fix(event_source): centralizing helper functions for query, header and base64 (aws-powertools#2496)

Author: leandrodamascena

aws_lambda_powertools/utilities/data_classes/active_mq_event.py

@@ -1,8 +1,7 @@
-import base64
-import json
 from typing import Any, Iterator, Optional
 
 from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import base64_decode
 
 
 class ActiveMQMessage(DictWrapper):
@@ -22,13 +21,13 @@ def data(self) -> str:
     @property
     def decoded_data(self) -> str:
         """Decodes the data as a str"""
-        return base64.b64decode(self.data.encode()).decode()
+        return base64_decode(self.data)
 
     @property
     def json_data(self) -> Any:
         """Parses the data as json"""
         if self._json_data is None:
-            self._json_data = json.loads(self.decoded_data)
+            self._json_data = self._json_deserializer(self.decoded_data)
         return self._json_data
 
     @property
@@ -125,7 +124,7 @@ def event_source_arn(self) -> str:
     @property
     def messages(self) -> Iterator[ActiveMQMessage]:
         for record in self["messages"]:
-            yield ActiveMQMessage(record)
+            yield ActiveMQMessage(record, json_deserializer=self._json_deserializer)
 
     @property
     def message(self) -> ActiveMQMessage:

aws_lambda_powertools/utilities/data_classes/api_gateway_authorizer_event.py

@@ -6,6 +6,8 @@
     BaseRequestContext,
     BaseRequestContextV2,
     DictWrapper,
+)
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
     get_header_value,
 )
 

aws_lambda_powertools/utilities/data_classes/appsync_resolver_event.py

@@ -1,7 +1,7 @@
 from typing import Any, Dict, List, Optional, Union
 
-from aws_lambda_powertools.utilities.data_classes.common import (
-    DictWrapper,
+from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
     get_header_value,
 )
 

aws_lambda_powertools/utilities/data_classes/aws_config_rule_event.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import json
 from typing import Any, Dict, List, Optional
 
 from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
@@ -303,9 +302,9 @@ def invoking_event(
     ) -> AWSConfigConfigurationChanged | AWSConfigScheduledNotification | AWSConfigOversizedConfiguration:
         """The invoking payload of the event."""
         if self._invoking_event is None:
-            self._invoking_event = self["invokingEvent"]
+            self._invoking_event = self._json_deserializer(self["invokingEvent"])
 
-        return get_invoke_event(json.loads(self._invoking_event))
+        return get_invoke_event(self._invoking_event)
 
     @property
     def raw_invoking_event(self) -> str:
@@ -316,9 +315,9 @@ def raw_invoking_event(self) -> str:
     def rule_parameters(self) -> Dict:
         """The parameters of the event."""
         if self._rule_parameters is None:
-            self._rule_parameters = self["ruleParameters"]
+            self._rule_parameters = self._json_deserializer(self["ruleParameters"])
 
-        return json.loads(self._rule_parameters)
+        return self._rule_parameters
 
     @property
     def result_token(self) -> str:

aws_lambda_powertools/utilities/data_classes/cloud_watch_logs_event.py

@@ -1,5 +1,4 @@
 import base64
-import json
 import zlib
 from typing import Dict, List, Optional
 
@@ -97,5 +96,6 @@ def decompress_logs_data(self) -> bytes:
     def parse_logs_data(self) -> CloudWatchLogsDecodedData:
         """Decode, decompress and parse json data as CloudWatchLogsDecodedData"""
         if self._json_logs_data is None:
-            self._json_logs_data = json.loads(self.decompress_logs_data.decode("UTF-8"))
+            self._json_logs_data = self._json_deserializer(self.decompress_logs_data.decode("UTF-8"))
+
         return CloudWatchLogsDecodedData(self._json_logs_data)

aws_lambda_powertools/utilities/data_classes/code_pipeline_job_event.py

@@ -1,4 +1,3 @@
-import json
 import tempfile
 import zipfile
 from typing import Any, Dict, List, Optional
@@ -22,7 +21,7 @@ def user_parameters(self) -> Optional[str]:
     def decoded_user_parameters(self) -> Optional[Dict[str, Any]]:
         """Json Decoded user parameters"""
         if self._json_data is None and self.user_parameters is not None:
-            self._json_data = json.loads(self.user_parameters)
+            self._json_data = self._json_deserializer(self.user_parameters)
         return self._json_data
 
