Re: [Bug-wget] [PATCH v4] Make wget capable of starting download from a specified position.

[Tim Ruehsen]

> > On Thursday 06 February 2014 10:27:37 Yousong Zhou wrote:
> > > On Wednesday, February 5, 2014, Tim Ruehsen <address@hidden> wrote:
> > > > First of all, thanks for your contribution.
> > > > 
> > > > I have some little remarks / questions:
> > > > 
> > > > - The documentation is not quite right: when using --start-pos and the
> > > > file
> > > > already exists, wget creates as expected a file.1.
> > > > But your docs say, --start-pos would overwrite an existing file !?
> > > > Could you make this point clear ?
> > > 
> > > Yes, 'overwrite' is wrong.
> > > 
> > > > - The combination with --continue works for me as expected. It would
> > > > simply
> > > > append the downloaded bytes to the existing file. Maybe you should
> > > > document
> > > > that as well. At least your sentence "... it would override the
> > 
> > behavior
> > 
> > > > of --
> > > > continue" seems not to be correct.
> > > 
> > > Sorry for the confusion.  --continue will detect size of existing file,
> > > then continue as if an equivalent --start-pos was specified.  By
> > 
> > 'override'
> > 
> > > I mean the new option has higher precedence over --continue.  Other than
> > > that, all existing behaviors of wget are supposed to remain unchanged.
> > > 
> > > > - What about extending the option to something like
> > > > --range=STARTPOS[-ENDPOS]
> > > > ?
> > > 
> > > You mean change the option name to 'range'?  IIRC, that's how curl does
> > 
> > it.
> > 
> > >  I am okay with --start-pos. ;)
> > 
> > I just wanted to mention a possible 'ENDPOS'. In that case --start-pos
> > isn't
> > appropriate any more and --range seems natural to me.
> 
> I thought ENDPOS was in the patch and once I did a quick look at it I know
> why I decided it should be --start-pos, without LEN or ENDPOS.
> 
>  - I thought the current implementation is simple, neat and easy.  Several
> lines of code really help at that time.
>  - Code of wget is old and mature enough, mimicing curl's --range is very
> likely to pose many compatibility and maintainance issues.  This is not
> what we want.
>  - I actually thought about LENGTH, but not ENDPOS and the main reason I
> give myself to not implement it is that we can achieve length limit with
> other utilities, e.g. dd.
> 
> So I do not have intention to implement curl-like --range option in wget.

I understand that and agreed with you.
For me, there is just this little documentation issue that I mentioned (here 
is my imperfect suggestion)

Start downloading at zero-based position @var{OFFSET}.  Offset may be 
expressed in bytes, kilobytes with the `k' suffix, or megabytes with the `m' 
suffix.

If combined with @samp{--continue} and the destination file exists, the 
downloaded data will be appended. To avoid appending, you may explicitly 
specify an output filename with @samp{-O FILE}.

Server support for the 'Range' header is needed, otherwise @samp{--start-pos}
cannot help.  See @samp{-c} for details.

Regards, Tim