# Copyright 2014 Amazon.com, Inc. or its affiliates. All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"). You # may not use this file except in compliance with the License. A copy of # the License is located at # # http://aws.amazon.com/apache2.0/ # # or in the "license" file accompanying this file. This file 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. """Response parsers for the various protocol types. The module contains classes that can take an HTTP response, and given an output shape, parse the response into a dict according to the rules in the output shape. There are many similarities amongst the different protocols with regard to response parsing, and the code is structured in a way to avoid code duplication when possible. The diagram below is a diagram showing the inheritance hierarchy of the response classes. :: +--------------+ |ResponseParser| +--------------+ ^ ^ ^ +--------------------+ | +-------------------+ | | | +----------+----------+ +------+-------+ +-------+------+ |BaseXMLResponseParser| |BaseRestParser| |BaseJSONParser| +---------------------+ +--------------+ +--------------+ ^ ^ ^ ^ ^ ^ | | | | | | | | | | | | | ++----------+-+ +-+-----------++ | | |RestXMLParser| |RestJSONParser| | +-----+-----+ +-------------+ +--------------+ +----+-----+ |QueryParser| |JSONParser| +-----------+ +----------+ The diagram above shows that there is a base class, ``ResponseParser`` that contains logic that is similar amongst all the different protocols (``query``, ``json``, ``rest-json``, ``rest-xml``). Amongst the various services there is shared logic that can be grouped several ways: * The ``query`` and ``rest-xml`` both have XML bodies that are parsed in the same way. * The ``json`` and ``rest-json`` protocols both have JSON bodies that are parsed in the same way. * The ``rest-json`` and ``rest-xml`` protocols have additional attributes besides body parameters that are parsed the same (headers, query string, status code). This is reflected in the class diagram above. The ``BaseXMLResponseParser`` and the BaseJSONParser contain logic for parsing the XML/JSON body, and the BaseRestParser contains logic for parsing out attributes that come from other parts of the HTTP response. Classes like the ``RestXMLParser`` inherit from the ``BaseXMLResponseParser`` to get the XML body parsing logic and the ``BaseRestParser`` to get the HTTP header/status code/query string parsing. Additionally, there are event stream parsers that are used by the other parsers to wrap streaming bodies that represent a stream of events. The BaseEventStreamParser extends from ResponseParser and defines the logic for parsing values from the headers and payload of a message from the underlying binary encoding protocol. Currently, event streams support parsing bodies encoded as JSON and XML through the following hierarchy. +--------------+ |ResponseParser| +--------------+ ^ ^ ^ +--------------------+ | +------------------+ | | | +----------+----------+ +----------+----------+ +-------+------+ |BaseXMLResponseParser| |BaseEventStreamParser| |BaseJSONParser| +---------------------+ +---------------------+ +--------------+ ^ ^ ^ ^ | | | | | | | | +-+----------------+-+ +-+-----------------+-+ |EventStreamXMLParser| |EventStreamJSONParser| +--------------------+ +---------------------+ Return Values ============= Each call to ``parse()`` returns a dict has this form:: Standard Response { "ResponseMetadata": {"RequestId": } } Error response { "ResponseMetadata": {"RequestId": } "Error": { "Code": , "Message": , "Type": , } } """ import base64 import http.client import json import logging import re from botocore.compat import ETree, XMLParseError from botocore.eventstream import EventStream, NoInitialResponseError from botocore.utils import ( is_json_value_header, lowercase_dict, merge_dicts, parse_timestamp, ) LOG = logging.getLogger(__name__) DEFAULT_TIMESTAMP_PARSER = parse_timestamp class ResponseParserFactory: def __init__(self): self._defaults = {} def set_parser_defaults(self, **kwargs): """Set default arguments when a parser instance is created. You can specify any kwargs that are allowed by a ResponseParser class. There are currently two arguments: * timestamp_parser - A callable that can parse a timestamp string * blob_parser - A callable that can parse a blob type """ self._defaults.update(kwargs) def create_parser(self, protocol_name): parser_cls = PROTOCOL_PARSERS[protocol_name] return parser_cls(**self._defaults) def create_parser(protocol): return ResponseParserFactory().create_parser(protocol) def _text_content(func): # This decorator hides the difference between # an XML node with text or a plain string. It's used # to ensure that scalar processing operates only on text # strings, which allows the same scalar handlers to be used # for XML nodes from the body and HTTP headers. def _get_text_content(self, shape, node_or_string): if hasattr(node_or_string, 'text'): text = node_or_string.text if text is None: # If an XML node is empty , # we want to parse that as an empty string, # not as a null/None value. text = '' else: text = node_or_string return func(self, shape, text) return _get_text_content class ResponseParserError(Exception): pass class ResponseParser: """Base class for response parsing. This class represents the interface that all ResponseParsers for the various protocols must implement. This class will take an HTTP response and a model shape and parse the HTTP response into a dictionary. There is a single public method exposed: ``parse``. See the ``parse`` docstring for more info. """ DEFAULT_ENCODING = 'utf-8' EVENT_STREAM_PARSER_CLS = None def __init__(self, timestamp_parser=None, blob_parser=None): if timestamp_parser is None: timestamp_parser = DEFAULT_TIMESTAMP_PARSER self._timestamp_parser = timestamp_parser if blob_parser is None: blob_parser = self._default_blob_parser self._blob_parser = blob_parser self._event_stream_parser = None if self.EVENT_STREAM_PARSER_CLS is not None: self._event_stream_parser = self.EVENT_STREAM_PARSER_CLS( timestamp_parser, blob_parser ) def _default_blob_parser(self, value): # Blobs are always returned as bytes type (this matters on python3). # We don't decode this to a str because it's entirely possible that the # blob contains binary data that actually can't be decoded. return base64.b64decode(value) def parse(self, response, shape): """Parse the HTTP response given a shape. :param response: The HTTP response dictionary. This is a dictionary that represents the HTTP request. The dictionary must have the following keys, ``body``, ``headers``, and ``status_code``. :param shape: The model shape describing the expected output. :return: Returns a dictionary representing the parsed response described by the model. In addition to the shape described from the model, each response will also have a ``ResponseMetadata`` which contains metadata about the response, which contains at least two keys containing ``RequestId`` and ``HTTPStatusCode``. Some responses may populate additional keys, but ``RequestId`` will always be present. """ LOG.debug('Response headers: %r', response['headers']) LOG.debug('Response body:\n%r', response['body']) if response['status_code'] >= 301: if self._is_generic_error_response(response): parsed = self._do_generic_error_parse(response) elif self._is_modeled_error_shape(shape): parsed = self._do_modeled_error_parse(response, shape) # We don't want to decorate the modeled fields with metadata return parsed else: parsed = self._do_error_parse(response, shape) else: parsed = self._do_parse(response, shape) # We don't want to decorate event stream responses with metadata if shape and shape.serialization.get('eventstream'): return parsed # Add ResponseMetadata if it doesn't exist and inject the HTTP # status code and headers from the response. if isinstance(parsed, dict): response_metadata = parsed.get('ResponseMetadata', {}) response_metadata['HTTPStatusCode'] = response['status_code'] # Ensure that the http header keys are all lower cased. Older # versions of urllib3 (< 1.11) would unintentionally do this for us # (see urllib3#633). We need to do this conversion manually now. headers = response['headers'] response_metadata['HTTPHeaders'] = lowercase_dict(headers) parsed['ResponseMetadata'] = response_metadata self._add_checksum_response_metadata(response, response_metadata) return parsed def _add_checksum_response_metadata(self, response, response_metadata): checksum_context = response.get('context', {}).get('checksum', {}) algorithm = checksum_context.get('response_algorithm') if algorithm: response_metadata['ChecksumAlgorithm'] = algorithm def _is_modeled_error_shape(self, shape): return