[reputation_calculation] added logic for trust computation and message_handler

src/data-hub/reputation-calculation-microservice/app/configs/routes.yml

@@ -4,7 +4,7 @@ paths:
   #####
   /use-cases/{use_case}/contexts/{context}/trust-adapters:
     get:
-      operationId: "routes.trust_adapter.all_for_use_case_and_context"
+      operationId: "lib.routes.trust_adapter.all_for_use_case_and_context"
       tags:
         - "Trust Adapter"
       summary: "Get all trust adapters for a use case"
@@ -26,7 +26,7 @@ paths:
         "404":
           description: "Use-Case or Context was not found"
     post:
-      operationId: "routes.trust_adapter.add"
+      operationId: "lib.routes.trust_adapter.add"
       tags:
         - "Trust Adapter"
       summary: "Add a new trust adapters to a use case/context"
@@ -57,7 +57,7 @@ paths:
   #####
   /use-cases/{use_case}/users:
     get:
-      operationId: "routes.user.all_for_use_case"
+      operationId: "lib.routes.user.all_for_use_case"
       tags:
         - "User"
       summary: "Get all users for a use case"
@@ -76,7 +76,7 @@ paths:
         "400":
           description: "Wrong or missing parameters"
     post:
-      operationId: "routes.user.add"
+      operationId: "lib.routes.user.add"
       tags:
         - "User"
       summary: "Adds a new user to the system"
@@ -100,7 +100,7 @@ paths:
   #####
   /use-cases/{use_case}/contexts:
     get:
-      operationId: "routes.context.all_for_use_case"
+      operationId: "lib.routes.context.all_for_use_case"
       tags:
         - "Context"
       summary: "Get all contexts for a use case"
@@ -117,7 +117,7 @@ paths:
         "404":
           description: "Use-Case was not found"
     post:
-      operationId: "routes.context.add"
+      operationId: "lib.routes.context.add"
       tags:
         - "Context"
       summary: "Adds a new context to the system"
@@ -182,6 +182,7 @@ definitions:
     required:
       - use_case
       - context
+      - table
       - user_source
       - volume_source
       - conversion
@@ -196,6 +197,9 @@ definitions:
       context: 
         type: string
         example: "context1"
+      table: 
+        type: string
+        example: "travel"
       user_source:
         type: string
         example: "user//id"

src/data-hub/reputation-calculation-microservice/app/database/entities/trust_adapter.py → src/data-hub/reputation-calculation-microservice/app/lib/database/entities/trust_adapter.py

@@ -2,12 +2,17 @@ from typing import Dict
 
 
 class TrustAdapter:
-    def __init__(self, use_case: str, context: str, user_source: str, volume_source: str,
-                 conversion: float, certainty: float, cutoff: float, bias_negative: float, bias_positive: float):
+    def __init__(self, use_case: str, context: str, table: str, user_source: str, volume_source: str,
+                 rating_source: str, rating_lower: float, rating_upper: float, conversion: float, 
+                 certainty: float, cutoff: float, bias_negative: float, bias_positive: float):
         self.use_case = use_case
         self.context = context
+        self.table = table
         self.user_source = user_source
         self.volume_source = volume_source
+        self.rating_source = rating_source
+        self.rating_lower = rating_lower
+        self.rating_upper = rating_upper
         self.conversion = conversion
         self.certainty = certainty
         self.cutoff = cutoff
@@ -18,8 +23,12 @@ class TrustAdapter:
         return {
             "use_case": self.use_case,
             "context": self.context,
+            "table": self.table,
             "user_source": self.user_source,
             "volume_source": self.volume_source,
+            "rating_source": self.rating_source,
+            "rating_lower": self.rating_lower,
+            "rating_upper": self.rating_upper,
             "conversion": self.conversion,
             "certainty": self.certainty,
             "cutoff": self.cutoff,
@@ -29,14 +38,18 @@ class TrustAdapter:
 
     @staticmethod
     def from_serializable_dict(data: Dict):
-        if "use_case" not in data.keys() or "context" not in data.keys() or "user_source" not in data.keys() or "volume_source" not in data.keys() or "conversion" not in data.keys() or "certainty" not in data.keys() or "cutoff" not in data.keys() or "bias_negative" not in data.keys() or "bias_positive" not in data.keys():
+        if "use_case" not in data.keys() or "context" not in data.keys() or "table" not in data.keys() or "user_source" not in data.keys() or "volume_source" not in data.keys() or "rating_source" not in data.keys() or "conversion" not in data.keys() or "certainty" not in data.keys() or "cutoff" not in data.keys() or "bias_negative" not in data.keys() or "bias_positive" not in data.keys():
             raise ValueError("Missing fields for TrustAdapter!")
 
