Related
I'm a bit new to PowerShell, and I've got a new requirement to get Data out of a MySQL database and into an Oracle one. The strategy I chose was to output to a CSV and then import the CSV into Oracle.
I wanted to get a progress bar for the export from MySQL into CSV, so I used the data reader to achieve this. It works, and begins to export, but somewhere during the export (around record 5,000 of 4.5mil -- not consistent) it will throw an error:
Exception calling "Read" with "0" argument(s): "Fatal error encountered during data read." Exception calling "Close" with "0" argument(s): "Timeout in IO operation" Method invocation failed because [System.Management.Automation.PSObject] does not contain a method named 'op_Addition'. Exception calling "ExecuteReader" with "0" argument(s): "The CommandText property has not been properly initialized."
Applicable code block is below. I'm not sure what I'm doing wrong here, and would appreciate any feedback possible. I've been pulling my hair out on this for days.
Notes: $tableObj is a custom object with a few string fields to hold table name and SQL values. Not showing those SQL queries here, but they work.
Write-Host "[INFO]: Gathering data from MySQL select statement..."
$conn = New-Object MySql.Data.MySqlClient.MySqlConnection
$conn.ConnectionString = $MySQLConnectionString
$conn.Open()
#
# Get Count of records in table
#
$countCmd = New-Object MySql.Data.MySqlClient.MySqlCommand($tableObj.SqlCount, $conn)
$recordCount = 0
try{
$recordCount = $countCmd.ExecuteScalar()
} Catch {
Write-Host "[ERROR]: (" $tableObj.Table ") Error getting Count."
Write-Host "---" $_.Exception.Message
Exit
}
$recordCountString = $recordCount.ToString('N0')
Write-Host "[INFO]: Count for table '" $tableObj.Table "' is " $recordCountString
#
# Compose the command
#
$cmd = New-Object MySql.Data.MySqlClient.MySqlCommand($tableObj.SqlExportInit, $conn)
#
# Write to CSV using DataReader
#
Write-Host "[INFO]: Data gathered into memory. Writing data to CSV file '" $tableObj.OutFile "'"
$counter = 0 # Tracks items selected
$reader=$cmd.ExecuteReader()
$dataRows = #()
# Read all rows into a hash table
while ($reader.Read())
{
$counter++
$percent = ($counter/$recordCount)*100
$percentString = [math]::Round($percent,3)
$counterString = $counter.ToString('N0')
Write-Progress -Activity '[INFO]: CSV Export In Progress' -Status "$percentString% Complete" -CurrentOperation "($($counterString) of $($recordCountString))" -PercentComplete $percent
$row = #{}
for ($i = 0; $i -lt $reader.FieldCount; $i++)
{
$row[$reader.GetName($i)] = $reader.GetValue($i)
}
# Convert hashtable into an array of PSObjects
$dataRows += New-Object psobject -Property $row
}
$conn.Close()
$dataRows | Export-Csv $tableObj.OutFile -NoTypeInformation
EDIT: Didn't work, but I also added this line to my connection string: defaultcommandtimeout=600;connectiontimeout=25 per MySQL timeout in powershell
Using #Carl Ardiente's thinking, the query is timing out, and you have to set the timeout to something insane to fully execute. You simply have to set the timeout value for your session before you start getting data.
Write-Host "[INFO]: Gathering data from MySQL select statement..."
$conn = New-Object MySql.Data.MySqlClient.MySqlConnection
$conn.ConnectionString = $MySQLConnectionString
$conn.Open()
# Set timeout on MySql
$cmd = New-Object MySql.Data.MySqlClient.MySqlCommand("set net_write_timeout=99999; set net_read_timeout=99999", $conn)
$cmd.ExecuteNonQuery()
#
# Get Count of records in table
#
...Etc....
Not that I've found the solution, but none of the connection string changes worked. Manually setting the timeout didn't seem to help either. It seemed to be caused from too many rows returned, so I broke up the function to run in batches, and append to a CSV as it goes. This gets rid of the IO / timeout error.
