class ParserUDF(UDF):
"""Parser UDF class."""
def __init__(
self,
structural: bool,
blacklist: Union[str, List[str]],
flatten: Union[str, List[str]],
lingual: bool,
lingual_parser: Optional[LingualParser],
strip: bool,
replacements: List[Tuple[str, str]],
tabular: bool,
visual: bool,
vizlink: Optional[VisualLinker],
pdf_path: Optional[str],
language: Optional[str],
**kwargs: Any,
) -> None:
"""Initialize Parser UDF.
:param visual: boolean, if True visual features are used in the model
:param pdf_path: directory where pdf are saved, if a pdf file is not
found, it will be created from the html document and saved in that
directory
:param replacements: a list of (_pattern_, _replace_) tuples where
_pattern_ isinstance a regex and _replace_ is a character string.
All occurents of _pattern_ in the text will be replaced by
_replace_.
"""
super().__init__(**kwargs)
# structural (html) setup
self.structural = structural
self.blacklist = blacklist if isinstance(blacklist,
list) else [blacklist]
self.flatten = flatten if isinstance(flatten, list) else [flatten]
# lingual setup
self.language = language
self.strip = strip
self.replacements: List[Tuple[Pattern, str]] = []
for (pattern, replace) in replacements:
self.replacements.append((re.compile(pattern,
flags=re.UNICODE), replace))
self.lingual = lingual
if lingual_parser:
self.lingual_parser = lingual_parser
else:
self.lingual_parser = SpacyParser(self.language)
# Fallback to SimpleParser if a tokenizer is not supported.
if not self.lingual_parser.has_tokenizer_support():
self.lingual_parser = SimpleParser()
if self.lingual and not self.lingual_parser.has_NLP_support():
logger.warning(f"Lingual mode will be turned off, "
f"as spacy doesn't provide support for this "
f"language ({self.language})")
self.lingual = False
# tabular setup
self.tabular = tabular
# visual setup
self.visual = visual
self.vizlink = vizlink
if self.visual:
self.pdf_path = pdf_path
if not self.vizlink:
# Use the provided pdf_path if present
if not self.pdf_path:
warnings.warn(
"Visual parsing failed: pdf_path is required. " +
"Proceeding without visual parsing.",
RuntimeWarning,
)
self.visual = False
else:
self.vizlink = VisualLinker(pdf_path)
def apply( # type: ignore
self,
document: Document,
pdf_path: Optional[str] = None,
**kwargs: Any) -> Document:
"""Parse a text in an instance of Document.
:param document: document to parse.
:param pdf_path: path of a pdf file that the document is visually linked with.
"""
try:
[y for y in self.parse(document, document.text)]
if self.visual:
# Use the provided pdf_path if present
self.pdf_path = pdf_path if pdf_path else self.pdf_path
if not self.vizlink.is_linkable(document.name, self.pdf_path):
warnings.warn(
(f"Visual parse failed. "
f"{self.pdf_path + document.name} not a PDF. "
f"Proceeding without visual parsing."),
RuntimeWarning,
)
else:
# Add visual attributes
[
y for y in self.vizlink.link(
document.name, document.sentences, self.pdf_path)
]
return document
except Exception as e:
warnings.warn((f"Document {document.name} not added to database, "
f"because of parse error: \n{e}"))
def _parse_table(self, node: HtmlElement,
state: Dict[str, Any]) -> Dict[str, Any]:
"""Parse a table node.
