Added function to map a URL path to a local gemini file.url-file-mapping

1 files changed, 28 insertions, 0 deletions

diff --git a/gemini.cl b/gemini.cl
index 9460439..67399a9 100644
--- a/gemini.cl
+++ b/gemini.cl
@@ -24,3 +24,31 @@
 
 (defun status->number (key)
   (cdr (assoc key (reverse-alist +status-codes+))))
+
+(defvar +site-root+ (pathname (user-homedir-pathname)))
+
+(defun find-resource (url-path-string)
+  ;; If the URL ends with a `.gmi` or `.gemini`, assume it points to a file and check if it exists.
+  ;; Otherwise, assume it points to a directory, and check if `index.gmi` or `index.gemini` exists in that directory.
+  ;; Returns the pathname of the file if it exists; nil otherwise.
+  (let ((path-local (merge-pathnames (pathname url-path-string) +site-root+)))
+    (cond (
+      (search ".." url-path-string)
+        ; TODO: Replace this with some sort of (is-unsafe-URL) function.
+        ; URL is unsafe.
+        nil)
+      ((or (string= "gmi" (pathname-type path-local))
+           (string= "gemini" (pathname-type path-local)))
+        ; URL points to a file.
+        (probe-file path-local))
+      (t
+        ; URL points to a directory.
+        ; Due to how pathnames work, we must ensure that the last character in the URL is a single "/" for it to be treated as a directory.
+        (let 
+          ((path-local-dir (pathname
+            (if (pathname-name path-local)
+              (pathname (concatenate 'string (namestring path-local) "/"))
+              path-local
+          ))))
+          (or (probe-file (merge-pathnames "index.gmi" path-local-dir))
+              (probe-file (merge-pathnames "index.gemini" path-local-dir))))))))
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