         return TrustAdapter(
             data["use_case"],
             data["context"],
+            data["table"],
             data["user_source"],
             data["volume_source"],
+            data["rating_source"],
+            data["rating_lower"],
+            data["rating_upper"],
             data["conversion"],
             data["certainty"],
             data["cutoff"],

src/data-hub/reputation-calculation-microservice/app/database/entities/trust_trace.py → src/data-hub/reputation-calculation-microservice/app/lib/database/entities/trust_trace.py

+from datetime import datetime
+from lib.trust.transaction import Transaction
 from typing import Dict
 
 
-class TrustTrace:
-    def __init__(self, use_case: str, context: str, user: str, volume: float, rating: float):
+class TrustTrace(Transaction):
+    def __init__(self, use_case: str, context: str, user: str, table: str, volume: float, timestamp: datetime, is_trustworthy: float = 1):
+        super().__init__(timestamp, volume, is_trustworthy=is_trustworthy)
+
         self.use_case = use_case
         self.context = context
         self.user = user
-        self.volume = volume
-        self.oracle_rating = rating
 
     def to_serializable_dict(self):
         return {
+            "volume": self.volume,
+            "trustworthy": self.trustworthy,
+            "timestamp": self.timestamp.isoformat(),
             "use_case": self.use_case,
             "context": self.user,
             "user": self.volume,
-            "volume": self.volume,
-            "oracle_rating": self.oracle_rating
+            "table": self.table,
         }
 
     @staticmethod
     def from_serializable_dict(data: Dict):
-        if "use_case" not in data.keys() or "context" not in data.keys() or "user" not in data.keys() or "volume" not in data.keys() or "oracle_rating" not in data.keys():
+        if "volume" not in data.keys() or "trustworthy" not in data.keys() or "timestamp" not in data.keys() or "use_case" not in data.keys() or "context" not in data.keys() or "user" not in data.keys() or "table" not in data.keys():
             raise ValueError("Missing fields for User!")
 
         return TrustTrace(
             data["use_case"],
             data["context"],
-            data["user"],
+            data["table"],
             data["volume"],
-            data["oracle_rating"],
+            datetime.fromisoformat(data["timestamp"]),
+            is_trustworthy=data["trustworthy"]
         )

src/data-hub/reputation-calculation-microservice/app/lib/database/entities/user.py

+from lib.database.entities.user_trust import UserTrust
+from datetime import datetime
+from typing import Dict, List
+
+
+class User:
+    def __init__(self, use_case: str, name: str, context_trust: List[UserTrust] = []):
+        self.use_case = use_case
+        self.name = name
+        self.context_trust = context_trust
+
+    def to_serializable_dict(self, include_trust: bool = False):
+        if include_trust:
+            return {
+                "use_case": self.use_case,
+                "name": self.name,
+                "context_trust": [t.to_serializable_dict() for t in self.context_trust]
+            }
+        else:
+            return {
+                "use_case": self.use_case,
+                "name": self.name
+            }
+
+    @staticmethod
+    def from_serializable_dict(data: Dict):
+        if "use_case" not in data.keys() or "name" not in data.keys():
+            raise ValueError("Missing fields for User!")
+
+        return User(data["use_case"], data["name"])

src/data-hub/reputation-calculation-microservice/app/database/entities/user.py → src/data-hub/reputation-calculation-microservice/app/lib/database/entities/user_trust.py

+from datetime import datetime
 from typing import Dict
 
-class User:
-    def __init__(self, use_case:str, name:str):
+class UserTrust:
+    def __init__(self, use_case: str, context: str, user: str, t: float, last_update: datetime):
         self.use_case = use_case
-        self.name = name
+        self.context = context
+        self.user = user
+        self.t = t
+        self.last_update = last_update
+
     
     def to_serializable_dict(self):
         return {
             "use_case": self.use_case,
-            "name": self.name
+            "context": self.context,
+            "user": self.user,
+            "t": self.t,
+            "last_update": self.last_update
         }
     
     @staticmethod
     def from_serializable_dict(data: Dict):
-        if "use_case" not in data.keys() or "name" not in data.keys():
+        if "use_case" not in data.keys() or "context" not in data.keys() or "user" not in data.keys() or "t" not in data.keys() or "last_update" not in data.keys():
             raise ValueError("Missing fields for User!")
 
