new draft: dynamic-opengraph-images-with-hugo

content/posts/dynamic-opengraph-images-with-hugo/index.md

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+---
+title: "Dynamic Opengraph Images With Hugo"
+date: 2024-02-18
+# lastmod: 2024-02-18
+draft: true
+description: "This is a new post about..."
+featured: false
+toc: true
+comments: true
+thumbnail: thumbnail.png
+categories: Backstage
+tags:
+  - hugo
+  - meta
+  - selfhosting
+---
+I've lately seen some folks on [social.lol](https://social.lol) posting about their various strategies for automatically generating [Open Graph images](https://ogp.me/) for their [Eleventy](https://11ty.dev) sites. So this weekend I started exploring ways to do that for my [Hugo](https://gohugo.io) site.
+
+During my search, I came across a few different approaches using external services or additional scripts to run at build time. I eventually came across a post from Aaro titled [Generating OpenGraph images with Hugo](https://aarol.dev/posts/hugo-og-image/) which seemed like exactly what I was after, as it uses Hugo's built-in [image functions](https://gohugo.io/functions/images/filter/) to dynamically create the image.
+
+I wound up borrowing heavily from Aaro's approach and then adding a few additional capabilities, notably the ability to overlay a designated thumbnail image on top of the resulting OpenGraph image. I'm sure this could be further optimized by someone who knows what they're doing[^future].
+
+[^future]: Like Future John, perhaps? Past John loves leaving stuff for that guy to figure out.
+
+In any case, here's what I did to get this working.
+
+### New resources
+Based on Aaro's suggestions, I started by creating a 1200x600 image to use as the base. I used [GIMP](https://www.gimp.org/) for this. I'm not a graphic designer[^web] so I kept it simple while emulating the "logo" displayed at the top of the page:
+
+![Red background with a command prompt displaying "[runtimeterror.dev] $" in white and red font.](og_base.png)
+
+[^web]: Or web designer, if I'm being honest.
+
+That fits with the theme of the site, and leaves plenty of room for text to be added to the image.
+
+The site uses the Fira Mono font family, and I'd like to use that to ensure the share image is consistent with the site styling. So I also grabbed `FiraMono-Regular.ttf` from the [Fira GitHub](https://github.com/mozilla/Fira).
+
+I stashed both of those resources in my `assets/` folder:
+![File explorer window showing a directory structure with folders such as '.github/workflows', 'archetypes', 'assets' with subfolders 'css', 'js', and files 'FiraMono-Regular.ttf', 'og_base.png' under 'RUNTIMETERROR'.](new_resources.png)
+
+### OpenGraph partial
+Hugo uses an [internal template](https://github.com/gohugoio/hugo/blob/master/tpl/tplimpl/embedded/templates/opengraph.html) for rendering OpenGraph properties by default. I'll need to import that as a partial so that I can override its behavior. So I drop the following in `layouts/partials/opengraph.html` as a starting point:
+
+```jinja-html
+// torchlight! {"lineNumbers": true}
+<meta property="og:title" content="{{ .Title }}" />
+<meta property="og:description" content="{{ with .Description }}{{ . }}{{ else }}{{if .IsPage}}{{ .Summary }}{{ else }}{{ with .Site.Params.description }}{{ . }}{{ end }}{{ end }}{{ end }}" />
+<meta property="og:type" content="{{ if .IsPage }}article{{ else }}website{{ end }}" />
+<meta property="og:url" content="{{ .Permalink }}" />
+<meta property="og:locale" content="{{ .Lang }}" />
+
+{{- if .IsPage }}
+{{- $iso8601 := "2006-01-02T15:04:05-07:00" -}}
+<meta property="article:section" content="{{ .Section }}" />
+{{ with .PublishDate }}<meta property="article:published_time" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end }}
+{{ with .Lastmod }}<meta property="article:modified_time" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end }}
+{{- end -}}
+
+{{- with .Params.audio }}<meta property="og:audio" content="{{ . }}" />{{ end }}
+{{- with .Params.locale }}<meta property="og:locale" content="{{ . }}" />{{ end }}
+{{- with .Site.Params.title }}<meta property="og:site_name" content="{{ . }}" />{{ end }}
+{{- with .Params.videos }}{{- range . }}
+<meta property="og:video" content="{{ . | absURL }}" />
+{{ end }}{{ end }}
+```