Can HtmlUnit render and scrape content from PDFs or other document types embedded in web pages?

HtmlUnit is a "GUI-less browser for Java programs," which means it's primarily designed to simulate a web browser, allowing Java programs to interact with web pages as a user would. This includes executing JavaScript, handling forms, managing cookies, and extracting content from HTML.

However, HtmlUnit does not natively support rendering and scraping content from embedded documents such as PDFs. When a web page embeds a PDF, it typically does so using an <iframe>, <embed>, or <object> tag, which points to the location of the PDF file. While HtmlUnit can detect these tags and download the PDF file by following the URL, it cannot render or extract text from the PDF itself.

To handle PDFs, you would need to combine HtmlUnit with a separate library that is capable of processing PDF files. For Java, a popular choice is Apache PDFBox. Here's a general overview of how you could use HtmlUnit together with PDFBox to download and extract text from a PDF embedded in a web page:

1. Use HtmlUnit to navigate to the page and find the URL of the embedded PDF.
2. Download the PDF using HtmlUnit or another HTTP library.
3. Use PDFBox to open the downloaded PDF and extract the content.

Here's an example in Java that demonstrates this process:

import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
import com.gargoylesoftware.htmlunit.html.HtmlElement;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;

import java.io.InputStream;
import java.net.URL;

public class HtmlUnitPDFScraper {
    public static void main(String[] args) {
        WebClient webClient = new WebClient();

        // Configure the webClient according to your needs
        webClient.getOptions().setJavaScriptEnabled(true);
        webClient.getOptions().setCssEnabled(false);

        try {
            HtmlPage page = webClient.getPage("http://example.com/page-with-embedded-pdf");

            // Locate the PDF <embed>, <object>, or <iframe> tag and get the URL
            HtmlElement pdfElement = page.getFirstByXPath("//embed[@type='application/pdf']");
            String pdfUrl = pdfElement.getAttribute("src");

            // Download the PDF
            try (InputStream pdfStream = new URL(pdfUrl).openStream()) {
                // Load the PDF document using PDFBox
                PDDocument document = PDDocument.load(pdfStream);

                // Extract text from the PDF document
                PDFTextStripper stripper = new PDFTextStripper();
                String text = stripper.getText(document);

                // Output the extracted text
                System.out.println(text);

                // Close the document
                document.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            webClient.close(); // Close the web client
        }
    }
}

Please note that this is a simplified example. In a real-world scenario, you would need to handle various edge cases, such as different methods of embedding PDFs, dynamically loaded content via JavaScript, and potentially more complex navigation to reach the PDF.

Additionally, if the web page uses JavaScript to manipulate the PDF after it is embedded, HtmlUnit's capabilities would be limited because it can't run the JavaScript within the PDF viewer itself. If you need that level of interaction, you would need to use a more fully-featured headless browser like Selenium with a browser that has PDF viewing capabilities.