Fix bugs in api and add examples (#3353)

### What problem does this PR solve?

Fix bugs in api.
Add simple examples for api.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

api/apps/sdk/dataset.py

@@ -487,12 +487,14 @@ def list(tenant_id):
     """
     id = request.args.get("id")
     name = request.args.get("name")
-    kbs = KnowledgebaseService.query(id=id, name=name, status=1)
-    if not kbs:
-        return get_error_data_result(message="The dataset doesn't exist")
-    for kb in kbs:
-        if not KnowledgebaseService.accessible(kb_id=kb.id,user_id=tenant_id):
-            return get_error_data_result(message=f"You don't own the dataset {kb.id}")
+    if id:
+        kbs = KnowledgebaseService.get_kb_by_id(id,tenant_id)
+        if not kbs:
+            return get_error_data_result(f"You don't own the dataset {id}")
+    if name:
+        kbs = KnowledgebaseService.get_kb_by_name(name,tenant_id)
+        if not kbs:
+            return get_error_data_result(f"You don't own the dataset {name}")
     page_number = int(request.args.get("page", 1))
     items_per_page = int(request.args.get("page_size", 30))
     orderby = request.args.get("orderby", "create_time")

api/db/services/knowledgebase_service.py

@@ -189,6 +189,22 @@ class KnowledgebaseService(CommonService):
             return False
         return True
 
+    @classmethod
+    @DB.connection_context()
+    def get_kb_by_id(cls, kb_id, user_id):
+        kbs = cls.model.select().join(UserTenant, on=(UserTenant.tenant_id == Knowledgebase.tenant_id)
+            ).where(cls.model.id == kb_id, UserTenant.user_id == user_id).paginate(0, 1)
+        kbs = kbs.dicts()
+        return list(kbs)
+
+    @classmethod
+    @DB.connection_context()
+    def get_kb_by_name(cls, kb_name, user_id):
+        kbs = cls.model.select().join(UserTenant, on=(UserTenant.tenant_id == Knowledgebase.tenant_id)
+            ).where(cls.model.name == kb_name, UserTenant.user_id == user_id).paginate(0, 1)
+        kbs = kbs.dicts()
+        return list(kbs)
+
     @classmethod
     @DB.connection_context()
     def accessible4deletion(cls, kb_id, user_id):