Support replacing route on redirect (#3072)

* Support replacing route on redirect

Support next/router `.replace` interface to change page without creating a
history entry.

* test_event: include test cases for new "replace" kwarg

reflex/.templates/web/utils/state.js

@@ -126,8 +126,13 @@ export const applyDelta = (state, delta) => {
 export const applyEvent = async (event, socket) => {
   // Handle special events
   if (event.name == "_redirect") {
-    if (event.payload.external) window.open(event.payload.path, "_blank");
-    else Router.push(event.payload.path);
+    if (event.payload.external) {
+      window.open(event.payload.path, "_blank");
+    } else if (event.payload.replace) {
+      Router.replace(event.payload.path);
+    } else {
+      Router.push(event.payload.path);
+    }
     return false;
   }
 

reflex/event.py

@@ -467,18 +467,27 @@ def fn():
     )
 
 
-def redirect(path: str | Var[str], external: Optional[bool] = False) -> EventSpec:
+def redirect(
+    path: str | Var[str],
+    external: Optional[bool] = False,
+    replace: Optional[bool] = False,
+) -> EventSpec:
     """Redirect to a new path.
 
     Args:
         path: The path to redirect to.
         external: Whether to open in new tab or not.
+        replace: If True, the current page will not create a new history entry.
 
     Returns:
         An event to redirect to the path.
     """
     return server_side(
-        "_redirect", get_fn_signature(redirect), path=path, external=external
+        "_redirect",
+        get_fn_signature(redirect),
+        path=path,
+        external=external,
+        replace=replace,
     )
 
 

tests/test_event.py

@@ -158,12 +158,29 @@ def test_fn_with_args(_, arg1, arg2):
 @pytest.mark.parametrize(
     "input,output",
     [
-        (("/path", None), 'Event("_redirect", {path:`/path`,external:false})'),
-        (("/path", True), 'Event("_redirect", {path:`/path`,external:true})'),
-        (("/path", False), 'Event("_redirect", {path:`/path`,external:false})'),
         (
-            (Var.create_safe("path"), None),
-            'Event("_redirect", {path:path,external:false})',
+            ("/path", None, None),
+            'Event("_redirect", {path:`/path`,external:false,replace:false})',
+        ),
+        (
+            ("/path", True, None),
+            'Event("_redirect", {path:`/path`,external:true,replace:false})',
+        ),
+        (
+            ("/path", False, None),
+            'Event("_redirect", {path:`/path`,external:false,replace:false})',
+        ),
+        (
+            (Var.create_safe("path"), None, None),
+            'Event("_redirect", {path:path,external:false,replace:false})',
+        ),
+        (
+            ("/path", None, True),
+            'Event("_redirect", {path:`/path`,external:false,replace:true})',
+        ),
+        (
+            ("/path", True, True),
+            'Event("_redirect", {path:`/path`,external:true,replace:true})',
         ),
     ],
 )
@@ -174,11 +191,13 @@ def test_event_redirect(input, output):
         input: The input for running the test.
         output: The expected output to validate the test.
     """
-    path, external = input
-    if external is None:
-        spec = event.redirect(path)
-    else:
-        spec = event.redirect(path, external=external)
+    path, external, replace = input
+    kwargs = {}
+    if external is not None:
+        kwargs["external"] = external
+    if replace is not None:
+        kwargs["replace"] = replace
+    spec = event.redirect(path, **kwargs)
     assert isinstance(spec, EventSpec)
     assert spec.handler.fn.__qualname__ == "_redirect"