Not flattening all fields on pdf via .NET

Aspose.PDF Product Family
,
1

I have a project that is filling pdfs with data, combining, then saving them all asynchronously. I am having an issue where sometimes a few of the documents in the packets are not getting flattened. I am calling FlattenAllFields() on the pdf form just before saving it to a new memory stream. I am not seeing any errors and the pdf gets saved and opens fine. Its just the fields are still editable and usually missing most of the data I was trying to fill with.
Aspose.pdf 24.3.0

Code:

public MemoryStream BuildPdfTemplate(Dictionary<string, string> dict, Stream stream)
{
if (dict == null) return new MemoryStream();

 var pdf = GetPdf(stream);
 MapPdfDataToFields(dict, pdf);
 var memStream = SavePdf(pdf);
 return memStream;

}
public Form GetPdf(Stream stream)
{
var pdf = new Form(stream);
return pdf;
}
public void MapPdfDataToFields(Dictionary<string, string> dict, Form pdf)
{
if (dict == null) return;

foreach (var fieldName in pdf.FieldNames)
{
    if (dict.TryGetValue(fieldName, out string? val)) { pdf.FillField(fieldName, val); }
}

}
public MemoryStream SavePdf(Form pdf)
{
var memStream = new MemoryStream();
pdf.FlattenAllFields();
pdf.Save(memStream);
memStream.Seek(0, SeekOrigin.Begin);
return memStream;
}

2

@cwithhart

It seems that you are encountering an issue where some fields in your PDF documents are not being flattened properly, even after calling the FlattenAllFields() method. Here are a few suggestions to help you troubleshoot and resolve this issue:

  1. Ensure All Fields Are Flattened: Instead of using FlattenAllFields(), you can iterate through each field in the form and flatten them individually. This can sometimes yield better results, especially if there are specific fields that are not being processed correctly. Here’s how you can modify your SavePdf method:

    public MemoryStream SavePdf(Form pdf)
{
    var memStream = new MemoryStream();
    // Flatten each field individually
    foreach (var field in pdf.FieldNames)
    {
        pdf.FlattenField(field);
    }
    pdf.Save(memStream);
    memStream.Seek(0, SeekOrigin.Begin);
    return memStream;
}

  2. Check for Field Types: Ensure that the fields you are trying to flatten are indeed flattenable. Some field types may not support flattening, which could lead to them remaining editable.

  3. Review Asynchronous Operations: Since you mentioned that you are saving documents asynchronously, ensure that there are no race conditions or timing issues that might affect the flattening process. It might be helpful to log the state of the fields before and after flattening to see if they are being modified as expected.

  4. Test with a Simple PDF: To isolate the issue, try testing your flattening logic with a simple PDF that contains only a few fields. This can help determine if the problem is with the specific PDFs you are using or with the flattening logic itself.

  5. Check for Errors: Although you mentioned not seeing any errors, consider adding error handling or logging to capture any exceptions that might occur during the flattening process.

By implementing these suggestions, you should be able to identify the cause of the issue and ensure that all fields are flattened correctly in your PDF documents. If the problem persists, consider providing more details about the specific types of fields that are not being flattened for further assistance.

3

I had considered doing a field by field flatting. So that will probably be something that I will add to my code.
One question I have, is there a way to check a pdf after to see if the form fields are flatted or not?
Also, are there examples or standards as to dependency injecting code that contains these libraries?
thanks again

4

@cwithhart

One question I have, is there a way to check a pdf after to see if the form fields are flatted or not?

You can check whether the PDF still has form fields in it after flattening the document. Also, please try using 24.11 version of the API which is the latest one. In case issue still persists, please share a problematic PDF document after filling it. You can save it without flattening and leave that part for us to reproduce the issue. We will test the scenario in our environment and address it accordingly.