feat: update gatsby plugins to use new createContentDigest helper

[DSchau]

Summary

We recently added a createContentDigest helper which is exposed to any gatsby plugin. This internalizes the unique key creation, which changes based on changing content.

We've added this to several packages, and we should now add it to any/all packages.

Basic example

Any plugin that implements the following code snippet (or close to it) can be refactored with this new helper:

const crypto = require(`crypto`)

module.exports = ({ createNode }) => {
  const obj = { whatever: true }

  // this is the key one!
  const contentDigest = crypto
  .createHash(`md5`)
  .update(JSON.stringify(obj))
  .digest(`hex`)

  createNode() // use content digest
}

can be replaced with

const { createContentDigest } = require('gatsby-core-utils');


module.exports = ({ createNode }) => {
  const obj = { whatever: true }

  // this is the key one!
  const contentDigest = createContentDigest(obj)

  createNode() // use content digest
}

Motivation

Cleaning up code and keeping it DRY 💪

Additional Info

Any plugin that implements this new API should also bump it's peerDependency on gatsby, e.g.

{
  "peerDependencies": {
    "gatsby": ">2.0.15"
  }
}

Greetings,

I would like to start contributing to Gatsby by helping with this feature / enhancement.

For clarification,

I was going through the published plugins library, and identified the unique key creation pattern stated above in the gatsby-source-filesystem plugin:

src/create-file-node.js

if (stats.isDirectory()) {
  const contentDigest = crypto
    .createHash(`md5`)
    .update(
      JSON.stringify({ stats: stats, absolutePath: slashedFile.absolutePath })
    )
    .digest(`hex`)

An example enhanced refactor could be:

exports.createFileNode = async (
  pathToFile,
  createContentDigest, // <-- add this
  createNodeId,
  pluginOptions = {}
) => {
  // other code

  if (stats.isDirectory()) {
    const obj = { stats: stats, absolutePath: slashedFile.absolutePath };

    const contentDigest = createContentDigest(obj)
                       // createContentDigest({ stats: stats, ... });

However,

src/create-remote-file-node.js

// line 223
const fileNode =
  await createFileNode(
    filename,
    createContentDigest, // <-- where would this come from? ****
    createNodeId,
    {}
  );

I'm not sure how to pass createContentDigest as a parameter nor where it comes from (is it the "main" repo?). The same situation is found in src/gatsby-node and in general, any file that imports create-file-node.js will need to pass this createContentDigest. I'll take a look around though and try to find it.

I wanted to make sure I understood the enhancement before requesting it!

Thanks!

Sam

P.S. I'm definitely going to rebuild some of my hobby projects with Gatsby!

Thank you for the reference. I'll do some testing on my own for some of the most popular plugins and report back / open a pr!

[amberleyromo]

@DSchau Maybe it would be useful to break this apart into different issues for the different plugins? Or at least a listing of todos in this issue description?