feat(v2): full AMQP 1.0 implementation

Signed-off-by: Tudor Plugaru <[email protected]>

Author: PlugaruT

src/cloudevents/core/bindings/amqp.py

@@ -0,0 +1,318 @@
+#  Copyright 2018-Present The CloudEvents Authors
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from typing import Any, Callable, Final
+
+from dateutil.parser import isoparse
+
+from cloudevents.core.base import BaseCloudEvent
+from cloudevents.core.formats.base import Format
+
+CE_PREFIX: Final[str] = "cloudEvents_"
+CONTENT_TYPE_PROPERTY: Final[str] = "content-type"
+
+
+@dataclass(frozen=True)
+class AMQPMessage:
+    """
+    Represents an AMQP 1.0 message containing CloudEvent data.
+
+    This dataclass encapsulates AMQP message properties, application properties,
+    and application data for transmitting CloudEvents over AMQP. It is immutable
+    to prevent accidental modifications and works with any AMQP 1.0 library
+    (e.g., Pika, aio-pika, qpid-proton, azure-servicebus).
+
+    Attributes:
+        properties: AMQP message properties as a dictionary
+        application_properties: AMQP application properties as a dictionary
+        application_data: AMQP application data section as bytes
+    """
+
+    properties: dict[str, Any]
+    application_properties: dict[str, Any]
+    application_data: bytes
+
+
+def _encode_amqp_value(value: Any) -> Any:
+    """
+    Encode a CloudEvent attribute value for AMQP application properties.
+
+    Handles special encoding for datetime objects to AMQP timestamp type
+    (milliseconds since Unix epoch as int). Per AMQP 1.0 CloudEvents spec,
+    senders SHOULD use native AMQP types when efficient.
+
+    :param value: The attribute value to encode
+    :return: Encoded value (int for datetime timestamp, original type otherwise)
+    """
+    if isinstance(value, datetime):
+        # AMQP 1.0 timestamp: milliseconds since Unix epoch (UTC)
+        timestamp_ms = int(value.timestamp() * 1000)
+        return timestamp_ms
+
+    return value
+
+
+def _decode_amqp_value(attr_name: str, value: Any) -> Any:
+    """
+    Decode a CloudEvent attribute value from AMQP application properties.
+
+    Handles special parsing for the 'time' attribute. Per AMQP 1.0 CloudEvents spec,
+    receivers MUST accept both native AMQP timestamp (int milliseconds since epoch)
+    and canonical string form (ISO 8601).
+
+    :param attr_name: The name of the CloudEvent attribute
+    :param value: The AMQP property value
+    :return: Decoded value (datetime for 'time' attribute, original type otherwise)
+    """
+    if attr_name == "time":
+        if isinstance(value, int):
+            # AMQP timestamp: milliseconds since Unix epoch
+            return datetime.fromtimestamp(value / 1000.0, tz=timezone.utc)
+        if isinstance(value, str):
+            # ISO 8601 string (canonical form, also accepted per spec)
+            return isoparse(value)
+
+    return value
+
+
+def to_binary(event: BaseCloudEvent, event_format: Format) -> AMQPMessage:
+    """
+    Convert a CloudEvent to AMQP binary content mode.
+
+    In binary mode, CloudEvent attributes are mapped to AMQP application properties
+    with the 'cloudEvents_' prefix, except for 'datacontenttype' which maps to the
+    AMQP 'content-type' property. The event data is placed directly in the AMQP
+    application-data section. Datetime values are encoded as AMQP timestamp type
+    (milliseconds since Unix epoch), while boolean and integer values are preserved
+    as native types.
