Скачать или смотреть Understanding Firebase: Do get() and onSnapshot() Share the Same Cache?

Explore how Firebase's `get()` and `onSnapshot()` methods interact with the offline cache when retrieving data. Get insights into optimizing your app's performance!
---
This video is based on the question https://stackoverflow.com/q/63330842/ asked by the user 'Ismael' ( https://stackoverflow.com/u/11401702/ ) and on the answer https://stackoverflow.com/a/63330999/ provided by the user 'Doug Stevenson' ( https://stackoverflow.com/u/807126/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Does get() and onSnapshot() share the same cache internally?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding Firebase: Do get() and onSnapshot() Share the Same Cache?

When working with Firebase's Cloud Firestore, developers often face decisions regarding data retrieval methods. Two commonly used methods are doc.get() and doc.onSnapshot(), each serving its unique purpose. However, a question arises: Do these two methods share the same cached data internally especially when offline mode is enabled?

In this guide, we will unravel this question and explain how cache sharing works between these two methods.

The Core Question

Imagine you have an application where you fetch a document's data using doc.get(). Later on, you decide to set up a real-time listener on that same document using doc.onSnapshot(). The burning question is: does the listener retrieve the cached data obtained from the earlier get() call, thereby optimizing retrieval time by avoiding a server request?

The Solution

Single Offline Cache

The answer to the question is a resounding yes. When using Firebase's offline capabilities, there exists a single offline cache that both get() and onSnapshot() utilize. This means:

Unified Cache Access: Regardless of whether you retrieve data through get() or onSnapshot(), if the data is cached, you will access the same cached content.

Performance Optimization: As a result, the onSnapshot() listener will have quicker access to data, potentially leading to faster app performance. This is especially beneficial in scenarios where minimizing server requests is important.

Key Benefits of Cache Sharing

Understanding how get() and onSnapshot() share the cache can significantly enhance your development process. Here are some advantages:

Faster Loading Times: Since the listener can quickly retrieve previously cached data, your app can provide users with a seamless experience.

Reduced Server Load: By leveraging cached data, you minimize the number of requests sent to the server, reducing bandwidth usage and improving overall efficiency.

Simpler Code Management: You can handle data retrieval through one unified cache, simplifying your codebase and eliminating redundancy.

Best Practices

To maximize the benefits of using Firebase’s caching with get() and onSnapshot(), consider the following best practices:

Enable Offline Persistence: Ensure your Firebase app has offline persistence enabled so that data caching can take place.

Use Listeners Wisely: Employ onSnapshot() for real-time updates to your UI while using get() for one-time data retrieval, understanding that both will benefit from the same cache.

Monitor Usage: Keep an eye on your app's performance metrics to assess the impact of utilizing both methods together.

Conclusion

In summary, the relationship between get() and onSnapshot() is crucial for developers using Firebase. Their shared cache enables a more responsive app, optimizing performance and efficiency. By tapping into this single offline cache, you can enhance your user's experience while maintaining a clean and effective codebase.

Now you can confidently build applications that make the most of Firebase's powerful features, ensuring that every data retrieval is both fast and efficient.