shape is not None and shape.metadata.get('exception', False) def _is_generic_error_response(self, response): # There are times when a service will respond with a generic # error response such as: # 'Http/1.1 Service Unavailable' # # This can also happen if you're going through a proxy. # In this case the protocol specific _do_error_parse will either # fail to parse the response (in the best case) or silently succeed # and treat the HTML above as an XML response and return # non sensical parsed data. # To prevent this case from happening we first need to check # whether or not this response looks like the generic response. if response['status_code'] >= 500: if 'body' not in response or response['body'] is None: return True body = response['body'].strip() return body.startswith(b'') or not body def _do_generic_error_parse(self, response): # There's not really much we can do when we get a generic # html response. LOG.debug( "Received a non protocol specific error response from the " "service, unable to populate error code and message." ) return { 'Error': { 'Code': str(response['status_code']), 'Message': http.client.responses.get( response['status_code'], '' ), }, 'ResponseMetadata': {}, } def _do_parse(self, response, shape): raise NotImplementedError("%s._do_parse" % self.__class__.__name__) def _do_error_parse(self, response, shape): raise NotImplementedError(f"{self.__class__.__name__}._do_error_parse") def _do_modeled_error_parse(self, response, shape, parsed): raise NotImplementedError( f"{self.__class__.__name__}._do_modeled_error_parse" ) def _parse_shape(self, shape, node): handler = getattr( self, f'_handle_{shape.type_name}', self._default_handle ) return handler(shape, node) def _handle_list(self, shape, node): # Enough implementations share list serialization that it's moved # up here in the base class. parsed = [] member_shape = shape.member for item in node: parsed.append(self._parse_shape(member_shape, item)) return parsed def _default_handle(self, shape, value): return value def _create_event_stream(self, response, shape): parser = self._event_stream_parser name = response['context'].get('operation_name') return EventStream(response['body'], shape, parser, name) def _get_first_key(self, value): return list(value)[0] def _has_unknown_tagged_union_member(self, shape, value): if shape.is_tagged_union: cleaned_value = value.copy() cleaned_value.pop("__type", None) if len(cleaned_value) != 1: error_msg = ( "Invalid service response: %s must have one and only " "one member set." ) raise ResponseParserError(error_msg % shape.name) tag = self._get_first_key(cleaned_value) if tag not in shape.members: msg = ( "Received a tagged union response with member " "unknown to client: %s. Please upgrade SDK for full " "response support." ) LOG.info(msg % tag) return True return False def _handle_unknown_tagged_union_member(self, tag): return {'SDK_UNKNOWN_MEMBER': {'name': tag}} class BaseXMLResponseParser(ResponseParser): def __init__(self, timestamp_parser=None, blob_parser=None): super().__init__(timestamp_parser, blob_parser) self._namespace_re = re.compile('{.*}') def _handle_map(self, shape, node): parsed = {} key_shape = shape.key value_shape = shape.value key_location_name = key_shape.serialization.get('name') or 'key' value_location_name = value_shape.serialization.get('name') or 'value' if shape.serialization.get('flattened') and not isinstance(node, list): node = [node] for keyval_node in node: for single_pair in keyval_node: # Within each there's a and a tag_name = self._node_tag(single_pair) if tag_name == key_location_name: key_name = self._parse_shape(key_shape, single_pair) elif tag_name == value_location_name: val_name = self._parse_shape(value_shape, single_pair) else: raise ResponseParserError("Unknown tag: %s" % tag_name) parsed[key_name] = val_name return parsed def _node_tag(self, node): return self._namespace_re.sub('', node.tag) def _handle_list(self, shape, node): # When we use _build_name_to_xml_node, repeated elements are aggregated # into a list. However, we can't tell the difference between a scalar # value and a single element flattened list. So before calling the # real _handle_list, we know that "node" should actually be a list if # it's flattened, and if it's not, then we make it a one element list. if shape.serialization.get('flattened') and