Web part to download file with different name

Question

I would like to create a web part that will reside in the dispform.aspx in a document library. When the user presses a customized button it should be able to download the file but with a different name.

Does anyone has a sample code?

Answer 1

You can create your own ashx-handler in _layouts folder. This handler will be responsible for starting download:

public class TestHandler: IHttpHandler
{
    public bool IsReusable
    {
        get { return true; }
    }

    public void ProcessRequest(HttpContext context)
    {
        //file itemId in document library 
        string itemId = context.Request.QueryString["itemId"];

        //your document library guid
        string listGuid = context.Request.QueryString["listGuid"];

        byte[] fileContents = null;
        using (SPSite site = new SPSite(SPContext.Current.Site.ID)
        {
             using (SPWeb web = site.OpenWeb(SPContext.Current.Web.ID)
             {
                 SPFile file = //here you get you file by listGuid and itemId
                 if (file.Exists)
                 {
                    fileContents = file.OpenBinary(SPOpenBinaryOptions.SkipVirusScan);
                 }
             }
        }

        //name  what you want
        string fileName = "MY_NAME.Extention";

        //starting downloading file 
        context.Response.Clear();
        context.Response.ContentType = IMAGE_MIMETYPE;
        context.Response.Headers["content-disposition"] = string.Format("attachment;filename={0}", fileName);
        context.Response.BinaryWrite(fileContents);
    }
}

After your handler is ready, you need to generate a link to your handler with file item id and list id (or list name), like "/_layouts/15/MyProject/TestHandler.ashx?fileId={0}&listGuid={1}". When custom button pressed - you're following this link and downloads the file with your name.