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from haystack.nodes.base import BaseComponent | |
from haystack.schema import Document | |
from haystack.nodes import PDFToTextOCRConverter, PDFToTextConverter | |
from haystack.nodes import TextConverter, DocxToTextConverter, PreProcessor | |
from typing import Callable, Dict, List, Optional, Text, Tuple, Union | |
from typing_extensions import Literal | |
import pandas as pd | |
import logging | |
import re | |
import string | |
from haystack.pipelines import Pipeline | |
def useOCR(file_path: str)-> Text: | |
""" | |
Converts image pdfs into text, Using the Farm-haystack[OCR] | |
Params | |
---------- | |
file_path: file_path of uploade file, returned by add_upload function in | |
uploadAndExample.py | |
Returns the text file as string. | |
""" | |
converter = PDFToTextOCRConverter(remove_numeric_tables=True, | |
valid_languages=["eng"]) | |
docs = converter.convert(file_path=file_path, meta=None) | |
return docs[0].content | |
class FileConverter(BaseComponent): | |
""" | |
Wrapper class to convert uploaded document into text by calling appropriate | |
Converter class, will use internally haystack PDFToTextOCR in case of image | |
pdf. Cannot use the FileClassifier from haystack as its doesnt has any | |
label/output class for image. | |
1. https://haystack.deepset.ai/pipeline_nodes/custom-nodes | |
2. https://docs.haystack.deepset.ai/docs/file_converters | |
3. https://github.com/deepset-ai/haystack/tree/main/haystack/nodes/file_converter | |
4. https://docs.haystack.deepset.ai/reference/file-converters-api | |
""" | |
outgoing_edges = 1 | |
def run(self, file_name: str , file_path: str, encoding: Optional[str]=None, | |
id_hash_keys: Optional[List[str]] = None, | |
) -> Tuple[dict,str]: | |
""" this is required method to invoke the component in | |
the pipeline implementation. | |
Params | |
---------- | |
file_name: name of file | |
file_path: file_path of uploade file, returned by add_upload function in | |
uploadAndExample.py | |
See the links provided in Class docstring/description to see other params | |
Return | |
--------- | |
output: dictionary, with key as identifier and value could be anything | |
we need to return. In this case its the List of Hasyatck Document | |
output_1: As there is only one outgoing edge, we pass 'output_1' string | |
""" | |
try: | |
if file_name.endswith('.pdf'): | |
converter = PDFToTextConverter(remove_numeric_tables=True) | |
if file_name.endswith('.txt'): | |
converter = TextConverter(remove_numeric_tables=True) | |
if file_name.endswith('.docx'): | |
converter = DocxToTextConverter() | |
except Exception as e: | |
logging.error(e) | |
return | |
documents = [] | |
document = converter.convert( | |
file_path=file_path, meta=None, | |
encoding=encoding, id_hash_keys=id_hash_keys | |
)[0] | |
text = document.content | |
# if file is image pdf then it will have {'content': "\x0c\x0c\x0c\x0c"} | |
# subsitute this substring with '',and check if content is empty string | |
text = re.sub(r'\x0c', '', text) | |
documents.append(Document(content=text, | |
meta={"name": file_name}, | |
id_hash_keys=id_hash_keys)) | |
# check if text is empty and apply pdfOCR converter. | |
for i in documents: | |
if i.content == "": | |
logging.info("Using OCR") | |
i.content = useOCR(file_path) | |
logging.info('file conversion succesful') | |
output = {'documents': documents} | |
return output, 'output_1' | |
def run_batch(): | |
""" | |
we dont have requirement to process the multiple files in one go | |
therefore nothing here, however to use the custom node we need to have | |
this method for the class. | |
""" | |
return | |
def basic(s:str, remove_punc:bool = False): | |
""" | |
Performs basic cleaning of text. | |
Params | |
---------- | |
s: string to be processed | |
removePunc: to remove all Punctuation including ',' and '.' or not | |
Returns: processed string: see comments in the source code for more info | |
""" | |
# Remove URLs | |
s = re.sub(r'^https?:\/\/.*[\r\n]*', ' ', s, flags=re.MULTILINE) | |
s = re.sub(r"http\S+", " ", s) | |
