Powershell: ConvertTo-Json

[he852100]

Steps to reproduce

@('a')|convertto-json

Expected behavior

[                                                                 
"a"                                                                                                   
]

Actual behavior

"a"

Environment data

[vexx32]

The pipeline by nature unwraps arrays into individual items. To a receiving cmdlet, there is no distinguishable difference between these two scenarios:

'a' | ConvertTo-Json

@('a') | ConvertTo-Json

If you need single-item arrays you will need to pass them directly to the -InputObject parameter rather than using the pipeline.

[thorsig]

Not sure if I should open up a new ticket or glue my similar issue to this one, so I'll go with the former and may the mods hit me over the head with a clue-stick if necessary :)

This is one thing I think ConvertTo-Json should handle:

PS /> ps
PID TTY TIME CMD
24618 pts/0 00:00:00 sudo
24622 pts/0 00:00:00 su
24623 pts/0 00:00:00 bash
25724 pts/0 00:00:01 pwsh
25757 pts/0 00:00:00 ps
PS ACTUAL> ps | ConvertTo-Json
[
" PID TTY TIME CMD",
"24618 pts/0 00:00:00 sudo",
"24622 pts/0 00:00:00 su",
"24623 pts/0 00:00:00 bash",
"25724 pts/0 00:00:01 pwsh",
"26184 pts/0 00:00:00 ps"
]
PS EXPECTED> ps | ConvertTo-Json
[
{
"PID": 24618,
"TTY": "pts/0",
"TIME": "00:00:00",
"CMD": "sudo"
},
{
"PID": 24622,
"TTY": "pts/0",
"TIME": "00:00:00",
"CMD": "su"
},
{
"PID": 24623,
"TTY": "pts/0",
"TIME": "00:00:00",
"CMD": "bash"
},
{
"PID": 25724,
"TTY": "pts/0",
"TIME": "00:00:00",
"CMD": "pwsh"
},
{
"PID": 26184,
"TTY": "pts/0",
"TIME": "00:00:00",
"CMD": "ps"
}
]

Because if it doesn't, then by default it could be replaced with something like this simple awk script :)

awk 'BEGIN{printf("["); c="n";}{printf("%st"%s"",c,$0); c=",n"; }END{print "n]";}'

user@wslhost:/mnt/c/Users/user$ ps | awk 'BEGIN{printf("["); c="n";}{printf("%st"%s"",c,$0); c=",n"; }END{print "n]";}'
[
" PID TTY TIME CMD",
" 218 pts/4 00:00:00 bash",
" 269 pts/4 00:00:00 ps",
" 270 pts/4 00:00:00 awk"
]

But then I may be overreaching?

[vexx32]

@thorsig bit of a different issue there. The alias ps that points to Start-Process in Windows editions of PowerShell (including recent versions of PowerShell 7 GA) is not actually present in linux, due to there being a native ps executable that many folks use.

That executable only ever emits string data, so ConvertTo-Json can only treat it as such.

What you seem to be wanting is still achievable with Get-Process | ConvertTo-Json. 🙂

If you instead want the text output from ps to be interpreted as some kind of object, you need to provide that conversion yourself; cmdlets in PowerShell can't afford to make any assumptions about the expected format of string data without breaking other users' assumptions in the process. It's for a similar reason that many very useful aliases were removed for Unix editions of PowerShell; many Unix users got very upset that PowerShell was "taking over" these native executables with its aliases and producing (for them) unexpected behaviour when using familiar commands.

[msftbot[bot]]

This issue has been marked as answered and has not had any activity for 1 day. It has been closed for housekeeping purposes.