Migrating a source plugin to v4: documentation code examples seem incomplete

[cdanny358]

In this source plugin migration document, section 2 talks about data mutations happening during sourceNodes or onCreateNode. However, the example code for The New Way has this line:

for (const { url } of remoteImages) {

remoteImages isn't defined anywhere, and nothing like it appears in The Old Way. How is this variable supposed to be generated?

[LekoArts]

You'd get the remoteImages from the // code to fetch data portion. So you call an API, get a list of URLs and then you iterate over that to download the file and create the node.

[cdanny358]

So now, rather than the remote images automatically appearing during createResolvers, we have to manually fetch them, at a point in the process where graphql isn't available, and you have to use either an external graphql client, or resort to a REST API with axios, as fetch doesn't work inside gatsby-node.js? I'm not sure I see how this is progress.

[LekoArts]

In createResolvers you also manually fetched them with the helper function createRemoteFileNode, it only abstracted the fetching logic away. fetch not being available in Node.js is a node limitation, not a Gatsby one.

You have two options to migrate:

• https://www.gatsbyjs.com/docs/reference/release-notes/migrating-source-plugin-from-v3-to-v4/#2-data-mutations-need-to-happen-during-sourcenodes-or-oncreatenode
• Source your image in onCreateNode: https://www.gatsbyjs.com/docs/how-to/images-and-media/preprocessing-external-images/

In order for e.g. DSG to work correctly we had to make this change.

[cdanny358]

Perhaps I should be a bit more specific about the problems I'm running into: I use Directus as my database of choice, which has a graphql interface, a REST interface, and a dedicated SDK. To source items from Directus, I use gatsby-source-graphql, then add a createResolvers call to generate remote file nodes for all the images used by the program. If I try to move the file generation code to onCreateNode, I run into the problem that almost all the nodes returned by gatsby-source-graphql are of type SitePage, with single nodes of types SiteBuildMetadata and GraphQLSource at the head. None of these nodes contain any information about the remote files contained within. It seems like in Gatsby V4 I would be forced to create a Directus source plugin from scratch, using either the REST API or the dedicated SDK, which is a huge amount of work compared to the present situation. Am I missing something obvious?