not isinstance(node, list): node = [node] return super()._handle_list(shape, node) def _handle_structure(self, shape, node): parsed = {} members = shape.members if shape.metadata.get('exception', False): node = self._get_error_root(node) xml_dict = self._build_name_to_xml_node(node) if self._has_unknown_tagged_union_member(shape, xml_dict): tag = self._get_first_key(xml_dict) return self._handle_unknown_tagged_union_member(tag) for member_name in members: member_shape = members[member_name] if ( 'location' in member_shape.serialization or member_shape.serialization.get('eventheader') ): # All members with locations have already been handled, # so we don't need to parse these members. continue xml_name = self._member_key_name(member_shape, member_name) member_node = xml_dict.get(xml_name) if member_node is not None: parsed[member_name] = self._parse_shape( member_shape, member_node ) elif member_shape.serialization.get('xmlAttribute'): attribs = {} location_name = member_shape.serialization['name'] for key, value in node.attrib.items(): new_key = self._namespace_re.sub( location_name.split(':')[0] + ':', key ) attribs[new_key] = value if location_name in attribs: parsed[member_name] = attribs[location_name] return parsed def _get_error_root(self, original_root): if self._node_tag(original_root) == 'ErrorResponse': for child in original_root: if self._node_tag(child) == 'Error': return child return original_root def _member_key_name(self, shape, member_name): # This method is needed because we have to special case flattened list # with a serialization name. If this is the case we use the # locationName from the list's member shape as the key name for the # surrounding structure. if shape.type_name == 'list' and shape.serialization.get('flattened'): list_member_serialized_name = shape.member.serialization.get( 'name' ) if list_member_serialized_name is not None: return list_member_serialized_name serialized_name = shape.serialization.get('name') if serialized_name is not None: return serialized_name return member_name def _build_name_to_xml_node(self, parent_node): # If the parent node is actually a list. We should not be trying # to serialize it to a dictionary. Instead, return the first element # in the list. if isinstance(parent_node, list): return self._build_name_to_xml_node(parent_node[0]) xml_dict = {} for item in parent_node: key = self._node_tag(item) if key in xml_dict: # If the key already exists, the most natural # way to handle this is to aggregate repeated # keys into a single list. # 12 -> {'foo': [Node(1), Node(2)]} if isinstance(xml_dict[key], list): xml_dict[key].append(item) else: # Convert from a scalar to a list. xml_dict[key] = [xml_dict[key], item] else: xml_dict[key] = item return xml_dict def _parse_xml_string_to_dom(self, xml_string): try: parser = ETree.XMLParser( target=ETree.TreeBuilder(), encoding=self.DEFAULT_ENCODING ) parser.feed(xml_string) root = parser.close() except XMLParseError as e: raise ResponseParserError( "Unable to parse response (%s), " "invalid XML received. Further retries may succeed:\n%s" % (e, xml_string) ) return root def _replace_nodes(self, parsed): for key, value in parsed.items(): if list(value): sub_dict = self._build_name_to_xml_node(value) parsed[key] = self._replace_nodes(sub_dict) else: parsed[key] = value.text return parsed @_text_content def _handle_boolean(self, shape, text): if text == 'true': return True else: return False @_text_content def _handle_float(self, shape, text): return float(text) @_text_content def _handle_timestamp(self, shape, text): return self._timestamp_parser(text) @_text_content def _handle_integer(self, shape, text): return int(text) @_text_content def _handle_string(self, shape, text): return text @_text_content def _handle_blob(self, shape, text): return self._blob_parser(text) _handle_character = _handle_string _handle_double = _handle_float _handle_long = _handle_integer class QueryParser(BaseXMLResponseParser): def _do_error_parse(self, response, shape): xml_contents = response['body'] root = self._parse_xml_string_to_dom(xml_contents) parsed = self._build_name_to_xml_node(root) self._replace_nodes(parsed) # Once we've converted xml->dict, we need to make one or two # more adjustments to extract nested errors and to be consistent # with ResponseMetadata for non-error responses: # 1. {"Errors": {"Error": {...