-        return User(data["use_case"], data["name"])
+        return UserTrust(data["use_case"], data["context"], data["user"], data["t"], data["last_update"])
\ No newline at end of file

src/data-hub/reputation-calculation-microservice/app/database/repositories/context_repository.py → src/data-hub/reputation-calculation-microservice/app/lib/database/repositories/context_repository.py

@@ -2,7 +2,7 @@
 import network_constants as netconst
 from database.MongoRepositoryBase import MongoRepositoryBase
 
-from database.entities.context import Context
+from lib.database.entities.context import Context
 from typing import List, Dict
 
 class ContextRepository(MongoRepositoryBase):
@@ -11,7 +11,7 @@ class ContextRepository(MongoRepositoryBase):
     def __init__(self):
         super().__init__(netconst.REPUTATION_CALCULATION_DB_HOSTNAME,
                          netconst.REPUTATION_CALCULATION_DB_PORT,
-                         'rest-gateway-db')
+                         'reputation-computation-db')
         self._collection = 'context'
 
     def add(self, context: Context):

src/data-hub/reputation-calculation-microservice/app/database/repositories/trust_adapter_repository.py → src/data-hub/reputation-calculation-microservice/app/lib/database/repositories/trust_adapter_repository.py

@@ -2,7 +2,7 @@
 import network_constants as netconst
 from database.MongoRepositoryBase import MongoRepositoryBase
 
-from database.entities.trust_adapter import TrustAdapter
+from lib.database.entities.trust_adapter import TrustAdapter
 from typing import List, Dict
 
 class TrustAdapterRepository(MongoRepositoryBase):
@@ -11,7 +11,7 @@ class TrustAdapterRepository(MongoRepositoryBase):
     def __init__(self):
         super().__init__(netconst.REPUTATION_CALCULATION_DB_HOSTNAME,
                          netconst.REPUTATION_CALCULATION_DB_PORT,
-                         'rest-gateway-db')
+                         'reputation-computation-db')
         self._collection = 'trust_adapter'
 
     def add(self, adapter: TrustAdapter):
@@ -22,16 +22,36 @@ class TrustAdapterRepository(MongoRepositoryBase):
 
         return list(result)
 
-    def one_for_use_case_and_context(self, use_case: str, context: str) -> List[Dict]:
+    def all_for_use_case_and_context(self, use_case: str, context: str) -> List[Dict]:
         result = super().get_entries(
             self._collection, 
             projection={'_id': False}, 
             selection={"use_case": use_case, "context": context}
         )
 
-        rows = list(result)
+        return list(result)
+    
+    def all_for_use_case_and_table(self, use_case: str, table: str) -> List[Dict]:
+        result = super().get_entries(
+            self._collection, 
+            projection={'_id': False}, 
+            selection={"use_case": use_case, "table": table}
+        )
+
+        return list(result)
 
-        if len(rows) == 0:
+    def one_for_use_case_and_context_and_table(self, use_case: str, context: str, table: str) -> Dict:
+        result = super().get_entries(
+            self._collection, 
+            projection={'_id': False}, 
+            selection={"use_case": use_case, "context": context, "table": table}
+        )
+
+        result = list(result)
+
+        if len(result) != 1:
             return None
-        
-        return rows[0]
+
+        return result[0]
\ No newline at end of file
+
+        
\ No newline at end of file

src/data-hub/reputation-calculation-microservice/app/database/repositories/trust_trace_repository.py → src/data-hub/reputation-calculation-microservice/app/lib/database/repositories/trust_trace_repository.py

@@ -2,31 +2,33 @@
 import network_constants as netconst
 from database.MongoRepositoryBase import MongoRepositoryBase
 
-from database.entities.trust_trace import TrustTrace
+from lib.database.entities.trust_trace import TrustTrace
 from typing import List, Dict
 
+
 class TrustTraceRepository(MongoRepositoryBase):
     '''This is a repository for MongoDb.'''
 
     def __init__(self):
         super().__init__(netconst.REPUTATION_CALCULATION_DB_HOSTNAME,
                          netconst.REPUTATION_CALCULATION_DB_PORT,
-                         'rest-gateway-db')
+                         'reputation-computation-db')
         self._collection = 'trust_trace'
 
     def add(self, trace: TrustTrace):
         super().insert_entry(self._collection, trace.to_serializable_dict())
 
     def all(self) -> List[Dict]:
-        result = super().get_entries(self._collection, projection={'_id': False})
+        result = super().get_entries(
+            self._collection, projection={'_id': False})
 
         return list(result)
 
     def all_for_use_case_and_context(self, use_case: str, context: str) -> List[Dict]:
         result = super().get_entries(
-            self._collection, 
-            projection={'_id': False}, 
+            self._collection,
+            projection={'_id': False},
             selection={"use_case": use_case, "context": context}
         )
 
