refactor(api): migrate remaining RESTX models to Pydantic (#40399)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Byron Wang <byron@dify.ai>

api/fields/workflow_draft_variable_fields.py

@@ -0,0 +1,137 @@
+from __future__ import annotations
+
+from typing import Any, override
+
+from pydantic import model_validator
+
+from fields.base import ResponseModel
+from graphon.file import helpers as file_helpers
+from graphon.variables.segment_group import SegmentGroup
+from graphon.variables.segments import ArrayFileSegment, FileSegment, Segment
+from models.workflow import WorkflowDraftVariable
+
+type JSONValue = str | int | float | bool | dict[str, "JSONValue"] | list["JSONValue"] | None
+
+
+def _convert_values_to_json_serializable_object(value: Segment) -> JSONValue:
+    match value:
+        case FileSegment():
+            return value.value.model_dump()
+        case ArrayFileSegment():
+            return [item.model_dump() for item in value.value]
+        case SegmentGroup():
+            return [_convert_values_to_json_serializable_object(item) for item in value.value]
+        case _:
+            return value.value
+
+
+def _serialize_var_value(variable: WorkflowDraftVariable) -> JSONValue:
+    value = variable.get_value()
+    # Create a copy to avoid mutating the model's cached deserialized value.
+    value = value.model_copy(deep=True)
+    # Refresh URL signatures immediately before returning file values to the client.
+    match value:
+        case FileSegment():
+            value.value.remote_url = value.value.generate_url()
+        case ArrayFileSegment():
+            for file in value.value:
+                file.remote_url = file.generate_url()
+    return _convert_values_to_json_serializable_object(value)
+
+
+class WorkflowDraftVariableFullContentResponse(ResponseModel):
+    size_bytes: int | None
+    value_type: str
+    length: int | None
+    download_url: str
+
+
+def _serialize_full_content(
+    variable: WorkflowDraftVariable,
+) -> WorkflowDraftVariableFullContentResponse | None:
+    """Serialize metadata for a variable whose complete value was offloaded."""
+    if not variable.is_truncated():
+        return None
+
+    variable_file = variable.variable_file
+    assert variable_file is not None
+
+    return WorkflowDraftVariableFullContentResponse(
+        size_bytes=variable_file.size,
+        value_type=str(variable_file.value_type.exposed_type()),
+        length=variable_file.length,
+        download_url=file_helpers.get_signed_file_url(variable_file.upload_file_id, as_attachment=True),
+    )
+
+
+def _serialize_without_value(variable: WorkflowDraftVariable) -> dict[str, Any]:
+    return {
+        "id": variable.id,
+        "type": str(variable.get_variable_type()),
+        "name": variable.name,
+        "description": variable.description,
+        "selector": variable.get_selector(),
+        "value_type": str(variable.value_type.exposed_type()),
+        "edited": variable.edited,
+        "visible": variable.visible,
+        "is_truncated": variable.is_truncated(),
+    }
+
+
+class WorkflowDraftVariableWithoutValueResponse(ResponseModel):
+    id: str
+    type: str
+    name: str
+    description: str
+    selector: list[str]
+    value_type: str
+    edited: bool
+    visible: bool
+    is_truncated: bool
+
+    @model_validator(mode="before")
+    @classmethod
+    def _from_workflow_draft_variable(cls, value: Any) -> Any:
+        if isinstance(value, WorkflowDraftVariable):
+            return _serialize_without_value(value)
+        return value
+
+
+class WorkflowDraftVariableResponse(WorkflowDraftVariableWithoutValueResponse):
+    value: JSONValue
+    full_content: WorkflowDraftVariableFullContentResponse | None
+
+    @model_validator(mode="before")
+    @classmethod
+    @override
+    def _from_workflow_draft_variable(cls, value: Any) -> Any:
+        if isinstance(value, WorkflowDraftVariable):
+            return {
+                **_serialize_without_value(value),
+                "value": _serialize_var_value(value),
+                "full_content": _serialize_full_content(value),
+            }
+        return value
+
+
+class WorkflowDraftVariableListWithoutValueResponse(ResponseModel):
+    items: list[WorkflowDraftVariableWithoutValueResponse]
+    total: int | None
+
+    @model_validator(mode="before")
+    @classmethod
+    def _from_workflow_draft_variable_list(cls, value: Any) -> Any:
+        if hasattr(value, "variables") and hasattr(value, "total"):
+            return {"items": value.variables, "total": value.total}
+        return value
+
+
+class WorkflowDraftVariableListResponse(ResponseModel):
+    items: list[WorkflowDraftVariableResponse]
+
+    @model_validator(mode="before")
+    @classmethod
+    def _from_workflow_draft_variable_list(cls, value: Any) -> Any:
+        if hasattr(value, "variables"):
+            return {"items": value.variables}
+        return value