Fix Base64 output from /exec on webOS 1

[throwaway96]

While #172 fixed the basic functionality of /exec on webOS 1, the Base64 fields of the response (stdoutBytes and stderrBytes) were not working as intended.

On Node.js v0.10.x, child_process.exec() doesn't appear to support passing stdout and stderr as Buffer objects to the callback. However, the binary encoding (an alias for latin1) can be used to get strings containing the raw program output. After creating Buffers from the strings, the data can be handled the same as on newer webOS/Node.js versions.

Testing

I verified that responses containing UTF-8 encoded data were handled identically between webOS 1 and 8.

webOS 8.1.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"/home/root/utf8.sh"}' | tee /dev/tty | sha256sum
{"returnValue":true,"stdoutString":"һȅḽḻ𝖔 𝙛гổḿ ꞩƭᑯ𝞼ʋ𝙩\n","stdoutBytes":"0rvIheG4veG4u/CdlpQg8J2Zm9Cz4buV4bi/IOqeqcat4ZGv8J2evMqL8J2ZqQo=","stderrString":"ȟęḽƚⲟ ᵮ𝓻őṁ ꜱ𝖙ḓ𝒆𝖗𝗋\n","stderrBytes":"yJ/EmeG4vcaa4rKfIOG1rvCdk7vFkeG5gSDqnLHwnZaZ4biT8J2ShvCdlpfwnZeLCg=="}
f4001c0d30d4a0553ef3581f97ef6c12426374aa96f4be32d4f183109a27d1dc  -

webOS 1.4.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"/home/root/utf8.sh"}' | tee /dev/tty | sha256sum
{"returnValue":true,"stdoutString":"һȅḽḻ𝖔 𝙛гổḿ ꞩƭᑯ𝞼ʋ𝙩\n","stdoutBytes":"0rvIheG4veG4u/CdlpQg8J2Zm9Cz4buV4bi/IOqeqcat4ZGv8J2evMqL8J2ZqQo=","stderrString":"ȟęḽƚⲟ ᵮ𝓻őṁ ꜱ𝖙ḓ𝒆𝖗𝗋\n","stderrBytes":"yJ/EmeG4vcaa4rKfIOG1rvCdk7vFkeG5gSDqnLHwnZaZ4biT8J2ShvCdlpfwnZeLCg=="}
f4001c0d30d4a0553ef3581f97ef6c12426374aa96f4be32d4f183109a27d1dc  -

/home/root/utf8.sh just outputs UTF-8 encoded text on stdout and stderr. The original files in Base64 form are 0rvIheG4veG4u/CdlpQg8J2Zm9Cz4buV4bi/IOqeqcat4ZGv8J2evMqL8J2ZqQo= (stdout) and yJ/EmeG4vcaa4rKfIOG1rvCdk7vFkeG5gSDqnLHwnZaZ4biT8J2ShvCdlpfwnZeLCg== (stderr). They were received unmodified on both webOS 1 and 8.

I also checked that a chunk of data from /dev/urandom made it through unchanged on webOS 1.

Limitations

/exec still doesn't behave exactly the same on all webOS versions. I have noticed that errorText is different, as can be seen with the false command.

webOS 8.1.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"false"}'
{"returnValue":false,"errorText":"Command failed: false\n","stdoutString":"","stdoutBytes":"","stderrString":"","stderrBytes":""}

webOS 1.4.0:

# luna-send -n 1 'luna://org.webosbrew.hbchannel.service/exec' '{"command":"false"}'
{"returnValue":false,"errorText":"Command failed: ","stdoutString":"","stdoutBytes":"","stderrString":"","stderrBytes":""}

In seems later versions generally include the failed command itself, while webOS 1 does not. This is not something we can easily change, though, and it is probably not that important.

[kitsuned]

I don’t have the ability to test it on a real device, looks nice tho!