uk.gov.service.notify.PdfUtils Maven / Gradle / Ivy

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package uk.gov.service.notify;

import java.io.ByteArrayInputStream;
import java.util.Base64;
import java.util.Scanner;

public class PdfUtils
{
    /**
     * A method to determine if a file is a pdf file
     *
     * @param base64String A base64 encoded string containing a PDF file to send via the API
     *
     * @return True if the file is a PDF, otherwise false
     *
     */
    public static boolean isBase64StringPDF(String base64String)
    {
        byte[] decoded = Base64.getDecoder().decode(base64String);

        Scanner input = new Scanner(new ByteArrayInputStream(decoded));

        return isPDF(input);
    }

    private static boolean isPDF(Scanner input)
    {
        while (input.hasNextLine())
        {
            final String checkLine = input.nextLine();
            if(checkLine.contains("%PDF-"))
            {
                return true;
            }
        }

        return false;
    }
}