+
+    Example:
+        >>> from cloudevents.core.v1.event import CloudEvent
+        >>> from cloudevents.core.formats.json import JSONFormat
+        >>>
+        >>> event = CloudEvent(
+        ...     attributes={"type": "com.example.test", "source": "/test"},
+        ...     data={"message": "Hello"}
+        ... )
+        >>> message = to_binary(event, JSONFormat())
+        >>> # message.application_properties = {"cloudEvents_type": "com.example.test", ...}
+        >>> # message.properties = {"content-type": "application/json"}
+        >>> # message.application_data = b'{"message": "Hello"}'
+
+    :param event: The CloudEvent to convert
+    :param event_format: Format implementation for data serialization
+    :return: AMQPMessage with CloudEvent attributes as application properties
+    """
+    properties: dict[str, Any] = {}
+    application_properties: dict[str, Any] = {}
+    attributes = event.get_attributes()
+
+    for attr_name, attr_value in attributes.items():
+        if attr_name == "datacontenttype":
+            properties[CONTENT_TYPE_PROPERTY] = str(attr_value)
+        else:
+            property_name = f"{CE_PREFIX}{attr_name}"
+            # Encode datetime to AMQP timestamp (milliseconds since epoch)
+            # Other types (bool, int, str, bytes) use native AMQP types
+            application_properties[property_name] = _encode_amqp_value(attr_value)
+
+    data = event.get_data()
+    datacontenttype = attributes.get("datacontenttype")
+    application_data = event_format.write_data(data, datacontenttype)
+
+    return AMQPMessage(
+        properties=properties,
+        application_properties=application_properties,
+        application_data=application_data,
+    )
+
+
+def from_binary(
+    message: AMQPMessage,
+    event_format: Format,
+    event_factory: Callable[
+        [dict[str, Any], dict[str, Any] | str | bytes | None], BaseCloudEvent
+    ],
+) -> BaseCloudEvent:
+    """
+    Parse an AMQP binary content mode message to a CloudEvent.
+
+    Extracts CloudEvent attributes from cloudEvents_-prefixed AMQP application
+    properties and treats the AMQP 'content-type' property as the 'datacontenttype'
+    attribute. The application-data section is parsed as event data according to
+    the content type. The 'time' attribute accepts both AMQP timestamp (int milliseconds)
+    and ISO 8601 string, while other native AMQP types (boolean, integer) are preserved.
+
+    Example:
+        >>> from cloudevents.core.v1.event import CloudEvent
+        >>> from cloudevents.core.formats.json import JSONFormat
+        >>>
+        >>> message = AMQPMessage(
+        ...     properties={"content-type": "application/json"},
+        ...     application_properties={
+        ...         "cloudEvents_type": "com.example.test",
+        ...         "cloudEvents_source": "/test",
+        ...         "cloudEvents_id": "123",
+        ...         "cloudEvents_specversion": "1.0"
+        ...     },
+        ...     application_data=b'{"message": "Hello"}'
+        ... )
+        >>> event = from_binary(message, JSONFormat(), CloudEvent)
+
+    :param message: AMQPMessage to parse
+    :param event_format: Format implementation for data deserialization
+    :param event_factory: Factory function to create CloudEvent instances
+    :return: CloudEvent instance
+    """
+    attributes: dict[str, Any] = {}
+
+    for prop_name, prop_value in message.application_properties.items():
+        if prop_name.startswith(CE_PREFIX):
+            attr_name = prop_name[len(CE_PREFIX) :]
+            # Decode timestamp (int or ISO 8601 string) to datetime, preserve other native types
+            attributes[attr_name] = _decode_amqp_value(attr_name, prop_value)
+
+    if CONTENT_TYPE_PROPERTY in message.properties:
+        attributes["datacontenttype"] = message.properties[CONTENT_TYPE_PROPERTY]
+
+    datacontenttype = attributes.get("datacontenttype")
+    data = event_format.read_data(message.application_data, datacontenttype)
+
+    return event_factory(attributes, data)
+
+
+def to_structured(event: BaseCloudEvent, event_format: Format) -> AMQPMessage:
+    """
+    Convert a CloudEvent to AMQP structured content mode.
+
+    In structured mode, the entire CloudEvent (attributes and data) is serialized
+    into the AMQP application-data section using the specified format. The
+    content-type property is set to the format's media type (e.g.,
+    "application/cloudevents+json").
