Extractous

Extractous is a Rust crate that provides a unified approach for detecting and extracting metadata and text content from various documents types such as PDF, Word, HTML, and many other formats.

Features

• High-level Rust API for extracting text and metadata content for many file formats.
• Strives to be efficient and fast.
• Internally it calls the Apache Tika for any file format that is not natively supported in the Rust core.
• Comprehensive documentation and examples to help you get started quickly.

Usage

• Create and configure an Extractor instance

use extractous::Extractor;
use extractous::PdfParserConfig;

fn main() {
    // Create a new extractor. Note it uses the consuming builder pattern
    let mut extractor = Extractor::new()
        .set_extract_string_max_length(1000);

    // can also perform conditional configuration
    let custom_pdf_config = true;
    if custom_pdf_config {
        extractor = extractor.set_pdf_config(
            PdfParserConfig::new().set_extract_annotation_text(false)
        );
    }
}

• Extracting a content of a file to a String

use extractous::Extractor;

fn main() {
  // Get the command-line arguments
  let args: Vec<String> = std::env::args().collect();
  let file_path = &args[1];

  // Extract the provided file content to a string
  let extractor = Extractor::new();
  let content = extractor.extract_file_to_string(file_path).unwrap();
  println!("{}", content);
}

• Extract a content of a file to a StreamReader and perform buffered reading

use std::io::{BufReader, Read};
use extractous::Extractor;

fn main() {
    // Get the command-line arguments
    let args: Vec<String> = std::env::args().collect();
    let file_path = &args[1];

    // Extract the provided file content to a string
    let extractor = Extractor::new();
    let stream = extractor.extract_file(file_path).unwrap();

    // Because stream implements std::io::Read trait we can perform buffered reading
    // For example we can use it to create a BufReader
    let mut reader = BufReader::new(stream);
    let mut buffer = Vec::new();
    reader.read_to_end(&mut buffer).unwrap();

    println!("{}", String::from_utf8(buffer).unwrap())
}

• Extract content of PDF with OCR. You need to have Tesseract installed with the language pack. For example on debian sudo apt install tesseract-ocr tesseract-ocr-deu
• If you get Parse error occurred : Unable to extract PDF content, it is most likely that OCR language pack is not installed

use extractous::Extractor;

fn main() {
  let file_path = "../test_files/documents/deu-ocr.pdf";
  
    let extractor = Extractor::new()
          .set_ocr_config(TesseractOcrConfig::new().set_language("deu"))
          .set_pdf_config(PdfParserConfig::new().set_ocr_strategy(PdfOcrStrategy::OCR_ONLY));
    // extract file with extractor
  let content = extractor.extract_file_to_string(file_path).unwrap();
  println!("{}", content);
}

Building

Requirements

• Extractous uses Apache Tika for file formats that are not natively supported in Rust. However, to achieve one of Extractous goals, which is speed and efficiency, we do not set up any Tika as a servers or run any Java code. We instead, compile Apache Tika as native shared libraries and use them on our Rust core as ffi. GraalVm is required to build Tika as native libs.
• The provided build script already takes care of installing the required GraalVM JDK. However, if you want to use a specific local version, you can do so by setting the GRAALVM_HOME environment variable
• We recommend using sdkman to install GraalVM JDKs
• sdk install java 22.0.1-graalce
• To be able to use it from IDEA, on Ubuntu for example add GRAALVM_HOME=$HOME/.sdkman/candidates/java/22.0.2-graalce to /etc/environment
• Confirm that GraalVM is installed correctly by running java -version. You should see something like:

openjdk 22.0.1 2024-04-16
OpenJDK Runtime Environment Liberica-NIK-24.0.1-1 (build 22.0.1+10)
OpenJDK 64-Bit Server VM Liberica-NIK-24.0.1-1 (build 22.0.1+10, mixed mode, sharing)

• On macOS the official GraalVM JDKs fail to work with code that use java awt. On macOS, we recommend using Bellsoft Liberica NIK
• sdk install java 24.0.1.r22-nik
• Extractous supports OCR through tesseract, make sure tesseract is installed on your system because some of the OCR tests will fail if no tesseract is found.
• sudo apt install tesseract-ocr
• Install any language extensions you want. for example to install German and Arabic:
• sudo apt install tesseract-ocr-deu tesseract-ocr-ara

Building Extractous

• To build Extractous, just run:
• cargo build

Running Tests

• To run tests, just run:
• cargo test