How To Ignore Cache For A Specific Query

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Introduction

As a Flutter developer, you may encounter situations where you need to fetch the latest data for a specific query, but the cache is holding onto outdated information. In this article, we will explore how to ignore cache for a specific query in Flutter, using the GraphQL library.

Understanding Cache in GraphQL

Before we dive into the solution, it's essential to understand how cache works in GraphQL. The GraphQL library in Flutter uses a cache to store the results of previous queries. This cache is designed to improve performance by reducing the number of requests made to the server. However, in some cases, you may need to fetch the latest data, which is not stored in the cache.

Ignoring Cache for a Specific Query

To ignore cache for a specific query, you can use the cachePolicy property of the GraphQLService class. This property allows you to specify the cache policy for a particular query.

Here's an example of how you can use the cachePolicy property to ignore cache for a specific query:

Future<void> refreshProfile() async {
  var req = GMeReq();
  var data = await GraphQLService()
      .client
      .request(req, cachePolicy: CachePolicy.ignoreCache)
      .firstWhere((data) => data.loading == false);

  currentProfile.value = User.fromMeData(data.data);
  await saveAccount();
}

In this example, we're using the ignoreCache policy to ignore the cache for the refreshProfile query. This will force the client to fetch the latest data from the server, rather than relying on the cached results.

Custom Cache Policy

If you need more control over the cache policy, you can create a custom cache policy class that extends the CachePolicy class. Here's an example of how you can create a custom cache policy class:

class CustomCachePolicy extends CachePolicy {
  @override
  bool shouldFetchFromCache(ExecutionResult result) {
    // Return true if the result is cached, false otherwise
    return false;
  }
}

In this example, we're creating a custom cache policy class that always returns false, indicating that the result should not be fetched from the cache.

Using the Custom Cache Policy

To use the custom cache policy, you can pass an instance of the CustomCachePolicy class to the cachePolicy property of the GraphQLService class:

Future<void> refreshProfile() async {
  var req = GMeReq();
  var data = await GraphQLService()
      .client
      .request(req, cachePolicy: CustomCachePolicy())
      .firstWhere((data) => data.loading == false);

  currentProfile.value = User.fromMeData(data.data);
  await saveAccount();
}

In this example, we're using the custom cache policy class to ignore the cache for the refreshProfile query.

Conclusion

In this article, we've explored how to ignore cache for a specific query in Flutter using the GraphQL library. We've discussed the cachePolicy property of the GraphQLService class and how to use it to ignore cache for a specific query. We've also created a custom cache policy class and demonstrated how to use it to ignore cache for a specific query. By following the techniques outlined in this article, you can ensure that your Flutter app always fetches the latest data for a specific query, even if the cache is holding onto outdated information.

Additional Tips and Tricks

Here are some additional tips and tricks to help you work with cache in GraphQL:

  • Use the cachePolicy property: The cachePolicy property is a powerful tool that allows you to control the cache behavior for a specific query. Use it to ignore cache for a specific query or to specify a custom cache policy.
  • Create a custom cache policy class: If you need more control over the cache policy, create a custom cache policy class that extends the CachePolicy class.
  • Use the shouldFetchFromCache method: The shouldFetchFromCache method is a key part of the cache policy class. Use it to determine whether the result should be fetched from the cache or not.
  • Test your cache policy: Test your cache policy to ensure that it's working as expected. Use tools like the GraphQL client to inspect the cache and verify that the results are being fetched correctly.

Example Use Cases

Here are some example use cases for ignoring cache for a specific query:

  • Real-time updates: If you need to fetch real-time updates for a specific query, you may want to ignore cache to ensure that you get the latest data.
  • User authentication: If you're working with user authentication, you may want to ignore cache to ensure that the user's credentials are always up-to-date.
  • Payment processing: If you're working with payment processing, you may want to ignore cache to ensure that the payment information is always accurate and up-to-date.

Conclusion

Q: What is cache in GraphQL?

A: Cache in GraphQL refers to the storage of query results in memory or on disk. This allows the client to reuse the results of previous queries, reducing the number of requests made to the server.

Q: Why would I want to ignore cache for a specific query?

A: You may want to ignore cache for a specific query if you need to fetch the latest data, even if the cache is holding onto outdated information. This is particularly useful for real-time updates, user authentication, and payment processing.

Q: How do I ignore cache for a specific query in Flutter?

A: To ignore cache for a specific query in Flutter, you can use the cachePolicy property of the GraphQLService class. This property allows you to specify the cache policy for a particular query.

Q: What are the different cache policies available in GraphQL?

A: The following cache policies are available in GraphQL:

  • CachePolicy.ignoreCache: Ignores the cache for a specific query.
  • CachePolicy.cacheFirst: Fetches the result from the cache first, and then from the server if the cache is empty.
  • CachePolicy.networkOnly: Fetches the result from the server only, ignoring the cache.

Q: How do I create a custom cache policy class in GraphQL?

A: To create a custom cache policy class in GraphQL, you can extend the CachePolicy class and override the shouldFetchFromCache method.

Q: What is the shouldFetchFromCache method in GraphQL?

A: The shouldFetchFromCache method is a key part of the cache policy class. It determines whether the result should be fetched from the cache or not.

Q: How do I test my cache policy in GraphQL?

A: To test your cache policy in GraphQL, you can use tools like the GraphQL client to inspect the cache and verify that the results are being fetched correctly.

Q: What are some example use cases for ignoring cache for a specific query?

A: Some example use cases for ignoring cache for a specific query include:

  • Real-time updates
  • User authentication
  • Payment processing

Q: Can I use a custom cache policy class with the GraphQLService class?

A: Yes, you can use a custom cache policy class with the GraphQLService class by passing an instance of the custom class to the cachePolicy property.

Q: How do I handle errors when ignoring cache for a specific query?

A: To handle errors when ignoring cache for a specific query, you can use try-catch blocks to catch any exceptions that may occur during the query execution.

Q: Can I use a cache policy with a specific query in a Flutter widget?

A: Yes, you can use a cache policy with a specific query in a Flutter widget by passing the cache policy to the GraphQLService class and using the resulting data in your widget.

Q: How do I optimize my cache policy for a specific query?

A: To optimize your cache policy for a specific query, you can use techniques like caching the results of previous queries, using a cache expiration policy, and optimizing the cache storage.

Q: Can I use a cache policy with a specific query in a GraphQL subscription?

A: Yes, you can use a cache policy with a specific query in a GraphQL subscription by passing the cache policy to the GraphQLService class and using the resulting data in your subscription.

Conclusion

In conclusion, ignoring cache for a specific query is a powerful technique that can help you ensure that your Flutter app always fetches the latest data. By using the cachePolicy property and creating a custom cache policy class, you can control the cache behavior for a specific query and ensure that your app always gets the latest data.