I'm trying to dynamically parse & build-up a data structure of some incoming JSON files I'm to be supplied with (that'll be in non-standard structure) via Powershell to then process the data in those files & hand them over to the next step.
As part of that, I'm trying to build up the data structure of the JSON file into essentially a list of of data-paths for me to parse through & grab the data out of, so that I can cope with arrays, nested JSON objects and so on. So far so good.
Where I fall into some sort of Powershell peculiarity is in handling 2+ levels of depth via a variable. Let me give you a nice code-block to demonstrate the problem...
# Generate a Quick JSON file with different data types & levels
[object]$QuickJson = #'
{
"Name" : "I am a JSON",
"Version" : "1.2.3.4",
"SomeBool" : true,
"NULLValue" : null,
"ArrayOfVersions" : [1.0,2.0,3.0],
"MyInteger" : 69,
"NestedJSON" : {
"Version" : 5.0,
"IsReady" : false
},
"DoubleNestedJSON" : {
"FirstLevel" : 1,
"DataValue" : "I am at first nested JSON level!",
"Second_JSON_Level" : {
"SecondLevel" : 2,
"SecondDataValue" : "I am on the 2nd nested level"
}
}
}
'#
# Import our JSON file into Powershell
[object]$MyPSJson = ConvertFrom-Json -InputObject $QuickJson
# Two quick string variables to access our JSON data paths
[string]$ShortJsonPath = "Name"
[string]$NestedJsonPath = "NestedJson.Version"
# Long string to access a double-nested JSON object
[string]$LongNestedJsonPath = "DoubleNestedJSON.Second_JSON_Level.SecondDataValue"
# Both of these work fine
Write-Host ("JSON Name (Direct) ==> " + $MyPSJson.Name)
Write-Host ("JSON Name (via Variable) ==> " + $MyPSJson.$ShortJsonPath)
# The following way to access a single nested Json Path works fine
Write-Host ("Nested JSON Version (via direct path) ==> " + $MyPSJson.NestedJson.Version)
# And THIS returns an empty line / is where I fall afoul of something in Powershell
Write-Host ("Nested JSON Version (via variable) ==> " + $MyPSJson.$NestedJsonPath)
# Other things I tried -- all returning an empty line / failing in effect
Write-Host ("Alternate Nested JSON Version ==> " + $($MyPSJson.$NestedJsonPath))
Write-Host ("Alternate Nested JSON Version ==> " + $MyPSJson.$($NestedJsonPath))
Write-Host ("Alternate Nested JSON Version ==> " + $($MyPSJson).$($NestedJsonPath))
# Similarly, while THIS works...
$MyPSJson | select-object -Property NestedJSON
# This will fail / return me nothing
$MyPSJson | select-object -Property NestedJSON.Version
... in doing a bunch of research around this, I came across a suggestion to transform this into a Hashtable -- but that has the same problem, sadly. So with the above code-snippet, the following will transform the JSON object into a hashtable.
# Same problem with a hash-table if constructed from the JSON file...
[hashtable]$MyHash = #{}
# Populate $MyHash with the data from our quickie JSON file...
$QuickJson | get-member -MemberType NoteProperty | Where-Object{ -not [string]::IsNullOrEmpty($QuickJson."$($_.name)")} | ForEach-Object {$MyHash.add($_.name, $QuickJson."$($_.name)")}
# ... and even then -- $MyHash."$($NestedJsonPath)" -- fails, while a single level deep string works fine in the variable! :(
So it's pretty clear that I'm running into "something" of a Powershell internal logic problem, but I can't get Powershell to be overly helpful in WHY that is. Adding a '-debug' or similar in an attempt to increase verbosity hasn't helped shed light on this.
I suspect it's something akin to the items raised in this article here ( https://blogs.technet.microsoft.com/heyscriptingguy/2011/10/16/dealing-with-powershell-hash-table-quirks/ ) but just specific with variables.
I've not had any luck in finding anything obvious in the Powershell language specification (3.0 still being the latest from here as far as I can tell -- https://www.microsoft.com/en-usdownload/details.aspx?id=36389 ) either. It may be in there, I may just miss it.
