Introduction
- PowerShell is a frequently used scripting language available for Linux, MacOS, Windows and other platforms.
- JS7 offers the JS7 - PowerShell Module for simplified access to the JS7 - REST Web Service API
- This article explains how to syntactically include PowerShell scripts with JS7 job scripts
Unix
In order to directly add PowerShell script code to a JS7 shell job script the recommended approach is to use a shebang like this:
Example how use PowerShell script code with a shebang#!/usr/bin/env pwsh Write-Output "Hello" Write-Output "world"
As an alternative the PowerShell executable can be invoked directly and can be parameterized like this
Example how to pass a variable to subsequent jobs with Windowspwsh -NoLogo -NonInteractive -Command '& { Echo "Hello"; Echo "World"; }'
Explanation:- Consider the quoting: when using the -Command parameter then the PowerShell script has to be specified from a string. This includes to
- quote the script by single quotes.
- quote code inside the script with double quotes or to use escape characters for single quotes.
- Consider that each PowerShell command has to be terminated with a semicolon.
- Consider the quoting: when using the -Command parameter then the PowerShell script has to be specified from a string. This includes to
- An even more weird way how to add PowerShell code to a job script includes:Example how to pass a variable to subsequent jobs with Windows
pwsh -NoLogo -NonInteractive -Command '& { ` Echo "Hello"; ` Echo "World"; ` }'
Explanation:- Consider use of single quotes and double quotes as from the previous example.
- In addition each line of script code has to be terminated with a backtick for line continuation.
Solution
- To address the problem of special characters use base64 encoding for variable values as this encoding results in a single printable string.
- To address the limitation concerning the size of environment variables do not use them and think about ways how to directly append lines to the temporary file indicated by
JS7_RETURN_VALUES
.
Example
- Let's assume two jobs to be executed in sequence:
- The first job creates a lengthy e-email body in HTML format,
- The second job sends e-mail and makes use of the HTML body. Find a number of possible implementations for the JS7 job script:Example for Shell version using environment variables on Unix
#!/user/bin/env bash mailBody="<html><body><b>hello</b> <i>world</i></body></html>" mailBodyEncoded=$(echo $mailBody | base64) echo "body=base64:$mailBodyEncoded" >> $JS7_RETURN_VALUES
Example for Shell version using files on Unix#!/user/bin/env bash echo "<html><body><b>hello</b> <i>world</i></body></html>" > /tmp/mail-body.html echo "body=base64:$(cat /tmp/mail-body.html | base64)" >> $JS7_RETURN_VALUES
Example for PowerShell version on Unix#!/usr/bin/env pwsh $mailBody = "<html><body><b>hello</b> <i>world</i></body></html>" $mailBodyEncoded = [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes( $mailBody )) "body=base64:$mailBodyEncoded" | Out-File $env:JS7_RETURN_VALUES -Append
Example for PowerShell version on Windows (multi-line)@@findstr/v "^@@f.*&" "%~f0"|pwsh.exe -&goto:eof $mailBody = "<html><body><b>hello</b> <i>world</i></body></html>" $mailBodyEncoded = [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes( $mailBody )) "body=base64:$mailBodyEncoded" | Out-File $env:JS7_RETURN_VALUES -Append
Example for PowerShell version on Windows (single-line)pwsh.exe -NoLogo -NonInteractive -Command "& { ""body=base64:$([System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes( '<html><body><b>hello</b> <i>world</i></body></html>' )) )"" | Out-File $env:JS7_RETURN_VALUES -Append }"
Explanation:In fact the e-mail body is not too lengthy, however, it suggests that an e-mail body of arbitrary size would be imported by some template file as e.g. for PowerShell with
$mailBody = Get-Content "mail-body.html"
- The above bash version with files and the PowerShell version both work with arbitrary length values.
- Base64 encoding is available from a number of sources such as the
base64
Unix utility or the .NET Core class. - The value of the
body
variable is prefixed withbase64:
to indicate the encoding. - The subsequent JS7 - JITL MailJob accepts the
body
variable, identifies the encoding and automatically decodes the argument value.
Overview
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