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import abc
from typing import Any, Dict, List, Optional, Tuple, Type
from xsdata.exceptions import XmlHandlerError
from xsdata.formats.bindings import AbstractParser
from xsdata.formats.dataclass.parsers.config import ParserConfig
from xsdata.models.enums import EventType
NoneStr = Optional[str]
class PushParser(AbstractParser):
"""
A generic interface for event based content handlers like sax.
:param config: Parser configuration.
"""
config: ParserConfig
ns_map: Dict
@abc.abstractmethod
def start(
self,
clazz: Optional[Type],
queue: List,
objects: List,
qname: str,
attrs: Dict,
ns_map: Dict,
):
"""Queue the next xml node for parsing."""
@abc.abstractmethod
def end(
self,
queue: List,
objects: List,
qname: str,
text: NoneStr,
tail: NoneStr,
) -> bool:
"""
Parse the last xml node and bind any intermediate objects.
:return: The result of the binding process.
"""
def register_namespace(self, prefix: NoneStr, uri: str):
"""
Add the given prefix-URI namespaces mapping if the prefix is new.
:param prefix: Namespace prefix
:param uri: Namespace uri
"""
if prefix not in self.ns_map:
self.ns_map[prefix] = uri
class XmlNode(abc.ABC):
"""
The xml node interface.
The nodes are responsible to find and queue the child nodes when a
new element starts and build the resulting object tree when the
element ends. The parser needs to maintain a queue for these nodes
and a list of all the intermediate object trees.
"""
@abc.abstractmethod
def child(self, qname: str, attrs: Dict, ns_map: Dict, position: int) -> "XmlNode":
"""
Initialize the next child node to be queued, when a new xml element
starts.
This entry point is responsible to create the next node type
with all the necessary information on how to bind the incoming
input data.
:param qname: Qualified name
:param attrs: Attribute key-value map
:param ns_map: Namespace prefix-URI map
:param position: The current objects position, to mark future
objects as children
"""
@abc.abstractmethod
def bind(self, qname: str, text: NoneStr, tail: NoneStr, objects: List) -> bool:
"""
Build the object tree for the ending element and return whether the
result was successful or not.
This entry point is called when an xml element ends and is
responsible to parse the current element attributes/text, bind
any children objects and initialize new object.
:param qname: Qualified name
:param text: Text content
:param tail: Tail content
:param objects: The list of intermediate parsed objects, eg
[(qname, object)]
"""
class XmlHandler:
"""
Abstract content handler.
:param parser: The parser instance to feed with events
:param clazz: The target binding model, auto located if omitted.
"""
__slots__ = ("parser", "clazz", "queue", "objects")
def __init__(self, parser: PushParser, clazz: Optional[Type]):
self.parser = parser
self.clazz = clazz
self.queue: List = []
self.objects: List = []
def parse(self, source: Any) -> Any:
"""Parse an XML document from a system identifier or an InputSource."""
raise NotImplementedError("This method must be implemented!")
def merge_parent_namespaces(self, ns_map: Dict) -> Dict:
"""
Merge and return the given prefix-URI map with the parent node.
Register new prefixes with the parser.
:param ns_map: Namespace prefix-URI map
"""
if self.queue:
parent_ns_map = self.queue[-1].ns_map
if not ns_map:
return parent_ns_map
result = parent_ns_map.copy() if parent_ns_map else {}
else:
result = {}
for prefix, uri in ns_map.items():
self.parser.register_namespace(prefix, uri)
result[prefix] = uri
return result
class EventsHandler(XmlHandler):
"""Sax content handler for pre-recorded events."""
__slots__ = ("data_frames", "flush_next")
def __init__(self, parser: PushParser, clazz: Optional[Type]):
super().__init__(parser, clazz)
self.data_frames: List = []
self.flush_next: Optional[str] = None
def parse(self, source: List[Tuple]) -> Any:
"""Forward the pre-recorded events to the main parser."""
for event, *args in source:
if event == EventType.START:
qname, attrs, ns_map = args
self.parser.start(
self.clazz,
self.queue,
self.objects,
qname,
attrs,
ns_map,
)
elif event == EventType.END:
qname, text, tail = args
self.parser.end(self.queue, self.objects, qname, text, tail)
elif event == EventType.START_NS:
prefix, uri = args
self.parser.register_namespace(prefix or None, uri)
else:
raise XmlHandlerError(f"Unhandled event: `{event}`.")
return self.objects[-1][1] if self.objects else None
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