init

internal/site/route.go

@@ -0,0 +1,36 @@
+package site
+
+import "strings"
+
+// splitTilde splits a site URL path into its project and the rest.
+//
+//	"/~proj"        -> ("proj", "",     true)
+//	"/~proj/"       -> ("proj", "/",    true)
+//	"/~proj/a/b"    -> ("proj", "/a/b", true)
+//	"/", "/x", "/~" -> ("", "", false)
+//
+// The remainder keeps its leading slash, because its absence is what
+// distinguishes "/~proj" — which has to be redirected before relative links
+// inside the page can resolve — from "/~proj/".
+//
+// This is hand-parsed rather than expressed as a ServeMux pattern because
+// net/http rejects "/~{project}/{path...}": its wildcards must start a path
+// segment. Registering "/" instead also keeps the mux's built-in ".." and "//"
+// redirects, though those are a convenience and not a defence — a
+// percent-encoded traversal arrives here already decoded and unredirected, so
+// Resolve does its own normalisation.
+func splitTilde(urlPath string) (project, rest string, ok bool) {
+	if !strings.HasPrefix(urlPath, "/~") {
+		return "", "", false
+	}
+	rest = urlPath[len("/~"):]
+	if i := strings.IndexByte(rest, '/'); i >= 0 {
+		project, rest = rest[:i], rest[i:]
+	} else {
+		project, rest = rest, ""
+	}
+	if project == "" {
+		return "", "", false
+	}
+	return project, rest, true
+}