refactor(api): migrate service conversation-variable responses to BaseModel

[ai-hpc]

Part of #28015

Summary

Migrate service API conversation-variable response serialization from Flask-RESTX @marshal_with(...) to Pydantic BaseModel response classes. Add schema models for variable item/pagination responses and preserve output behavior by normalizing value_type and datetime fields.

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint and make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-04-14 17:51:40.961865292 +0000
+++ /tmp/pyrefly_pr.txt	2026-04-14 17:51:30.345884904 +0000
@@ -14,6 +14,8 @@
   --> controllers/console/setup.py:65:2
 ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
   --> controllers/console/version.py:30:2
+ERROR Object of class `object` has no attribute `value` [missing-attribute]
+  --> controllers/service_api/app/conversation.py:86:24
 ERROR Class member `EasyUIBasedGenerateTaskPipeline._application_generate_entity` overrides parent class `BasedGenerateTaskPipeline` in an inconsistent manner [bad-override]
   --> core/app/task_pipeline/easy_ui_based_generate_task_pipeline.py:75:5
 ERROR `+=` is not supported between `list[PromptMessageContentUnionTypes]` and `str` [unsupported-operation]
@@ -2115,11 +2117,11 @@
 ERROR Argument `list[dict[str, Any]] | None` is not assignable to parameter `obj` with type `Sized` in function `len` [bad-argument-type]
    --> tests/unit_tests/controllers/service_api/app/test_completion.py:156:20
 ERROR Argument value `Literal[0]` violates Pydantic `ge` constraint `Literal[1]` for field `limit` [bad-argument-type]
-  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:80:35
+  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:84:35
 ERROR Argument value `Literal[101]` violates Pydantic `le` constraint `Literal[100]` for field `limit` [bad-argument-type]
-  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:85:35
+  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:89:35
 ERROR Missing argument `session` in function `services.conversation_service.ConversationService.pagination_by_last_id` [missing-argument]
-   --> tests/unit_tests/controllers/service_api/app/test_conversation.py:383:59
+   --> tests/unit_tests/controllers/service_api/app/test_conversation.py:426:59
 ERROR Argument value `Literal[0]` violates Pydantic `ge` constraint `Literal[1]` for field `limit` [bad-argument-type]
   --> tests/unit_tests/controllers/service_api/app/test_message.py:94:63
 ERROR Argument value `Literal[101]` violates Pydantic `le` constraint `Literal[100]` for field `limit` [bad-argument-type]

[Copilot]

Pull request overview

This PR migrates Service API conversation-variable response serialization from Flask-RESTX @marshal_with(...) models to Pydantic ResponseModel classes in api/controllers/service_api/app/conversation.py, aiming to keep the response shape consistent while normalizing value_type and timestamps.

Changes:

• Introduces Pydantic response models for conversation-variable item and infinite-scroll pagination responses.
• Updates the conversation-variable list/update endpoints to return model_dump(mode="json") output instead of RESTX marshalling.
• Adds unit tests covering value_type and timestamp normalization plus basic controller serialization checks.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
api/controllers/service_api/app/conversation.py	Adds Pydantic response models + swaps endpoint serialization from RESTX marshalling to model_validate(...).model_dump(...).
api/tests/unit_tests/controllers/service_api/app/test_conversation.py	Adds unit tests for the new response models and controller response serialization.

---

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[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-04-14 18:19:04.933855331 +0000
+++ /tmp/pyrefly_pr.txt	2026-04-14 18:18:54.020721458 +0000
@@ -14,6 +14,8 @@
   --> controllers/console/setup.py:65:2
 ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
   --> controllers/console/version.py:30:2
+ERROR Object of class `object` has no attribute `value` [missing-attribute]
+  --> controllers/service_api/app/conversation.py:87:24
 ERROR Class member `EasyUIBasedGenerateTaskPipeline._application_generate_entity` overrides parent class `BasedGenerateTaskPipeline` in an inconsistent manner [bad-override]
   --> core/app/task_pipeline/easy_ui_based_generate_task_pipeline.py:75:5
 ERROR `+=` is not supported between `list[PromptMessageContentUnionTypes]` and `str` [unsupported-operation]
@@ -2117,11 +2119,11 @@
 ERROR Argument `list[dict[str, Any]] | None` is not assignable to parameter `obj` with type `Sized` in function `len` [bad-argument-type]
    --> tests/unit_tests/controllers/service_api/app/test_completion.py:156:20
 ERROR Argument value `Literal[0]` violates Pydantic `ge` constraint `Literal[1]` for field `limit` [bad-argument-type]
-  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:80:35
+  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:84:35
 ERROR Argument value `Literal[101]` violates Pydantic `le` constraint `Literal[100]` for field `limit` [bad-argument-type]
-  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:85:35
+  --> tests/unit_tests/controllers/service_api/app/test_conversation.py:89:35
 ERROR Missing argument `session` in function `services.conversation_service.ConversationService.pagination_by_last_id` [missing-argument]
-   --> tests/unit_tests/controllers/service_api/app/test_conversation.py:383:59
+   --> tests/unit_tests/controllers/service_api/app/test_conversation.py:427:59
 ERROR Argument value `Literal[0]` violates Pydantic `ge` constraint `Literal[1]` for field `limit` [bad-argument-type]
   --> tests/unit_tests/controllers/service_api/app/test_message.py:94:63
 ERROR Argument value `Literal[101]` violates Pydantic `le` constraint `Literal[100]` for field `limit` [bad-argument-type]