:param node: The lxml table node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
if not self.tabular:
logger.error("Called _parse_table without tabular activated.")
return state
if node.tag == "table":
table_idx = state["table"]["idx"]
stable_id = f"{state['document'].name}::{'table'}:{state['table']['idx']}"
# Set name for Table
name = node.attrib["name"] if "name" in node.attrib else None
# Create the Table in the DB
parts = {}
parts["document"] = state["document"]
parts["stable_id"] = stable_id
parts["name"] = name
parts["position"] = table_idx
parent = state["parent"][node]
if isinstance(parent, Cell):
parts["section"] = parent.table.section
elif isinstance(parent, Section):
parts["section"] = parent
else:
raise NotImplementedError(
"Table is not within a Section or Cell")
state["context"][node] = Table(**parts)
# Local state for each table. This is required to support nested
# tables
state["table"][table_idx] = {
"grid": defaultdict(int),
"cell_pos": 0,
"row_idx": -1,
"col_idx": 0,
}
# Increment table counter
state["table"]["idx"] += 1
elif node.tag == "tr":
if not isinstance(state["parent"][node], Table):
raise NotImplementedError("Table row parent must be a Table.")
state["table"][state["parent"][node].position]["col_idx"] = 0
state["table"][state["parent"][node].position]["row_idx"] += 1
elif node.tag in ["td", "th"]:
if not isinstance(state["parent"][node], Table):
raise NotImplementedError("Cell parent must be a Table.")
if not state["table"][state["parent"]
[node].position]["row_idx"] >= 0:
raise NotImplementedError(
"Table cell encountered before a table row.")
# calculate row_start/col_start
while state["table"][state["parent"][node].position]["grid"][(
state["table"][state["parent"][node].position]["row_idx"],
state["table"][state["parent"][node].position]["col_idx"],
)]: # while a cell on the grid is occupied, keep moving
state["table"][state["parent"][node].position]["col_idx"] += 1
col_start = state["table"][state["parent"]
[node].position]["col_idx"]
row_start = state["table"][state["parent"]
[node].position]["row_idx"]
# calculate row_end/col_end
row_end = row_start
if "rowspan" in node.attrib:
try:
row_end += int(node.get("rowspan")) - 1
except ValueError:
logger.error(
f"Rowspan has invalid value: '{node.get('rowspan')}'")
col_end = col_start
if "colspan" in node.attrib:
try:
col_end += int(node.get("colspan")) - 1
except ValueError:
logger.error(
f"Colspan has invalid value: '{node.get('colspan')}'")
# update grid with occupied cells
for r, c in itertools.product(list(range(row_start, row_end + 1)),
list(range(col_start, col_end + 1))):
state["table"][state["parent"][node].position]["grid"][(r,
c)] = 1
# Set name for Cell
name = node.attrib["name"] if "name" in node.attrib else None
# construct cell
parts = defaultdict(list)
parts["document"] = state["document"]
parts["name"] = name
parts["table"] = state["parent"][node]
parts["row_start"] = row_start
parts["row_end"] = row_end
parts["col_start"] = col_start
parts["col_end"] = col_end
parts["position"] = state["table"][state["parent"]
[node].position]["cell_pos"]
stable_id = (f"{parts['document'].name}"
f"::"
f"{'cell'}"
f":"
f"{parts['table'].position}"
f":"
f"{row_start}"
f":"
f"{col_start}")
parts["stable_id"] = stable_id
# Create the Cell in the DB
state["context"][node] = Cell(**parts)
# Update position
state["table"][state["parent"][node].position]["col_idx"] += 1
state["table"][state["parent"][node].position]["cell_pos"] += 1
return state
def _parse_figure(self, node: HtmlElement,
state: Dict[str, Any]) -> Dict[str, Any]:
"""Parse the figure node.
:param node: The lxml img node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
if node.tag not in ["img", "figure"]:
return state
# Process the Figure
stable_id = (f"{state['document'].name}"
f"::"
f"{'figure'}"
f":"
f"{state['figure']['idx']}")
# Set name for Figure
name = node.attrib["name"] if "name" in node.attrib else None
# img within a Figure get's processed in the parent Figure
if node.tag == "img" and isinstance(state["parent"][node], Figure):
