Feat/dataset service api (#1245)

Co-authored-by: jyong <jyong@dify.ai>
Co-authored-by: StyleZhang <jasonapring2015@outlook.com>

api/fields/message_fields.py

@@ -0,0 +1,43 @@
+from flask_restful import fields
+
+from libs.helper import TimestampField
+
+feedback_fields = {
+    'rating': fields.String
+}
+
+retriever_resource_fields = {
+    'id': fields.String,
+    'message_id': fields.String,
+    'position': fields.Integer,
+    'dataset_id': fields.String,
+    'dataset_name': fields.String,
+    'document_id': fields.String,
+    'document_name': fields.String,
+    'data_source_type': fields.String,
+    'segment_id': fields.String,
+    'score': fields.Float,
+    'hit_count': fields.Integer,
+    'word_count': fields.Integer,
+    'segment_position': fields.Integer,
+    'index_node_hash': fields.String,
+    'content': fields.String,
+    'created_at': TimestampField
+}
+
+message_fields = {
+    'id': fields.String,
+    'conversation_id': fields.String,
+    'inputs': fields.Raw,
+    'query': fields.String,
+    'answer': fields.String,
+    'feedback': fields.Nested(feedback_fields, attribute='user_feedback', allow_null=True),
+    'retriever_resources': fields.List(fields.Nested(retriever_resource_fields)),
+    'created_at': TimestampField
+}
+
+message_infinite_scroll_pagination_fields = {
+    'limit': fields.Integer,
+    'has_more': fields.Boolean,
+    'data': fields.List(fields.Nested(message_fields))
+}