Golang调用PowerShell.exe总是返回ASCII字符

Question

I am using PowerShell from an application written in Go, but am unable to get it to return non-ASCII characters. At first I used go-powershell, but experience the same issue: https://github.com/gorillalabs/go-powershell/issues/10 and now using a slightly more basic approach:

package main

import (
        "bytes"
        "fmt"
        "os/exec"
)

type PowerShell struct {
        powerShell string
}

func New() *PowerShell {
        ps, _ := exec.LookPath("powershell.exe")
        return &PowerShell{
                powerShell: ps,
        }
}

func (p *PowerShell) Execute(args ...string) (stdOut string, stdErr string, err error) {
        args = append([]string{"-NoProfile", "-NonInteractive"}, args...)
        cmd := exec.Command(p.powerShell, args...)

        var stdout bytes.Buffer
        var stderr bytes.Buffer
        cmd.Stdout = &stdout
        cmd.Stderr = &stderr

        err = cmd.Run()
        stdOut, stdErr = stdout.String(), stderr.String()
        return
}

func main() {
        posh := New()
        stdout, stderr, err := posh.Execute("$OutputEncoding = [Console]::OutputEncoding; (Get-VMSwitch).Name")

        fmt.Println(stdout)
        fmt.Println(stderr)

        if err != nil {
                fmt.Println(err)
        }
}

but the same happens. Instead of gettting Przełąś, it returns Przelas. This will result in issues when further in the code a VM is created using this Virtual Switch name. It does not get recognized and errors.

Note: $OutputEncoding = [Console]::OutputEncoding; did not have any effect. It does get changed, but the result remains the same.

Note 2: invoking the same command directly from the command prompt does NOT have issues: powershell.exe -NoProfile -NonInteractive $OutputEncoding = [Console]::OutputEncoding; (Get-VMSwitch).Name") or even powershell.exe -NoProfile -NonInteractive (Get-VMSwitch).Name"). In other words, it does this only from Go when using exec.Command.

Note 3: this is for fixing an issue with a virtual machine driver when it comes to the localized names. Yes, it could work with an GUID (.Id) instead, but this issue persists in different parts of the system.

Answer 1

Man, Powershell is interesting. This was mostly the result of a bunch of trial and error.

Basically, you want to set [Console]::OutputEncoding, not capture it.

However, to clean up after yourself, it doesn't hurt to set it back to it's original value. I haven't fully wrapped my head around it, but the change persists through multiple exec() calls.

Here's an example:

<... everything else is as above ...>

func main() {
        posh := New()

        fmt.Println("With encoding change:")
        stdout, stderr, err := posh.Execute(
                "$test = \"Przełąś\"
" +
                "$old = [Console]::OutputEncoding
" +
                "[Console]::OutputEncoding = [Text.Encoding]::UTF8
" +
                "[Console]::OutputEncoding
" +
                "$test
" +
                "[Console]::OutputEncoding = $old")
        fmt.Println(stdout)
        fmt.Println(stderr)
        if err != nil {
                fmt.Println(err)
        }

        fmt.Println("Without encoding change:")
        stdout, stderr, err = posh.Execute(
                "$test = \"Przełąś\"
" +
                "[Console]::OutputEncoding
" +
                "$test")
        fmt.Println(stdout)
        fmt.Println(stderr)
        if err != nil {
                fmt.Println(err)
        }
}

Output:

$ ./exec-powershell.exe
With encoding change:


BodyName          : utf-8
EncodingName      : Unicode (UTF-8)
HeaderName        : utf-8
WebName           : utf-8
WindowsCodePage   : 1200
IsBrowserDisplay  : True
IsBrowserSave     : True
IsMailNewsDisplay : True
IsMailNewsSave    : True
IsSingleByte      : False
EncoderFallback   : System.Text.EncoderReplacementFallback
DecoderFallback   : System.Text.DecoderReplacementFallback
IsReadOnly        : False
CodePage          : 65001

Przełąś




Without encoding change:


IsSingleByte      : True
BodyName          : IBM437
EncodingName      : OEM United States
HeaderName        : IBM437
WebName           : IBM437
WindowsCodePage   : 1252
IsBrowserDisplay  : False
IsBrowserSave     : False
IsMailNewsDisplay : False
IsMailNewsSave    : False
EncoderFallback   : System.Text.InternalEncoderBestFitFallback
DecoderFallback   : System.Text.InternalDecoderBestFitFallback
IsReadOnly        : True
CodePage          : 437

Przelas