaScript API through JSNI works, but I went with a hybrid approach that saved me tons of headaches. Created a simple REST endpoint on my server that proxies to Google Sheets API. Server handles OAuth and sheet operations using the standard Java client library, while GWT just makes regular HTTP requests to my endpoints. You get the reliability of server-side without JSNI complexities. Stored OAuth tokens server-side and tied them to user sessions. More initial setup, but way more maintainable and no API key exposure in client code. Plus debugging’s much easier when things break.