Perl LWP::UserAgent only reading first line of posted jpg file - perl

Question

I'm sure this has been asked but I could not find a good question to my answer. I've got two scripts, one makes a post using LWP::UserAgent and the other basically receives the data, in this case I'm just looking to write a file. The file does get written but it can't be opened and the size is 1262 which leads me to believe only some of it is being read.
Here's what I'm doing (It's worth noting, I was uri/base64 encoding the file and passing everything via json, which was working, but my new task is the split the files out and pass everything as form params):
post script:
open (IMAGE, "./flower.jpg") or die "$!";
$raw_string1 = do{ local $/ = undef; <IMAGE>; };
my $req = HTTP::Request->new(POST => $url);
$req->content_type("application/x-www-form-urlencoded");
$req->content("json_string=$json&file_1=$raw_string1");
my $ua = LWP::UserAgent->new;
$res = $ua->request($req);
print $res->content;
Receiver script:
$cgi = CGI->new;
my $json_post = $cgi->param('json_string');
my $file_1 = $cgi->param('file_1');
open my $fh, '>', "$path/flower.jpg" or die $!;
binmode $fh;
print $fh $file_1;
close $fh;
Thanks for help in advance!

Answer 1

As previously mentioned, you have an encoding problem. The solution is simple:
my $req = HTTP::Request->new(POST => $url, [
json_string => $json,
file_1 => $raw_string1,
]);
which is short for
my $req = HTTP::Request->new(POST => $url,
Content_Type => 'application/x-www-form-urlencoded',
Content => [
json_string => $json,
file_1 => $raw_string1,
]
);
It's far more typical to use multipart/form-data to upload files, though. And if you do, you can even let HTTP::Request load the file for you!
my $req = HTTP::Request->new(POST => $url,
Content_Type => 'multipart/form-data',
Content => [
json_string => $json,
file_1 => [ 'flower.jpg' ],
]
);
CGI.pm will handle that no problem. See the section of the docs titled "PROCESSING A FILE UPLOAD FIELD".

Answer 2

You're not encoding the $raw_string1 data before sticking it into the HTTP POST body. That means that if the data in flower.jpg includes a hex 0x26 byte (the & char) -- at position 1263, let's say -- then the POST data will look like this:
json_string={ ... JSON data ... }&file_1=...1262 bytes of raw JPEG data...&...more JPEG data...
... which means that anything parsing the form body for form variables will truncate file_1 after 1262 bytes.
I'd recommend continuing to encode the $raw_string1 data with base64 or something similar, even if you pass it through as its own POST variable rather than adding it to the JSON data.