Any advice in how to get Powershell to play nice with this would be greatly appreciated. I'm not sure how / why Powershell is fine with a simple string but seems to have issues with a 'something.somethingelse' type string here.
Thank you.
Further notes & addenda to the original:
It seems there are several issues to attack. One is "dealing with a single nested level". The "quick fix" for that seems to be using "Invoke-Expression" to resolve the statement, so for instance (IMPORTANT - take note of the back-tick with the first variable!):
iex "`$MyPSJson.$NestedJsonPath"
That use of Invoke-Expression also works with multi-nested situations:
iex "`$MyPSJson.$LongNestedJsonPath"
An alternative approach that was mentioned is the use of multiple select statements ... but I've not been able to get that to work with multi-nested objects (Powershell seems to not resolve those properly for some reason).
So for instance in this scenario:
($MyComp | select $_.DoubleNestedJSON | select FirstLevel)
Powershell returns
FirstLevel
----------
... instead of the actual data value. So - for now, it seems that selects won't work with multi-level nested objects due to Powershell apparently not resolving them?
When you write something like
$MyPSJson.Name
this will attempt to retrieve the member named Name from the object $MyPSJson. If there is no such member, you'll get $null.
Now, when you do that with variables for the member name:
$MyPSJson.$ShortJsonPath
this works pretty much identical in that the member with the name stored in $ShortJsonPath is looked up and its value retrieved. No surprises here.
When you try that with a member that doesn't exist on the object, such as
$MyPSJson.$NestedJsonPath
# equivalent to
# $MyPSJson.'NestedJSON.Version'
you'll get $null, as detailed before. The . operator will only ever access a member of the exact object that is the result of its left-hand-side expression. It will never go through a member hierarchy in the way you seem to expect it to do. To be frank, I'm not aware of a language that works that way.
The reason it works with Invoke-Expression is, that you effectively converting the $NestedJsonPath string into part of an expression resulting in:
$MyPSJson.NestedJSON.Version
which Invoke-Expression then evaluates.
You can, of course, define your own function that works that way (and I'd much prefer that instead of using Invoke-Expression, a cmdlet that should rarely, if ever, used (heck, it's eval for PowerShell – few languages with eval advocate its use)):
function Get-DeepProperty([object] $InputObject, [string] $Property) {
$path = $Property -split '\.'
$obj = $InputObject
$path | %{ $obj = $obj.$_ }
$obj
}
PS> Get-DeepProperty $MyPSJson NestedJson.Version
5,0
You could even make it a filter, so you can use it more naturally on the pipeline:
filter Get-DeepProperty([string] $Property) {
$path = $Property -split '\.'
$obj = $_
$path | %{ $obj = $obj.$_ }
$obj
}
PS> $MyPSJson | Get-DeepProperty nestedjson.version
5,0
Why this doesn't work
When you provide the properties that you'd like within a string, like this
[string]$NestedJsonPath = "NestedJson.Version"
Powershell looks for a property called NestedJSon.Version. It's not actually traversing the properties, but looking for a string literal which contains a period. In fact, if I add a property like that to your JSON like so.
[object]$QuickJson = #'
{
"Name" : "I am a JSON",
"Version" : "1.2.3.4",
"SomeBool" : true,
"NULLValue" : null,
"ArrayOfVersions" : [1.0,2.0,3.0],
"MyInteger" : 69,
"NestedJSON.Version" : 69,
"NestedJSON" : {
"Version" : 5.0,
"IsReady" : false
}
}
I now get a value back, like so:
>$MyPSJson.$NestedJsonPath
69
The best way to get your values back is to use two separate variables, like this.
$NestedJson = "NestedJson"
$property = "Version"
>$MyPSJson.$NestedJson.$property
5.0
Or, alternatively, you could use select statements, as seen in the original answer below.
$MyPSJson | select $_.NestedJSON | select Version
Version
-------
1.2.3.4
If you use multiple Select-Object statements, they'll discard the other properties and allow you to more easily drill down to the value you'd like.
I followed Joey's filter example. However, I found it did not support accessing arrays.
