Implement get handler

src/get_handler.c

@@ -1,6 +1,30 @@
-static enum MHD_Result handle_get(struct MHD_Connection *connection, SV url, SV base_path, SV username) {
-    (void)url;
-    (void)username;
-    (void)base_path;
-    return send_response(connection, 200, sv("TODO: Get\n"), false);
+static enum MHD_Result handle_get(struct MHD_Connection *connection, SV url, Settings settings, SV username) {
+    noh_arena_save(&temp);
+    Noh_String fs_path = build_path(false, &settings.base_path, &username, &url);
+
+    noh_log(NOH_INFO, "Physical path: "Nsv_Fmt, Nsv_Arg(fs_path));
+
+    if (!noh_sv_ends_with(noh_sv_from_string(fs_path), sv(".epub"))) {
+        return send_response(connection, 400, sv("File is not an epub file."), false);
+    }
+
+    noh_string_append_null(&fs_path);
+
+    // Try to open the file.
+    FILE *file = fopen(fs_path.elems, "r");
+    if (file == NULL) {
+        if (errno == ENOENT) {
+            noh_arena_reset(&temp);
+            return send_response(connection, 404, sv("File does not exist."), false);
+        } else {
+            noh_log(NOH_ERROR, "Opening file failed.");
+            noh_arena_reset(&temp);
+            return send_response(connection, 500, sv(""), false);
+        }
+    }
+
+    fseek(file, 0L, SEEK_END);
+    size_t file_size = ftell(file);
+    fseek(file, 0L, SEEK_SET);
+    return send_epub_file(connection, fileno(file), file_size);
 }