feat: caching

[robinmetral]

This is already handled by Gatsby pretty well, but the Cache API can be leveraged to make sure the pulled images are persisted between builds.

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Relevant Gatsby PRs about caching for plugins:

• Guide plugin authors to write source plugins that correctly interact with the cache gatsbyjs/gatsby#11785
• feat(gatsby): selective cache invalidation gatsbyjs/gatsby#8379
• chore(gatsby-source-filesystem): allow createRemoteFileNode and createFileNodeFromBuffer to receive getCache gatsbyjs/gatsby#22090

Relevant docs:

• https://www.gatsbyjs.org/docs/creating-a-source-plugin/#caching-data-between-runs

[Vacilando]

This would really be lovely - potentially a huge time-saver.

Cache API by itself very easy to use:

let obj = await cache.get(cacheKey)
...
await cache.set(cacheKey, obj)

Though I am not sure how complex will it be to use it for each and every fetched image.

[robinmetral]

That sounds great @Vacilando! I've been pushing this back because I never really used the Gatsby cache explicitly 😅—do you want to open a PR for it?

[Vacilando]

@robinmetral I've looked into caching imageFile in onCreateNode() - then realized that if the Gatsby flag PRESERVE_FILE_DOWNLOAD_CACHE the image files are already being used from cache (thanks to the use of plugin gatsby-source-filesystem).

Where else do you see we could use caching to improve the cache efficiency?

[moonmeister]

Thanks for your interest in this project. This plugin is moving into the Gatsby User Collective and this repo will be archived. Please open an issue in that repository, submit a PR if you'd like to see this implemented, or Join us on Discord if you have questions!