1 files changed, 167 insertions, 0 deletions
diff --git a/src/http/tpl.go b/src/http/tpl.go
new file mode 100644
index 0000000..3e1a2ba
--- /dev/null
+++ b/src/http/tpl.go
@@ -0,0 +1,167 @@
+package http
+
+import (
+	"embed"
+	"fmt"
+	"html/template"
+	"io/fs"
+	"net/http"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/http/apiutil"
+)
+
+//go:embed tpl
+var tplFS embed.FS
+
+func mustReadTplFile(fileName string) string {
+	path := filepath.Join("tpl", fileName)
+
+	b, err := fs.ReadFile(tplFS, path)
+	if err != nil {
+		panic(fmt.Errorf("reading file %q from tplFS: %w", path, err))
+	}
+
+	return string(b)
+}
+
+func (a *api) blogURL(path string, abs bool) string {
+	// filepath.Join strips trailing slash, but we want to keep it
+	trailingSlash := strings.HasSuffix(path, "/")
+
+	res := filepath.Join("/", path)
+
+	if trailingSlash && res != "/" {
+		res += "/"
+	}
+
+	if abs {
+		res = a.params.PublicURL.String() + res
+	}
+
+	return res
+}
+
+func (a *api) postURL(id string, abs bool) string {
+	path := filepath.Join("posts", id)
+	return a.blogURL(path, abs)
+}
+
+func (a *api) postsURL(abs bool) string {
+	return a.blogURL("posts", abs)
+}
+
+func (a *api) assetsURL(abs bool) string {
+	return a.blogURL("assets", abs)
+}
+
+func (a *api) draftURL(id string, abs bool) string {
+	path := filepath.Join("drafts", id)
+	return a.blogURL(path, abs)
+}
+
+func (a *api) draftsURL(abs bool) string {
+	return a.blogURL("drafts", abs)
+}
+
+func (a *api) tplFuncs() template.FuncMap {
+	return template.FuncMap{
+		"BlogURL": func(path string) string {
+			return a.blogURL(path, false)
+		},
+		"StaticURL": func(path string) string {
+			path = filepath.Join("static", path)
+			return a.blogURL(path, false)
+		},
+		"StaticInlineCSS": func(path string) (template.CSS, error) {
+			path = filepath.Join("static", path)
+			b, err := staticFS.ReadFile(path)
+			return template.CSS(b), err
+		},
+		"PostURL": func(id string) string {
+			return a.postURL(id, false)
+		},
+		"AssetURL": func(id string) string {
+			path := filepath.Join("assets", id)
+			return a.blogURL(path, false)
+		},
+		"DraftURL": func(id string) string {
+			return a.draftURL(id, false)
+		},
+		"DateTimeFormat": func(t time.Time) string {
+			return t.Format("2006-01-02")
+		},
+	}
+}
+
+func (a *api) parseTpl(name, tplBody string) (*template.Template, error) {
+
+	tpl := template.New(name)
+	tpl = tpl.Funcs(a.tplFuncs())
+
+	var err error
+
+	if tpl, err = tpl.Parse(tplBody); err != nil {
+		return nil, err
+	}
+
+	return tpl, nil
+}
+
+func (a *api) mustParseTpl(name string) *template.Template {
+	return template.Must(a.parseTpl(name, mustReadTplFile(name)))
+}
+
+func (a *api) mustParseBasedTpl(name string) *template.Template {
+	tpl := a.mustParseTpl(name)
+	tpl = template.Must(tpl.New("base.html").Parse(mustReadTplFile("base.html")))
+	return tpl
+}
+
+type tplData struct {
+	Payload interface{}
+}
+
+// executeTemplate expects to be the final action in an http.Handler
+func executeTemplate(
+	rw http.ResponseWriter, r *http.Request,
+	tpl *template.Template, payload interface{},
+) {
+
+	tplData := tplData{
+		Payload: payload,
+	}
+
+	if err := tpl.Execute(rw, tplData); err != nil {
+		apiutil.InternalServerError(
+			rw, r, fmt.Errorf("rendering template: %w", err),
+		)
+		return
+	}
+}
+
+func (a *api) executeRedirectTpl(
+	rw http.ResponseWriter, r *http.Request, url string,
+) {
+	executeTemplate(rw, r, a.redirectTpl, struct {
+		URL string
+	}{
+		URL: url,
+	})
+}
+
+func (a *api) renderDumbTplHandler(tplName string) http.Handler {
+
+	tpl := a.mustParseBasedTpl(tplName)
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		if err := tpl.Execute(rw, nil); err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("rendering %q: %w", tplName, err),
+			)
+			return
+		}
+	})
+}