Package extension -> extensions

middleware/extensions/ext.go

@@ -0,0 +1,89 @@
+// Package extension is middleware for clean URLs. The root path
+// of the site is passed in as well as possible extensions to try
+// internally for paths requested that don't match an existing
+// resource. The first path+ext combination that matches a valid
+// file will be used.
+package extensions
+
+import (
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/mholt/caddy/middleware"
+)
+
+// New creates a new instance of middleware that assumes extensions
+// so the site can use cleaner, extensionless URLs
+func New(c middleware.Controller) (middleware.Middleware, error) {
+	root := c.Root()
+
+	extensions, err := parse(c)
+	if err != nil {
+		return nil, err
+	}
+
+	return func(next middleware.Handler) middleware.Handler {
+		return Ext{
+			Next:       next,
+			Extensions: extensions,
+			Root:       root,
+		}
+	}, nil
+}
+
+// Ext can assume an extension from clean URLs.
+// It tries extensions in the order listed in Extensions.
+type Ext struct {
+	// Next handler in the chain
+	Next middleware.Handler
+
+	// Path to ther root of the site
+	Root string
+
+	// List of extensions to try
+	Extensions []string
+}
+
+// ServeHTTP implements the middleware.Handler interface.
+func (e Ext) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
+	urlpath := strings.TrimSuffix(r.URL.Path, "/")
+	if path.Ext(urlpath) == "" {
+		for _, ext := range e.Extensions {
+			if resourceExists(e.Root, urlpath+ext) {
+				r.URL.Path = urlpath + ext
+				break
+			}
+		}
+	}
+	return e.Next.ServeHTTP(w, r)
+}
+
+// parse sets up an instance of extension middleware
+// from a middleware controller and returns a list of extensions.
+func parse(c middleware.Controller) ([]string, error) {
+	var extensions []string
+
+	for c.Next() {
+		// At least one extension is required
+		if !c.NextArg() {
+			return extensions, c.ArgErr()
+		}
+		extensions = append(extensions, c.Val())
+
+		// Tack on any other extensions that may have been listed
+		extensions = append(extensions, c.RemainingArgs()...)
+	}
+
+	return extensions, nil
+}
+
+// resourceExists returns true if the file specified at
+// root + path exists; false otherwise.
+func resourceExists(root, path string) bool {
+	_, err := os.Stat(root + path)
+	// technically we should use os.IsNotExist(err)
+	// but we don't handle any other kinds of errors anyway
+	return err == nil
+}