""" :mod:`pandas.io.xml` is a module for reading XML. """ from __future__ import annotations import io from typing import Sequence from pandas._typing import ( CompressionOptions, FilePath, ReadBuffer, StorageOptions, XMLParsers, ) from pandas.compat._optional import import_optional_dependency from pandas.errors import ( AbstractMethodError, ParserError, ) from pandas.util._decorators import ( deprecate_nonkeyword_arguments, doc, ) from pandas.core.dtypes.common import is_list_like from pandas.core.frame import DataFrame from pandas.core.shared_docs import _shared_docs from pandas.io.common import ( file_exists, get_handle, is_fsspec_url, is_url, stringify_path, ) from pandas.io.parsers import TextParser @doc(decompression_options=_shared_docs["decompression_options"] % "path_or_buffer") class _XMLFrameParser: """ Internal subclass to parse XML into DataFrames. Parameters ---------- path_or_buffer : a valid JSON str, path object or file-like object Any valid string path is acceptable. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. xpath : str or regex The XPath expression to parse required set of nodes for migration to `Data Frame`. `etree` supports limited XPath. namespacess : dict The namespaces defined in XML document (`xmlns:namespace='URI') as dicts with key being namespace and value the URI. elems_only : bool Parse only the child elements at the specified `xpath`. attrs_only : bool Parse only the attributes at the specified `xpath`. names : list Column names for Data Frame of parsed XML data. encoding : str Encoding of xml object or document. stylesheet : str or file-like URL, file, file-like object, or a raw string containing XSLT, `etree` does not support XSLT but retained for consistency. {decompression_options} .. versionchanged:: 1.4.0 Zstandard support. storage_options : dict, optional Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc., See also -------- pandas.io.xml._EtreeFrameParser pandas.io.xml._LxmlFrameParser Notes ----- To subclass this class effectively you must override the following methods:` * :func:`parse_data` * :func:`_parse_nodes` * :func:`_parse_doc` * :func:`_validate_names` * :func:`_validate_path` See each method's respective documentation for details on their functionality. """ def __init__( self, path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str], xpath: str, namespaces: dict[str, str] | None, elems_only: bool, attrs_only: bool, names: Sequence[str] | None, encoding: str | None, stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None, compression: CompressionOptions, storage_options: StorageOptions, ): self.path_or_buffer = path_or_buffer self.xpath = xpath self.namespaces = namespaces self.elems_only = elems_only self.attrs_only = attrs_only self.names = names self.encoding = encoding self.stylesheet = stylesheet self.is_style = None self.compression = compression self.storage_options = storage_options def parse_data(self) -> list[dict[str, str | None]]: """ Parse xml data. This method will call the other internal methods to validate xpath, names, parse and return specific nodes. """ raise AbstractMethodError(self) def _parse_nodes(self) -> list[dict[str, str | None]]: """ Parse xml nodes. This method will parse the children and attributes of elements in xpath, conditionally for only elements, only attributes or both while optionally renaming node names. Raises ------ ValueError * If only elements and only attributes are specified. Notes ----- Namespace URIs will be removed from return node values.Also, elements with missing children or attributes compared to siblings will have optional keys filled withi None values. """ raise AbstractMethodError(self) def _validate_path(self) -> None: """ Validate xpath. This method checks for syntax, evaluation, or empty nodes return. Raises ------ SyntaxError * If xpah is not supported or issues with namespaces. ValueError * If xpah does not return any nodes. """ raise AbstractMethodError(self) def _validate_names(self) -> None: """ Validate names. This method will check if names is a list-like and aligns