feat: Human Input Node (#32060)

The frontend and backend implementation for the human input node.

Co-authored-by: twwu <twwu@dify.ai>
Co-authored-by: JzoNg <jzongcode@gmail.com>
Co-authored-by: yyh <92089059+lyzno1@users.noreply.github.com>
Co-authored-by: zhsama <torvalds@linux.do>

api/core/workflow/graph_events/__init__.py

@@ -38,6 +38,8 @@ from .loop import (
 from .node import (
     NodeRunExceptionEvent,
     NodeRunFailedEvent,
+    NodeRunHumanInputFormFilledEvent,
+    NodeRunHumanInputFormTimeoutEvent,
     NodeRunPauseRequestedEvent,
     NodeRunRetrieverResourceEvent,
     NodeRunRetryEvent,
@@ -60,6 +62,8 @@ __all__ = [
     "NodeRunAgentLogEvent",
     "NodeRunExceptionEvent",
     "NodeRunFailedEvent",
+    "NodeRunHumanInputFormFilledEvent",
+    "NodeRunHumanInputFormTimeoutEvent",
     "NodeRunIterationFailedEvent",
     "NodeRunIterationNextEvent",
     "NodeRunIterationStartedEvent",

api/core/workflow/graph_events/graph.py

@@ -1,11 +1,16 @@
 from pydantic import Field
 
 from core.workflow.entities.pause_reason import PauseReason
+from core.workflow.entities.workflow_start_reason import WorkflowStartReason
 from core.workflow.graph_events import BaseGraphEvent
 
 
 class GraphRunStartedEvent(BaseGraphEvent):
-    pass
+    # Reason is emitted for workflow start events and is always set.
+    reason: WorkflowStartReason = Field(
+        default=WorkflowStartReason.INITIAL,
+        description="reason for workflow start",
+    )
 
 
 class GraphRunSucceededEvent(BaseGraphEvent):

api/core/workflow/graph_events/node.py

@@ -54,6 +54,22 @@ class NodeRunRetryEvent(NodeRunStartedEvent):
     retry_index: int = Field(..., description="which retry attempt is about to be performed")
 
 
+class NodeRunHumanInputFormFilledEvent(GraphNodeEventBase):
+    """Emitted when a HumanInput form is submitted and before the node finishes."""
+
+    node_title: str = Field(..., description="HumanInput node title")
+    rendered_content: str = Field(..., description="Markdown content rendered with user inputs.")
+    action_id: str = Field(..., description="User action identifier chosen in the form.")
+    action_text: str = Field(..., description="Display text of the chosen action button.")
+
+
+class NodeRunHumanInputFormTimeoutEvent(GraphNodeEventBase):
+    """Emitted when a HumanInput form times out."""
+
+    node_title: str = Field(..., description="HumanInput node title")
+    expiration_time: datetime = Field(..., description="Form expiration time")
+
+
 class NodeRunPauseRequestedEvent(GraphNodeEventBase):
     reason: PauseReason = Field(..., description="pause reason")