Sharing the code that I got to work for this. Hopefully it will help others as well. Awesome thread!
filter Get-DeepProperty([string] $Property) {
$path = $Property -split '\.'
$obj = $_
foreach($node in $path){
if($node -match '.*\[\d*\]'){
$keyPieces = $node -split ('\[')
$arrayKey = $keyPieces[0]
$arrayIndex = $keyPieces[1] -replace ('\]','')
$obj = $obj.$arrayKey[$arrayIndex]
} else {
$obj = $obj.$node
}
}
$obj
}
Example usage:
$path = "nested.nestedtwo.steps[2]"
$payload | Get-DeepProperty $path
I had the same problem, so I wrote a function that does the trick.
It enables accessing any level of the json by variable path (string):
function getNestedJsonValue() {
param(
[Parameter(Mandatory = $true, ValueFromPipeline)] [PSCustomObject] $inputObj,
[Parameter(Mandatory = $true)] [string] $valuePath
)
if (($valuePath -eq $null) -or ($valuePath.length -eq 0) -or ($inputObj -eq $null)) {
return $inputObj
}
[System.Array] $nodes = "$valuePath" -split '\.'
foreach ($node in $nodes) {
if (($node -ne $null) -and ($node.length -gt 0) -and ($inputObj -ne $null)) {
$inputObj = $inputObj.$node
} else {
return $inputObj
}
}
return $inputObj
}
Usage: getNestedJsonValue -valuePath $nestedValuePath -inputObj $someJson
Pipe usage: $someJson | getNestedJsonValue -valuePath $nestedValuePath
An example nestedValuePath would be $nestedValuePath="some.nested.path"
Credit to wOxxOm for getting things on the right track.
Invoke-Expression does seem to work perfectly for this situation (if somewhat expensive, but that's fine in my personal example & situation), and it can cope with multiple levels of nesting.
So as examples for the above code snippet, the following will resolve just fine (Key point - pay attention to the initial back-tick. That caught me off guard):
Write-Host ("Single level JSON test ==> " + (iex "`$MyPSJson.$NestedJsonPath"))
Write-Host ("Double level JSON test ==> " + (iex "`$MyPSJson.$LongNestedJsonPath"))
That'll return our desired results:
Single level JSON test ==> 5.0
Double level JSON test ==> I am on the 2nd nested level
FoxDeploy's answer of using multi-level selects doesn't seem to work with 2+ levels of nesting, unfortunately for some bizarre reason.
Using:
($MyPSJson | select $_.DoubleNestedJSON | select FirstLevel)
We get the following back from Powershell:
FirstLevel
----------
... it seems that Powershell doesn't resolve nested objects in its entirety? We get a similar results if we intentionally use something that doesn't exist:
($MyPSJson | select $_.DoubleNestedJSON | select Doesnotexist)
... also simply returns:
Doesnotexist
------------
So - for now - it seems as if "Invoke-Expression" works most reliably (and most easily, as it's just a case of handing it a variable with the path'ed string).
I still can't explain the WHY of any of this so far (since I've used 'dotwalk'-ing with multiple variables through arrays quite happily), but at least there's a solution for now ... and that is Invoke-Expression !
The best (/least bad?) explanations for Invoke-Expression I've found so far are here (Microsoft's own description of the cmdlet doesn't really make a great job of hinting that it'd help in situations such as this):
http://ss64.com/ps/invoke-expression.html
https://www.adminarsenal.com/powershell/invoke-expression/
I'm trying to dynamically parse & build-up a data structure of some incoming JSON files I'm to be supplied with (that'll be in non-standard structure) via Powershell to then process the data in those files & hand them over to the next step.
As part of that, I'm trying to build up the data structure of the JSON file into essentially a list of of data-paths for me to parse through & grab the data out of, so that I can cope with arrays, nested JSON objects and so on. So far so good.
Where I fall into some sort of Powershell peculiarity is in handling 2+ levels of depth via a variable. Let me give you a nice code-block to demonstrate the problem...