with length of parse nodes. Raises ------ ValueError * If value is not a list and less then length of nodes. """ raise AbstractMethodError(self) def _parse_doc(self, raw_doc) -> bytes: """ Build tree from path_or_buffer. This method will parse XML object into tree either from string/bytes or file location. """ raise AbstractMethodError(self) class _EtreeFrameParser(_XMLFrameParser): """ Internal class to parse XML into DataFrames with the Python standard library XML module: `xml.etree.ElementTree`. """ def parse_data(self) -> list[dict[str, str | None]]: from xml.etree.ElementTree import XML if self.stylesheet is not None: raise ValueError( "To use stylesheet, you need lxml installed and selected as parser." ) self.xml_doc = XML(self._parse_doc(self.path_or_buffer)) self._validate_path() self._validate_names() return self._parse_nodes() def _parse_nodes(self) -> list[dict[str, str | None]]: elems = self.xml_doc.findall(self.xpath, namespaces=self.namespaces) dicts: list[dict[str, str | None]] if self.elems_only and self.attrs_only: raise ValueError("Either element or attributes can be parsed not both.") elif self.elems_only: if self.names: dicts = [ { **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ nm: ch.text.strip() if ch.text else None for nm, ch in zip(self.names, el.findall("*")) }, } for el in elems ] else: dicts = [ { ch.tag: ch.text.strip() if ch.text else None for ch in el.findall("*") } for el in elems ] elif self.attrs_only: dicts = [ {k: v.strip() if v else None for k, v in el.attrib.items()} for el in elems ] else: if self.names: dicts = [ { **el.attrib, **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ nm: ch.text.strip() if ch.text else None for nm, ch in zip(self.names, el.findall("*")) }, } for el in elems ] else: dicts = [ { **el.attrib, **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ ch.tag: ch.text.strip() if ch.text else None for ch in el.findall("*") }, } for el in elems ] dicts = [ {k.split("}")[1] if "}" in k else k: v for k, v in d.items()} for d in dicts ] keys = list(dict.fromkeys([k for d in dicts for k in d.keys()])) dicts = [{k: d[k] if k in d.keys() else None for k in keys} for d in dicts] if self.names: dicts = [{nm: v for nm, v in zip(self.names, d.values())} for d in dicts] return dicts def _validate_path(self) -> None: """ Notes ----- `etree` supports limited XPath. If user attempts a more complex expression syntax error will raise. """ msg = ( "xpath does not return any nodes. " "If document uses namespaces denoted with " "xmlns, be sure to define namespaces and " "use them in xpath." ) try: elems = self.xml_doc.find(self.xpath, namespaces=self.namespaces) if elems is None: raise ValueError(msg) if elems is not None and elems.find("*") is None and elems.attrib is None: raise ValueError(msg) except (KeyError, SyntaxError): raise SyntaxError( "You have used an incorrect or unsupported XPath " "expression for etree library or you used an " "undeclared namespace prefix." ) def _validate_names(self) -> None: if self.names: parent = self.xml_doc.find(self.xpath, namespaces=self.namespaces) children = parent.findall("*") if parent else [] if is_list_like(self.names): if len(self.names) < len(children): raise ValueError( "names does not match length of child elements in xpath." ) else: raise TypeError( f"{type(self.names).__name__} is not a valid type for names" ) def _parse_doc(self, raw_doc) -> bytes: from xml.etree.ElementTree import ( XMLParser, parse, tostring, ) handle_data = get_data_from_filepath( filepath_or_buffer=raw_doc, encoding=self.encoding, compression=self.compression, storage_options=self.storage_options, ) with preprocess_data(handle_data) as xml_data: curr_parser = XMLParser(encoding=self.encoding) r = parse(xml_data, parser=curr_parser) return tostring(r.getroot()) class _LxmlFrameParser(_XMLFrameParser): """ Internal class to parse XML into DataFrames with third-party full-featured XML library, `lxml`, that supports XPath 1.0 and XSLT 1.0. """ def parse_data(self) -> list[dict[str, str | None]]: """ Parse xml data. This method will