Initial commit

Gemini repository browsing

1 files changed, 118 insertions, 0 deletions

diff --git a/gemini.go b/gemini.go
new file mode 100644
index 0000000..6222684
--- /dev/null
+++ b/gemini.go
@@ -0,0 +1,118 @@
+package syw
+
+import (
+	"bytes"
+	"context"
+	"mime"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	"tildegit.org/tjp/sliderule"
+	"tildegit.org/tjp/sliderule/gemini"
+)
+
+const (
+	repokey     = "syw_repo"
+	reponamekey = "syw_reponame"
+)
+
+func GeminiRouter(repodir string) *sliderule.Router {
+	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"))
+
+	router := &sliderule.Router{}
+	router.Route("/", geminiRoot(repodir))
+	router.Mount("/:"+reponamekey, repoRouter)
+
+	return router
+}
+
+func assignRepo(repodir string) sliderule.Middleware {
+	return func(h sliderule.Handler) sliderule.Handler {
+		return sliderule.HandlerFunc(func(ctx context.Context, request *sliderule.Request) *sliderule.Response {
+			repo := Open(filepath.Join(repodir, sliderule.RouteParams(ctx)[reponamekey]))
+			return h.Handle(context.WithValue(ctx, repokey, repo), request)
+		})
+	}
+}
+
+func geminiRoot(repodir string) sliderule.Handler {
+	return sliderule.HandlerFunc(func(ctx context.Context, request *sliderule.Request) *sliderule.Response {
+		entries, err := os.ReadDir(repodir)
+		if err != nil {
+			return gemini.Failure(err)
+		}
+
+		names := []string{}
+		for _, item := range entries {
+			if Open(filepath.Join(repodir, item.Name())) != nil {
+				names = append(names, item.Name())
+			}
+		}
+
+		buf := &bytes.Buffer{}
+		if err := geminiTemplate.ExecuteTemplate(buf, "repo_root.gmi", names); err != nil {
+			return gemini.Failure(err)
+		}
+
+		return gemini.Success("text/gemini; charset=utf-8", buf)
+	})
+}
+
+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)
+	}
+
+	repo := ctx.Value(repokey).(*Repository)
+
+	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"
+	}
+
+	return gemini.Success(mediaType, bytes.NewBuffer(body))
+}
+
+func gmiTemplate(tmpl *template.Template, name string) sliderule.Handler {
+	return runTemplate(tmpl, name, "text/gemini; charset=utf-8")
+}
+
+func runTemplate(tmpl *template.Template, name, mimetype string) sliderule.Handler {
+	return sliderule.HandlerFunc(func(ctx context.Context, request *sliderule.Request) *sliderule.Response {
+		obj := map[string]any{
+			"Ctx":    ctx,
+			"Repo":   ctx.Value(repokey),
+			"Params": sliderule.RouteParams(ctx),
+		}
+		buf := &bytes.Buffer{}
+
+		if err := tmpl.ExecuteTemplate(buf, name, obj); err != nil {
+			return gemini.Failure(err)
+		}
+
+		return gemini.Success(mimetype, buf)
+	})
+}