wordpress-source-plugin-tutorial (#5235)

* wordpress-source-plugin-tutorial

Not sure if I got all the code samples formatted correctly.

Still need to edit the index.js page so the <p> tags don't render!!

Then, need a screenshot of the final result without <p> tags!

* removed unnecessary backticks and corrected link to Part 7 of tutorial

* Make links relative

* Use graphql for syntax highlighting + minor copy edits

Author: shannonbux

docs/docs/wordpress-source-plugin-tutorial.md

@@ -0,0 +1,156 @@
+## How to create a site with data pulled from WordPress 
+
+### What this tutorial covers:
+
+In this tutorial, you will install the `gatsby-source-wordpress` plugin in order to pull blog and image data from a WordPress install into your Gatsby site and render that data. This [Gatsby + Wordpress demo site](https://using-wordpress.gatsbyjs.org/) shows you a sample of what you’re going to be building in this tutorial., although it’s missing the cool images you’ll be adding :D
+
+### Why go through this tutorial? 
+
+While each source plugin may operate differently from others, it’s worth going through this tutorial because you will almost definitely be using a source plugin in most Gatsby sites you build. This tutorial will walk you through the basics of connecting your Gatsby site to a CMS, pulling in data, and using React to render that data in beautiful ways on your site.
+
+If you’d like to look at the growing number source plugins available to you, search for “source” in the [Gatsby plugin library](/plugins/?=source).
+
+### Creating a site with the `gatsby-source-wordpress` plugin
+
+Create a new Gatsby project and change directories into the new project you just created:
+
+```shell
+gatsby new wordpress-tutorial-site
+cd wordpress-tutorial-site
+```
+
+Install the `gatsby-source-wordpress` plugin. For extra reading on the plugin’s features and examples of GraphQL queries not included in this tutorial, see the [`gatsby-source-wordpress` plugin’s READme file](/packages/gatsby-source-wordpress/?=wordpress).
+
+```shell
+npm install --save gatsby-source-wordpress
+```
+
+Add the `gatsby-source-wordpress` plugin to `gatsby-config.js` using the following code, which you can also find in the [demo site’s source code](https://github.com/gatsbyjs/gatsby/blob/master/examples/using-wordpress/gatsby-config.js). 
+
+```javascript{32-58}
+ module.exports = {
+  siteMetadata: {
+    title: 'Gatsby Wordpress Tutorial',
+  },
+  plugins: [
+    // https://public-api.wordpress.com/wp/v2/sites/gatsbyjsexamplewordpress.wordpress.com/pages/
+    /*
+     * Gatsby's data processing layer begins with “source”
+     * plugins. Here the site sources its data from Wordpress.
+     */
+    {
+      resolve: `gatsby-source-wordpress`,
+      options: {
+        /*
+        * The base URL of the Wordpress site without the trailingslash and the protocol. This is required.
+        * Example : 'gatsbyjswpexample.wordpress.com' or 'www.example-site.com'
+        */
+        baseUrl: `dev-gatbsyjswp.pantheonsite.io`,
+        // The protocol. This can be http or https.
+        protocol: `http`,
+        // Indicates whether the site is hosted on wordpress.com.
+        // If false, then the asumption is made that the site is self hosted.
+        // If true, then the plugin will source its content on wordpress.com using the JSON REST API V2.
+        // If your site is hosted on wordpress.org, then set this to false.
+        hostingWPCOM: false,
+        // If useACF is true, then the source plugin will try to import the Wordpress ACF Plugin contents.
+        // This feature is untested for sites hosted on Wordpress.com
+        useACF: true,
+      },
+    },
+  ],
+}
+```
+
+### Creating GraphQL queries that pull data from WordPress
+
+Now you are ready to create a GraphQL query to pull in some data from the WordPress site. You will create a query that pulls in the title of the blogposts, date they were posted, and blogpost content.
+
+Run:
+
+```shell
+gatsby develop
+```
+
+Open localhost:8000 and localhost:8000/__graphql. 
+
+This query will pull in the blogpost content from WordPress:
+
+```graphql
+query {
+  allWordpressPage {
+    edges {
+      node {
+        id
+        title
+        excerpt
+        slug
+        date(formatString: "MMMM DD, YYYY")
+      }
+    }
+  }
+}
+```
+
+
+This query will pull in a sorted list of those blogposts:
+
+```graphql
+{
+  allWordpressPost(sort: { fields: [date] }) {
+    edges {
+      node {
+        title
+        excerpt
+        Slug
+        ...PostIcons
+      }
+    }
+  }
+}
+```
+
+
+### Rendering the blogposts to `index.js`
+
+Here is what your `index.js` should look like:
+
+```jsx
+import React from 'react'
+
+export default ({ data }) => {
+ console.log(data)
+ return (
+   <div>
+     <h1>My WordPress Blog</h1>
+     <h4>Posts</h4>
+     {data.allWordpressPost.edges.map(({ node }) => (
+       <div>
+         <p>{node.title}</p>
+         <p>{node.excerpt}</p>
+       </div>
+     ))}
+   </div>
+ )T
+}
+
+// Set here the ID of the home page.
+export const pageQuery = graphql`
+ query MyFiles {
+   allWordpressPost(sort: { fields: [date] }) {
+     edges {
+       node {
+         title
+         excerpt
+         slug
+       }
+     }
+   }
+ }
+`
+```
+
+[Note to editors: it would be useful to insert a screenshot of the final result here]
+
+### Create slugs for each blogpost and link to them from `index.js`
+[Part 7](/tutorial/part-seven/) of the foundational tutorial goes through this process.