 

aws_lambda_powertools/utilities/data_classes/common.py

@@ -4,6 +4,10 @@
 from typing import Any, Callable, Dict, Iterator, List, Optional
 
 from aws_lambda_powertools.shared.headers_serializer import BaseHeadersSerializer
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
+    get_header_value,
+    get_query_string_value,
+)
 
 
 class DictWrapper(Mapping):
@@ -90,26 +94,6 @@ def raw_event(self) -> Dict[str, Any]:
         return self._data
 
 
-def get_header_value(
-    headers: Dict[str, str], name: str, default_value: Optional[str], case_sensitive: Optional[bool]
-) -> Optional[str]:
-    """Get header value by name"""
-    # If headers is NoneType, return default value
-    if not headers:
-        return default_value
-
-    if case_sensitive:
-        return headers.get(name, default_value)
-    name_lower = name.lower()
-
-    return next(
-        # Iterate over the dict and do a case-insensitive key comparison
-        (value for key, value in headers.items() if key.lower() == name_lower),
-        # Default value is returned if no matches was found
-        default_value,
-    )
-
-
 class BaseProxyEvent(DictWrapper):
     @property
     def headers(self) -> Dict[str, str]:
@@ -166,8 +150,9 @@ def get_query_string_value(self, name: str, default_value: Optional[str] = None)
         str, optional
             Query string parameter value
         """
-        params = self.query_string_parameters
-        return default_value if params is None else params.get(name, default_value)
+        return get_query_string_value(
+            query_string_parameters=self.query_string_parameters, name=name, default_value=default_value
+        )
 
     def get_header_value(
         self, name: str, default_value: Optional[str] = None, case_sensitive: Optional[bool] = False
@@ -187,7 +172,9 @@ def get_header_value(
         str, optional
             Header value
         """
-        return get_header_value(self.headers, name, default_value, case_sensitive)
+        return get_header_value(
+            headers=self.headers, name=name, default_value=default_value, case_sensitive=case_sensitive
+        )
 
     def header_serializer(self) -> BaseHeadersSerializer:
         raise NotImplementedError()

aws_lambda_powertools/utilities/data_classes/kafka_event.py

@@ -2,6 +2,9 @@
 from typing import Any, Dict, Iterator, List, Optional
 
 from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
+    get_header_value,
+)
 
 
 class KafkaEventRecord(DictWrapper):
@@ -69,17 +72,10 @@ def decoded_headers(self) -> Dict[str, bytes]:
 
     def get_header_value(
         self, name: str, default_value: Optional[Any] = None, case_sensitive: bool = True
-    ) -> Optional[bytes]:
+    ) -> Optional[str]:
         """Get a decoded header value by name."""
-        if case_sensitive:
-            return self.decoded_headers.get(name, default_value)
-        name_lower = name.lower()
-
-        return next(
-            # Iterate over the dict and do a case-insensitive key comparison
-            (value for key, value in self.decoded_headers.items() if key.lower() == name_lower),
-            # Default value is returned if no matches was found
-            default_value,
+        return get_header_value(
+            headers=self.decoded_headers, name=name, default_value=default_value, case_sensitive=case_sensitive
         )
 
 

aws_lambda_powertools/utilities/data_classes/rabbit_mq_event.py

@@ -1,8 +1,7 @@
-import base64
-import json
 from typing import Any, Dict, List
 
 from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import base64_decode
 
 
 class BasicProperties(DictWrapper):
@@ -83,13 +82,13 @@ def data(self) -> str:
     @property
     def decoded_data(self) -> str:
         """Decodes the data as a str"""
-        return base64.b64decode(self.data.encode()).decode()
+        return base64_decode(self.data)
 
