1 files changed, 93 insertions, 0 deletions
diff --git a/repo/repo.go b/repo/repo.go
new file mode 100644
index 0000000..2c052d6
--- /dev/null
+++ b/repo/repo.go
@@ -0,0 +1,93 @@
+package repo
+
+import (
+	"bytes"
+	_ "embed"
+	"fmt"
+	"html/template"
+	"net/http"
+	"strings"
+)
+
+//go:embed meta.html
+var tmplStr string
+
+type Repo struct {
+	VCS        string `toml:"vcs"`
+	Repository string `toml:"repo"`
+	Home       string `toml:"source,omitempty"`
+	Directory  string `toml:"directory"`
+	File       string `toml:"file"`
+}
+
+type RepoHandler struct {
+	Pages map[string][]byte
+}
+
+func New(repo map[string]Repo) (*RepoHandler, error) {
+	m, err := NewMeta()
+	if err != nil {
+		return nil, err
+	}
+	h := &RepoHandler{Pages: map[string][]byte{}}
+	for k, v := range repo {
+		if v.Home == "" {
+			v.Home = "_"
+		}
+
+		b, err := m.Exec(k, v)
+		if err != nil {
+			return nil, err
+		}
+		h.Pages[k] = b
+	}
+	return h, nil
+}
+
+func (h *RepoHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	key := fmt.Sprintf("%s%s", r.Host, r.URL.Path)
+	key = strings.TrimSuffix(key, "/")
+
+	page, ok := h.Pages[key]
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+
+	if r.FormValue("go-get") == "1" {
+		w.Header().Set("Cache-Control", "public, max-age=86400, immutable")
+		w.Header().Set("Vary", "Host")
+		w.Header().Set("Content-Type", "text/html")
+		w.Write(page)
+	} else {
+		url := fmt.Sprintf("https://pkg.go.dev/%s", key)
+		http.Redirect(w, r, url, http.StatusFound)
+	}
+}
+
+type Meta struct {
+	tmpl *template.Template
+}
+
+func NewMeta() (*Meta, error) {
+	tmpl, err := template.New("meta").Parse(tmplStr)
+	if err != nil {
+		return nil, err
+	}
+	return &Meta{tmpl: tmpl}, nil
+}
+
+func (m *Meta) Exec(pkg string, repo Repo) ([]byte, error) {
+	var buf bytes.Buffer
+	data := struct {
+		Package string
+		Repo
+	}{
+		Package: pkg,
+		Repo:    repo,
+	}
+	if err := m.tmpl.Execute(&buf, data); err != nil {
+		return nil, fmt.Errorf("exec template for %v: %w", pkg, err)
+	}
+	return buf.Bytes(), nil
+}