This is the final post of this series and we will understand the mechanism of storing data on the server-side using an out of box feature of API Policy in Cloudhub.
Applying API Policy Caching in CloudHub
In my previous post, I demonstrated the step-by-step guide on how to implement caching inside a Mule4 project. I will demonstrate a second approach on how to achieve the same end result but using a better, more innovative way from CloudHub meaning you don’t need to implement it from inside your Mule4 project.
The following steps are applicable once your application is deployed in the environment you selected. Ensure you have permission to apply ‘Policies’.
Go to API Manager, select your application on API Administration, and click on your application.
In the Policies section, click on Apply New Policy
It will display a window with all categories applicable to your application.
Configure with the following mandatory fields:
|HTTP Caching Key||#[attributes.requestPath]|
|Maximum Cache Entries||10000|
|Entry Time To Live (in seconds)||600|
|Conditional Request Caching Expression||#[attributes.method == ‘GET’ or attributes.method == ‘HEAD’]|
|Conditional Response Caching Expression||#[[200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501] contains attributes.statusCode]|
Method & Resource conditions:
Apply configurations to all API methods & resources
Confirm and verify all configurations as image below
Applying and enforcing the API Policy will need to redeploy the application.
As a result, logs will reflect the following:
Testing HTTP Caching policy
Use curl to send a request and obtain a verbose response
Verify Object Store at application
As a result, the HTTP request path is used to check against policy resource matching.
Testing second time Caching Policy
New keys on Object Store
Re-testing first request.
Pay special attention to the ‘age’ header. (In seconds)
Once TTL is reached, Object Store is updated
Enables the underlying cache to be distributed. Select this option if the deployment target is a cluster or multiple cloudhub workers. To use distributed caching in Cloudhub the objectStoreV2 checkbox must be checked in runtime manager application properties.
Indicates if the cache will be persistent across runtime restart. To use persistent caching in Cloudhub the objectStoreV2 checkbox must be checked in runtime manager application properties.
HTTP Caching Directives
Enables the usage of Cache-Control header directives. Supported headers are “Cache-Control” with supported values: max-age=<seconds>, s-maxage=<seconds>, no-cache and no-store; and “Expires” whose value is <date in RFC 1123 format> (E.g. “Mon, 25 June 2018 19:29:52 GMT”). It supports comma-separated multiple values.
Conditional Request Caching Expression
Only the requests for which this expression is true will interact with the cache. This field is a dataweave expression. For further information on additional variables available check the documentation cited in the HTTP Caching key description.
#[attributes.method == ‘GET’ or attributes.method == ‘HEAD’]
Conditional Response Caching Expression
Only the responses for which this expression is true will be stored in the cache. This field is a dataweave expression. For further information on additional variables available check the documentation cited in the HTTP Caching key description.
#[[200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501] contains attributes.statusCode]
Configuring Policy Parameters
Summary of configuration available in API Manager.
|HTTP Caching Key||Dataweave expression.||#[attributes.requestPath]||Yes|
|Maximum Cache Entries||A maximum number of entries that can be stored in the cache at any given time.||10000||Yes|
|Entry Time To Live||Amount of time (seconds) after which the entry expires from the cache||600||Yes|
|Distributed||To be distributed among different nodes in a cluster.||false||Yes|
|Persistent Cache||To persist between different restarts of the mule instance.||false||Yes|
|Follow HTTP Caching directives||Use of Cache-Control header directives||true||Yes|
|Conditional Request Caching Expression||Dataweave expression to determine which requests are cached.#[attributes.method == ‘GET’ or attributes.method == ‘HEAD’]||–||No|
|Conditional Response Caching Expression||Dataweave expression to determine which responses are cached.#[[200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501] contains attributes.statusCode]||–||No|
API REST Countries API
Obtain a Free API Key
Retrieve a list of countries
Retrieve a country – FullText
Retrieve a country – Partial
Retrieve a country by capital
Read the other S Platform blog posts written by our experts.
If you are interested in working with the Devoteam S Platform, click here!