-        return list(result)
+        return list(result)
\ No newline at end of file

src/data-hub/reputation-calculation-microservice/app/database/repositories/user_repository.py → src/data-hub/reputation-calculation-microservice/app/lib/database/repositories/user_repository.py

@@ -2,27 +2,58 @@
 import network_constants as netconst
 from database.MongoRepositoryBase import MongoRepositoryBase
 
-from database.entities.user import User
+from lib.database.entities.user import User
+from lib.database.entities.user_trust import UserTrust
+from lib.database.repositories.user_trust_repository import UserTrustRepository
 from typing import List, Dict
 
+
 class UserRepository(MongoRepositoryBase):
     '''This is a repository for MongoDb.'''
 
+    _user_trust_repository = UserTrustRepository()
+
     def __init__(self):
         super().__init__(netconst.REPUTATION_CALCULATION_DB_HOSTNAME,
                          netconst.REPUTATION_CALCULATION_DB_PORT,
-                         'rest-gateway-db')
+                         'reputation-computation-db')
         self._collection = 'user'
 
     def add(self, user: User):
         super().insert_entry(self._collection, user.to_serializable_dict())
 
-    def all(self) -> List[Dict]:
-        result = super().get_entries(self._collection, projection={'_id': False})
+    def all(self) -> List[User]:
+        result = super().get_entries(
+            self._collection, projection={'_id': False})
+        result = [User.from_serializable_dict(row) for row in list(result)]
+
+        for user in result:
+            self._enrich_user(user)
+
+        return result
+
+    def all_for_use_case(self, use_case: str) -> List[User]:
+        result = super().get_entries(self._collection, projection={
+            '_id': False}, selection={"use_case": use_case})
+
+        result = [User.from_serializable_dict(row) for row in list(result)]
+
+        for user in result:
+            self._enrich_user(user)
+
+        return result
+
+    def one_by_use_case_and_username(self, use_case: str, username: str) -> User:
+        result = super().get_entries(self._collection, projection={
+            '_id': False}, selection={"use_case": use_case, "name": username})
+
+        if len(result) != 1:
+            return None
 
-        return list(result)
+        user: User = User.from_serializable_dict(result[0])
+        self._enrich_user(user)
 
-    def all_for_use_case(self, use_case: str) -> List[Dict]:
-        result = super().get_entries(self._collection, projection={'_id': False}, selection={"use_case": use_case})
+        return user
 
-        return list(result)
+    def _enrich_user(self, user: User) -> User:
\ No newline at end of file
+        user.context_trust = self._user_trust_repository.all_for_user(user)

src/data-hub/reputation-calculation-microservice/app/lib/database/repositories/user_trust_repository.py

+# global imports (dont't worry, red is normal)
+import network_constants as netconst
+from database.MongoRepositoryBase import MongoRepositoryBase
+
+from lib.database.entities.user import User
+from lib.database.entities.user_trust import UserTrust
+from typing import List, Dict
+
+
+class UserTrustRepository(MongoRepositoryBase):
+    '''This is a repository for MongoDb.'''
+
+    def __init__(self):
+        super().__init__(netconst.REPUTATION_CALCULATION_DB_HOSTNAME,
+                         netconst.REPUTATION_CALCULATION_DB_PORT,
+                         'reputation-computation-db')
+        self._collection = 'user_trust'
+
+    def add(self, user_trust: UserTrust):
+        super().insert_entry(self._collection, user_trust.to_serializable_dict())
+
+    def all(self) -> List[UserTrust]:
+        result = super().get_entries(
+            self._collection, projection={'_id': False})
+
+        return [UserTrust.from_serializable_dict(row) for row in list(result)]
+
+    def all_for_use_case(self, use_case: str) -> List[UserTrust]:
+        result = super().get_entries(self._collection, projection={
+            '_id': False}, selection={"use_case": use_case})
+
+        return [UserTrust.from_serializable_dict(row) for row in list(result)]
+
+    def all_for_user(self, user: User) -> List[UserTrust]:
+        result = super().get_entries(self._collection, projection={
+            '_id': False}, selection={"use_case": user.use_case, "user": user.name})
+
+        return [UserTrust.from_serializable_dict(row) for row in list(result)]
+
+    def one_for_user_and_context(self, user: User, context: str) -> UserTrust:
+        result = super().get_entries(self._collection, projection={'_id': False}, selection={
+            "use_case": user.use_case, "user": user.name, "context": context})
+
+        result = list(result)
+
+        if len(result) != 1:
+            return None
+
+        return UserTrust.from_serializable_dict(result[0])
+
+    def update(self, user_trust: UserTrust):
+        collection = self._database[self._collection]
+        collection.update_one({"use_case": user_trust.use_case, "context": user_trust.context, "user": user_trust.user}, {
+                              "$set": user_trust.to_serializable_dict()})

src/data-hub/reputation-calculation-microservice/app/routes/trust_adapter.py → src/data-hub/reputation-calculation-microservice/app/lib/routes/trust_adapter.py

