feat(gatsby) : add createContentDigest helper

docs/docs/source-plugin-tutorial.md

@@ -116,11 +116,10 @@ With the setup done, move on to adding the plugin's functionality.
 Create a new file called `gatsby-node.js` in your `gatsby-source-pixabay` directory, and add the following:
 
 ```js:title=gatsby-node.js
-const crypto = require("crypto")
 const fetch = require("node-fetch")
 const queryString = require("query-string")
 
-exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
+exports.sourceNodes = ({ actions, createNodeId, createContentDigest }, configOptions) => {
   const { createNode } = actions
 
   // Gatsby adds a configOption that's not needed for this plugin, delete it
@@ -136,15 +135,14 @@ exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
 What did you do by adding this code? You started by importing the dependencies that you added earlier (along with one built in dependency):
 
 ```js
-const crypto = require("crypto")
 const fetch = require("node-fetch")
 const queryString = require("query-string")
 ```
 
-Then you implemented Gatsby's [`sourceNodes` API](/docs/node-apis/#sourceNodes) which Gatsby will run as part of its bootstrap process. When Gatsby calls `sourceNodes`, it'll pass in some helper functions (`actions` and `createNodeId`) along with any config options that are provided in your project's `gatsby-config.js` file:
+Then you implemented Gatsby's [`sourceNodes` API](/docs/node-apis/#sourceNodes) which Gatsby will run as part of its bootstrap process. When Gatsby calls `sourceNodes`, it'll pass in some helper functions (`actions`, `createNodeId` and `createContentDigest`) along with any config options that are provided in your project's `gatsby-config.js` file:
 
 ```js
-exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
+exports.sourceNodes = ({ actions, createNodeId, createContentDigest }, configOptions) => {
 ```
 
 You do some initial setup:
@@ -211,9 +209,8 @@ Update `gatsby-node.js` in your `plugins/gatsby-source-pixabay/` directory:
 ```js{11-30}:title=gatsby-node.js
 const fetch = require("node-fetch")
 const queryString = require("query-string")
-const crypto = require("crypto")
 
-exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
+exports.sourceNodes = ({ actions, createNodeId, createContentDigest }, configOptions) => {
   const { createNode } = actions
 
   // Gatsby adds a configOption that's not needed for this plugin, delete it
@@ -266,14 +263,13 @@ You're ready to add the final step of your plugin - converting this data into a
 
 ### Use `createNode` function
 
-You're adding a helper function on lines 12 to 32 and processing the data into a node on lines 49 to 52:
+You're adding a helper function on lines 11 to 27 and processing the data into a node on lines 44 to 47:
 
-```js{12-32,49-52}:title=gatsby-node.js
+```js{11-27,44-47}:title=gatsby-node.js
 const fetch = require("node-fetch")
 const queryString = require("query-string")
-const crypto = require("crypto")
 
-exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
+exports.sourceNodes = ({ actions, createNodeId, createContentDigest }, configOptions) => {
   const { createNode } = actions
 
   // Gatsby adds a configOption that's not needed for this plugin, delete it
@@ -283,10 +279,6 @@ exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
   const processPhoto = photo => {
     const nodeId = createNodeId(`pixabay-photo-${photo.id}`)
     const nodeContent = JSON.stringify(photo)
-    const nodeContentDigest = crypto
-      .createHash("md5")
-      .update(nodeContent)
-      .digest("hex")
 
     const nodeData = Object.assign({}, photo, {
       id: nodeId,
@@ -295,7 +287,7 @@ exports.sourceNodes = ({ actions, createNodeId }, configOptions) => {
       internal: {
         type: `PixabayPhoto`,
         content: nodeContent,
-        contentDigest: nodeContentDigest,
+        contentDigest: createContentDigest(nodeContent),
       },
     })
 

packages/gatsby/src/utils/__tests__/create-content-digest.js

@@ -0,0 +1,19 @@
+const createContentDigest = require(`../create-content-digest`)
+
+describe(`Create content digest`, () => {
+  it(`returns the content digest`, () => {
+    const content = JSON.stringify({ id: 1 })
+
+    const contentDigest = createContentDigest(content)
+
+    expect(contentDigest).toEqual(`d2ce28b9a7fd7e4407e2b0fd499b7fe4`)
+  })
+
+  it(`throws an error when the data argument is not a string`, () => {
+    const content = [{ id: 1 }]
+
+    expect(() => {
+      createContentDigest(content)
+    }).toThrow()
+  })
+})

packages/gatsby/src/utils/api-node-docs.js

@@ -82,9 +82,7 @@ exports.createPagesStatefully = true
  *
  * See also the documentation for [`createNode`](/docs/actions/#createNode).
  * @example
- * const crypto = require(`crypto`)
- *
- * exports.sourceNodes = ({ actions, createNodeId }) => {
+ * exports.sourceNodes = ({ actions, createNodeId, createContentDigest }) => {
  *   const { createNode } = actions
  *
  *   // Data can come from anywhere, but for now create it manually
@@ -95,10 +93,6 @@ exports.createPagesStatefully = true
  *   }
  *
  *   const nodeContent = JSON.stringify(myData)
- *   const nodeContentDigest = crypto
- *     .createHash(`md5`)
- *     .update(nodeContent)
- *     .digest(`hex`)
  *
  *   const nodeMeta = {
  *     id: createNodeId(`my-data-${myData.key}`),
@@ -108,7 +102,7 @@ exports.createPagesStatefully = true
  *       type: `MyNodeType`,
  *       mediaType: `text/html`,
  *       content: nodeContent,
- *       contentDigest: nodeContentDigest
+ *       contentDigest: createContentDigest(nodeContent)
  *     }
  *   }
  *

packages/gatsby/src/utils/api-runner-node.js

@@ -7,6 +7,7 @@ const reporter = require(`gatsby-cli/lib/reporter`)
 const cache = require(`./cache`)
 const apiList = require(`./api-node-docs`)
 const createNodeId = require(`./create-node-id`)
+const createContentDigest = require(`./create-content-digest`)
 
 // Bind action creators per plugin so we can auto-add
 // metadata to actions they create.
@@ -107,6 +108,7 @@ const runAPI = (plugin, api, args) => {
         getNodeAndSavePathDependency,
         cache,
         createNodeId: namespacedCreateNodeId,
+        createContentDigest,
         tracing,
       },
       plugin.pluginOptions,

packages/gatsby/src/utils/create-content-digest.js

@@ -0,0 +1,16 @@
+const crypto = require(`crypto`)
+
+/**
+ * createContentDigest() Encrypts a String using md5 hash of hexadecimal digest.
+ *
+ * @param {String} data - A JSON string representing the input data
+ *
+ * @return {String} - The content digest
+ */
+const createContentDigest = data =>
+  crypto
+    .createHash(`md5`)
+    .update(data)
+    .digest(`hex`)
+
+module.exports = createContentDigest