}}} -> {"Error": {...}} # 2. {"RequestId": "id"} -> {"ResponseMetadata": {"RequestId": "id"}} if 'Errors' in parsed: parsed.update(parsed.pop('Errors')) if 'RequestId' in parsed: parsed['ResponseMetadata'] = {'RequestId': parsed.pop('RequestId')} return parsed def _do_modeled_error_parse(self, response, shape): return self._parse_body_as_xml(response, shape, inject_metadata=False) def _do_parse(self, response, shape): return self._parse_body_as_xml(response, shape, inject_metadata=True) def _parse_body_as_xml(self, response, shape, inject_metadata=True): xml_contents = response['body'] root = self._parse_xml_string_to_dom(xml_contents) parsed = {} if shape is not None: start = root if 'resultWrapper' in shape.serialization: start = self._find_result_wrapped_shape( shape.serialization['resultWrapper'], root ) parsed = self._parse_shape(shape, start) if inject_metadata: self._inject_response_metadata(root, parsed) return parsed def _find_result_wrapped_shape(self, element_name, xml_root_node): mapping = self._build_name_to_xml_node(xml_root_node) return mapping[element_name] def _inject_response_metadata(self, node, inject_into): mapping = self._build_name_to_xml_node(node) child_node = mapping.get('ResponseMetadata') if child_node is not None: sub_mapping = self._build_name_to_xml_node(child_node) for key, value in sub_mapping.items(): sub_mapping[key] = value.text inject_into['ResponseMetadata'] = sub_mapping class EC2QueryParser(QueryParser): def _inject_response_metadata(self, node, inject_into): mapping = self._build_name_to_xml_node(node) child_node = mapping.get('requestId') if child_node is not None: inject_into['ResponseMetadata'] = {'RequestId': child_node.text} def _do_error_parse(self, response, shape): # EC2 errors look like: # # # # InvalidInstanceID.Malformed # Invalid id: "1343124" # # # 12345 # # This is different from QueryParser in that it's RequestID, # not RequestId original = super()._do_error_parse(response, shape) if 'RequestID' in original: original['ResponseMetadata'] = { 'RequestId': original.pop('RequestID') } return original def _get_error_root(self, original_root): for child in original_root: if self._node_tag(child) == 'Errors': for errors_child in child: if self._node_tag(errors_child) == 'Error': return errors_child return original_root class BaseJSONParser(ResponseParser): def _handle_structure(self, shape, value): final_parsed = {} if shape.is_document_type: final_parsed = value else: member_shapes = shape.members if value is None: # If the comes across the wire as "null" (None in python), # we should be returning this unchanged, instead of as an # empty dict. return None final_parsed = {} if self._has_unknown_tagged_union_member(shape, value): tag = self._get_first_key(value) return self._handle_unknown_tagged_union_member(tag) for member_name in member_shapes: member_shape = member_shapes[member_name] json_name = member_shape.serialization.get('name', member_name) raw_value = value.get(json_name) if raw_value is not None: final_parsed[member_name] = self._parse_shape( member_shapes[member_name], raw_value ) return final_parsed def _handle_map(self, shape, value): parsed = {} key_shape = shape.key value_shape = shape.value for key, value in value.items(): actual_key = self._parse_shape(key_shape, key) actual_value = self._parse_shape(value_shape, value) parsed[actual_key] = actual_value return parsed def _handle_blob(self, shape, value): return self._blob_parser(value) def _handle_timestamp(self, shape, value): return self._timestamp_parser(value) def _do_error_parse(self, response, shape): body = self._parse_body_as_json(response['body']) error = {"Error": {"Message": '', "Code": ''}, "ResponseMetadata": {}} headers = response['headers'] # Error responses can have slightly different structures for json. # The basic structure is: # # {"__type":"ConnectClientException", # "message":"The error message."} # The error message can either come in the 'message' or 'Message' key # so we need to check for both. error['Error']['Message'] = body.get( 'message', body.get('Message', '') ) # if the message did not contain an error code # include the response status code response_code = response.get('status_code') code = body.get('__type', response_code and str(response_code)) if code is not None: # code has a couple forms as well: # * "com.aws.dynamodb.vAPI#ProvisionedThroughputExceededException" # * "ResourceNotFoundException" if '#' in code: code = code.rsplit('#', 1)[1] if 'x-amzn-query-error' in headers: code = self._do_query_compatible_error_parse( code, headers, error ) error['Error']['Code'] = code self._inject_response_metadata(error, response['headers']) return error def _do_query_compatible_error_parse(self, code, headers, error): """ Error response may contain an x-amzn-query-error header to translate errors codes from former `query` services into `json`. We use this to do our lookup in the errorfactory for modeled errors. """ query_error = headers['x-amzn-query-error'] query_error_components = query_error.split(';') if len(query_error_components) == 2 and query_error_components[0]: error['Error']['QueryErrorCode'] = code error['Error']['Type'] = query_error_components[1] return query_error_components[0] return code def _inject_response_metadata(self, parsed, headers): if 'x-amzn-requestid' in headers: parsed.setdefault('ResponseMetadata', {})['RequestId'] = headers[ 'x-amzn-requestid' ] def _parse_body_as_json(self, body_contents): if not body_contents: return {} body = body_contents.decode(self.DEFAULT_ENCODING) try: original_parsed = json.loads(body) return original_parsed except ValueError: # if the body cannot be parsed, include # the literal string as the message return {'message': body} class BaseEventStreamParser(ResponseParser): def _do_parse(self, response, shape): final_parsed = {} if shape.serialization.get('eventstream'): event_type = response['headers'].get(':event-type') event_shape = shape.members.get(event_type) if event_shape: final_parsed[event_type] = self._do_parse( response, event_shape ) else: self._parse_non_payload_attrs( response, shape, shape.members, final_parsed ) self._parse_payload(response, shape, shape.members, final_parsed) return final_parsed def _do_error_parse(self, response, shape): exception_type = response['headers'].get(':exception-type') exception_shape = shape.members.get(exception_type) if exception_shape is not None: original_parsed = self._initial_body_parse(response['body']) body = self._parse_shape(exception_shape, original_parsed) error = { 'Error': { 'Code': exception_type, 'Message': body.get('Message', body.get('message', '')), } } else: error = { 'Error': { 'Code': response['headers'].get(':error-code', ''), 'Message': response['headers'].get(':error-message', ''), } } return error def _parse_payload(self, response, shape, member_shapes, final_parsed): if shape.serialization.get('event'): for name in member_shapes: member_shape = member_shapes[name] if member_shape.serialization.get('eventpayload'): body = response['body'] if member_shape.type_name == 'blob': parsed_body = body elif member_shape.type_name == 'string': parsed_body = body.decode(self.DEFAULT_ENCODING) else: raw_parse = self._initial_body_parse(body) parsed_body = self._parse_shape( member_shape, raw_parse ) final_parsed[name] = parsed_body return # If we didn't find an explicit payload, use the current shape original_parsed = self._initial_body_parse(response['body']) body_parsed = self._parse_shape(shape, original_parsed) final_parsed.update(body_parsed) def _parse_non_payload_attrs( self, response, shape, member_shapes, final_parsed ): headers = response['headers'] for name in member_shapes: member_shape = member_shapes[name] if member_shape.serialization.get('eventheader'): if name in headers: value = headers[name] if member_shape.type_name == 'timestamp': # Event stream timestamps are an in milleseconds so we # divide by 1000 to convert to seconds. value = self._timestamp_parser(value / 1000.0) final_parsed[name] = value def _initial_body_parse(self, body_contents): # This method should do the initial xml/json parsing of the # body. We we still need to walk the parsed body in order # to convert types, but this method will do the first round # of parsing. raise NotImplementedError("_initial_body_parse") class EventStreamJSONParser(BaseEventStreamParser, BaseJSONParser): def _initial_body_parse(self, body_contents): return self._parse_body_as_json(body_contents) class EventStreamXMLParser(BaseEventStreamParser, BaseXMLResponseParser): def _initial_body_parse(self, xml_string): if not xml_string: return ETree.Element('') return self._parse_xml_string_to_dom(xml_string) class