Question

我们有一个包含可填写字段的PDF表单库，可以在Adobe Reader中打开并由最终用户填写。请注意，我们不是生成PDF而只是使用现有的PDF。所有这些表单都受到保护，不会通过密码编辑Acrobat中的不可填写字段。

问题在于，当我们在代码中打开PDF以预填充某些字段时，密码保护会丢失，并且在Acrobat中可以编辑提供的表单。

所以：

有没有办法在不解锁PDF和结果输出流的情况下使用iTextSharp预填充可填写字段？
有没有办法重新锁定表单，同时仍然允许最终用户在Reader中打开，填写可填写的字段，打印等，没有需要密码？

以下是我们目前使用的代码的简化示例。我们已经尝试锁定输出流（代码当前不可用），但文件无法，然后Reader提示用户输入密码。

System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
Byte[] password = encoding.GetBytes("secretPassword");
PdfReader reader = null;
MemoryStream outputStream = null;
PdfStamper stamper = null;
pdfStream.Seek(0, SeekOrigin.Begin);
reader = new PdfReader(pdfStream, password);
outputStream = new MemoryStream();
stamper = new PdfStamper(reader, outputStream);

AcroFields fields = stamper.AcroFields;
fields.SetField("prefillField1", "Some text");
stamper.Close();
outputStream.Close();
reader.Close();
// outputStream sent to user/browser. PDF opens in Reader, but the form can be opened in 
// Acrobat without a password and edited.

Answer 1

如果受密码保护，则无法编辑PDF。你希望你必须用密码打开它来编辑它。有了它，您似乎正在创建该文档的副本并呈现给用户。您可以使用编辑密码加密PDF。这是我发现我使用itextsharp的方法的副本。如果您在保留editPassword null的同时设置openPassword，那么您的用户应该能够查看pdf并与之交互，但无法根据您设置的权限对其进行编辑。希望这会有所帮助。

    /// <summary>
    /// Adds the given Open (User) and Edit (Owner) password to the PDF and optionally sets
    /// the various Allow/Not Allowed restrictions
    /// </summary>
    /// <param name="openPassword">Open/User password</param>
    /// <param name="editPassword">Edit/Owner password</param>
    /// <param name="allowAssemply">Assembly means merging, extracting, etc the PDF pages</param>
    /// <param name="allowCopy">Copy means right-click copying the content of the PDF to the system</param>
    /// <param name="allowDegradedPrinting">Can print low quality version of the PDF</param>
    /// <param name="allowFillIn">Can insert data into any AcroForms in the PDF</param>
    /// <param name="allowModifyAnnotations">Modification of any annotations</param>
    /// <param name="allowModifyContents">Modification of any content in the PDF</param>
    /// <param name="allowPrinting">Allows printing at any quality level</param>
    /// <param name="allowScreenReaders">Allows the content to be parsed/repurposed for screen readers</param>
    public byte[] GetEncryptedPDF(byte[] pdf,
         string openPassword, string editPassword,
         bool allowAssemply, bool allowCopy,
         bool allowDegradedPrinting, bool allowFillIn,
         bool allowModifyAnnotations, bool allowModifyContents,
         bool allowPrinting, bool allowScreenReaders)
    {
        int permissions = 0;
        if (allowAssemply) 
            permissions = permissions | PdfWriter.ALLOW_ASSEMBLY;
        if (allowCopy) 
            permissions = permissions | PdfWriter.ALLOW_COPY;
        if (allowDegradedPrinting)  
            permissions = permissions | PdfWriter.ALLOW_DEGRADED_PRINTING; 
        if (allowFillIn) 
            permissions = permissions | PdfWriter.ALLOW_FILL_IN; 
        if (allowModifyAnnotations) 
            permissions = permissions | PdfWriter.ALLOW_MODIFY_ANNOTATIONS; 
        if (allowModifyContents) 
            permissions = permissions | PdfWriter.ALLOW_MODIFY_CONTENTS; 
        if (allowPrinting) 
            permissions = permissions | PdfWriter.ALLOW_PRINTING; 
        if (allowScreenReaders) 
            permissions = permissions | PdfWriter.ALLOW_SCREENREADERS; 

        PdfReader reader = new PdfReader(pdf);
        using (MemoryStream memoryStream = new MemoryStream())
        {
            PdfEncryptor.Encrypt(reader, memoryStream, true, openPassword, editPassword, permissions);
            reader.Close();
            return memoryStream.ToArray();
        }
    }

预填充然后锁定

1 个答案: