Attaching binary files to requests doesn't work

[wusticality]

Hey @pashky, thanks for such a fantastic Emacs package. :)

Binary files are not attached properly to requests when specified as an external file. For example, something like this:

POST http://foobar.com
Content-type: application/gzip

< /path/to/some/file.json.gz

I've verified that this is broken by running the corresponding command in curl:

curl -X "POST" --data-binary "@/path/to/some/file.json.gz" -H "Content-Type: application/gzip" http://foobar.com

I had to use --data-binary instead of -d on the command line to attach the gzipped file. It looks like restclient.el always emits -d when extracting the request as a curl command. I'm guessing that the code doesn't necessarily use curl internally and will need to be fixed in multiple places.

Perhaps there should be different syntax for attaching binary files? Perhaps something like this:

POST http://foobar.com
Content-type: application/gzip

& /path/to/some/file.json.gz

Thanks very much for all your hard work!

Cheers, K