Download file segments c#

Basically when you open the response stream in your code, you are reading bytes in order which means you could technically define stream ranges and read them in parallel and therefore use the power of multiple cores n your machine to achieve faster download. Similar principle is used in download manager applications with addition for download resuming. The following approach enables the power of parallel operations on multi-core machines and can be used as a base for download resume.

This is only the base implementation which allows downloading files in chunks in parallel. And now to begin with hands on code. First thing I decided to do is to do is to handle the response stream ranges in a collection of model objects. I could got with dictionary in this case, but using a model class seemed more readable solution.

Before we switch to the logic we need to declare a model for a result. We are going to need few infos for the invoker of the download method. I found following properties useful, so I put them as a part of a download result method. And now to the main stuff.

The following method accepts the download url, destination path as well as optional number of parallel downloads and whether you want to skip SSL validation if you are downloading from HTTPS url. The class and method are static and they are setting ServicePointManager class properties which is also static. That makes this class not thread safe.

Now to give a test run to the code. Post your question to a community of , developers. Sign in Join Now. New Post. DBC User. I would like to know how can I do this in segments so that if the download fails, I will able to download from the the place where the download fails. Follow Post Reply. For this to work you need to control both ends of the transmition, do you? Nicholas Paldino [. I believe you can use HTTP for this. The 1. This way, you can indicate which byte to start at, and then just append to your file.

Hope this helps. Joerg Jooss. Hello Nicholas Paldino [. This header is called "Range". Using it, one can specify one or multiple byte segments to be retrieved. Benny Raymond. It should be noted that you cannot assume that all servers will allow this. So in that case you'll need to restart the entire download if the server you are connecting to doesn't support Range.

Hello Benny, It should be noted that you cannot assume that all servers will allow this. That's correct. A server that supports Range requests should advertise this capability using the "Accept-Ranges" header. I am writing a tray item do this task. The following code shows how to download file synchronously. This method blocks the main thread until the file is downloaded or an error occur in this case the WebException is thrown.

You can also set event handlers to show progress and to detect that the file is downloaded. Note: Although you use asynchronous method, it can block the main thread for a while.