return state
# NOTE: We currently do NOT support nested figures.
parts: Dict[str, Any] = {}
parent = state["parent"][node]
if isinstance(parent, Section):
parts["section"] = parent
elif isinstance(parent, Cell):
parts["section"] = parent.table.section
parts["cell"] = parent
else:
logger.warning(f"Figure is nested within {state['parent'][node]}")
return state
parts["document"] = state["document"]
parts["stable_id"] = stable_id
parts["name"] = name
parts["position"] = state["figure"]["idx"]
# If processing a raw img
if node.tag == "img":
# Create the Figure entry in the DB
parts["url"] = node.get("src")
state["context"][node] = Figure(**parts)
elif node.tag == "figure":
# Pull the image from a child img node, if one exists
imgs = [child for child in node if child.tag == "img"]
# In case the image from the child img node doesn't exist
if len(imgs) == 0:
logger.warning("No image found in Figure.")
return state
if len(imgs) > 1:
logger.warning("Figure contains multiple images.")
# Right now we don't support multiple URLs in the Figure context
# As a workaround, just ignore the outer Figure and allow processing
# of the individual images. We ignore the accompanying figcaption
# by marking it as visited.
captions = [
child for child in node if child.tag == "figcaption"
]
state["visited"].update(captions)
return state
img = imgs[0]
state["visited"].add(img)
# Create the Figure entry in the DB
parts["url"] = img.get("src")
state["context"][node] = Figure(**parts)
state["figure"]["idx"] += 1
return state
def _parse_sentence(self, paragraph: Paragraph, node: HtmlElement,
state: Dict[str, Any]) -> Iterator[Sentence]:
"""Parse the Sentences of the node.
:param node: The lxml node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
text = state["paragraph"]["text"]
field = state["paragraph"]["field"]
# Set name for Sentence
name = node.attrib["name"] if "name" in node.attrib else None
# Lingual Parse
document = state["document"]
for parts in self.lingual_parser.split_sentences(text):
abs_offset = state["sentence"]["abs_offset"]
parts["abs_char_offsets"] = [
char_offset + abs_offset
for char_offset in parts["char_offsets"]
]
parts["document"] = document
# NOTE: Why do we overwrite this from the spacy parse?
parts["position"] = state["sentence"]["idx"]
abs_sentence_offset_end = (state["sentence"]["abs_offset"] +
parts["char_offsets"][-1] +
len(parts["words"][-1]))
parts["stable_id"] = construct_stable_id(
document,
"sentence",
state["sentence"]["abs_offset"],
abs_sentence_offset_end,
)
parts["name"] = name
state["sentence"]["abs_offset"] = abs_sentence_offset_end
if self.structural:
context_node = node.getparent() if field == "tail" else node
tree = lxml.etree.ElementTree(state["root"])
parts["xpath"] = tree.getpath(context_node)
parts["html_tag"] = context_node.tag
parts["html_attrs"] = [
"=".join(x) for x in list(context_node.attrib.items())
]
# Extending html style attribute with the styles
# from inline style class for the element.
cur_style_index = None
for index, attr in enumerate(parts["html_attrs"]):
if attr.find("style") >= 0:
cur_style_index = index
break
head = state["root"].find("head")
styles = None
if head is not None:
styles = head.find("style")
if styles is not None:
for x in list(context_node.attrib.items()):
if x[0] == "class":
exp = r"(." + x[1] + r")([\n\s\r]*)\{(.*?)\}"
r = re.compile(exp, re.DOTALL)
if r.search(styles.text) is not None:
if cur_style_index is not None:
parts["html_attrs"][cur_style_index] += (
r.search(styles.text).group(3).replace(
"\r",
"").replace("\n",
"").replace("\t", ""))
else:
parts["html_attrs"].extend([
"style=" + re.sub(
r"\s{1,}",
" ",
r.search(
styles.text).group(3).replace(
"\r", "").replace(
"\n", "").replace(
"\t", "").strip(),
)
])
break
parts["position"] = state["sentence"]["idx"]
# If tabular, consider own Context first in case a Cell
# was just created. Otherwise, defer to the parent.
parent = paragraph
if isinstance(parent, Paragraph):
parts["section"] = parent.section
parts["paragraph"] = parent
if parent.cell: # if True self.tabular is also always True
parts["table"] = parent.cell.table
parts["cell"] = parent.cell
parts["row_start"] = parent.cell.row_start
parts["row_end"] = parent.cell.row_end
parts["col_start"] = parent.cell.col_start
parts["col_end"] = parent.cell.col_end
else:
raise NotImplementedError("Sentence parent must be Paragraph.")
