Generating PDFs using Phantom JS on .NET applications
I don't know about best practices, but, I'm using phantomJS with no problems with the following code.
public ActionResult DownloadStatement(int id)
{
string serverPath = HttpContext.Server.MapPath("~/Phantomjs/");
string filename = DateTime.Now.ToString("ddMMyyyy_hhmmss") + ".pdf";
new Thread(new ParameterizedThreadStart(x =>
{
ExecuteCommand("cd " + serverPath + @" & phantomjs rasterize.js http://localhost:8080/filetopdf/" + id.ToString() + " " + filename + @" ""A4""");
})).Start();
var filePath = Path.Combine(HttpContext.Server.MapPath("~/Phantomjs/"), filename);
var stream = new MemoryStream();
byte[] bytes = DoWhile(filePath);
return File(bytes, "application/pdf", filename);
}
private void ExecuteCommand(string Command)
{
try
{
ProcessStartInfo ProcessInfo;
Process Process;
ProcessInfo = new ProcessStartInfo("cmd.exe", "/K " + Command);
ProcessInfo.CreateNoWindow = true;
ProcessInfo.UseShellExecute = false;
Process = Process.Start(ProcessInfo);
}
catch { }
}
public ViewResult FileToPDF(int id)
{
var viewModel = file.Get(id);
return View(viewModel);
}
private byte[] DoWhile(string filePath)
{
byte[] bytes = new byte[0];
bool fail = true;
while (fail)
{
try
{
using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
bytes = new byte[file.Length];
file.Read(bytes, 0, (int)file.Length);
}
fail = false;
}
catch
{
Thread.Sleep(1000);
}
}
System.IO.File.Delete(filePath);
return bytes;
}
Here is the action flow:
The user clicks on a link to DownloadStatement Action
. Inside there, a new Thread
is created to call the ExecuteCommand
method.
The ExecuteCommand
method is responsible to call phantomJS. The string passed as an argument do the following.
Go to the location where the phantomJS app is and, after that, call rasterize.js
with an URL, the filename to be created and a print format. (More about rasterize here).
In my case, what I really want to print is the content delivered by the action
filetoupload. It's a simple action that returns a simple view. PhantomJS will call the URL passed as parameter and do all the magic.
While phantomJS is still creating the file, (I guess) I can not return the request made by the client. And that is why I used the DoWhile
method. It will hold the request until the file is created by phantomJS and loaded by the app to the request.