Introduction
Scans pdfs for links written in plaintext and checks if they are active or returns an error code. It then generates a report of its findings. Extract references (pdf, url, doi, arxiv) and metadata from a PDF.
Features
- Extract references and metadata from a given PDF.
- Detects pdf, url, arxiv and doi references.
- Checks for valid SSL certificate.
- Find broken hyperlinks (using the -c flag).
- Output as text or JSON (using the -j flag).
- Extract the PDF text (using the --text flag).
- Use as command-line tool or Python package.
- Works with local and online pdfs.
Installation
Grab a copy of the code with pip:
pip install linkrot
Usage
linkrot can be used to extract info from a PDF in two ways:
- Command line/Terminal tool
linkrot - Python library
import linkrot
1. Command Line/Terminal tool
linkrot [pdf-file-or-url]
Run linkrot -h to see the help output:
linkrot -h
usage:
linkrot [-h] [-d OUTPUT_DIRECTORY] [-c] [-j] [-v] [-t] [-o OUTPUT_FILE] [--version] pdf
Extract metadata and references from a PDF, and optionally download all referenced PDFs.
Arguments
positional arguments:
pdf (Filename or URL of a PDF file)
optional arguments:
-h, --help (Show this help message and exit)
-d OUTPUT_DIRECTORY, --download-pdfs OUTPUT_DIRECTORY (Download all referenced PDFs into specified directory)
-c, --check-links (Check for broken links)
-j, --json (Output infos as JSON (instead of plain text))
-v, --verbose (Print all references (instead of only PDFs))
-t, --text (Only extract text (no metadata or references))
-o OUTPUT_FILE, --output-file OUTPUT_FILE (Output to specified file instead of console)
--version (Show program's version number and exit)
Examples
Extract text to console
linkrot https://example.com/example.pdf -t
Extract text to file
linkrot https://example.com/example.pdf -t -o pdf-text.txt
Check Links
linkrot https://example.com/example.pdf -c
2. Main Python Library
Import the library:
import linkrot
Create an instance of the linkrot class like so:
pdf = linkrot.linkrot("filename-or-url.pdf") #pdf is the instance of the linkrot class
Now the following function can be used to extract specific data from the pdf:
get_metadata()
Arguments: None
Usage:
metadata = pdf.get_metadata() #pdf is the instance of the linkrot class
Return type: Dictionary
Information Provided: All metadata, secret metadata associated with the PDF including Creation date, Creator, Title, etc...
get_text()
Arguments: None
Usage:
text = pdf.get_text() #pdf is the instance of the linkrot class
Return type: String
Information Provided: The entire content of the PDF in string form.
get_references(reftype=None, sort=False)
Arguments:
reftype: The type of reference that is needed
values: 'pdf', 'url', 'doi', 'arxiv'.
default: Provides all reference types.
sort: Whether reference should be sorted or not
values: True or False.
default: Is not sorted.
Usage:
references_list = pdf.get_references() #pdf is the instance of the linkrot class
Return type: Set
of
linkrot.backends.Reference object has 3 member variables:
- ref: actual URL/PDF/DOI/ARXIV
- reftype: type of reference
- page: page on which it was referenced
Information Provided: All references with their corresponding type and page number.
get_references_as_dict(reftype=None, sort=False)
Arguments:
reftype: The type of reference that is needed
values: 'pdf', 'url', 'doi', 'arxiv'.
default: Provides all reference types.
sort: Whether reference should be sorted or not
values: True or False.
default: Is not sorted.
Usage:
references_dict = pdf.get_references_as_dict() #pdf is the instance of the linkrot class
Return type: Dictionary
with keys 'pdf', 'url', 'doi', 'arxiv' that each have a list
of refs of that type.
Information Provided: All references in their corresponding type list.
download_pdfs(target_dir)
Arguments:
target_dir: The path of the directory to which the reference pdfs should be downloaded
Usage:
pdf.download_pdfs("target-directory") #pdf is the instance of the linkrot class
Return type: None
Information Provided: Downloads all the reference pdfs to specified directory.
3. Linkrot downloader functions
Import:
from linkrot.downloader import sanitize_url, get_status_code, check_refs
sanitize_url(url)
Arguments:
url: The url to be sanitized.
Usage:
new_url = sanitize_url(old_url)
Return type: String
Information Provided: URL is prefixed with 'http://' if it was not before and makes sure it is in utf-8 format.
get_status_code(url)
Arguments:
url: The url to be checked for its status.
Usage:
status_code = get_status_code(url)
Return type: String
Information Provided: Checks if the url is active or broken.
check_refs(refs, verbose=True, max_threads=MAX_THREADS_DEFAULT)
Arguments:
refs: set of linkrot.backends.Reference objects
verbose: whether it should print every reference with its code or just the summary of the link checker
max_threads: number of threads for multithreading
Usage:
check_refs(pdf.get_references()) #pdf is the instance of the linkrot class
Return type: None
Information Provided: Prints references with their status code and a summary of all the broken/active links on terminal.
4. Linkrot extractor functions
Import:
from linkrot.extractor import extract_urls, extract_doi, extract_arxiv
Get pdf text:
text = pdf.get_text() #pdf is the instance of the linkrot class
extract_urls(text)
Arguments:
text: String of text to extract urls from
Usage:
urls = extract_urls(text)
Return type: Set
of URLs
Information Provided: All URLs in the text
extract_arxiv(text)
Arguments:
text: String of text to extract arxivs from
Usage:
arxiv = extract_arxiv(text)
Return type: Set
of arxivs
Information Provided: All arxivs in the text
extract_doi(text)
Arguments:
text: String of text to extract dois from
Usage:
doi = extract_doi(text)
Return type: Set
of dois
Information Provided: All dois in the text
Code of Conduct
To view our code of conduct please visit our Code of Conduct page.
License
This program is licensed with an MIT License.
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