Automated filedownload using WebBrowser without url

Question

I've been working on a WebCrawler written in C# using System.Windows.Forms.WebBrowser. I am trying to download a file off a website and save it on a local machine. More importantly, I would like this to be fully automated. The file download can be started by clicking a button that calls a javascript function that sparks the download displaying a “Do you want to open or save this file?” dialog. I definitely do not want to be manually clicking “Save as”, and typing in the file name.

I am aware of HttpWebRequest and WebClient’s download functions, but since the download is started with a javascript, I do now know the url of the file. Fyi, the javascript is a doPostBack function that changes some values and submits a form.

I’ve tried getting focus on the save as dialog from WebBrowser to automate it from in there without much success. I know there’s a way to force the download to save instead of asking to save or open by adding a header to the http request, but I don’t know how to specify the filepath to download to.

Any thoughts would be greatly appreciated.

Thanks, Sharath

Answer 1

I think you should prevent the download dialog from even showing. Here might be a way to do that:

• The Javascript code causes your WebBrowser control to navigate to a specific Url (what would cause the download dialog to appear)

• To prevent the WebBrowser control from actually Navigating to this Url, attach a event handler to the Navigating event.

• In your Navigating event you'd have to analyze if this is the actual Navigation action you'd want to stop (is this one the download url, perhaps check for a file extension, there must be a recognizable format). Use the WebBrowserNavigatingEventArgs.Url to do so.

• If this is the right Url, stop the Navigation by setting the WebBrowserNavigatingEventArgs.Cancel property.

• Continue the download yourself with the HttpWebRequest or WebClient classes

Have a look at this page for more info on the event:
http://msdn.microsoft.com/en-us/library/system.windows.forms.webbrowser.navigating.aspx

Answer 2

similar solution is available at http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/d338a2c8-96df-4cb0-b8be-c5fbdd7c9202/?prof=required

This work perfectly if there is direct URL including downloading file-name.

But sometime some URL generate file dynamically. So URL don't have file name but after requesting that URL some website create file dynamically and then open/save dialog comes.

for example some link generate pdf file on the fly.

How to handle such type of URL?