How to only download first 200 bytes of an image ?

Preben has asked for the wisdom of the Perl Monks concerning the following question:

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Re: How to only download first 200 bytes of an image ? by samtregar (Abbot) on Sep 13, 2007 at 20:19 UTC
That depends on the server. If the server supports it you can pass a Range header requesting just the first 200 bytes. The server may decide to just send you the whole thing anyway. If you're willing to write your own HTTP client you could have it close the connection after it gets enough of the image. -sam	[reply]
Re: How to only download first 200 bytes of an image ? by ikegami (Patriarch) on Sep 13, 2007 at 20:22 UTC
HTTP/1.1 (and maybe earlier) allow you to specify a `Range` header to specify which parts of the document you wish to download. The server may ignore the `Range` request and return the entire document. In that event, you could simply close the connection once you've received enough bytes.	[reply] [d/l] [select]
Re^2: How to only download first 200 bytes of an image ? by Joost (Canon) on Sep 13, 2007 at 20:31 UTC
Note that if the image is small enough, you may be better off to just receive the whole image anyway, since closing and re-opening a connection may be slower than receiving a few hundred extra bytes (many modern HTTP implementations keep the connection open for consecutive requests by default, though I'm not sure if LWP::UserAgent does). To OP: check the content-length header. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]
Re: How to only download first 200 bytes of an image ? by blah (Novice) on Sep 13, 2007 at 20:53 UTC
from WWW::Anonymouse: `sub _ua_content_cb { my ($data, $res, $proto) = @_; $res->add_content(\$data); # Abort the request if enough content is received to parse for sta +tus. die if length $res->content > MAX_BYTES; } my $res = $self->{ua}->post( $self->_url, \%fields, Referer => $self->_referer, ':read_size_hint' => MAX_BYTES, ':content_cb' => \&_ua_content +_cb, );` [download]	[reply] [d/l]
Re: How to only download first 200 bytes of an image ? by Anonymous Monk on Sep 14, 2007 at 00:30 UTC
`my $ua = LWP::UserAgent->new(max_size => 200);`	[reply] [d/l]