README
¶
Meta Image Generator
An open graph meta image generator for social previews.
- Pass the title of your page via URL and get an optimized .jpg returned.
- Customize templates via Golang templates.
- Images are cached and only generated once.
- URLs can be signed via a query param to prevent image bombs.
To run locally:
- Confirm Go is installed:
go version - Clone this repo:
git clone git@github.com:robbymilo/go-meta-image-generator.git && cd go-meta-image-generator - Run locally:
make start - Visit
localhost:3000/Hello world.jpgin your browser.
Then, in your website template you can use:
<head>
<meta property="og:image" content="http://localhost:3000/Title of my Page.jpg" />
</head>
Run locally with docker:
docker run -p 3000:3000 --name=meta --rm robbymilo/go-meta-image-generator:latest
Updating the template
Follow the instructions above to run locally, then navigate to localhost:3000/render/Hello world.jpg. Here you can inspect the template in your browser with dev tools.
Signed URLs
When running in production, you can sign the URLs to prevent a scripter from crashing your server by generating countless images.
Set the environmental variable SIGNATURE to a secret key, ex:
docker run -p 3000:3000 -e SIGNATURE=milo --name=meta --rm robbymilo/go-meta-image-generator
In your HTML template, you can generate the hash of the URL with your secret key, base64 encode it, then pass it to the signature query param.
With Hugo:
{{ $title := "Hello world" }}
{{ $hashed := base64Encode (sha256 (print $title "milo")) }}
{{ return (print "http://localhost:3000/" $title ".jpg?signature=" $hashed) }}
Images will not be returned without the correct signature passed to the query param when the SIGNATURE env var is set.
Why not:
- https://github.com/vercel/og-image Only designed to run on vercel/serverless, and templates are not flexible and cannot be previewed in the browser.
Todo:
- Add tests
Documentation
¶
There is no documentation for this package.
Source Files
