Add guide on Client state and and fix default values of components

.changeset/puny-planets-cover.md

@@ -0,0 +1,5 @@
+---
+"gradio": patch
+---
+
+feat:Add guide on Client state and and fix default values of components

client/python/test/test_client.py

@@ -1083,8 +1083,8 @@ def test_layout_components_in_output(self, hello_world_with_group):
                             {
                                 "label": "name",
                                 "parameter_name": "name",
-                                "parameter_has_default": True,
-                                "parameter_default": "",
+                                "parameter_has_default": False,
+                                "parameter_default": None,
                                 "type": {"type": "string"},
                                 "python_type": {"type": "str", "description": ""},
                                 "component": "Textbox",
@@ -1117,8 +1117,8 @@ def test_layout_and_state_components_in_output(
                             {
                                 "label": "name",
                                 "parameter_name": "name",
-                                "parameter_has_default": True,
-                                "parameter_default": "",
+                                "parameter_has_default": False,
+                                "parameter_default": None,
                                 "type": {"type": "string"},
                                 "python_type": {"type": "str", "description": ""},
                                 "component": "Textbox",

gradio/_simple_templates/simpletextbox.py

@@ -19,7 +19,7 @@ class SimpleTextbox(FormComponent):
 
     def __init__(
         self,
-        value: str | Callable | None = "",
+        value: str | Callable | None = None,
         *,
         placeholder: str | None = None,
         label: str | None = None,

gradio/components/html.py

@@ -23,7 +23,7 @@ class HTML(Component):
 
     def __init__(
         self,
-        value: str | Callable = "",
+        value: str | Callable | None = None,
         *,
         label: str | None = None,
         every: float | None = None,

gradio/components/markdown.py

@@ -25,7 +25,7 @@ class Markdown(Component):
 
     def __init__(
         self,
-        value: str | Callable = "",
+        value: str | Callable | None = None,
         *,
         label: str | None = None,
         every: float | None = None,

gradio/components/textbox.py

@@ -30,7 +30,7 @@ class Textbox(FormComponent):
 
     def __init__(
         self,
-        value: str | Callable | None = "",
+        value: str | Callable | None = None,
         *,
         lines: int = 1,
         max_lines: int = 20,

gradio/templates.py

@@ -20,7 +20,7 @@ class TextArea(components.Textbox):
 
     def __init__(
         self,
-        value: str | Callable | None = "",
+        value: str | Callable | None = None,
         *,
         lines: int = 7,
         max_lines: int = 20,

guides/08_gradio-clients-and-lite/01_getting-started-with-the-python-client.md

@@ -295,3 +295,40 @@ job = client.submit("abcdef")
 time.sleep(3)
 job.cancel()  # job cancels after 2 iterations
 ```
+
+## Demos with Session State
+
+Gradio demos can include [session state](https://www.gradio.app/guides/state-in-blocks), which provides a way for demos to persist information from user interactions within a page session.
+
+For example, consider the following demo, which maintains a list of words that a user has submitted in a `gr.State` component. When a user submits a new word, it is added to the state, and the number of previous occurrences of that word is displayed:
+
+```python
+import gradio as gr
+
+def count(word, list_of_words):
+    return list_of_words.count(word), list_of_words + [word]
+
+with gr.Blocks() as demo:
+    words = gr.State([])
+    textbox = gr.Textbox()
+    number = gr.Number()
+    textbox.submit(count, inputs=[textbox, words], outputs=[number, words])
+
+demo.launch()
+```
+
+If you were to connect this this Gradio app using the Python Client, you would notice that the API information only shows a single input and output:
+
+```csv
+Client.predict() Usage Info
+---------------------------
+Named API endpoints: 1
+
+ - predict(word, api_name="/count") -> value_31
+    Parameters:
+     - [Textbox] word: str (required)  
+    Returns:
+     - [Number] value_31: float 
+```
+
+That is because the Python client handles state automatically for you -- as you make a series of requests, the returned state from one request is stored internally and automatically supplied for the subsequent request. If you'd like to reset the state, you can do that by calling `Client.reset_session()`.

test/test_components.py

@@ -84,7 +84,7 @@ def test_component_functions(self):
             "lines": 1,
             "max_lines": 20,
             "placeholder": None,
-            "value": "",
+            "value": None,
             "name": "textbox",
             "show_copy_button": False,
             "show_label": True,