Replace all URL rendering within templates by a URLConstructor

2 files changed, 178 insertions, 4 deletions

diff --git a/src/render/methods.go b/src/render/methods.go
index 9b5a41e..ee22dfd 100644
--- a/src/render/methods.go
+++ b/src/render/methods.go
@@ -56,6 +56,8 @@ type Methods struct {
 	ctx              context.Context
 	url              *url.URL
 	publicURL        *url.URL
+	httpURL          *url.URL
+	geminiURL        *url.URL
 	geminiGatewayURL *url.URL
 	postStore        post.Store
 	postAssetStore   asset.Store
@@ -71,6 +73,8 @@ func NewMethods(
 	ctx context.Context,
 	url *url.URL,
 	publicURL *url.URL,
+	httpURL *url.URL,
+	geminiURL *url.URL,
 	geminiGatewayURL *url.URL,
 	postStore post.Store,
 	postAssetStore asset.Store,
@@ -81,6 +85,8 @@ func NewMethods(
 		ctx,
 		url,
 		publicURL,
+		httpURL,
+		geminiURL,
 		geminiGatewayURL,
 		postStore,
 		postAssetStore,
@@ -91,6 +97,10 @@ func NewMethods(
 	}
 }
 
+func (m *Methods) RootURL() URLBuilder {
+	return NewURLBuilder(m.publicURL, m.httpURL, m.geminiURL)
+}
+
 func (m *Methods) GetTags() ([]string, error) {
 	return m.postStore.GetTags()
 }
@@ -263,7 +273,3 @@ func (m *Methods) GetPath() (string, error) {
 }
 
 func (m *Methods) Add(a, b int) int { return a + b }
-
-func (m *Methods) URLIsSafe(s string) template.URL {
-	return template.URL(s)
-}
diff --git a/src/render/url.go b/src/render/url.go
new file mode 100644
index 0000000..eb9756b
--- /dev/null
+++ b/src/render/url.go
@@ -0,0 +1,168 @@
+package render
+
+import (
+	"html/template"
+	"net/url"
+	"path"
+	"strconv"
+	"strings"
+)
+
+const (
+	urlBasePublic = iota
+	urlBaseHTTP
+	urlBaseGemini
+)
+
+// URLBuilder is used to construct a URL for the site. The API of URLBuilder is
+// designed to be convenient to used from a go template.
+type URLBuilder struct {
+	publicURL, httpURL, geminiURL *url.URL
+
+	abs          bool
+	base         int
+	path, method string
+	page         int
+}
+
+func NewURLBuilder(publicURL, httpURL, geminiURL *url.URL) URLBuilder {
+	return URLBuilder{
+		publicURL: publicURL,
+		httpURL:   httpURL,
+		geminiURL: geminiURL,
+	}
+}
+
+func (b URLBuilder) String() string {
+	var u *url.URL
+	switch b.base {
+	case urlBasePublic:
+		u = b.publicURL
+	case urlBaseHTTP:
+		u = b.httpURL
+	case urlBaseGemini:
+		u = b.geminiURL
+	}
+
+	u = u.JoinPath(b.path)
+
+	if u.Scheme == "gemini" &&
+		u.Host == b.geminiURL.Host &&
+		!strings.HasSuffix(u.Path, "/") &&
+		path.Ext(u.Path) == "" {
+		u.Path += ".gmi"
+	}
+
+	{
+		query := url.Values{}
+		if b.method != "" {
+			query.Set("method", b.method)
+		}
+		if b.page > 0 {
+			query.Set("page", strconv.Itoa(b.page))
+		}
+		if len(query) > 0 {
+			u.RawQuery = query.Encode()
+		}
+	}
+
+	if abs := b.abs || u.Scheme != b.publicURL.Scheme; !abs {
+		u.Scheme = ""
+		u.Host = ""
+	}
+
+	return u.String()
+}
+
+func (b URLBuilder) HTMLSafe() template.URL {
+	return template.URL(b.String())
+}
+
+// Absolute returns a URLBuilder which will always construct a URL containing
+// scheme and host.
+func (b URLBuilder) Absolute() URLBuilder {
+	b.abs = true
+	return b
+}
+
+func (b URLBuilder) Gemini() URLBuilder {
+	b.base = urlBaseGemini
+	return b
+}
+
+func (b URLBuilder) HTTP() URLBuilder {
+	b.base = urlBaseHTTP
+	return b
+}
+
+func (b URLBuilder) Assets() URLBuilder {
+	b.path = "assets/"
+	return b
+}
+
+func (b URLBuilder) Asset(id string) URLBuilder {
+	b.path = "assets/" + id
+	return b
+}
+
+func (b URLBuilder) Posts() URLBuilder {
+	b.path = "posts/"
+	return b
+}
+
+func (b URLBuilder) Post(id string) URLBuilder {
+	b.path = "posts/" + id
+	return b
+}
+
+func (b URLBuilder) Drafts() URLBuilder {
+	b.base = urlBaseHTTP
+	b.path = "drafts/"
+	return b
+}
+
+func (b URLBuilder) Draft(id string) URLBuilder {
+	b.base = urlBaseHTTP
+	b.path = "drafts/" + id
+	return b
+}
+
+func (b URLBuilder) Static(staticPath string) URLBuilder {
+	b.base = urlBaseHTTP
+	b.path = path.Join("static", staticPath)
+	return b
+}
+
+func (b URLBuilder) Path(p string) URLBuilder {
+	b.path = p
+	return b
+}
+
+func (b URLBuilder) Page(page int) URLBuilder {
+	b.page = page
+	return b
+}
+
+func (b URLBuilder) MethodEdit() URLBuilder {
+	b.base = urlBaseHTTP
+	b.method = "edit"
+	return b
+}
+
+func (b URLBuilder) MethodManage() URLBuilder {
+	b.base = urlBaseHTTP
+	b.method = "manage"
+	return b
+}
+
+func (b URLBuilder) MethodDelete() URLBuilder {
+	b.base = urlBaseHTTP
+	b.method = "delete"
+	return b
+}
+
+func (b URLBuilder) MethodPreview() URLBuilder {
+	b.base = urlBaseHTTP
+	b.method = "preview"
+	return b
+}