[Bug-wget] Re : Re: limit download size -- 201901233

[clu]

----- Yousong Zhou <address@hidden> wrote :
> On Thu, 24 Jan 2019 at 02:32, Tim Rühsen <address@hidden> wrote:
> >
> > On 23.01.19 03:47, address@hidden wrote:
> > > Hi,
> > >   acording to
> > >     $wget --help
> > >   i should send reports and suggestions to this address, so i hope i'm 
> > > doing right here.
> > >
> > >    the version of my distribution, given by the above command, is "GNU 
> > > Wget 1.18"
> > >
> > >    and i don't seem to see an option to limit the retrieval to a certain 
> > > amount of data or a range.
> > >    is it possible?
> > >
> > > thanks in advance and happy new year,
> > >
> > > Zui
> > > 201901233
> > >
> >
> > You could set the Range HTTP header - many servers support it.
> >
> > Like
> >
> > wget --header "Range: bytes=0-10000" https://www.example.com/filename
> >
> > Regards, Tim
> >
> 
> At least for wget 1.19.1, it will ignore 206 "Partial Content", unless
> we need to make it think it's continuing previous partial download.
> Specifying Range header is not an reliable option in this regard
> 
>     echo -n aaa >b
>     wget -c -O b --header "Range: 3-1000" URL
> 
>                 yousong
Thank you both for your input...
  and, as yousong wrote the Range header is not handled correctly by wget 
(removing boring parts) :
    $ wget --header "Range: bytes=500-1000" https://free.fr
      --2019-01-24 02:22:25--  https://server.dom/
      Resolving server.dom (server.dom)... <addr>
      Connecting to server.dom (server.dom)... <addr>  connected.
      HTTP request sent, awaiting response... 206 Partial Content
      Retrying.

      --2019-01-24 02:22:26--  (try: 2)  https://server.dom/
      Connecting to server.dom (server.dom)... <addr>  connected.
      HTTP request sent, awaiting response... 206 Partial Content
      Retrying.

      <...loop af retries...>
  
  but curl is not exempt of problems as in (both cases bring the whole thing):
      $ curl   https://ddg.gg > a
        % Total    % Received % Xferd  Average Speed   Time    Time     Time  
Current
                                      Dload  Upload   Total   Spent    Left  
Speed
      100   178  100   178    0     0    310      0 --:--:-- --:--:-- --:--:--  
 370
      $ curl --header "Range: bytes=10-40"  https://ddg.gg > a
        % Total    % Received % Xferd  Average Speed   Time    Time     Time  
Current
                                      Dload  Upload   Total   Spent    Left  
Speed
      100   178  100   178    0     0    314      0 --:--:-- --:--:-- --:--:--  
 376

  as for using "| head -c (end-start)" as you apply in mget, doesn' it actually 
generate more traffic
  than the expected (end-start) nimber of bytes?
  (i mean, since the download goes systematically till the end, if i am correct)

zui
201901244