Serializer: more detailed docs / examples / confirmation it works

[andrewdever]

*I currently don't use ghost.org–but want to use this plugin for gatsby in general–so I'm posting feedback here.

I can't seem to get serializer working.

In gatsby-config.js I have: (NB: the rest of the plugin settings are fine, including the query for allBlogPost)

                mapping: {
                    allBlogpost: {
                        sitemap: `blogposts`,
                        serializer: (allBlogpost) => {
                            return allBlogpost.edges.map(edge=>{
                                return {
                                    url: 'dummy-url.com',
                                    changefreq: 'weekly',
                                    lastmod: edge.node.lastmod,
                                    priority: 0.8,
                                }
                            })
                        }
                    }
                },

sitemap-blogposts.xml output: (NB: file was generated but no priority, changefreq, i.e. not serializer didn't impact output)

<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="sitemap.xsl"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
    xmlns:image="http://www.google.com/schemas/sitemap-image/1.1">
    <url>
        <loc>http://localhost:8000/blog/example-blog-post</loc>
        <lastmod>2021-03-17T18:14:51.012Z</lastmod>
    </url>
</urlset>

1/ Is there an issue with my serializer code? Example/s in the docs would be tres helpful!
2/ Does Serializer only work for ghost.org queries?

[andrewdever]

Further details and an update–

My goal is to add changefreq and priority to entries in the generated sitemap.

I realized my last code was giving errors (cannot read property __typeface of undefined, etc.). I've updated my code in gatsby-config.js for the plugin as follows:

{
            resolve: `gatsby-plugin-advanced-sitemap`,
            options: {
                query: `
                {
                    allBlogpost {
                        edges {
                            node {
                                id
                                slug: uid
                                updated_at: last_publication_date(formatString: "YYYY-MM-DD")
                            }
                        }
                    }
                }`,
                output: "/custom-sitemap.xml",
                mapping: {
                    allBlogpost: {
                        sitemap: `blog-posts`,
                        prefix: 'blog/',
                        // Custom Serializer
                        serializer: (edges) => {
                            const sitemapEntries = []
                            edges.forEach((edge) => {
                                edge.node.changefreq = 'weekly'
                                edge.node.priority = 0.8
                                sitemapEntries.push(edge)
                            })
                            return sitemapEntries
                        }
                    },
                },
                // etc. code redacted
            }
        },

I noticed to access the node object–where slug and updated_at variables are–I had to use edge.node.

sitemapEntries outputs:

[
  [Object: null prototype] {
    node: [Object: null prototype] {
      id: '511e9e6d-241f-5d92-a031-ebe62950210d',
      slug: 'another-blog-post',
      updated_at: '2021-03-18',
      changefreq: 'weekly',
      priority: 0.8
    }
  },
  [Object: null prototype] {
    node: [Object: null prototype] {
      id: '93aa0024-c068-5765-b4f0-402e1b8c6f20',
      slug: 'a-blogpost',
      updated_at: '2021-03-18',
      changefreq: 'weekly',
      priority: 0.8
    }
  },
  [Object: null prototype] {
    node: [Object: null prototype] {
      id: '95312c66-c0f1-5b97-a8f9-1c6df24ea3bd',
      slug: 'example-blog-post',
      updated_at: '2021-03-17',
      changefreq: 'weekly',
      priority: 0.8
    }
  }
]

So it seems the output of my serializer is valid; however, changefreq and priority aren't showing in the outputted sitemap file!

NB: I also tried edge.changefreq instead of edge.node.changefreq to no effect in outputted sitemap.

I couldn't find any documentation, examples, or solutions online. Would be great to have one as changefreq and priority I assume would be the major use case for the serializer for most people using the plugin.

[kloh-fr]

Thank you @andrewdever for your research shared here, you saved my day!

I was facing a similar issue with slugs coming from a WordPress source (issue just linked above) and the edge.node thing made the work. 😄

[Viktor19931]

any chance to add images ?