Paginating GatsbyJS pages when filtering Wordpress posts by category

问题

Can anyone shed some insight on how I would go about paginating pages in Gatsby when filtering Wordpress posts by category?

For context, my gatsby-node file:

const path = require('path')


module.exports.createPages = async ({ graphql, actions }) => {

 // import { paginate } from 'gatsby-awesome-pagination';


  const { createPage } = actions
  const blogPostTemplate = path.resolve('./src/templates/blog-post.js')
  const blogCategoryFilter = path.resolve('./src/templates/blog-filter-category.js')
  const blogArchiveFilter = path.resolve('./src/templates/blog-filter-archive.js')

  const res = await graphql(`
      query {
        allWordpressPost {
          edges {
            node {
              slug
              date(formatString:"YYYY-MM")
            }
          }
        }
        allWordpressCategory {
          edges {
            node {
              slug
            }
          }
        }
      }
    `)

 // UNPAGINATED
  //Blog list - organized by category
  res.data.allWordpressCategory.edges.forEach((edge) => {
    createPage({
      component: blogCategoryFilter,
      path: `/blog/category/${edge.node.slug}`,
      context: {
        slug: edge.node.slug,
      }
    })
  })
}

The blog-filter-category.js file that I use as my template:

import React from 'react'
import { graphql, Link } from 'gatsby'

import Layout from '../components/layout'
import BlogNav from '../components/blognav'

import blogStyles from '../components/modules/blog.module.css'

export const query = graphql`
  query($slug: String!) {
    allWordpressPost (filter: {categories: {elemMatch: {slug: { eq: $slug }}}}) {
      edges {
        node {
          title
          slug
          content
          date(formatString: "MMMM DD, YYYY")
        }
      }
    }
  }
`






export default ({ data }) => {
  //const post = data.allWordpressPost.edges[0].node
  return (
    <Layout>
      <div className={blogStyles.blog_container}>
        <div className={blogStyles.blogContent_container}>
          <ol>
            {data.allWordpressPost.edges.map((edge) => {
              return (
                <div className={blogStyles.blogPost_container}>
                  <li className={blogStyles.blog_list}>
                    <h2><Link to={`/blog/${edge.node.slug}`} className={blogStyles.blog_title} dangerouslySetInnerHTML={{ __html: edge.node.title }}></Link></h2>
                    <p className={blogStyles.blog_date}>{edge.node.date}</p>
                    <p className={blogStyles.blog_content} dangerouslySetInnerHTML={{ __html: edge.node.content }} />
                  </li>
                </div>
              )
            })}
          </ol>
        </div>
        <BlogNav />
      </div>

    </Layout>
  )
}

I tried reading through the documentation of some relevant plugins (gatsby-paginate, gatsby-awesome-paginate, etc) and this article (https://www.gatsbycentral.com/pagination-in-gatsby) but it was all going a little over my head. It seemed to make sense for blog posts that I'm generating on to a template and simply sorting chronologically, but I get confused when I start filtering by category, archived months, etc.

Any tips? Can I paginate using the code structures above or do I have to rethink how I'm throwing this together?

Thank you!

回答1:

Let's assume we chose to use the gatsby-awesome-pagination plugin, as mentioned in the question.

This is from the plugin's quick start instructions:

import { paginate } from 'gatsby-awesome-pagination';

exports.createPages = ({ actions, graphql }) => {
  const { createPage } = actions;

  // Fetch your items (blog posts, categories, etc).
  const blogPosts = doSomeMagic();

  // Create your paginated pages
  paginate({
    createPage, // The Gatsby `createPage` function
    items: blogPosts, // An array of objects
    itemsPerPage: 10, // How many items you want per page
    pathPrefix: '/blog', // Creates pages like `/blog`, `/blog/2`, etc
    component: path.resolve('...'), // Just like `createPage()`
  })
}

What we're interested in in order to paginate by category is:

1. items: we need an array of posts grouped by category
2. pathPrefix: the category name to generate paths

We can get these by using a GraphQL query:

query MyQuery {
  allWordpressPost {
    group(field: categories___name) {
      nodes {
        title
        # any other post data you need
      }
      fieldValue
    }
  }
}

This will return something like:

{
  "data": {
    "allWordpressPost": {
      "group": [
        {
          "nodes": [
            {
              "title": "Abyssinians"
            }
          ],
          "fieldValue": "Cats"
        },
        {
          "nodes": [
            {
              "title": "Teckels"
            },
            {
              "title": "Poodles"
            }
          ],
          "fieldValue": "Dogs"
        }
      ]
    }
  }
}

Now we can create paginated pages in gatsby-node.js. An implementation could look like this:

import { paginate } from 'gatsby-awesome-pagination';

exports.createPages = ({ actions, graphql }) => {
  const { createPage } = actions;

  const { data } = await graphql(`
    query {
      allWordpressPost {
        group(field: categories___name) {
          nodes {
            title
            # any other post data you need
          }
          fieldValue
        }
      }
    }
  `)

  // create paginated pages for each category
  data.allWordpressPost.group.forEach(({ nodes: posts, fieldValue: category }) => {
    paginate({
      createPage,
      items: posts,
      itemsPerPage: 10,
      pathPrefix: category, // use category name for pages
      component: path.resolve('...'), // your template for post lists
    })

    // TODO create a page for each post
    // you can do it manually or use the plugin's `createPagePerItem` API:
    // https://github.com/GatsbyCentral/gatsby-awesome-pagination#createpageperitem
  }
}

The key here is to take advantage of GraphQL to build the right query.

Hope it helps!

来源：https://stackoverflow.com/questions/59419055/paginating-gatsbyjs-pages-when-filtering-wordpress-posts-by-category