Drupal 10

I previously looked at injecting context providers into context aware plugins. This time I will explore more about creating our own context providers to plug into this system.

The context provider system is an ideal way to provide context to context aware plugins, with blocks being the prime example. You would use a context provider to inject an entity or value into the block so that actions can be taken using that data.

For example, we could load the currently loaded node from the route object using the context so that we didn't have to bake the route provider logic into the block.

The values we inject also plug into the cache systems and so we don't need to worry about making sure we integrate the cache systems within the block system. That is all taken care of upstream.

When developing plugins in Drupal a common task is to inject context so that certain tasks can be performed.

For example, we might have a block plugin that needs to know about the content entity of the page it is currently being rendered on. We could potentially inject the routing system into the plugin and use this to find the currently loaded entity, but there is a drawback to this. There is a fair amount of custom logic involved in finding the content entity from the route and we would need to use this same code every time we want to solve this problem.

This method also hard codes the route into the plugin and so makes it difficult to select any other sort of context. There is also a problem when it comes to caching as you also need to inform the plugin about the use of routing so that the caching layers know how to cache things.