Resuming a download (or partial download)

[Anonymous]

Please could someone point me to what protocol is used (and, I hope,
implemented in Perl) to resume a filedownload, or to obtain a particular
missing part of a long file

 

[attn.steven.kuo]

Please could someone point me to what protocol is used (and, I hope,
implemented in Perl) to resume a filedownload, or to obtain a particular
missing part of a long file

Is this a stealth CGI question? HTTP/1.1 allows one to
make range requests. Viz.,

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.5

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.27

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35

 

[Jürgen Exner]

Please could someone point me to what protocol is used (and, I hope,
implemented in Perl) to resume a filedownload, or to obtain a
particular missing part of a long file

Your question is confused.
You use a protocol to communicate between two processes or programs, e.g. a
server and a client. There are many, many different protocols, many are
supported by Perl. If you tell us which protocol you are using, then we may
be able to tell you if there is a Perl module supporting that particular
protocol. Or even better just search CPAN for yourself.
Now, if a particular protocol supports a "resume" command is a totally
different question and depends on the particular protocol. Many do not.
Please see the definition of your protocol.

jue

 

[Joe Smith]

Is this a stealth CGI question? HTTP/1.1 allows one to
make range requests. Viz.,

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.5
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.27
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35

And if it is a stealth FTP question, the equivalent of

linux% man ftp
reget remote-file [local-file]
Reget acts like get, except that if local-file exists and is
smaller than remote-file, local-file is presumed to be a par-
tially transferred copy of remote-file and the transfer is
continued from the apparent point of failure. This command
is useful when transferring very large files over networks
that are prone to dropping connections.

in perl is

linux% perldoc Net::FTP
get ( REMOTE_FILE [, LOCAL_FILE [, WHERE]] )
Get "REMOTE_FILE" from the server and store locally. "LOCAL_FILE"
may be a filename or a filehandle. If not specified, the file will
be stored in the current directory with the same leafname as the
remote file.
If "WHERE" is given then the first "WHERE" bytes of the file will
not be transfered, and the remaining bytes will be appended to the
local file if it already exists.


So, in order to determine what the client needs to do, first you
need to determine what type of server you are downloading from.
-Joe

 

[Anonymous]

Thanks to all. The information about the confused nature of my question was
also helpful because it clarified a distinction of which I was unaware