# Remove new line characters | |
s = re.sub('\n', ' ', s) | |
# Remove punctuations | |
if remove_punc == True: | |
translator = str.maketrans(' ', ' ', string.punctuation) | |
s = s.translate(translator) | |
# Remove distracting single quotes and dotted pattern | |
s = re.sub("\'", " ", s) | |
s = s.replace("..","") | |
return s.strip() | |
class UdfPreProcessor(BaseComponent): | |
""" | |
class to preprocess the document returned by FileConverter. It will check | |
for splitting strategy and splits the document by word or sentences and then | |
synthetically create the paragraphs. | |
1. https://docs.haystack.deepset.ai/docs/preprocessor | |
2. https://docs.haystack.deepset.ai/reference/preprocessor-api | |
3. https://github.com/deepset-ai/haystack/tree/main/haystack/nodes/preprocessor | |
""" | |
outgoing_edges = 1 | |
def run(self, documents:List[Document], remove_punc:bool=False, | |
split_by: Literal["sentence", "word"] = 'sentence', | |
split_length:int = 2, split_respect_sentence_boundary:bool = False, | |
split_overlap:int = 0): | |
""" this is required method to invoke the component in | |
the pipeline implementation. | |
Params | |
---------- | |
documents: documents from the output dictionary returned by Fileconverter | |
remove_punc: to remove all Punctuation including ',' and '.' or not | |
split_by: document splitting strategy either as word or sentence | |
split_length: when synthetically creating the paragrpahs from document, | |
it defines the length of paragraph. | |
split_respect_sentence_boundary: Used when using 'word' strategy for | |
splititng of text. | |
split_overlap: Number of words or sentences that overlap when creating | |
the paragraphs. This is done as one sentence or 'some words' make sense | |
when read in together with others. Therefore the overlap is used. | |
Return | |
--------- | |
output: dictionary, with key as identifier and value could be anything | |
we need to return. In this case the output will contain 4 objects | |
the paragraphs text list as List, Haystack document, Dataframe and | |
one raw text file. | |
output_1: As there is only one outgoing edge, we pass 'output_1' string | |
""" | |
if split_by == 'sentence': | |
split_respect_sentence_boundary = False | |
else: | |
split_respect_sentence_boundary = split_respect_sentence_boundary | |
preprocessor = PreProcessor( | |
clean_empty_lines=True, | |
clean_whitespace=True, | |
clean_header_footer=True, | |
split_by=split_by, | |
split_length=split_length, | |
split_respect_sentence_boundary= split_respect_sentence_boundary, | |
split_overlap=split_overlap, | |
# will add page number only in case of PDF not for text/docx file. | |
add_page_number=True | |
) | |
for i in documents: | |
# # basic cleaning before passing it to preprocessor. | |
# i = basic(i) | |
docs_processed = preprocessor.process([i]) | |
for item in docs_processed: | |
item.content = basic(item.content, remove_punc= remove_punc) | |
df = pd.DataFrame(docs_processed) | |
all_text = " ".join(df.content.to_list()) | |
para_list = df.content.to_list() | |
logging.info('document split into {} paragraphs'.format(len(para_list))) | |
output = {'documents': docs_processed, | |
'dataframe': df, | |
'text': all_text, | |
'paraList': para_list | |
} | |
return output, "output_1" | |
def run_batch(): | |
""" | |
we dont have requirement to process the multiple files in one go | |
therefore nothing here, however to use the custom node we need to have | |
this method for the class. | |
""" | |
return | |
def processingpipeline(): | |
""" | |
Returns the preprocessing pipeline. Will use FileConverter and UdfPreProcesor | |
from utils.preprocessing | |
""" | |
preprocessing_pipeline = Pipeline() | |
file_converter = FileConverter() | |
custom_preprocessor = UdfPreProcessor() | |
preprocessing_pipeline.add_node(component=file_converter, | |
name="FileConverter", inputs=["File"]) | |
preprocessing_pipeline.add_node(component = custom_preprocessor, | |
name ='UdfPreProcessor', inputs=["FileConverter"]) | |
return preprocessing_pipeline | |