support template overrides

2 files changed, 57 insertions, 32 deletions

diff --git a/gemini.go b/gemini.go
index 6222684..e6e936f 100644
--- a/gemini.go
+++ b/gemini.go
@@ -19,19 +19,24 @@ const (
 	reponamekey = "syw_reponame"
 )
 
-func GeminiRouter(repodir string) *sliderule.Router {
+func GeminiRouter(repodir string, overrides *template.Template) *sliderule.Router {
+	tmpl, err := addTemplates(geminiTemplate, overrides)
+	if err != nil {
+		panic(err)
+	}
+
 	repoRouter := &sliderule.Router{}
 	repoRouter.Use(assignRepo(repodir))
-	repoRouter.Route("/", gmiTemplate(geminiTemplate, "repo_home.gmi"))
-	repoRouter.Route("/branches", gmiTemplate(geminiTemplate, "branch_list.gmi"))
-	repoRouter.Route("/tags", gmiTemplate(geminiTemplate, "tag_list.gmi"))
-	repoRouter.Route("/refs/:ref/", gmiTemplate(geminiTemplate, "ref.gmi"))
-	repoRouter.Route("/refs/:ref/tree/*path", sliderule.HandlerFunc(geminiTreePath))
-	repoRouter.Route("/diffstat/:fromref/:toref", runTemplate(geminiTemplate, "diffstat.gmi", "text/plain"))
-	repoRouter.Route("/diff/:fromref/:toref", runTemplate(geminiTemplate, "diff.gmi", "text/x-diff"))
+	repoRouter.Route("/", gmiTemplate(tmpl, "repo_home.gmi"))
+	repoRouter.Route("/branches", gmiTemplate(tmpl, "branch_list.gmi"))
+	repoRouter.Route("/tags", gmiTemplate(tmpl, "tag_list.gmi"))
+	repoRouter.Route("/refs/:ref/", gmiTemplate(tmpl, "ref.gmi"))
+	repoRouter.Route("/refs/:ref/tree/*path", geminiTreePath(tmpl))
+	repoRouter.Route("/diffstat/:fromref/:toref", runTemplate(tmpl, "diffstat.gmi", "text/plain"))
+	repoRouter.Route("/diff/:fromref/:toref", runTemplate(tmpl, "diff.gmi", "text/x-diff"))
 
 	router := &sliderule.Router{}
-	router.Route("/", geminiRoot(repodir))
+	router.Route("/", geminiRoot(repodir, tmpl))
 	router.Mount("/:"+reponamekey, repoRouter)
 
 	return router
@@ -46,7 +51,7 @@ func assignRepo(repodir string) sliderule.Middleware {
 	}
 }
 
-func geminiRoot(repodir string) sliderule.Handler {
+func geminiRoot(repodir string, tmpl *template.Template) sliderule.Handler {
 	return sliderule.HandlerFunc(func(ctx context.Context, request *sliderule.Request) *sliderule.Response {
 		entries, err := os.ReadDir(repodir)
 		if err != nil {
@@ -61,7 +66,7 @@ func geminiRoot(repodir string) sliderule.Handler {
 		}
 
 		buf := &bytes.Buffer{}
-		if err := geminiTemplate.ExecuteTemplate(buf, "repo_root.gmi", names); err != nil {
+		if err := tmpl.ExecuteTemplate(buf, "repo_root.gmi", names); err != nil {
 			return gemini.Failure(err)
 		}
 
@@ -69,31 +74,33 @@ func geminiRoot(repodir string) sliderule.Handler {
 	})
 }
 
-func geminiTreePath(ctx context.Context, request *sliderule.Request) *sliderule.Response {
-	params := sliderule.RouteParams(ctx)
-	if params["path"] == "" || strings.HasSuffix(params["path"], "/") {
-		return gmiTemplate(geminiTemplate, "tree.gmi").Handle(ctx, request)
-	}
+func geminiTreePath(tmpl *template.Template) sliderule.Handler {
+	return sliderule.HandlerFunc(func(ctx context.Context, request *sliderule.Request) *sliderule.Response {
+		params := sliderule.RouteParams(ctx)
+		if params["path"] == "" || strings.HasSuffix(params["path"], "/") {
+			return gmiTemplate(tmpl, "tree.gmi").Handle(ctx, request)
+		}
 
-	repo := ctx.Value(repokey).(*Repository)
+		repo := ctx.Value(repokey).(*Repository)
 
-	body, err := repo.Blob(ctx, params["ref"], params["path"])
-	if err != nil {
-		return gemini.Failure(err)
-	}
+		body, err := repo.Blob(ctx, params["ref"], params["path"])
+		if err != nil {
+			return gemini.Failure(err)
+		}
 
-	mediaType := ""
-	ext := path.Ext(params["path"])
-	if ext == ".gmi" {
-		mediaType = "text/gemini; charset=utf-8"
-	} else {
-		mediaType = mime.TypeByExtension(ext)
-	}
-	if mediaType == "" {
-		mediaType = "application/octet-stream"
-	}
+		mediaType := ""
+		ext := path.Ext(params["path"])
+		if ext == ".gmi" {
+			mediaType = "text/gemini; charset=utf-8"
+		} else {
+			mediaType = mime.TypeByExtension(ext)
+		}
+		if mediaType == "" {
+			mediaType = "application/octet-stream"
+		}
 
-	return gemini.Success(mediaType, bytes.NewBuffer(body))
+		return gemini.Success(mediaType, bytes.NewBuffer(body))
+	})
 }
 
 func gmiTemplate(tmpl *template.Template, name string) sliderule.Handler {
diff --git a/templates.go b/templates.go
index ddce7ea..e31f06f 100644
--- a/templates.go
+++ b/templates.go
@@ -8,3 +8,21 @@ import (
 //go:embed templates/*.gmi
 var geminiTemplateFS embed.FS
 var geminiTemplate = template.Must(template.ParseFS(geminiTemplateFS, "templates/*.gmi"))
+
+func addTemplates(base *template.Template, additions *template.Template) (*template.Template, error) {
+	base, err := base.Clone()
+	if err != nil {
+		return nil, err
+	}
+	if additions == nil {
+		return base, nil
+	}
+
+	for _, addition := range additions.Templates() {
+		if _, err := base.AddParseTree(addition.Name(), addition.Tree); err != nil {
+			return nil, err
+		}
+	}
+
+	return base, nil
+}