JSONParser(BaseJSONParser): EVENT_STREAM_PARSER_CLS = EventStreamJSONParser """Response parser for the "json" protocol.""" def _do_parse(self, response, shape): parsed = {} if shape is not None: event_name = shape.event_stream_name if event_name: parsed = self._handle_event_stream(response, shape, event_name) else: parsed = self._handle_json_body(response['body'], shape) self._inject_response_metadata(parsed, response['headers']) return parsed def _do_modeled_error_parse(self, response, shape): return self._handle_json_body(response['body'], shape) def _handle_event_stream(self, response, shape, event_name): event_stream_shape = shape.members[event_name] event_stream = self._create_event_stream(response, event_stream_shape) try: event = event_stream.get_initial_response() except NoInitialResponseError: error_msg = 'First event was not of type initial-response' raise ResponseParserError(error_msg) parsed = self._handle_json_body(event.payload, shape) parsed[event_name] = event_stream return parsed def _handle_json_body(self, raw_body, shape): # The json.loads() gives us the primitive JSON types, # but we need to traverse the parsed JSON data to convert # to richer types (blobs, timestamps, etc. parsed_json = self._parse_body_as_json(raw_body) return self._parse_shape(shape, parsed_json) class BaseRestParser(ResponseParser): def _do_parse(self, response, shape): final_parsed = {} final_parsed['ResponseMetadata'] = self._populate_response_metadata( response ) self._add_modeled_parse(response, shape, final_parsed) return final_parsed def _add_modeled_parse(self, response, shape, final_parsed): if shape is None: return final_parsed member_shapes = shape.members self._parse_non_payload_attrs( response, shape, member_shapes, final_parsed ) self._parse_payload(response, shape, member_shapes, final_parsed) def _do_modeled_error_parse(self, response, shape): final_parsed = {} self._add_modeled_parse(response, shape, final_parsed) return final_parsed def _populate_response_metadata(self, response): metadata = {} headers = response['headers'] if 'x-amzn-requestid' in headers: metadata['RequestId'] = headers['x-amzn-requestid'] elif 'x-amz-request-id' in headers: metadata['RequestId'] = headers['x-amz-request-id'] # HostId is what it's called whenever this value is returned # in an XML response body, so to be consistent, we'll always # call is HostId. metadata['HostId'] = headers.get('x-amz-id-2', '') return metadata def _parse_payload(self, response, shape, member_shapes, final_parsed): if 'payload' in shape.serialization: # If a payload is specified in the output shape, then only that # shape is used for the body payload. payload_member_name = shape.serialization['payload'] body_shape = member_shapes[payload_member_name] if body_shape.serialization.get('eventstream'): body = self._create_event_stream(response, body_shape) final_parsed[payload_member_name] = body elif body_shape.type_name in ['string', 'blob']: # This is a stream body = response['body'] if isinstance(body, bytes): body = body.decode(self.DEFAULT_ENCODING) final_parsed[payload_member_name] = body else: original_parsed = self._initial_body_parse(response['body']) final_parsed[payload_member_name] = self._parse_shape( body_shape, original_parsed ) else: original_parsed = self._initial_body_parse(response['body']) body_parsed = self._parse_shape(shape, original_parsed) final_parsed.update(body_parsed) def _parse_non_payload_attrs( self, response, shape, member_shapes, final_parsed ): headers = response['headers'] for name in member_shapes: member_shape = member_shapes[name] location = member_shape.serialization.get('location') if location is None: continue elif location == 'statusCode': final_parsed[name] = self._parse_shape( member_shape, response['status_code'] ) elif location == 'headers': final_parsed[name] = self._parse_header_map( member_shape, headers ) elif location == 'header': header_name = member_shape.serialization.get('name', name) if header_name in headers: final_parsed[name] = self._parse_shape( member_shape, headers[header_name] ) def _parse_header_map(self, shape, headers): # Note that headers are case insensitive, so we .lower() # all header names and header prefixes. parsed = {} prefix = shape.serialization.get('name', '').lower() for header_name in headers: if header_name.lower().startswith(prefix): # The