Cache management

Here we describe the strategy we use to manage the cache.

We have three kinds of services:
  • Without any cache (no_cache).
  • Cache related to the application version (public_cache).
  • Cache related to the application version and the current role (private_cache).

For some service we also set the header Vary to Accept-Language to have one cache per language.

Server side

On the server side we set the Cache-Control header with a different value depending on the cache type.

  • no_cache: no-cache.
  • public_cache: max-age=864000, public.
  • private_cache: max-age=864000, public or max-age=864000, private if we are logged in.

The max-age is configurable in a vars file in the default_max_age attribute.

Client side

On the client side, some attributes are added in the URL parameters to force to have the right version of the cache. It will be done automatically by the route_url method.

  • no_cache: nothing to add (be sure that the lib does not add custom cache).
  • public_cache: add the query param named cache_version.
  • private_cache: add the query param named cache_version and role.

In an ngeo client, you have the cache_version variable.

In a CGXP client, you have the variables version_params, version_role_params and version_role_user_params that help you to create the right url.

Service list

No cache

  • cgxp_index
  • ngeo index
  • mobile index
  • api js
  • xapi js
  • api help
  • xapi help
  • auto login form (loginform403)
  • login
  • logout
  • login change password
  • echo
  • export csv
  • full text search
  • layers/read_many
  • layers/read_one
  • layers/count
  • layers/create
  • layers/update
  • layers/delete
  • WMS/GetMap
  • WMS/GetFeatureInfo
  • WFS/GetFeature
  • WFS all POST
  • PDF report
  • print/report.pdf
  • print/status
  • print/get file
  • profile
  • raster
  • shortener

Public cache

  • login form
  • layers/enumerate_attribute_values
  • WMS/GetLegendGraphic

Private cache

  • cgxp viewer
  • mobile config
  • themes
  • layers/metadata
  • WMS/GetCapabilities
  • WMS/DescribeLayer
  • WFS/GetCapabilities
  • WFS/DescribeFeaturesType
  • print/capabilities.json