How to access remote and encrypted PDF text without writing to local drive

Question

I am very new to the coding world and have been stuck on this one problem for 3 days now, searching everywhere for an answer, so any help will be greatly appreciated. I am needing to extract a small amount of text from a url-located Pdf file. I'm using sessions.get(chart_PDF) as the driver for locating the URL where chart_PDF is the example url below.

Example url is https://www.airservicesaustralia.com/aip/pending/dap/PADGN01-166_09SEP2021.pdf

I know I am able to write it to my local drive but I don't want to do that, I want to be able to do it remotely, since I only need a couple of numbers from it.

I have tried finding the password from the url page for decrypting, couldn't find. I've tried to use PyPDF2, pdfminer and pikepdf (probably not well).

I only need to retrieve two numbers near the bottom of the PDF that can be used for the rest of my code. Please help, even if it is a simple fix, I'm new to all this and need some help. Thanks.

from io import BytesIO
from pikepdf import Pdf as PDF
from pdfminer import high_level
chart_PDF = https://www.airservicesaustralia.com/aip/pending/dap/PADGN01-166_09SEP2021.pdf
retrieve = s.get(chart_PDF)
content = retrieve.content

response =urllib.request.urlopen(chart_PDF)
p = BytesIO(content)
p.getbuffer()
check = PDFPage.get_pages(p, check_extractable=False)
extract = high_level.extract_text(p)

I'm getting:

PDFTextExtractionNotAllowedWarning: The PDF <_io.BytesIO object at 0x000001B007ABEC20> contains a metadata field indicating that it should not allow text extraction. Ignoring this field and proceeding.warnings.warn(warning_msg, PDFTextExtractionNotAllowedWarning)

Alternately, if I try this:

from pikepdf import Pdf as PDF
from pdfminer.pdfpage import PDFPage
from PyPDF2 import PdfFileReader
new_pdf = PDF.new()
with PDF.open(p) as pdf:
    print(len(pdf.pages))
    page1 = pdf.pages[0]
    if PdfFileReader.getIsEncrypted(pdf):
        print(True)
        PdfFileReader.decrypt(page1, password='')
pdf.close()

I get:

line 1987, in decrypt return self._decrypt(password) AttributeError: _decrypt

UPDATE 3/8/21 Thank you so much K J! You've seriously been a huge help!

from io import BytesIO
from pdfminer.pdfpage import PDFPage
from pdfminer import high_level

retrieve = s.get(chart_PDF)
content = retrieve.content
bytes = BytesIO(content)
bytes.getbuffer()
PDFPage.get_pages(bytes, check_extractable=False)
extract = high_level.extract_text(bytes, password='') #THIS LINE THROWS ERROR
joined = ''.join(extract)
find_txt = re.findall(r'[(]\d*[-]\d[.]\d[)]', joined)
print(find_txt)
bytes.close()

This is now working well and I have been able to pull the numbers that I need (I have basically pulled all numbers from inside brackets off the PDF). I'll sort through that to find which one I need.

Strangely enough, although its giving me what I need, my extract = high_level.extract_text(bytes, password='') line still throws the Warning: (warning_msg, PDFTextExtractionNotAllowedWarning) which is rather annoying. Not sure how this process works but its still letting the info out.

I can't use try except or it skips over it. What is the way around this? how can I stop that error coming up?

FINAL UPDATE

I got around the warning and it works well now.

with warnings.catch_warnings():
    warnings.simplefilter("ignore")
    extract = high_level.extract_text(bytes)

Cheers fellas for putting up with my ignorance, you've helped so much.

Answer 1

The whole file has to be downloaded to a device via RAM so the blob as a FILE can be parsed at the very END for one OR more %%EOF and the location of page 0 (it gets converted to 1 or i) it could be ANYWHERE IN THE STREAM,.

THEN you can navigate to other sequential numbered pages in the RANDOM order they are built. Any complaints please contact Adobe.

However it is easiest if it is cached as a physical FILE object. If you dont want that on disk use a ram drive for your browser.

Again those two objects at bottom of page one could be anywhere mixed into the content of "page" 99's objects, or otherwise. each letter in a PDF can in its extreme be more than one object anywhere in the file. but a good authoring editor would try to keep them as lines by lines. (there is no such PDF thing as a word or paragraph.)

We can Print the file as Plain Text to see how it is composited and although (secured) that is allowed.

I tried printing from browser with little success but know that can depend on browser system and OS print drivers. Here I have printed the page as text using Acrobat portable, so we can see the sequential offsets of each text block from Left Hand margin JUST LIKE a PDF VIEWER would need to rebuild them.

UPDATE You said your target is (1380-4.4) to the RIGHT of ALTERNATE but again A PDF has no concept of Left and Right or BEFORE or AFTER so we find IN THIS FILE the variable target is in 2 separate pieces PRIOR to the KNOWN characters which luckily is a complete single block (alternate). Thus here proximity of plain text could well work if the capture is confined to that nearby locality. However there is no guarantee that ALTERNATE would always be a single block.

It was perhaps not a good Idea To show the way a Printer would be given a stream of sequential data Here is the way one PDF viewer goes about decrypting the file

As stated on this occasion the word ALTERNATE is defined as text however the next item is the "3" under "B" which is text as a vector path it is not called a "character" although it looks like one but a numbered glyph from a font table. We do see later that some of those numbers are stored as "text" and for your target it is mixed in with similar text in the same object.

Thus you need to call a PDF interpreter to give you a meaningful translation of all bits and pieces of objects so that you can extract the "right" text.

The easiest way for a "simple" one line target in a complex file is to use MuPDF to first tidy up the file

    mutool clean -gggg -D infile.pdf outfile.pdf

combined with

    PDFTOTXT -layout outfile.pdf outfile.txt

or similar to hopefully export that text on a line by line basis, such that you can consistently find your target instantly before ! or after ALTERNATE.

N.B Mutool convert to HTML would place the target value in a table entry AFTER the key word, and if the lines are consistent in number that would be a simpler way to find or grep.