Add basic documentation for node interface and hacker news source plugin

CONTRIBUTING.md

@@ -10,7 +10,7 @@ If you want your issue to be resolved quickly, please include in your issue:
   changes you've made there.
 
 ## Contributing
-You can install the latest `master` version of Gatsby by following these steps:
+You can install the latest version of Gatsby by following these steps:
 
 * Clone the repo, navigate to its directory.
 * Install dependencies using `npm install` in the root of the repo.
@@ -20,7 +20,7 @@ The usual contributing steps are:
 * Fork the [official repository](https://github.com/gatsbyjs/gatsby).
 * Clone your fork: git clone `git@github.com:<your-username>/gatsby.git`
 * Install lerna, and gatsby-dev-cli globally: `npm install -g lerna gatsby-dev-cli@canary`
-* Checkout to the 1.0 branch: `git checkout 1.0`
+* Checkout the 1.0 branch: `git checkout 1.0`
 * Install dependencies: `npm install && lerna bootstrap`
 * Make sure tests are passing for you: `npm test`
 * Create a topic branch: `git checkout -b topics/new-feature-name`

docs/docs/node-interface.md

@@ -2,4 +2,54 @@
 title: Node Interface
 ---
 
-Coming soon.
+The "node" is the center of Gatsby's data system. All data that's
+added to Gatsby is modeled using nodes.
+
+The basic node data structure is as follows:
+
+```flow
+id: String,
+children: Array[String],
+parent: String,
+internal: {
+  contentDigest: String,
+  mediaType: String,
+  type: String,
+  pluginName: String,
+  content: String,
+}
+...other node type specific fields
+```
+
+## Source plugins
+
+New nodes are added to Gatsby by "source" plugins. A common one that many
+Gatsby sites use is the [Filesystem source
+plugin](/docs/packages/gatsby-source-filesystem/) which turns files on disk
+into File nodes.
+
+Other source plugins pull data from external APIs such as the [Drupal](/docs/packages/gatsby-source-drupal/) and
+[Hacker News](/docs/packages/gatsby-source-hacker-news/)
+
+## Transformer plugins
+
+Transformer plugins transform source nodes into new types of nodes. It is very
+common when building Gatsby sites to install both source plugin(s) and transformer
+plugins.
+
+Nodes created by transformer plugins are set as "children" of their "parent"
+nodes.
+
+* The [Remark
+(Markdown library) transformer
+plugin](/docs/packages/gatsby-transformer-remark/) looks for new nodes that
+are created with a `mediaType` of `text/x-markdown` and then transforms these
+nodes into `MarkdownRemark` nodes with an `html` field.
+* The [YAML transformer plugin](/docs/packages/gatsby-transformer-yaml/) looks
+for new nodes with a media type of `text/yaml` (e.g. a `.yaml` file) and creates new
+YAML child node(s) by parsing the YAML source into JavaScript objects.
+
+## GraphQL
+
+Gatsby automatically infers the structure of your site's nodes and creates
+a GraphQL schema which you can then query from your site's components.

docs/docs/plugins.md

@@ -34,6 +34,7 @@ mean converting this file into a JS component).
 * [gatsby-plugin-typescript](/docs/packages/gatsby-plugin-typescript/)
 * [gatsby-source-filesystem](/docs/packages/gatsby-source-filesystem/)
 * [gatsby-source-drupal](/docs/packages/gatsby-source-drupal/)
+* [gatsby-source-hacker-news](/docs/packages/gatsby-source-hacker-news/)
 * [gatsby-remark-autolink-headers](/docs/packages/gatsby-remark-autolink-headers/)
 * [gatsby-remark-copy-linked-files](/docs/packages/gatsby-remark-copy-linked-files/)
 * [gatsby-remark-prismjs](/docs/packages/gatsby-remark-prismjs/)

packages/gatsby-source-hacker-news/README.md

@@ -0,0 +1,47 @@
+# gatsby-source-hacker-news
+
+Source plugin for pulling data into Gatsby from the [Hacker News
+API](https://github.com/HackerNews/API)
+
+## Install
+
+`npm install --save gatsby-source-hacker-news`
+
+## How to use
+
+```javascript
+// In your gatsby-config.js
+plugins: [
+  `gatsby-source-hacker-news`,
+]
+```
+
+## How to query
+
+You can query nodes created from Hacker News like the following:
+
+```graphql
+query StoriesQuery {
+  allHnStory(sortBy: {fields: [order]}) {
+    edges {
+      node {
+        id
+        title
+        score
+        order
+        domain
+        url
+        by
+        descendants
+        timeISO(fromNow: true)
+        children {
+          id
+          text
+          timeISO(fromNow: true)
+          by
+        }
+      }
+    }
+  }
+}
+```

packages/gatsby/src/redux/actions.js

@@ -108,7 +108,10 @@ actions.createNode = (node, plugin = ``) => {
   }
 
   // Check if the node has already been processed.
-  if (getNode(node.id) && !hasNodeChanged(node.id, node.contentDigest)) {
+  if (
+    getNode(node.id) &&
+    !hasNodeChanged(node.id, node.internal.contentDigest)
+  ) {
     return {
       type: `TOUCH_NODE`,
       plugin,

packages/gatsby/src/redux/index.js

@@ -73,13 +73,13 @@ exports.hasNodeChanged = (id, digest) => {
   if (!node) {
     return true
   } else {
-    return node.contentDigest !== digest
+    return node.internal.contentDigest !== digest
   }
 }
 
 exports.loadNodeContent = node => {
-  if (node.content) {
-    return Promise.resolve(node.content)
+  if (node.internal.content) {
+    return Promise.resolve(node.internal.content)
   } else {
     return new Promise(resolve => {
       // Load plugin's loader function