SUMMARY

Currently, the filters state is being stored in the URL to allow users to preserve their current interactions in case of a refresh and also to share specific states with other users. The most common example is when a user, after exploring a dashboard using filters, wishes to share their findings with other users.

The problem with this approach is that when the size of the state is big, it provokes URL length problems with the major browsers.

The proposed solution in this PR is to store the filters state on the server-side and keep in the URL only a secure key that gives access to the stored content. To do that, we'll extend the current dashboard endpoint with an additional path that supports the storage of information in the form of key-value entries. By making this endpoint relative to the main resource we can reuse the security model and access grants.

The additional endpoint and the supported operations are:

POST api/v1/dashboard/<id>/filter_state

BODY 
{
   // Any type of JSON supported text.
   value: <string>,
}

RESPONSE
{
   // The key generated on the server-side
   key: <string>
}

PUT api/v1/dashboard/<id>/filter_state/<key>

BODY
{
   // Any type of JSON supported text.
   value: <string>,
}

RESPONSE
{
   // The result of the operation
   message: <string>
}

GET api/v1/dashboard/<id>/filter_state/<key>

RESPONSE
{
   // Any type of JSON supported text.
   value: <string>,
}

DELETE api/v1/dashboard/<id>/filter_state/<key>

RESPONSE
{
   // The result of the operation
   message: <string>
}

The keys are generated on the server-side using the https://docs.python.org/3/library/secrets.html#secrets.token_urlsafe function and the value can be any JSON supported text.

To store the key-value entries, this PR uses Flask-Caching, which enables support to different backends like Redis, Memcached, file system, etc. It also allows the configuration of expiration times for the stored entries in order to discard the ones that are not being used anymore and optimize the required storage space.

This PR also allows a configuration to preserve actively accessed entries by renewing the expiration time every time a value is retrieved.

Follow-up of #17337

TESTING INSTRUCTIONS

1 - Execute Python tests
2 - All tests should pass

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API