@@ -5,32 +5,34 @@ from database.repositories.context_repository import ContextRepository
 from database.repositories.trust_adapter_repository import TrustAdapterRepository
 
 from flask import request, Response
-from typing import List
+from typing import List, Dict
 
 context_repository: ContextRepository = ContextRepository()
 trust_adapter_repository: TrustAdapterRepository = TrustAdapterRepository()
 
+
 def add(use_case: str, context: str):
     _ensure_context_exists_for_use_case(use_case, context)
 
     data = request.json
 
-    adapter_reference = trust_adapter_repository.one_for_use_case_and_context(use_case, context)
-    if adapter_reference != None:
-        return Response(status=400, response="There already exists a TrustAdapter.")
-
-    adapter_new = None
+    adapter_new: TrustAdapter = None
     try:
         adapter_new = TrustAdapter.from_serializable_dict(data)
     except ValueError:
         return Response(status=400, response="Missing fields in request")
-    
+
     if adapter_new.context != context:
         return Response(status=400, response="Context in body and url do not match!")
 
     if adapter_new.use_case != use_case:
         return Response(status=400, response="Use-Cases in body and url do not match!")
 
+    adapter_reference = trust_adapter_repository.one_for_use_case_and_context_and_table(
+        use_case, context, adapter_new.table)
+    if adapter_reference != None:
+        return Response(status=400, response="There already exists a TrustAdapter for this use-case/context/table")
+
     trust_adapter_repository.add(adapter_new)
 
     return adapter_new.to_serializable_dict()
@@ -39,7 +41,8 @@ def add(use_case: str, context: str):
 def all_for_use_case_and_context(use_case: str, context: str):
     _ensure_context_exists_for_use_case(use_case, context)
 
-    return trust_adapter_repository.one_for_use_case_and_context(use_case, context)
+    return trust_adapter_repository.all_for_use_case_and_context(use_case, context)
+
 
 def _ensure_context_exists_for_use_case(use_case: str, context: str) -> Context:
     contexts: List[Context] = context_repository.all_for_use_case(use_case)
@@ -51,4 +54,4 @@ def _ensure_context_exists_for_use_case(use_case: str, context: str) -> Context:
     if target_context == None:
         return Response(status=404, response=f"Context {context} not found!")
 
-    return Context.from_serializable_dict(target_context)
+    return Context.from_serializable_dict(target_context)
\ No newline at end of file

src/data-hub/reputation-calculation-microservice/app/routes/user.py → src/data-hub/reputation-calculation-microservice/app/lib/routes/user.py

@@ -21,4 +21,4 @@ def add(use_case: str):
     return user_new.to_serializable_dict()
 
 def all_for_use_case(use_case: str):
-    return user_repository.all_for_use_case(use_case)
+    return [user.to_serializable_dict(include_trust=True) for user in user_repository.all_for_use_case(use_case)]

src/data-hub/reputation-calculation-microservice/app/lib/services/trust_service.py

