✨ feat: add Open Graph image generation for paste previews

The commit adds functionality to generate preview images for pastes that can be used in Open Graph meta tags. This includes:

1. New endpoint for generating paste preview images
2. Image generation service using Go's graphics libraries
3. Syntax highlighting in generated images
4. Watermark support
5. Updated meta tags to use generated images for pastes

go.mod

@@ -30,6 +30,12 @@ require (
 
 require github.com/watzon/hdur v1.0.0
 
+require (
+	github.com/fogleman/gg v1.3.0 // indirect
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
+	golang.org/x/image v0.22.0 // indirect
+)
+
 require (
 	github.com/andybalholm/brotli v1.1.1 // indirect
 	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.6.6 // indirect

go.sum

@@ -59,6 +59,8 @@ github.com/dlclark/regexp2 v1.11.4 h1:rPYF9/LECdNymJufQKmri9gV604RvvABwgOA8un7yA
 github.com/dlclark/regexp2 v1.11.4/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
+github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fsnotify/fsnotify v1.8.0 h1:dAwr6QBTBZIkG8roQaJjGof0pp0EeF+tNV7YBP3F/8M=
@@ -79,6 +81,8 @@ github.com/gofiber/utils v1.1.0 h1:vdEBpn7AzIUJRhe+CiTOJdUcTg4Q9RK+pEa0KPbLdrM=
 github.com/gofiber/utils v1.1.0/go.mod h1:poZpsnhBykfnY1Mc0KeEa6mSHrS3dV0+oBWyeQmb2e0=
 github.com/golang-migrate/migrate/v4 v4.18.1 h1:JML/k+t4tpHCpQTCAD62Nu43NUFzHY4CV3uAuvHGC+Y=
 github.com/golang-migrate/migrate/v4 v4.18.1/go.mod h1:HAX6m3sQgcdO81tdjn5exv20+3Kb13cmGli1hrD6hks=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/pprof v0.0.0-20240409012703-83162a5b38cd h1:gbpYu9NMq8jhDVbvlGkMFWCjLFlqqEZjEmObmhUy6Vo=
@@ -201,6 +205,8 @@ golang.org/x/crypto v0.29.0 h1:L5SG1JTTXupVV3n6sUqMTeWbjAyfPwoda2DLX8J8FrQ=
 golang.org/x/crypto v0.29.0/go.mod h1:+F4F4N5hv6v38hfeYwTdx20oUvLLc+QfrE9Ax9HtgRg=
 golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f h1:XdNn9LlyWAhLVp6P/i8QYBW+hlyhrhei9uErw2B5GJo=
 golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f/go.mod h1:D5SMRVC3C2/4+F/DB1wZsLRnSNimn2Sp/NPsCrsv8ak=
+golang.org/x/image v0.22.0 h1:UtK5yLUzilVrkjMAZAZ34DXGpASN8i8pj8g+O+yd10g=
+golang.org/x/image v0.22.0/go.mod h1:9hPFhljd4zZ1GNSIZJ49sqbp45GKK9t6w+iXvGqZUz4=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=

internal/server/handlers/paste.go

@@ -107,3 +107,20 @@ func (h *PasteHandlers) HandleDeletePaste(c *fiber.Ctx) error {
 func (h *PasteHandlers) HandleUpdateExpiration(c *fiber.Ctx) error {
 	return h.services.Paste.UpdateExpiration(c, getPasteID(c))
 }
+
+// HandleGetPasteImage returns an image of the paste suitable for Open Graph
+func (h *PasteHandlers) HandleGetPasteImage(c *fiber.Ctx) error {
+	id := getPasteID(c)
+
+	// Get extension from locals if available
+	if ext := c.Locals("extension"); ext != nil {
+		id = id + "." + ext.(string)
+	}
+
+	paste, err := h.services.Paste.GetPaste(id)
+	if err != nil {
+		return err
+	}
+
+	return h.services.Paste.GetPasteImage(c, paste)
+}

internal/server/server.go

@@ -148,11 +148,16 @@ func (s *Server) SetupRoutes() {
 		c.Locals("extension", c.Params("ext"))
 		return s.handlers.Paste.HandleDownload(c)
 	})
+	s.app.Get("/p/:id.:ext/image", func(c *fiber.Ctx) error {
+		c.Locals("extension", c.Params("ext"))
+		return s.handlers.Paste.HandleGetPasteImage(c)
+	})
 
 	// Handle paste routes without extensions
 	s.app.Get("/p/:id/raw", s.handlers.Paste.HandleRawView)
 	s.app.Get("/p/:id/download", s.handlers.Paste.HandleDownload)
 	s.app.Delete("/p/:id/:key", s.handlers.Paste.HandleDeleteWithKey)
+	s.app.Get("/p/:id/image", s.handlers.Paste.HandleGetPasteImage)
 
 	// Handle URL redirects
 	s.app.Get("/u/:id", s.handlers.URL.HandleRedirect)