Kelp::Module::SendFile - Dancer-style file sending with Kelp
use Kelp::Module::SendFile;
Kelp::Module::SendFile enables returning a file from a route handler while controlling various aspects of the delivery
Lets the current route handler send a file to the client.
sub some_route_handler {
# Do your processing
...
return send_file(params->{file});
}
Send file supports streaming possibility using PSGI streaming. The server should support it but normal streaming is supported on most, if not all.
sub your_route_handler{
# Process...
return send_file( params->{file}, streaming => 1 );
}
You can control the delivery using callbacks.
First, around_content allows you to get the writer object and the chunk of
content read, and then decide what to do with each chunk:
sub some_route_handler {
return send_file(
$file,
streaming => 1,
callbacks => {
around_content => sub {
my ( $writer, $chunk ) = @_;
$writer->write("* $chunk");
},
},
);
}
You can use around to all get all the content (whether a filehandle if it's
a regular file or a full string if it's a scalar ref) and decide what to do with
it:
sub some_route_handler {
# Process ...
return send_file(
$file,
streaming => 1,
callbacks => {
around => sub {
my ( $writer, $content ) = @_;
# we know it's a text file, so we'll just stream
# line by line
while ( my $line = <$content> ) {
$writer->write($line);
}
},
},
);
}
Or you could use override to control the entire streaming callback request:
sub some_route_handler {
# Process ...
return send_file(
$file,
streaming => 1,
callbacks => {
override => sub {
my ( $responder, $response ) = @_;
my $writer = $responder->( [ $newstatus, $newheaders ] );
$writer->write("some line");
},
},
);
}
You can also set the number of bytes that will be read at a time (default being
42K bytes) using bytes:
sub some_route_handler {
return send_file(
params->{file},
streaming => 1,
bytes => 524288, # 512K
);
};
The content-type will be set depending on the current MIME types definition
If your filename does not have an extension, or you need to force a
specific mime type, you can pass it to send_file as follows:
return send_file($file, content_type => 'image/png');
If you have your data in a scalar variable, send_file can be useful
as well. Pass a reference to that scalar, and send_file will behave
as if there was a file with that contents:
return send_file( \$data, content_type => 'image/png' );
Note that this module is unable to guess the content type from the data
contents. Therefore you might need to set the content_type
properly. For this kind of usage an attribute named filename can be
useful. It is used as the Content-Disposition header, to hint the
brower about the filename it should use.
return send_file( \$data, content_type => 'image/png'
filename => 'onion.png' );
Gurunandan R. Bhat [email protected]
Copyright 2013- Gurunandan R. Bhat
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
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