+from lib.database.entities.trust_trace import TrustTrace
+from lib.database.entities.user_trust import UserTrust
+from lib.trust.oracle import TrustOracle
+from lib.database.entities.trust_adapter import TrustAdapter
+from lib.database.entities.user import User
+from typing import Dict, List
+import logging
+from datetime import datetime
+
+LOGGER = logging.getLogger(__name__)
+
+
+class TrustService:
+
+    def __init__(self, adapter_repository, user_repository, user_trust_repository, trust_trace_repository):
+        self._adapter_repository = adapter_repository
+        self._user_repository = user_repository
+        self._user_trust_repository = user_trust_repository
+        self._trust_trace_repository = trust_trace_repository
+
+    def updateSystem(self, use_case: str, table: str, properties: Dict):
+        adapters: List[TrustAdapter] = self._adapter_repository.all_for_use_case_and_table(
+            use_case, table)
+
+        if len(adapters) == 0:
+            LOGGER.warning(
+                f"No Trust-Adapters found for Trace(use-case:{use_case}, table:{table}), aborting...")
+            return
+
+        for adapter in adapters:
+            if adapter.user_source not in properties.keys() or adapter.volume_source not in properties.keys() or adapter.rating_source not in properties.keys():
+                raise ValueError(
+                    f"Trace does not contain needed fields for trust-computation. Required fields: {adapter.user_source}, {adapter.volume_source}. Present fields: {properties.keys()}")
+
+            username: str = properties[adapter.user_source]
+            volume: float = properties[adapter.volume_source]
+            rating: float = properties[adapter.rating_source]
+
+            # retrieve user (create one if it doesnt exist)
+            user: User = self._user_repository.one_by_use_case_and_username(
+                use_case, username)
+            if user == None:
+                user = User(use_case, username)
+                self._user_repository.add(user)
+            
+            trace: TrustTrace = TrustTrace(
+                use_case,
+                adapter.context,
+                user.name,
+                adapter.table,
+                volume,
+                datetime.now(),
+                is_trustworthy=(((rating - adapter.rating_lower) /
+                                 (adapter.rating_upper - adapter.rating_lower)) * 2) - 1
+            )
+
+            # retrieve user_trust for the trace (create one if it doesnt exist)
+            target_trust: UserTrust = None
+            for user_trust in user.context_trust:
+                if user_trust.context == adapter.context:
+                    target_trust = user_trust
+                    break
+            if target_trust == None:
+                target_trust = UserTrust(
+                    use_case, adapter.context, user.name, 0, datetime(1, 1, 1, 0, 0))
+                self._user_trust_repository.add(target_trust)
+                user.context_trust.append(target_trust)
+
+            oracle: TrustOracle = TrustOracle(
+                adapter.conversion, adapter.certainty)
+            delta_t = oracle.calculate_trust_single(trace)
+
+            target_trust.t += delta_t
+            target_trust.last_update = trace.timestamp
+
+            self._trust_trace_repository.add(trace)
+            self._user_trust_repository.update(target_trust)

src/data-hub/reputation-calculation-microservice/app/lib/trust/message_handler.py

+from lib.services.trust_service import TrustService
+from lib.database.entities.trust_trace import TrustTrace
+from lib.database.entities.user_trust import UserTrust
+from lib.trust.oracle import TrustOracle
+from lib.trust.transaction import Transaction
+from lib.database.entities.trust_adapter import TrustAdapter
+from lib.database.entities.user import User
+from typing import Dict, List
+import json
+import logging
+from datetime import datetime
+
+LOGGER = logging.getLogger(__name__)
+
+
+class MessageHandler:
+    def __init__(self, trust_adapter_repository, user_repository, user_trust_repository, trust_trace_repository):
+        self.trust_adapter_repository = trust_adapter_repository
+        self.user_repository = user_repository
+        self.user_trust_repository = user_trust_repository
+        self.trust_trace_repository = trust_trace_repository
+
+    def handle(self, body: str):
+        # decode the message
+        data: Dict = None
+        try:
+            data = json.loads(body)
+        except json.decoder.JSONDecodeError:
+            raise ValueError("Invalid Message: Not in JSON format")
+
+        if "type" not in data.keys() or "content" not in data.keys():
+            raise ValueError(
+                "Invalid Message: Missing fields \"type\" or \"content\"")
+
+        if data["type"] != "new-trace":
+            return
+
+        content: Dict = data["content"]
+
+        if "use_case" not in content.keys() or "table" not in content.keys() or "properties" not in content.keys():
+            raise ValueError(
+                "Invalid Message: Missing fields \"use_case\" or \"table\" or \"properties\"")
+
+        use_case: str = content["use_case"]
+        table: str = content["table"]
+        properties: Dict = content["properties"]
+
+        trust_service: TrustService = TrustService(
+            self.trust_adapter_repository,
+            self.user_repository,
+            self.user_trust_repository,
+            self.trust_trace_repository
+        )
+
+        trust_service.updateSystem(use_case, table, properties)
+
+        # adapters: List[TrustAdapter] = self.trust_adapter_repository.all_for_use_case_and_table(
+        #     use_case, table)
+
+        # if len(adapters) == 0:
+        #     LOGGER.warning(
+        #         f"No Trust-Adapters found for Trace(use-case:{use_case}, table:{table}), aborting...")
+        #     return
+
+        # for adapter in adapters:
+        #     if adapter.user_source not in properties.keys() or adapter.volume_source not in properties.keys() or adapter.rating_source not in properties.keys():
+        #         raise ValueError(
+        #             f"Trace does not contain needed fields for trust-computation. Required fields: {adapter.user_source}, {adapter.volume_source}. Present fields: {properties.keys()}")
+
+        #     username: str = properties[adapter.user_source]
+        #     volume: float = properties[adapter.volume_source]
+        #     rating: float = properties[adapter.rating_source]
+
+        #     trace: TrustTrace = TrustTrace(
+        #         use_case,
+        #         adapter.context,
+        #         user.name,
+        #         adapter.table,
+        #         volume,
+        #         datetime.now(),
+        #         is_trustworthy=(((rating - adapter.rating_lower) /
+        #                          (adapter.rating_upper - adapter.rating_lower)) * 2) - 1
+        #     )
+
+        #     # retrieve user (create one if it doesnt exist)
+        #     user: User = self.user_repository.one_by_use_case_and_username(
+        #         use_case, username)
+        #     if user == None:
+        #         user = User(use_case, username)
+        #         self.user_repository.add(user)
+
+        #     # retrieve user_trust for the trace (create one if it doesnt exist)
+        #     target_trust: UserTrust = None
+        #     for user_trust in user.context_trust:
+        #         if user_trust.context == adapter.context:
+        #             target_trust = user_trust
+        #             break
+        #     if target_trust == None:
+        #         target_trust = UserTrust(
+        #             use_case, adapter.context, user.name, 0, datetime(1, 1, 1, 0, 0))
+        #         self.user_trust_repository.add(target_trust)
+        #         user.context_trust.append(target_trust)
+
+        #     oracle: TrustOracle = TrustOracle(
+        #         adapter.conversion, adapter.certainty)
+        #     delta_t = oracle.calculate_trust_single(trace)
+
+        #     target_trust.t += delta_t
+        #     target_trust.last_update = trace.timestamp
+
+        #     self.trust_trace_repository.add(trace)
+        #     self.user_trust_repository.update(target_trust)