+
+    Example:
+        >>> from cloudevents.core.v1.event import CloudEvent
+        >>> from cloudevents.core.formats.json import JSONFormat
+        >>>
+        >>> event = CloudEvent(
+        ...     attributes={"type": "com.example.test", "source": "/test"},
+        ...     data={"message": "Hello"}
+        ... )
+        >>> message = to_structured(event, JSONFormat())
+        >>> # message.properties = {"content-type": "application/cloudevents+json"}
+        >>> # message.application_data = b'{"type": "com.example.test", ...}'
+
+    :param event: The CloudEvent to convert
+    :param event_format: Format implementation for serialization
+    :return: AMQPMessage with structured content in application-data
+    """
+    content_type = event_format.get_content_type()
+
+    properties = {CONTENT_TYPE_PROPERTY: content_type}
+    application_properties: dict[str, Any] = {}
+
+    application_data = event_format.write(event)
+
+    return AMQPMessage(
+        properties=properties,
+        application_properties=application_properties,
+        application_data=application_data,
+    )
+
+
+def from_structured(
+    message: AMQPMessage,
+    event_format: Format,
+    event_factory: Callable[
+        [dict[str, Any], dict[str, Any] | str | bytes | None], BaseCloudEvent
+    ],
+) -> BaseCloudEvent:
+    """
+    Parse an AMQP structured content mode message to a CloudEvent.
+
+    Deserializes the CloudEvent from the AMQP application-data section using the
+    specified format. Any cloudEvents_-prefixed application properties are ignored
+    as the application-data contains all event metadata.
+
+    Example:
+        >>> from cloudevents.core.v1.event import CloudEvent
+        >>> from cloudevents.core.formats.json import JSONFormat
+        >>>
+        >>> message = AMQPMessage(
+        ...     properties={"content-type": "application/cloudevents+json"},
+        ...     application_properties={},
+        ...     application_data=b'{"type": "com.example.test", "source": "/test", ...}'
+        ... )
+        >>> event = from_structured(message, JSONFormat(), CloudEvent)
+
+    :param message: AMQPMessage to parse
+    :param event_format: Format implementation for deserialization
+    :param event_factory: Factory function to create CloudEvent instances
+    :return: CloudEvent instance
+    """
+    return event_format.read(event_factory, message.application_data)
+
+
+def from_amqp(
+    message: AMQPMessage,
+    event_format: Format,
+    event_factory: Callable[
+        [dict[str, Any], dict[str, Any] | str | bytes | None], BaseCloudEvent
+    ],
+) -> BaseCloudEvent:
+    """
+    Parse an AMQP message to a CloudEvent with automatic mode detection.
+
+    Automatically detects whether the message uses binary or structured content mode:
+    - If content-type starts with "application/cloudevents" → structured mode
+    - Otherwise → binary mode
+
+    This function provides a convenient way to handle both content modes without
+    requiring the caller to determine the mode beforehand.
+
+    Example:
+        >>> from cloudevents.core.v1.event import CloudEvent
+        >>> from cloudevents.core.formats.json import JSONFormat
+        >>>
+        >>> # Works with binary mode
+        >>> binary_msg = AMQPMessage(
+        ...     properties={"content-type": "application/json"},
+        ...     application_properties={"cloudEvents_type": "com.example.test", ...},
+        ...     application_data=b'...'
+        ... )
+        >>> event1 = from_amqp(binary_msg, JSONFormat(), CloudEvent)
+        >>>
+        >>> # Also works with structured mode
+        >>> structured_msg = AMQPMessage(
+        ...     properties={"content-type": "application/cloudevents+json"},
+        ...     application_properties={},
+        ...     application_data=b'{"type": "com.example.test", ...}'
+        ... )
+        >>> event2 = from_amqp(structured_msg, JSONFormat(), CloudEvent)
+
+    :param message: AMQPMessage to parse
+    :param event_format: Format implementation for deserialization
+    :param event_factory: Factory function to create CloudEvent instances
+    :return: CloudEvent instance
+    """
+    content_type = message.properties.get(CONTENT_TYPE_PROPERTY, "")
+
+    if isinstance(content_type, str) and content_type.lower().startswith(
+        "application/cloudevents"
+    ):
+        return from_structured(message, event_format, event_factory)
+
+    return from_binary(message, event_format, event_factory)