PDF file creation using the ItextSharp library with ASP.NET

Introduction

Today I am going to explain how to create a PDF file on a server using ASP.NET and how to delete it from the server.

I was trying to create a PDF file with help of ItextSharp, which was relatively easy task. After creation, I wanted to load this file on the web browser for the user. Once loaded, I wanted to delete the file from the server. I searched on the web regarding this topic, but found almost nothing of help. After a lot of thinking, I came up with this solution. If you have a better solution, please share it with me.

Background

The primary requirements for this application are a PDF file template, a data source (data that will go inside the PDF file), and the ItextSharp library. Download ItextSharp from SourceForge.net. I would like to thank the authors of ItextSharp for creating such a nice library which makes PDF creation a piece of cake.

Please read this article for understanding how to create a PDF file.

Using the code

I will explain how to load the PDF file into a web browser from a server directory once the PDF file is created, we will also see how to delete the file once it is displayed.

Step 1: Create a directory on the server, for example "/pdfFactory/". Use this folder as the output path from the PDF file creation method.

Step 2: Once the file is created, construct a thread:

protected void Page_Load(object sender, EventArgs e){
    .
    .
    .

    string filePath = Server.MapPath("/pdfFactory/")+"/pdfFile.pdf"; 
    if (File.Exist(filePath)){
        Thread t = new Thread( deleteMe); 

        t.Start(filePath); 

        Response.Redirect("/pdfFactory/pdfFile.pdf"); 
    }
    .
    .
    .
}

static void deleteMe(object fileObject){
    string filePath = (string) fileObject; 
    Thread.Sleep(5000); 
    if(File.Exist(filePath)){
    File.Delete(filePath); 
    }
}

Explanation

Once the PDF file is created inside the "pdfFactory" folder, it can be loaded directly to the browser with a relative URL. The Response.Redirect method uses this path to load the newly created PDF file into the web browser. Once the file is redirected with the above method, server side control is lost. So, we need another event to delete the file from the client browser. But, it requires another server call from the client. To overcome this problem, we are using a Thread.

The created thread "t" calls the deleteMe method. This method takes a filePath parameter. Once started, it sleeps until the file is loaded to the client machine. After 5000 milliseconds, the server deletes this file with the File object.

If the client wishes to save this file, the client can save it on their local machine. This way, the server is not loaded with a lot of files.