src/data-hub/reputation-calculation-microservice/app/lib/trust/node.py

+class Node:
+    def __init__(self, initial_t=0):
+        self.t = initial_t
\ No newline at end of file

src/data-hub/reputation-calculation-microservice/app/lib/trust/oracle.py

+import math
+from enum import Enum
+from lib.trust.transaction import Transaction
+from lib.trust.node import Node
+from datetime import datetime
+from typing import List, Dict
+
+
+class TrustLabel(Enum):
+    UNTRUSTWORTHY = 1
+    UNSURE = 2
+    TRUSTWORTHY = 3
+
+
+class TrustOracle:
+    def __init__(self, translate_value: float, knowledge_border: float):
+        # translates transaction volume into unitless x-axis value for sigmoid input
+        self.translate_value = translate_value
+        # nodes must reach a value of at least |trust(node)| = knowledge_border to get a definite label
+        self.knowledge_border = knowledge_border
+
+    def rate_node(self, node: Node) -> TrustLabel:
+        if node.t < -self.knowledge_border:
+            return TrustLabel.UNTRUSTWORTHY
+
+        if node.t > self.knowledge_border:
+            return TrustLabel.TRUSTWORTHY
+
+        return TrustLabel.UNSURE
+
+    def calculate_trust_single(self, node_transaction: Transaction):
+        return self.calculate_trust([node_transaction])
+
+    def calculate_trust(self, node_transactions: List[Transaction]):
+        trust_total = 0
+
+        for transaction in node_transactions:
+            transaction_t = abs(transaction.volume / self.translate_value)
+            trust_total += transaction_t
+
+        return self.translate_t_to_trust_value(trust_total)
+
+    def translate_t_to_trust_value(self, t_value: float):
+        # classic sigmoid function as in https://en.wikipedia.org/wiki/Sigmoid_function
+        sig = 1 / (1 + math.exp(-t_value))
+
+        # rescale it st.:
+        # values are between ]-1;1[
+        sig *= 2
+        sig -= 1
+
+        return sig

src/data-hub/reputation-calculation-microservice/app/lib/trust/transaction.py

+class Transaction:
+    def __init__(self, timestamp, volume=1, is_trustworthy: float = 1):
+        self.volume = volume
+        self.trustworthy = is_trustworthy
+        self.timestamp = timestamp

