implement search request handler

src/app/browser/window/tab/item/page/client.rs

@@ -73,9 +73,17 @@ impl Client {
             time: now(),
             value: query.to_string(),
         });
-        Request::parse(query, None)
-            .unwrap() // @TODO
-            .handle(self, self.new_cancellable(), callback);
+        match Request::parse(query, None) {
+            Ok(request) => request.handle(self, self.new_cancellable(), callback),
+            Err(e) => callback(match e {
+                // return failure response on unsupported scheme detected
+                request::Error::Unsupported => Response::Failure(response::Failure::Error {
+                    message: "Request scheme yet not supported".to_string(),
+                }),
+                // request redirection to default search provider
+                _ => Response::Redirect(response::Redirect::Foreground(request::search(query))),
+            }),
+        }
     }
 
     /// Get new [Cancellable](https://docs.gtk.org/gio/class.Cancellable.html) by cancel previous one

src/app/browser/window/tab/item/page/client/request.rs

@@ -1,9 +1,10 @@
 mod error;
 mod feature;
 mod gemini;
+mod search;
 
 use super::{Client, Response};
-use error::Error;
+pub use error::Error;
 use feature::Feature;
 use gtk::{
     gio::Cancellable,
@@ -47,7 +48,7 @@ impl Request {
                 feature: feature.unwrap_or_default(),
                 referrer: referrer.map(Box::new),
                 uri,
-            }),
+            }), // @TODO validate request len by constructor
             "titan" => Ok(Self::Titan {
                 referrer: referrer.map(Box::new),
                 uri,
@@ -105,3 +106,14 @@ impl Request {
         1 + count
     }
 }
+
+// Tools
+
+/// Create new search `Request`
+/// @TODO
+// * implement DNS lookup before apply this option
+// * make search provider optional
+// * validate request len by gemini specifications
+pub fn search(query: &str) -> Request {
+    Request::from_uri(search::tgls(query), None, None).unwrap() // no handler as unexpected
+}

src/app/browser/window/tab/item/page/client/request/search.rs

@@ -0,0 +1,17 @@
+//! Search providers asset
+
+use gtk::glib::{Uri, UriFlags};
+
+/// Default search provider
+pub fn tgls(query: &str) -> Uri {
+    Uri::build(
+        UriFlags::NONE,
+        "gemini",
+        None,
+        Some("tlgs.one"),
+        -1,
+        "/search",
+        Some(&Uri::escape_string(query, None, false)),
+        None,
+    )
+}