Pass multiple parameter to Powershell function from command line?

Question

I am editing a script function to add a function called CloneGitPackage. This is the function I wrote:

function CloneGitPackage {
    $PACKAGE_URL = $args[1]
    $PACKAGE_NAME = $args[2]

    write-verbose "Downloading package: $PACKAGE_URL $PACKAGE_NAME"
    git clone --depth 1 $PACKAGE_URL $PACKAGE_NAME 2>$null
    write-verbose ""
}

But the original script has some more other functions:

[CmdletBinding()]
param(
    [Parameter(Mandatory = $false, Position = 0)]
    [string]$command,
    [Parameter(Mandatory = $false)]
    [switch] $coverage
)

...

try{
    switch ($command){
        "bootstrap" { Bootstrap }
        "install" { Install }
        "run_tests" { RunTests }
        "clone_git_package" { CloneGitPackage }
    }
}catch {
    throw $_
}

I am calling the script like this:

 .\script.ps1 "clone_git_package" "https://github.com" "Folder" -verbose

But it is complaining:

script.ps1 : A positional parameter cannot be found that accepts argument 'https://github.com'.
At line:1 char:19
+ ... .\script.ps1 "clone_git_package" "https://github.com/ ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [script.ps1], ParameterBindingException
    + FullyQualifiedErrorId : PositionalParameterNotFound,script.ps1

Command executed with exception: A positional parameter cannot be found that accepts argument 'https://github.com'.

I supposed the problem is that stranger header the original script already have:

[CmdletBinding()]
param(
    [Parameter(Mandatory = $false, Position = 0)]
    [string]$command,
    [Parameter(Mandatory = $false)]
    [switch] $coverage
)

These are some valid calls to the script accordingly to its header:

.\script.ps1 "bootstrap" -verbose
.\script.ps1 "install" -verbose
.\script.ps1 "run_tests" -coverage -verbose

I need to be able to call the script passing the new function name, on this case clone_git_package and give its arguments, a string git URL and another string directory name.

How can I fix this, without breaking backward compatibility with the other stuff on the script which already uses this stuff?

TheMadTechnician · Accepted Answer · 2018-02-08 01:16:37Z

In order to be able to pass parameters to your function you will need to update the script's parameters to accommodate your additional parameters. So let's start with your parameters on your function. Right now you reference:

$PACKAGE_URL = $args[1]
$PACKAGE_NAME = $args[2]

This is not particularly good scripting. A better option would be to create actual parameters for your function:

function CloneGitPackage {
Param(
    $PACKAGE_URL,
    $PACKAGE_NAME
)

This essentially does the same thing you were doing before, since parameters are positional based on the order they are listed. We could get fancier, but really there's no need. So if we apply that same logic to the script's parameters it comes out like (keeping the switch at the bottom so that it's the last expected parameter):

param(
    [Parameter(Mandatory = $false, Position = 0)]
    [string]$command,
    $PACKAGE_URL,
    $PACKAGE_NAME,
    [Parameter(Mandatory = $false)]
    [switch] $coverage
)

Now the script knows what to do with your parameters when you give it the additional info! After that you just need to update how the script calls your function to include those parameters when it calls it, and you should be all set.

switch ($command){
    "bootstrap" { Bootstrap }
    "install" { Install }
    "run_tests" { RunTests }
    "clone_git_package" { CloneGitPackage $PACKAGE_URL $PACKAGE_NAME }
}

Evandro Coan · Accepted Answer · 2018-02-08 01:14:37Z

0

I did this, and it seemed to be working fine:

[CmdletBinding()]
param(
    [Parameter(Mandatory = $false, Position = 0)]
    [string]$command,
    [Parameter(Mandatory = $false, Position = 1)]
    [string]$package_url,
    [Parameter(Mandatory = $false, Position = 2)]
    [string]$package_name,
    [Parameter(Mandatory = $false)]
    [switch] $coverage
)

...

function CloneGitPackage {
    $PACKAGE_PATH = "$TARGET_FOLDER\$package_name"

    write-verbose "Downloading package: $package_url $PACKAGE_PATH"
    git clone --depth 1 $package_url $PACKAGE_PATH 2>$null
    write-verbose ""
}

try{
    switch ($command){
        "bootstrap" { Bootstrap }
        "install" { Install }
        "run_tests" { RunTests }
        "clone_git_package" { CloneGitPackage }
    }
}catch {
    throw $_
}

When calling it as:

.\script.ps1 "bootstrap" -verbose
.\script.ps1 "install" -verbose
.\script.ps1 "run_tests" -coverage -verbose
.\script.ps1 "clone_git_package" "https://github.com" "Folder" -verbose

answered Feb 8, 2018 at 1:14

Evandro Coan

9,66115 gold badges103 silver badges163 bronze badges

2 Comments

TheMadTechnician Over a year ago

Well shoot, here I went and wrote up an answer and you more or less figured it out on your own.

Evandro Coan Over a year ago

I just got luck. I do not almost nothing about Powershell and just tried something which seemed symmetry to the code the script already had. Your answer is better, by passing the parameters directly to the function.

Collectives™ on Stack Overflow

Pass multiple parameter to Powershell function from command line?

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related