A client to send request to a piston instance from the comfort of your terminal. If you send data through stdin then it will be sent along as stdin for your program.

piston.sh

#!/bin/sh
host=https://emkc.org/api/v1/piston
POST=$host/execute
GET=$host/versions

usage() {
	echo "$0 [debug] {version OR FILENAME [ARG1 [ARG2 [...]]]}"
	echo
	echo "\tdebug   : Display the json request sent to the api."
	echo "\t          It has no effect when used with version."
	echo "\tversion : Get available languages, their version and aliases from $GET."
	echo "\tFILENAME: The file containing the code to be run by piston,"
	echo "\t          if the file doesn't exist then vim is launched."
	echo "\tARGs    : Your program will run with those as command line arguments."
	exit
}

debug=0
if [ "$1" = "debug" ]
then
	debug=1
	shift
fi

# if there is no more arguments, exit with usage information
[ $# = '0' ] && usage

# get the available versions for supported lgges.
if [ "$1" = "version" ]
then
	curl $GET 2> /dev/null
	exit
fi

req=$(mktemp   reqXXXX.piston)
stdin=$(mktemp stdinXXXX.piston)

# get stdin if any
tty > /dev/null || dd of=$stdin status=none

# get the lgge from file extension
lgge=$(basename $1)
lgge=${lgge##*.}

# the file containing the source code
code=$1
[ ! -f "$code" ] && vim $code < /dev/tty > /dev/tty

# get the remaining args as a json array
shift
jsonargs="[]"
while [ $# != '0' ]
do
	jsonargs=$(echo $jsonargs | jq -cr ". +[\"$1\"]")
	shift
done

echo | jq -sc "{\
	language: \"$lgge\",\
	source: $(jq -Rsc "" $code),\
	args: $jsonargs,\
	stdin: $(jq -Rsc "" $stdin)\
}" > $req

[ $debug = '1' ] && cat $req

# send the request
curl -d "@$req" -X POST -H "Content-Type: application/json" $POST 2> /dev/null

rm $req
rm $stdin