key name inserted into the parsed hash # strips off the prefix. name = header_name[len(prefix) :] parsed[name] = headers[header_name] return parsed def _initial_body_parse(self, body_contents): # This method should do the initial xml/json parsing of the # body. We we still need to walk the parsed body in order # to convert types, but this method will do the first round # of parsing. raise NotImplementedError("_initial_body_parse") def _handle_string(self, shape, value): parsed = value if is_json_value_header(shape): decoded = base64.b64decode(value).decode(self.DEFAULT_ENCODING) parsed = json.loads(decoded) return parsed def _handle_list(self, shape, node): location = shape.serialization.get('location') if location == 'header' and not isinstance(node, list): # List in headers may be a comma separated string as per RFC7230 node = [e.strip() for e in node.split(',')] return super()._handle_list(shape, node) class RestJSONParser(BaseRestParser, BaseJSONParser): EVENT_STREAM_PARSER_CLS = EventStreamJSONParser def _initial_body_parse(self, body_contents): return self._parse_body_as_json(body_contents) def _do_error_parse(self, response, shape): error = super()._do_error_parse(response, shape) self._inject_error_code(error, response) return error def _inject_error_code(self, error, response): # The "Code" value can come from either a response # header or a value in the JSON body. body = self._initial_body_parse(response['body']) if 'x-amzn-errortype' in response['headers']: code = response['headers']['x-amzn-errortype'] # Could be: # x-amzn-errortype: ValidationException: code = code.split(':')[0] error['Error']['Code'] = code elif 'code' in body or 'Code' in body: error['Error']['Code'] = body.get('code', body.get('Code', '')) def _handle_integer(self, shape, value): return int(value) _handle_long = _handle_integer class RestXMLParser(BaseRestParser, BaseXMLResponseParser): EVENT_STREAM_PARSER_CLS = EventStreamXMLParser def _initial_body_parse(self, xml_string): if not xml_string: return ETree.Element('') return self._parse_xml_string_to_dom(xml_string) def _do_error_parse(self, response, shape): # We're trying to be service agnostic here, but S3 does have a slightly # different response structure for its errors compared to other # rest-xml serivces (route53/cloudfront). We handle this by just # trying to parse both forms. # First: # # # Sender # InvalidInput # Invalid resource type: foo # # request-id # if response['body']: # If the body ends up being invalid xml, the xml parser should not # blow up. It should at least try to pull information about the # the error response from other sources like the HTTP status code. try: return self._parse_error_from_body(response) except ResponseParserError: LOG.debug( 'Exception caught when parsing error response body:', exc_info=True, ) return self._parse_error_from_http_status(response) def _parse_error_from_http_status(self, response): return { 'Error': { 'Code': str(response['status_code']), 'Message': http.client.responses.get( response['status_code'], '' ), }, 'ResponseMetadata': { 'RequestId': response['headers'].get('x-amz-request-id', ''), 'HostId': response['headers'].get('x-amz-id-2', ''), }, } def _parse_error_from_body(self, response): xml_contents = response['body'] root = self._parse_xml_string_to_dom(xml_contents) parsed = self._build_name_to_xml_node(root) self._replace_nodes(parsed) if root.tag == 'Error': # This is an S3 error response. First we'll populate the # response metadata. metadata = self._populate_response_metadata(response) # The RequestId and the HostId are already in the # ResponseMetadata, but are also duplicated in the XML # body. We don't need these values in both places, # we'll just remove them from the parsed XML body. parsed.pop('RequestId', '') parsed.pop('HostId', '') return {'Error': parsed, 'ResponseMetadata': metadata} elif 'RequestId' in parsed: # Other rest-xml services: parsed['ResponseMetadata'] = {'RequestId': parsed.pop('RequestId')} default = {'Error': {'Message': '', 'Code': ''}} merge_dicts(default, parsed) return default @_text_content def _handle_string(self, shape, text): text = super()._handle_string(shape, text) return text PROTOCOL_PARSERS = { 'ec2': EC2QueryParser, 'query': QueryParser, 'json': JSONParser, 'rest-json': RestJSONParser, 'rest-xml': RestXMLParser, }