     @property
     def json_data(self) -> Any:
         """Parses the data as json"""
         if self._json_data is None:
-            self._json_data = json.loads(self.decoded_data)
+            self._json_data = self._json_deserializer(self.decoded_data)
         return self._json_data
 
 

aws_lambda_powertools/utilities/data_classes/s3_object_event.py

@@ -1,7 +1,7 @@
 from typing import Dict, Optional
 
-from aws_lambda_powertools.utilities.data_classes.common import (
-    DictWrapper,
+from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
     get_header_value,
 )
 

aws_lambda_powertools/utilities/data_classes/shared_functions.py

@@ -0,0 +1,81 @@
+from __future__ import annotations
+
+import base64
+from typing import Any
+
+
+def base64_decode(value: str) -> str:
+    """
+    Decodes a Base64-encoded string and returns the decoded value.
+
+    Parameters
+    ----------
+    value: str
+        The Base64-encoded string to decode.
+
+    Returns
+    -------
+    str
+        The decoded string value.
+    """
+    return base64.b64decode(value).decode("UTF-8")
+
+
+def get_header_value(
+    headers: dict[str, Any], name: str, default_value: str | None, case_sensitive: bool | None
+) -> str | None:
+    """
+    Get the value of a header by its name.
+
+    Parameters
+    ----------
+    headers: Dict[str, str]
+        The dictionary of headers.
+    name: str
+        The name of the header to retrieve.
+    default_value: str, optional
+        The default value to return if the header is not found. Default is None.
+    case_sensitive: bool, optional
+        Indicates whether the header name should be case-sensitive. Default is None.
+
+    Returns
+    -------
+    str, optional
+        The value of the header if found, otherwise the default value or None.
+    """
+    # If headers is NoneType, return default value
+    if not headers:
+        return default_value
+
+    if case_sensitive:
+        return headers.get(name, default_value)
+    name_lower = name.lower()
+
+    return next(
+        # Iterate over the dict and do a case-insensitive key comparison
+        (value for key, value in headers.items() if key.lower() == name_lower),
+        # Default value is returned if no matches was found
+        default_value,
+    )
+
+
+def get_query_string_value(
+    query_string_parameters: dict[str, str] | None, name: str, default_value: str | None = None
+) -> str | None:
+    """
+    Retrieves the value of a query string parameter specified by the given name.
+
+    Parameters
+    ----------
+    name: str
+        The name of the query string parameter to retrieve.
+    default_value: str, optional
+        The default value to return if the parameter is not found. Defaults to None.
+
+    Returns
+    -------
+    str. optional
+        The value of the query string parameter if found, or the default value if not found.
+    """
+    params = query_string_parameters
+    return default_value if params is None else params.get(name, default_value)

aws_lambda_powertools/utilities/data_classes/vpc_lattice.py

@@ -1,9 +1,10 @@
-import base64
 from typing import Any, Dict, Optional
 
-from aws_lambda_powertools.utilities.data_classes.common import (
-    DictWrapper,
+from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.data_classes.shared_functions import (
+    base64_decode,
     get_header_value,
+    get_query_string_value,
 )
 
 
@@ -35,7 +36,7 @@ def decoded_body(self) -> str:
         """Dynamically base64 decode body as a str"""
         body: str = self["body"]
         if self.is_base64_encoded:
-            return base64.b64decode(body.encode()).decode()
+            return base64_decode(body)
         return body
 
     @property
@@ -67,8 +68,9 @@ def get_query_string_value(self, name: str, default_value: Optional[str] = None)
         str, optional
             Query string parameter value
         """
-        params = self.query_string_parameters
-        return default_value if params is None else params.get(name, default_value)
+        return get_query_string_value(
+            query_string_parameters=self.query_string_parameters, name=name, default_value=default_value
+        )
 
     def get_header_value(
         self, name: str, default_value: Optional[str] = None, case_sensitive: Optional[bool] = False
@@ -88,4 +90,6 @@ def get_header_value(
         str, optional
             Header value
         """
-        return get_header_value(self.headers, name, default_value, case_sensitive)
+        return get_header_value(
+            headers=self.headers, name=name, default_value=default_value, case_sensitive=case_sensitive
+        )