call the other internal methods to validate xpath, names, optionally parse and run XSLT, and parse original or transformed XML and return specific nodes. """ from lxml.etree import XML self.xml_doc = XML(self._parse_doc(self.path_or_buffer)) if self.stylesheet is not None: self.xsl_doc = XML(self._parse_doc(self.stylesheet)) self.xml_doc = XML(self._transform_doc()) self._validate_path() self._validate_names() return self._parse_nodes() def _parse_nodes(self) -> list[dict[str, str | None]]: elems = self.xml_doc.xpath(self.xpath, namespaces=self.namespaces) dicts: list[dict[str, str | None]] if self.elems_only and self.attrs_only: raise ValueError("Either element or attributes can be parsed not both.") elif self.elems_only: if self.names: dicts = [ { **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ nm: ch.text.strip() if ch.text else None for nm, ch in zip(self.names, el.xpath("*")) }, } for el in elems ] else: dicts = [ { ch.tag: ch.text.strip() if ch.text else None for ch in el.xpath("*") } for el in elems ] elif self.attrs_only: dicts = [el.attrib for el in elems] else: if self.names: dicts = [ { **el.attrib, **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ nm: ch.text.strip() if ch.text else None for nm, ch in zip(self.names, el.xpath("*")) }, } for el in elems ] else: dicts = [ { **el.attrib, **( {el.tag: el.text.strip()} if el.text and not el.text.isspace() else {} ), **{ ch.tag: ch.text.strip() if ch.text else None for ch in el.xpath("*") }, } for el in elems ] if self.namespaces or "}" in list(dicts[0].keys())[0]: dicts = [ {k.split("}")[1] if "}" in k else k: v for k, v in d.items()} for d in dicts ] keys = list(dict.fromkeys([k for d in dicts for k in d.keys()])) dicts = [{k: d[k] if k in d.keys() else None for k in keys} for d in dicts] if self.names: dicts = [{nm: v for nm, v in zip(self.names, d.values())} for d in dicts] return dicts def _validate_path(self) -> None: msg = ( "xpath does not return any nodes. " "Be sure row level nodes are in xpath. " "If document uses namespaces denoted with " "xmlns, be sure to define namespaces and " "use them in xpath." ) elems = self.xml_doc.xpath(self.xpath, namespaces=self.namespaces) children = self.xml_doc.xpath(self.xpath + "/*", namespaces=self.namespaces) attrs = self.xml_doc.xpath(self.xpath + "/@*", namespaces=self.namespaces) if elems == []: raise ValueError(msg) if elems != [] and attrs == [] and children == []: raise ValueError(msg) def _validate_names(self) -> None: """ Validate names. This method will check if names is a list and aligns with length of parse nodes. Raises ------ ValueError * If value is not a list and less then length of nodes. """ if self.names: children = self.xml_doc.xpath( self.xpath + "[1]/*", namespaces=self.namespaces ) if is_list_like(self.names): if len(self.names) < len(children): raise ValueError( "names does not match length of child elements in xpath." ) else: raise TypeError( f"{type(self.names).__name__} is not a valid type for names" ) def _parse_doc(self, raw_doc) -> bytes: from lxml.etree import ( XMLParser, fromstring, parse, tostring, ) handle_data = get_data_from_filepath( filepath_or_buffer=raw_doc, encoding=self.encoding, compression=self.compression, storage_options=self.storage_options, ) with preprocess_data(handle_data) as xml_data: curr_parser = XMLParser(encoding=self.encoding) if isinstance(xml_data, io.StringIO): if self.encoding is None: raise TypeError( "Can not pass encoding None when input is StringIO." ) doc = fromstring( xml_data.getvalue().encode(self.encoding), parser=curr_parser ) else: doc = parse(xml_data, parser=curr_parser) return tostring(doc) def _transform_doc(self) -> bytes: """ Transform original tree using stylesheet. This method will transform original xml using XSLT script into am ideally flatter xml document for easier parsing and migration to Data Frame. """ from lxml.etree import XSLT transformer = XSLT(self.xsl_doc) new_doc = transformer(self.xml_doc) return bytes(new_doc) def get_data_from_filepath( filepath_or_buffer: FilePath | bytes | ReadBuffer[bytes] | ReadBuffer[str], encoding: str | None, compression: CompressionOptions, storage_options: StorageOptions, ) -> str | bytes | ReadBuffer[bytes] | ReadBuffer[str]: """ Extract raw XML data. The method accepts three input types: 1. filepath (string-like) 2. file-like object (e.g. open file object, StringIO) 3. XML string or bytes This method turns (1) into (2) to simplify the rest of the processing. It returns input types (2) and (3) unchanged. """ if not isinstance(filepath_or_buffer, bytes): filepath_or_buffer = stringify_path(filepath_or_buffer) if ( isinstance(filepath_or_buffer, str) and not filepath_or_buffer.startswith((" io.StringIO | io.BytesIO: """ Convert extracted raw data. This method will return underlying data of extracted XML content. The data either has a `read` attribute (e.g. a file object or a StringIO/BytesIO) or is a string or bytes that is an XML document. """ if isinstance(data, str): data = io.StringIO(data) elif isinstance(data, bytes): data = io.BytesIO(data) return data def _data_to_frame(data, **kwargs) -> DataFrame: """ Convert parsed data to Data Frame. This method will bind xml dictionary data of keys and values into named columns of Data Frame using the built-in TextParser class that build Data Frame and infers specific dtypes. """ tags = next(iter(data)) nodes = [list(d.values()) for d in data] try: with TextParser(nodes, names=tags, **kwargs) as tp: return tp.read() except ParserError: raise ParserError( "XML document may be too complex for import. " "Try to flatten document and use distinct " "element and attribute names." ) def _parse( path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str], xpath: str, namespaces: dict[str, str] | None, elems_only: bool, attrs_only: bool, names: Sequence[str] | None, encoding: str | None, parser: XMLParsers, stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None, compression: CompressionOptions, storage_options: StorageOptions, **kwargs, ) -> DataFrame: """ Call internal parsers. This method will conditionally call internal parsers: LxmlFrameParser and/or EtreeParser. Raises ------ ImportError * If lxml is not installed if selected as parser. ValueError * If parser is not lxml or etree. """ p: _EtreeFrameParser | _LxmlFrameParser if parser == "lxml": lxml = import_optional_dependency("lxml.etree", errors="ignore") if lxml is not None: p = _LxmlFrameParser( path_or_buffer, xpath, namespaces, elems_only, attrs_only, names, encoding, stylesheet, compression, storage_options, ) else: raise ImportError("lxml not found, please install or use the etree parser.") elif parser == "etree": p = _EtreeFrameParser( path_or_buffer, xpath, namespaces, elems_only, attrs_only, names, encoding, stylesheet, compression, storage_options, ) else: raise ValueError("Values for parser can only be lxml or etree.") data_dicts = p.parse_data() return _data_to_frame(data=data_dicts, **kwargs) @deprecate_nonkeyword_arguments( version=None, allowed_args=["path_or_buffer"], stacklevel=2 ) @doc( storage_options=_shared_docs["storage_options"], decompression_options=_shared_docs["decompression_options"] % "path_or_buffer", ) def read_xml( path_or_buffer: FilePath | ReadBuffer[bytes] | ReadBuffer[str], xpath: str = "./*", namespaces: dict[str, str] | None = None, elems_only: bool = False, attrs_only: bool = False, names: Sequence[str] | None = None, # encoding can not be None for lxml and StringIO input encoding: str | None = "utf-8", parser: XMLParsers = "lxml", stylesheet: FilePath | ReadBuffer[bytes] | ReadBuffer[str] | None = None, compression: CompressionOptions = "infer", storage_options: StorageOptions = None, ) -> DataFrame: r""" Read XML document into a ``DataFrame`` object. .. versionadded:: 1.3.0 Parameters ---------- path_or_buffer : str, path object, or file-like object String, path object (implementing ``os.PathLike[str]``), or file-like object implementing a ``read()`` function. The string can be any valid XML string or a path. The string can further be a URL. Valid URL schemes include http, ftp, s3, and file. xpath : str, optional, default './\*' The XPath to parse required set of nodes for migration to DataFrame. XPath should return a collection of elements and not a single element. Note: The ``etree`` parser supports limited XPath expressions. For more complex XPath, use ``lxml`` which requires installation. namespaces : dict, optional The namespaces defined in XML document as dicts with key being namespace prefix and value the URI. There is no need to include all namespaces in XML, only the ones used in ``xpath`` expression. Note: if XML document uses default namespace denoted as `xmlns=''` without a prefix, you must assign any temporary namespace prefix such as 'doc' to the URI in order to parse underlying nodes and/or attributes. For example, :: namespaces = {{"doc": "https://example.com"}} elems_only : bool, optional, default False Parse only the child elements at the specified ``xpath``. By default, all child elements and non-empty text nodes are returned. attrs_only : bool, optional, default False Parse only the attributes at the specified ``xpath``. By default, all attributes are returned. names : list-like, optional Column names for DataFrame of parsed XML data. Use this parameter to rename original element names and distinguish same named elements. encoding : str, optional, default 'utf-8' Encoding of XML document. parser : {{'lxml','etree'}}, default 'lxml' Parser module to use for retrieval of data. Only 'lxml' and 'etree' are supported. With 'lxml' more complex XPath searches and ability to use XSLT stylesheet are supported. stylesheet : str, path object or file-like object A URL, file-like object, or a raw string containing an XSLT script. This stylesheet should flatten complex, deeply nested XML documents for easier parsing. To use this feature you must have ``lxml`` module installed and specify 'lxml' as ``parser``. The ``xpath`` must reference nodes of transformed XML document generated after XSLT transformation and not the original XML document. Only XSLT 1.0 scripts and not later versions is currently supported. {decompression_options} .. versionchanged:: 1.4.0 Zstandard support. {storage_options} Returns ------- df A DataFrame. See Also -------- read_json : Convert a JSON string to pandas object. read_html : Read HTML tables into a list of DataFrame objects. Notes ----- This method is best designed to import shallow XML documents in following format which is the ideal fit for the two-dimensions of a ``DataFrame`` (row by column). :: data data data ... ... ... As a file format, XML documents can be designed any way including layout of elements and attributes as long as it conforms to W3C specifications. Therefore, this method is a convenience handler for a specific flatter design and not all possible XML structures. However, for more complex XML documents, ``stylesheet`` allows you to temporarily redesign original document with XSLT (a special purpose language) for a flatter version for migration to a DataFrame. This function will *always* return a single :class:`DataFrame` or raise exceptions due to issues with XML document, ``xpath``, or other parameters. Examples -------- >>> xml = ''' ... ... ... square ... 360 ... 4.0 ... ... ... circle ... 360 ... ... ... ... triangle ... 180 ... 3.0 ... ... ''' >>> df = pd.read_xml(xml) >>> df shape degrees sides 0 square 360 4.0 1 circle 360 NaN 2 triangle 180 3.0 >>> xml = ''' ... ... ... ... ... ''' >>> df = pd.read_xml(xml, xpath=".//row") >>> df shape degrees sides 0 square 360 4.0 1 circle 360 NaN 2 triangle 180 3.0 >>> xml = ''' ... ... ... square ... 360 ... 4.0 ... ... ... circle ... 360 ... ... ... ... triangle ... 180 ... 3.0 ... ... ''' >>> df = pd.read_xml(xml, ... xpath="//doc:row", ... namespaces={{"doc": "https://example.com"}}) >>> df shape degrees sides 0 square 360 4.0 1 circle 360 NaN 2 triangle 180 3.0 """ return _parse( path_or_buffer=path_or_buffer, xpath=xpath, namespaces=namespaces, elems_only=elems_only, attrs_only=attrs_only, names=names, encoding=encoding, parser=parser, stylesheet=stylesheet, compression=compression, storage_options=storage_options, )