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Bash Native Messaging host. Echo JSON string that does not include (escaped) double quotes.
#!/bin/bash
# Bash Native Messaging host, guest271314 2022
# Echo JSON string that does not include (escaped) double quotes
# https://stackoverflow.com/a/24777120
sendMessage() {
message=\"$1\"
# Calculate the byte size of the string.
# NOTE: This assumes that byte length is identical to the string length!
# Do not use multibyte (unicode) characters, escape them instead, e.g.
# message='"Some unicode character:\u1234"'
messagelen=${#message}
# Convert to an integer in native byte order.
# If you see an error message in Chrome's stdout with
# "Native Messaging host tried sending a message that is ... bytes long.",
# then just swap the order, i.e. messagelen1 <-> messagelen4 and
# messagelen2 <-> messagelen3
messagelen1=$((($messagelen) & 0xFF))
messagelen2=$((($messagelen >> 8) & 0xFF))
messagelen3=$((($messagelen >> 16) & 0xFF))
messagelen4=$((($messagelen >> 24) & 0xFF))
# Print the message byte length followed by the actual message.
printf "$(printf '\\x%x\\x%x\\x%x\\x%x' \
$messagelen1 $messagelen2 $messagelen3 $messagelen4)%s" "$message"
}
getMessage() {
input=""
datacount=0
doublequotecount=0
# Loop forever, to deal with chrome.runtime.connectNative
while true; do
IFS= read -res -n1 data
# Do not process encoded length of JSON.
# TODO: Process encoded length of JSON (1st $data read).
if ((datacount++)); then
# Do not write double quotation marks to variable $input.
if [ "$data" == "\"" ]; then
# Pass $input to sendMessage to echo when 2d double quotation mark is read
if ((doublequotecount++)); then
sendMessage "$input"
break
fi
continue
fi
# Write $data (stdin) that is not double quotation marks to $input.
if [ "$data" != "\"" ]; then
# Read the first message
# Assuming that the message ALWAYS ends with a },
# with no }s in the string. Adopt this piece of code if needed.
input="${input}${data}"
fi
continue
fi
done
}
getMessage
var input = new String(`Test`);
(async()=>{
self.port = chrome.runtime.connectNative('nm_bash')
port.onMessage.addListener((message)=>{
if (chrome.runtime.lastError) {
console.log(chrome.runtime.lastError.message)
}
console.log(message);
}
)
port.onDisconnect.addListener(()=>{
if (chrome.runtime.lastError) {
console.log(chrome.runtime.lastError.message)
}
console.log('Disconnected')
}
)
port.postMessage(input)
}
)();
chrome.runtime.sendNativeMessage('nm_bash', input)
.then((msg)=>console.log(msg))
.catch(console.error);
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