src/data-hub/reputation-calculation-microservice/app/tests/test_messaging.py

+from lib.database.entities.trust_trace import TrustTrace
+from lib.database.entities.user_trust import UserTrust
+from lib.database.entities.user import User
+from lib.database.entities.trust_adapter import TrustAdapter
+from lib.trust.message_handler import MessageHandler
+from typing import List, Dict
+import unittest
+import json
+
+
+class DummyTrustAdapterRepo:
+    _adapters: List[TrustAdapter] = [
+        TrustAdapter(
+            "car-sharing",
+            "context1",
+            "travel",
+            "user",
+            "cost",
+            "rating",
+            1,
+            5,
+            2000,
+            0.75,
+            8,
+            1,
+            1
+        )
+    ]
+
+    def add(self, adapter: TrustAdapter):
+        self._adapters.append(adapter)
+
+    def all(self) -> List[Dict]:
+        return self._adapters
+
+    def all_for_use_case_and_context(self, use_case: str, context: str) -> List[Dict]:
+        return [adapter for adapter in self._adapters if (adapter.use_case == use_case and adapter.context == context)]
+
+    def all_for_use_case_and_table(self, use_case: str, table: str) -> List[Dict]:
+        return [adapter for adapter in self._adapters if (adapter.use_case == use_case and adapter.table == table)]
+
+    def one_for_use_case_and_context_and_table(self, use_case: str, context: str, table: str) -> Dict:
+        result = [adapter for adapter in self._adapters if (
+            adapter.use_case == use_case and adapter.context == context and adapter.table == table)]
+
+        if len(result) != 1:
+            return None
+
+        return result[0]
+
+
+class DummyUserRepo:
+    _users: List[User] = []
+
+    def clear(self):
+        self._users.clear()
+
+    def add(self, user: User):
+        self._users.append(user)
+
+    def all(self) -> List[User]:
+        return self._users
+
+    def all_for_use_case(self, use_case: str) -> List[User]:
+        return [user for user in self._users if (user.use_case == use_case)]
+
+    def one_by_use_case_and_username(self, use_case: str, username: str) -> User:
+        result = [user for user in self._users if (
+            user.use_case == use_case and user.name == username)]
+
+        if len(result) != 1:
+            return None
+
+        return result[0]
+
+
+class DummyUserTrustRepo:
+    _user_trusts: List[UserTrust] = []
+
+    def add(self, user_trust: UserTrust):
+        self._user_trusts.append(user_trust)
+
+    def all(self) -> List[UserTrust]:
+        return self._user_trusts
+
+    def all_for_use_case(self, use_case: str) -> List[UserTrust]:
+        return [user_trust for user_trust in self._user_trusts if (user_trust.use_case == use_case)]
+
+    def all_for_user(self, user: User) -> List[UserTrust]:
+        return [user_trust for user_trust in self._user_trusts if (user_trust.use_case == user.use_case and user_trust.user == user.name)]
+
+    def one_for_user_and_context(self, user: User, context: str) -> UserTrust:
+        result = [user_trust for user_trust in self.user_trust if (
+            user_trust.use_case == user.use_case and user_trust.name == user.name and user_trust.context == context)]
+
+        if len(result) != 1:
+            return None
+
+        return result[0]
+
+    def update(self, user_trust: UserTrust):
+        pass
+
+
+class DummyTrustTraceRepository:
+    _traces: List[TrustTrace] = []
+
+    def add(self, trace: TrustTrace):
+        self._traces.append(trace)
+
+    def all(self) -> List[Dict]:
+        return [trace.to_serializable_dict() for trace in self._traces]
+
+    def all_for_use_case_and_context(self, use_case: str, context: str) -> List[Dict]:
+        result = [trace for trace in self._traces if (
+            trace.use_case == use_case and trace.context == context)]
+
+        return [trace.to_serializable_dict() for trace in result]
+
+
+class Test_Messages(unittest.TestCase):
+
+    user_repo = None
+    message_handler: MessageHandler = None
+
+    def setUp(self):
+        self.user_repo = DummyUserRepo()
+        self.message_handler = MessageHandler(
+            DummyTrustAdapterRepo(),
+            self.user_repo,
+            DummyUserTrustRepo(),
+            DummyTrustTraceRepository()
+        )
+
+    def _buildTrace(self):
+        return json.dumps({
+            "type": "new-trace",
+            "content": {
+                "use_case": "car-sharing",
+                "table": "travel",
+                "id": "092870924809481f",
+                "properties": {
+                    "user": "Bob",
+                    "cost": 201.12,
+                    "rating": 4
+                }
+            }
+        })
+
+    def test_message_no_json(self):
+        message: str = "abcdefg"
+
+        try:
+            self.message_handler.handle(message)
+        except ValueError:
+            pass
+
+    def test_message_valid(self):
+        message = self._buildTrace()
+
+        self.user_repo.clear()
+        self.assertEqual(0, len(self.user_repo.all()))
+
+        self.message_handler.handle(message)
+
+        self.assertEqual(1, len(self.user_repo.all())) # ensure user was added
+
+
+if __name__ == '__main__':
+    unittest.main()