yield Sentence(**parts)
state["sentence"]["idx"] += 1
def _parse_paragraph(self, node: HtmlElement,
state: Dict[str, Any]) -> Iterator[Sentence]:
"""Parse a Paragraph of the node.
:param node: The lxml node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
# Both Paragraphs will share the same parent
parent = (state["context"][node]
if node in state["context"] else state["parent"][node])
# Set name for Paragraph
name = node.attrib["name"] if "name" in node.attrib else None
for field in ["text", "tail"]:
text = getattr(node, field)
text = text.strip() if text and self.strip else text
# Skip if "" or None
if not text:
continue
# Run RegEx replacements
for (rgx, replace) in self.replacements:
text = rgx.sub(replace, text)
# Process the Paragraph
stable_id = (f"{state['document'].name}"
f"::"
f"{'paragraph'}"
f":"
f"{state['paragraph']['idx']}")
parts = {}
parts["stable_id"] = stable_id
parts["name"] = name
parts["document"] = state["document"]
parts["position"] = state["paragraph"]["idx"]
if isinstance(parent, Caption):
if parent.table:
parts["section"] = parent.table.section
elif parent.figure:
parts["section"] = parent.figure.section
parts["caption"] = parent
elif isinstance(parent, Cell):
parts["section"] = parent.table.section
parts["cell"] = parent
elif isinstance(parent, Section):
parts["section"] = parent
elif isinstance(parent,
Figure): # occurs with text in the tail of an img
parts["section"] = parent.section
elif isinstance(parent,
Table): # occurs with text in the tail of a table
parts["section"] = parent.section
else:
raise NotImplementedError(
f"Para '{text}' parent must be Section, Caption, or Cell, "
f"not {parent}")
# Create the entry in the DB
paragraph = Paragraph(**parts)
state["paragraph"]["idx"] += 1
state["paragraph"]["text"] = text
state["paragraph"]["field"] = field
yield from self._parse_sentence(paragraph, node, state)
def _parse_section(self, node: HtmlElement,
state: Dict[str, Any]) -> Dict[str, Any]:
"""Parse a Section of the node.
Note that this implementation currently creates a Section at the
beginning of the document and creates Section based on tag of node.
:param node: The lxml node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
if node.tag not in ["html", "section"]:
return state
# Add a Section
stable_id = (f"{state['document'].name}"
f"::"
f"{'section'}"
f":"
f"{state['section']['idx']}")
# Set name for Section
name = node.attrib["name"] if "name" in node.attrib else None
state["context"][node] = Section(
document=state["document"],
name=name,
stable_id=stable_id,
position=state["section"]["idx"],
)
state["section"]["idx"] += 1
return state
def _parse_caption(self, node: HtmlElement,
state: Dict[str, Any]) -> Dict[str, Any]:
"""Parse a Caption of the node.
:param node: The lxml node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
"""
if node.tag not in ["caption",
"figcaption"]: # captions used in Tables
return state
# Add a Caption
parent = state["parent"][node]
stable_id = (f"{state['document'].name}"
f"::"
f"{'caption'}"
f":"
f"{state['caption']['idx']}")
# Set name for Section
name = node.attrib["name"] if "name" in node.attrib else None
if isinstance(parent, Table):
state["context"][node] = Caption(
document=state["document"],
table=parent,
figure=None,
stable_id=stable_id,
name=name,
position=state["caption"]["idx"],
)
elif isinstance(parent, Figure):
state["context"][node] = Caption(
document=state["document"],
table=None,
figure=parent,
stable_id=stable_id,
name=name,
position=state["caption"]["idx"],
)
else:
raise NotImplementedError(
"Caption must be a child of Table or Figure.")
state["caption"]["idx"] += 1
return state
def _parse_node(self, node: HtmlElement,
state: Dict[str, Any]) -> Iterator[Sentence]:
"""Entry point for parsing all node types.
