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from abc import ABC, abstractmethod
from pathlib import Path
from urllib.parse import urlparse
import requests
import fitz
import io
import re
import hashlib
import os
class FileTypeError(Exception):
"""Raised when the file type does not match the expected file type."""
class FileSchemeError(Exception):
"""Raised when the file scheme does not match the expected file scheme."""
class FileProcessor(ABC):
type = None
def __init__(self, path):
self.path = path
self.file_scheme = self._get_file_scheme()
self.__class__._check_file_type(path)
@abstractmethod
def get_file_data(self):
pass
@abstractmethod
def _get_file_metadata(self):
pass
@abstractmethod
def _get_file_paragraphs(self):
pass
@classmethod
def _check_file_type(cls, path):
file_type = Path(path).suffix.lower()[1:]
if file_type != cls.type:
raise FileTypeError(
f"Invalid file type. {cls.__name__} expects a {cls.type} file"
)
def _get_file_scheme(self):
parsed_path = urlparse(self.path)
if (
not parsed_path.scheme
or parsed_path.scheme.lower() == "file"
or os.path.isfile(self.path)
):
return "local"
elif parsed_path.scheme.lower() in ["http", "https", "ftp"]:
return "url"
else:
raise FileSchemeError("Unknown scheme")
def _preprocess_text(self, text):
text = text.replace("\n", " ")
text = re.sub("\s+", " ", text)
text = text.encode("utf-8", "ignore").decode("utf-8", "ignore")
return text
def _generate_hash(self, string):
hash_object = hashlib.md5()
hash_object.update(string.encode("utf-8", "ignore"))
hex_dig = hash_object.hexdigest()
return hex_dig
def generate_paragraphs():
raise NotImplementedError
def generate_metadata():
raise NotImplementedError
class PDFProcessor(FileProcessor):
type = "pdf"
def __init__(self, path):
super().__init__(path)
def get_file_data(self, merge_length=200):
file = self._open_file()
file_metadata = self._get_file_metadata(file)
file_paragraphs = self._get_file_paragraphs(
file, file_metadata, start_page=1, end_page=None, merge_length=merge_length
)
file.close()
return file_metadata, file_paragraphs
def _get_file_metadata(self, file):
file_metadata = dict()
metadata = file.metadata
unique_string = str(Path(self.path).name) + metadata["title"]
file_metadata["id"] = self._generate_hash(unique_string)
file_metadata["title"] = metadata["title"]
file_metadata["author"] = metadata["author"]
file_metadata["subject"] = metadata["subject"]
file_metadata["creation_date"] = metadata["creationDate"]
file_metadata["modification_date"] = metadata["modDate"]
file_metadata["n_pages"] = file.page_count
if self.file_scheme == "local":
file_metadata["url"] = str(Path(self.path).resolve())
else:
file_metadata["url"] = self.path
file_metadata["file_name"] = Path(self.path).name
file_metadata["short_name"] = Path(self.path).name
file_metadata["release_date"] = ""
file_metadata["report_type"] = ""
file_metadata["source"] = ""
return file_metadata
def _get_file_paragraphs(
self, file, file_metadata, start_page=1, end_page=None, merge_length=200
):
if end_page is None:
end_page = file_metadata["n_pages"]
file_paragraphs = []
for page_num in range(start_page - 1, end_page):
page = file.load_page(page_num)
blocks = page.get_text("blocks")
for block in blocks:
paragraph = self._process_block(
block, page, page_num + start_page, file_metadata["id"]
)
if paragraph is None:
continue
first_char = paragraph["content"][0]
if len(file_paragraphs) > 0:
if (
len(file_paragraphs[-1]["content"]) + len(paragraph["content"])
< merge_length
) or (first_char.islower() and first_char.isalpha()):
file_paragraphs[-1]["content"] += " " + paragraph["content"]
file_paragraphs[-1]["length"] = len(
file_paragraphs[-1]["content"]
)
else:
file_paragraphs.append(paragraph)
else:
file_paragraphs.append(paragraph)
return file_paragraphs
def _open_file(self):
if self.file_scheme == "url":
response = requests.get(self.path)
file = fitz.open(stream=io.BytesIO(response.content), filetype="pdf")
elif self.file_scheme == "local":
file = fitz.open(self.path)
return file
def _process_block(self, block, page, page_number, file_id):
x0, y0, x1, y1, content, block_no, block_type = block
if content.isspace() or block_type == 1:
return None
content = self._preprocess_text(content)
unique_content_string = "_".join(map(str, block))
paragraph_id = self._generate_hash(unique_content_string)
w, h = page.rect.width, page.rect.height
paragraph = {
"id": paragraph_id,
"document_id": file_id,
"content_type": "text" if block_type == 0 else "image",
"content": content,
"length": len(content),
"idx_block": block_no,
"page_number": page_number,
"x0": x0 / h,
"y0": y0 / w,
"x1": x1 / h,
"y1": y1 / w,
}
return paragraph
class HTMLProcessor(FileProcessor):
type = "html"
def __init__(self, path):
super().__init__(path)
def get_file_data(self):
pass
def _get_file_metadata(self):
pass
def _get_file_paragraphs(self):
pass
def _open_file(self):
if self.file_scheme == "url":
response = requests.get(self.path)
file = response.text
elif self.file_scheme == "local":
file = open(self.path, "r").read()
return file
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