Resume property determines if wodHttpDLX will try to retrieve
remote resource partially - starting from nonzero position.
Typically, you will use this property is you
Aborted previous
download.
If you
set this property, you should also point Response.Filename property
to partially downloaded file that should be resumed. wodHttpDLX will
check size of local content and send appropriate headers ('Range'
header, to be precise) with the request. You should set this
property before you call
Get method.
If server supports partial content, it will return Response.StatusCode
206. Content will be appended to your local file in that case.
Progress event will be fired during download, but will not start
from 0 - it will actually start from previously aborted position.
It is possible that Response.Length
property shows invalid information when Resume is used. It will
contain total number of bytes that will be received, and usually you
are interested to see size of remote resource. You can use
Progress
event and it's argument Total to determine size of the
resource, or you can check its size when it's completely retrieved.
If server respond with StatusCode 416 (invalid download range),
this usually means that local file is larger than remote one.
Servers typically send full resource to the client in such cases.
However, wodHttpDLX will abort the download in this case (so your
local file is not overwritten). You can download resource again, but
you need to set Resume=False thus allowing local file to be
overwritten.
Warning: not all servers allow resume
feature. It is possible that server sends full resource back -
overwriting your old one.