:param node: The lxml HTML node to parse
:param state: The global state necessary to place the node in context
of the document as a whole.
:return: a *generator* of Sentences
"""
# Processing on entry of node
state = self._parse_section(node, state)
state = self._parse_figure(node, state)
if self.tabular:
state = self._parse_table(node, state)
state = self._parse_caption(node, state)
yield from self._parse_paragraph(node, state)
def parse(self, document: Document, text: str) -> Iterator[Sentence]:
"""Depth-first search over the provided tree.
Implemented as an iterative procedure. The structure of the state
needed to parse each node is also defined in this function.
:param document: the Document context
:param text: the structured text of the document (e.g. HTML)
:return: a *generator* of Sentences.
"""
stack = []
root = lxml.html.fromstring(text)
# flattens children of node that are in the 'flatten' list
if self.flatten:
lxml.etree.strip_tags(root, self.flatten)
# Strip comments
lxml.etree.strip_tags(root, lxml.etree.Comment)
# Assign the text, which was stripped of the 'flatten'-tags, to the document
document.text = lxml.etree.tostring(root, encoding="unicode")
# This dictionary contain the global state necessary to parse a
# document and each context element. This reflects the relationships
# defined in parser/models. This contains the state necessary to create
# the respective Contexts within the document.
state = {
"visited": set(),
"parent": {}, # map of parent[child] = node used to discover child
"context":
{}, # track the Context of each node (context['td'] = Cell)
"root": root,
"document": document,
"section": {
"idx": 0
},
"paragraph": {
"idx": 0
},
"figure": {
"idx": 0
},
"caption": {
"idx": 0
},
"table": {
"idx": 0
},
"sentence": {
"idx": 0,
"abs_offset": 0
},
}
# NOTE: Currently the helper functions directly manipulate the state
# rather than returning a modified copy.
# Iterative Depth-First Search
stack.append(root)
state["parent"][root] = document
state["context"][root] = document
tokenized_sentences: List[Sentence] = []
while stack:
node = stack.pop()
if node not in state["visited"]:
state["visited"].add(node) # mark as visited
# Process
if self.lingual:
tokenized_sentences += [
y for y in self._parse_node(node, state)
]
else:
yield from self._parse_node(node, state)
# NOTE: This reversed() order is to ensure that the iterative
# DFS matches the order that would be produced by a recursive
# DFS implementation.
for child in reversed(node):
# Skip nodes that are blacklisted
if self.blacklist and child.tag in self.blacklist:
continue
stack.append(child)
# store the parent of the node, which is either the parent
# Context, or if the parent did not create a Context, then
# use the node's parent Context.
state["parent"][child] = (state["context"][node]
if node in state["context"] else
state["parent"][node])
if self.lingual:
yield from self.lingual_parser.enrich_sentences_with_NLP(
tokenized_sentences)
def test_simple_parser_support():
lingual_parser = SimpleParser()
assert lingual_parser.has_tokenizer_support()
assert not lingual_parser.has_NLP_support()
def test_simple_parser_support():
"""Unit test of simple parser support."""
lingual_parser = SimpleParser()
assert lingual_parser.has_tokenizer_support()
assert not lingual_parser.has_NLP_support()
def test_simple_parser_support(caplog):
caplog.set_level(logging.INFO)
lingual_parser = SimpleParser()
assert lingual_parser.has_tokenizer_support()
assert not lingual_parser.has_NLP_support()