Regex transformation for router

2 files changed, 71 insertions, 0 deletions

diff --git a/tests/router.scm b/tests/router.scm
new file mode 100644
index 0000000..5bdbd51
--- /dev/null
+++ b/tests/router.scm
@@ -0,0 +1,33 @@
+(use-modules (srfi srfi-11)
+             (srfi srfi-64)
+             (weeb router))
+
+;; Private imports for testing purposes.
+(define uri-template->regexp-string
+  (@@ (weeb router) uri-template->regexp-string))
+
+(test-runner-current (test-runner-simple))
+
+(test-begin "weeb-router")
+
+(test-group "simple static route"
+  (let-values (((re vars) (uri-template->regexp-string "/health")))
+    (test-equal "/health" re)
+    (test-equal '() vars)))
+
+(test-group "single variable route"
+  (let-values (((re vars) (uri-template->regexp-string "/user/:id:")))
+    (test-equal "/user/([^/]+)" re)
+    (test-equal '(id) vars)))
+
+(test-group "multiple variables with trailing slash"
+  (let-values (((re vars) (uri-template->regexp-string "/org/:org_id:/user/:user_id:/")))
+    (test-equal "/org/([^/]+)/user/([^/]+)" re)
+    (test-equal '(org_id user_id) vars)))
+
+(test-group "middle variables"
+  (let-values (((re vars) (uri-template->regexp-string "/api/:version:/data")))
+    (test-equal "/api/([^/]+)/data" re)
+    (test-equal '(version) vars)))
+
+(test-end)
diff --git a/weeb/router.scm b/weeb/router.scm
new file mode 100644
index 0000000..8c4b502
--- /dev/null
+++ b/weeb/router.scm
@@ -0,0 +1,38 @@
+;;; Weeb --- Web microframework for GNU Guile
+;;; Copyright © 2026 Jakob Kreuze <zerodaysfordays@sdf.org>
+;;;
+;;; This file is part of Weeb.
+;;;
+;;; Weeb is free software: you can redistribute it and/or modify it
+;;; under the terms of the GNU Affero General Public License as
+;;; published by the Free Software Foundation, either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; Weeb is distributed in the hope that it will be useful, but WITHOUT
+;;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+;;; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General
+;;; Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Affero General Public
+;;; License along with Weeb. If not, see <https://www.gnu.org/licenses/>.
+
+(define-module (weeb router)
+  #:use-module (ice-9 regex)
+  #:use-module (weeb struct)
+  #:export (define-router))
+
+(define (uri-template->regexp-string template)
+  ;; TODO: Assert that the first character is a slash.
+  (define trailing-slash? (string-match ".*/$" template))
+  (define components
+    (map (lambda (component)
+           (let ((variable-match (string-match ":(.*):" component)))
+             (if variable-match
+                 (list (string->symbol (match:substring variable-match 1)) "([^/]+)")
+                 (list #f component))))
+         (string-split (if trailing-slash?
+                           (substring template 1 (- (string-length template) 1))
+                           (substring template 1))
+                       #\/)))
+  (values (string-append "/" (string-join (map cadr components) "/"))
+          (filter symbol? (map car components))))