Update different arrays via a common function - arrays

Question

I'm currently making a Powershell script that will analyze multiple log files from a mail server to gather various statistics that will be stored in a number of different arrays.
I have the following code snippet as an example of updating one of the arrays.
#Update arrays
#Overall array
$objNewValue = New-Object -TypeName PSObject
$objNewValue = $PSOSSLOverall | Where-Object {($_.Version -contains $strVersion -and $_.Cipher -contains $strCipher -and $_.Bits -contains $strBits)}
If ($objNewValue -ne $null) {
try {
Write-Verbose "$strVersion $strCipher $strBits is already in the array, so we'll update TimeSeen value"
$objNewValue.TimesSeen++
$objNewValue.LastSeen = $dtTimestamp
} #try
catch {
Write-Host "Something whent wrong while attempting to update an existing object in the overall array" -BackgroundColor DarkRed
Write-Host "Current line: $strtemp[$i]"
Write-Host "Current values: $dtTimestamp <-> $strVersion <-> $strCipher <-> $strBits"
Write-Host "Current array:"
$PSOSSLOverall | Sort-Object -Property Version, Cipher -Descending | Format-Table -AutoSize
Write-Host "Exception object:"
$_
} #catch
} #If Check for existence in Overall array
Else {
try {
Write-Verbose "$strVersion $strCipher $strBits is not in the array, so it will be added "
$objNewValue = New-Object -TypeName PSObject
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'Version' -Value $strVersion
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'Cipher' -Value $strCipher
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'Bits' -Value $strBits
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'TimesSeen' -Value 1
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'Percentage' -Value 0
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'FirstSeen' -Value $dtTimestamp
Add-Member -InputObject $objNewValue -MemberType 'NoteProperty' -Name 'LastSeen' -Value $dtTimestamp
$PSOSSLOverall += $objNewValue
} #try
catch {
Write-Host "Something whent wrong while attempting to add a new object to the overall array"
Write-Host "Current line: $strtemp[$i]"
Write-Host "Current values: $dtTimestamp <-> $strVersion <-> $strCipher <-> $strBits"
Write-Host "Exception object:"
$_
} #catch
} #Else Check for existence in Overall array
However, when I have up to 10 or more arrays that I need to update, the result will be a lot of similar code as there's only relatively few lines that change each time - like the array being updated, the where clause, the variables used and number of columns in the arrays.
Would it be possible to create a function that can handle updating the different arrays?
Thanks in advance.
-Update-
To explain the code snippet above: All the variables are already set before this part of the script is run. $strtemp[$i] is actually where all the data comes from as that the current line in the log file from which I then extract the needed data and place it in various variables.
First I search the array in question, which in this case is $PSOSSLOverall, to see if the data from the current line is already in the array. If $objNewValue is not null, then the data is already there, and I then increment a counter and update a date stamp for that "row" of data. If $objNewValue is null, then the data is not already there, and then we added a now object (row) to the array with the data from various variables.
Each attempt is equipped with try/catch section for error handling.
The end result will be an array that looks like this (the percentage column is calculated elsewhere):
The other arrays have various number of columns, which I what I guess makes it difficult to make a common function to update them.

Answer 1

I have found myself in a similar situation once or twice. You'll have to refactor your code, converting inflexible static definitions into parameter variables. The idea is to separate the data from program logic so you can do something like pass a different set of attribute names and values into the same function for different circumstances.
Here were a couple places I found to improve flexibility:
Parameterize the Where-Object expressions used to find matching records so you don't write the same code for each combination of columns and values. See hasPropertyValues below. All it does is perform an -and concatenated -contains operation on each name-value pair you pass to it.
Parameterize the data you want changed for each eventuality. Your code does something when it finds matching records and when it finds no matching records. Pull those actions out of the script body and into an input parameter that can change when you're done working with the encryption dataset and have to move onto another. The UpdateRecords function takes hashtable parameters defining the shape of the data when new records are added and when matching records are found.
See below for the example. I think you can adapt some of the ideas in here to your code.
# this is a convenience function allowing us to test multiple name-value pairs against an object
function hasPropertyValues {
Param(
[object] $inputObject,
[hashtable] $properties
)
$result = $true
foreach($name in $properties.Keys){
$result = $result -and ($inputObject.$name -contains $properties[$name])
}
Write-Output $result
}
# this function evaluates each object in $inputDataset
# if an object matches the name-values defined in $matchProperties
# it updates the records according to $updateRecordProperties
# if no records are found which match $matchProperties
# a new object is created with the properties in both $matchProperties
# and $newRecordProperties
# All results are written to the pipeline, including unmodified objects
function UpdateRecords{
Param (
[object[]] $inputDataset,
[hashtable] $matchProperties,
[hashtable] $updateRecordProperties,
[hashtable] $newRecordProperties
)
$numberOfMatchingRecords = 0
foreach ($record in $inputDataset){
if ( hasPropertyValues -inputObject $record -properties $matchProperties) {
# a record with matching property values found.
# Update required attributes
$numberOfMatchingRecords++
foreach($name in $updateRecordProperties.Keys){
if ($updateRecordProperties[$name] -is 'ScriptBlock'){
# if the update is a scriptblock, we invoke the scriptblock
# passing the record as input. The result of the invocation
# will be set as the new attribute value
$newValue = & $updateRecordProperties[$name] $record
} else {
$newValue = $updateRecordProperties[$name]
}
$record | Add-Member -Force -MemberType NoteProperty -Name $name -Value $newValue
}
}
Write-Output $record
}
if ($numberOfMatchingRecords -eq 0) {
# no records found with the search parameters
$newRecord = New-Object -TypeName psobject -Property $newRecordProperties
foreach($key in $matchProperties.Keys){
$newRecord | Add-Member -MemberType NoteProperty -Name $key -Value $matchProperties[$key] -Force
}
Write-Output $newRecord
}
}
[object[]] $TestDataset= #(New-Object psobject -Property #{
version='TLSv1.2'
cipher='ECDHE-RSA-AES256-GCM-SHA384'
Bits=256
TimesSeen = 1833
Percentage = 87578
FirstSeen = [DateTime]::Now
LastSeen = [DateTime]::Now
})
function TestUpdateRecords{
$encryptionNewRecordDefaults = #{
TimesSeen = 1
Percentage = 0
FirstSeen = [DateTime]::Now
LastSeen = [DateTime]::Now
}
$encryptionUpdateAttributes = #{
LastSeen = [DateTime]::Now
TimesSeen = {$ARGS[0].TimesSeen + 1}
}
# test adding a new record
UpdateRecords -inputDataset $TestDataset `
-matchProperties #{ Version='TLSv1.0';cipher='unbreakable';bits=720} `
-updateRecordProperties $encryptionUpdateAttributes `
-newRecordProperties $encryptionNewRecordDefaults
# test modifying a matching record
UpdateRecords -inputDataset $things `
-matchProperties #{Version='TLSv1.2';cipher='ECDHE-RSA-AES256-GCM-SHA384';bits=256} `
-updateRecordProperties $encryptionUpdateAttributes `
-newRecordProperties $encryptionNewRecordDefaults
}
TestUpdateRecords
There are a lot of different ways to implement this kind of refactoring. You could, for instance, extract dataset-specific logic into scriptblocks and pass these to your main loop function.
Another possibility is to dig into the object-oriented features of PowerShell and try to build classes around each of your datasets. This could encapsulate the 'Update' and 'New' actions in a pleasant way. I'm not yet literate enough in powershell OO features to try.