Creating and downloading a PDF or DOCX in ASP.NET Core | Software Engineering - JOYK Joy of Geek, Geek News, Link all geek

The post shows how a PDF can be created from data in an ASP.NET Core backend and downloaded using an API. The data could be loaded from different locations and exported then as a PDF or a docx or whatever you require.

Code: https://github.com/damienbod/AspNetCoreCreatePdf

Why GemBox?

There are many different tools to generate PDF all with advantages and disadvantages. I required a tool to download PDFs created in an ASP.NET Core backend using data from a database. This was recommended to me and after trying this out, I think this is a good choice. GemBox.document has a good licensing model, it is simple to use and it provides PDF signing. You can create different formats direct from C# data classes. It is easy to use and does not require a windows host environment.

Import the GemBox Nuget package

The GemBox.Document Nuget package is added to project and you have everything you require.

Note:

If deploying to Linux, add the HarfBuzzSharp.NativeAssets.Linux Nuget package as well.

Create an API to download PDF/Docx

The download controller is used as the public API. This class has two methods, one for downloading the data as a PDF and a second method to download the same data as a docx file.

public class DownloadController(DocumentService _documentService) : ControllerBase

{

[Route("pdf/{id}")]

[HttpGet]

public FileStreamResult DownloadPdf(string id)

{

var stream = _documentService.GeneratePdf(id);

return File(stream, "application/pdf");

}

[Route("docx/{id}")]

[HttpGet]

public FileStreamResult DownloadDocx(string id)

{

var stream = _documentService.GenerateDocx(id);

return File(stream,

"application/vnd.openxmlformats-officedocument.wordprocessingml.document");

}

The Document service class implements the document specification. This service uses data from a C# DTO and creates a GemBox document which can be exported to many different formats.

using GemBox.Document;

namespace ApiCreatePdf;

public class DocumentService

{

public Stream GeneratePdf(string id)

{

var documentData = GetDocumentData(id, SaveOptions.PdfDefault);

var pdf = new MemoryStream();

var document = CreateDocument(documentData);

document.Save(pdf, SaveOptions.PdfDefault);

return pdf;

}

public Stream GenerateDocx(string id)

{

var documentData = GetDocumentData(id, SaveOptions.DocxDefault);

var docx = new MemoryStream();

var document = CreateDocument(documentData);

document.Save(docx, SaveOptions.DocxDefault);

return docx;

}

private static DocumentModel CreateDocument(DocumentData documentData)

{

// If using the Professional version, put your serial key below.

ComponentInfo.SetLicense("FREE-LIMITED-KEY");

var document = new DocumentModel();

var section = new Section(document);

document.Sections.Add(section);

// Main text

var paragraph = new Paragraph(document);

section.Blocks.Add(paragraph);

var run = new Run(document, documentData.MainContentText);

paragraph.Inlines.Add(run);

var bookmarkName = "TopOfDocument";

document.Sections.Add(

new Section(document,

new Paragraph(document,

new BookmarkStart(document, bookmarkName),

new Run(document, "This is a 'TopOfDocument' bookmark."),

new BookmarkEnd(document, bookmarkName)),

new Paragraph(document,

new Run(document, "The following is a link to "),

new Hyperlink(document, "https://www.gemboxsoftware.com/document", "GemBox.Document Overview"),

new Run(document, " page.")),

new Paragraph(document,

new SpecialCharacter(document, SpecialCharacterType.PageBreak),

new Run(document, "This is a document's second page."),

new SpecialCharacter(document, SpecialCharacterType.LineBreak),

new Hyperlink(document, bookmarkName, "Return to 'TopOfDocument'.") { IsBookmarkLink = true })));

return document;

}

private DocumentData GetDocumentData(string id, SaveOptions docType)

{

return new DocumentData

{

MainContentText = $"{docType.ContentType} created for id: {id}"

};

}

Downloading files

When the application is started, a PDF or a docx file can be downloaded and opened. the data can come from the database or anywhere. This is just a demo and when using data from user inputs and returning it to the clients, the data needs to be validated and sanitized.