# Generate a Quick JSON file with different data types & levels
[object]$QuickJson = #'
{
"Name" : "I am a JSON",
"Version" : "1.2.3.4",
"SomeBool" : true,
"NULLValue" : null,
"ArrayOfVersions" : [1.0,2.0,3.0],
"MyInteger" : 69,
"NestedJSON" : {
"Version" : 5.0,
"IsReady" : false
},
"DoubleNestedJSON" : {
"FirstLevel" : 1,
"DataValue" : "I am at first nested JSON level!",
"Second_JSON_Level" : {
"SecondLevel" : 2,
"SecondDataValue" : "I am on the 2nd nested level"
}
}
}
'#
# Import our JSON file into Powershell
[object]$MyPSJson = ConvertFrom-Json -InputObject $QuickJson
# Two quick string variables to access our JSON data paths
[string]$ShortJsonPath = "Name"
[string]$NestedJsonPath = "NestedJson.Version"
# Long string to access a double-nested JSON object
[string]$LongNestedJsonPath = "DoubleNestedJSON.Second_JSON_Level.SecondDataValue"
# Both of these work fine
Write-Host ("JSON Name (Direct) ==> " + $MyPSJson.Name)
Write-Host ("JSON Name (via Variable) ==> " + $MyPSJson.$ShortJsonPath)
# The following way to access a single nested Json Path works fine
Write-Host ("Nested JSON Version (via direct path) ==> " + $MyPSJson.NestedJson.Version)
# And THIS returns an empty line / is where I fall afoul of something in Powershell
Write-Host ("Nested JSON Version (via variable) ==> " + $MyPSJson.$NestedJsonPath)
# Other things I tried -- all returning an empty line / failing in effect
Write-Host ("Alternate Nested JSON Version ==> " + $($MyPSJson.$NestedJsonPath))
Write-Host ("Alternate Nested JSON Version ==> " + $MyPSJson.$($NestedJsonPath))
Write-Host ("Alternate Nested JSON Version ==> " + $($MyPSJson).$($NestedJsonPath))
# Similarly, while THIS works...
$MyPSJson | select-object -Property NestedJSON
# This will fail / return me nothing
$MyPSJson | select-object -Property NestedJSON.Version
... in doing a bunch of research around this, I came across a suggestion to transform this into a Hashtable -- but that has the same problem, sadly. So with the above code-snippet, the following will transform the JSON object into a hashtable.
# Same problem with a hash-table if constructed from the JSON file...
[hashtable]$MyHash = #{}
# Populate $MyHash with the data from our quickie JSON file...
$QuickJson | get-member -MemberType NoteProperty | Where-Object{ -not [string]::IsNullOrEmpty($QuickJson."$($_.name)")} | ForEach-Object {$MyHash.add($_.name, $QuickJson."$($_.name)")}
# ... and even then -- $MyHash."$($NestedJsonPath)" -- fails, while a single level deep string works fine in the variable! :(
So it's pretty clear that I'm running into "something" of a Powershell internal logic problem, but I can't get Powershell to be overly helpful in WHY that is. Adding a '-debug' or similar in an attempt to increase verbosity hasn't helped shed light on this.
I suspect it's something akin to the items raised in this article here ( https://blogs.technet.microsoft.com/heyscriptingguy/2011/10/16/dealing-with-powershell-hash-table-quirks/ ) but just specific with variables.
I've not had any luck in finding anything obvious in the Powershell language specification (3.0 still being the latest from here as far as I can tell -- https://www.microsoft.com/en-usdownload/details.aspx?id=36389 ) either. It may be in there, I may just miss it.
Any advice in how to get Powershell to play nice with this would be greatly appreciated. I'm not sure how / why Powershell is fine with a simple string but seems to have issues with a 'something.somethingelse' type string here.
Thank you.
Further notes & addenda to the original:
It seems there are several issues to attack. One is "dealing with a single nested level". The "quick fix" for that seems to be using "Invoke-Expression" to resolve the statement, so for instance (IMPORTANT - take note of the back-tick with the first variable!):
iex "`$MyPSJson.$NestedJsonPath"
That use of Invoke-Expression also works with multi-nested situations:
iex "`$MyPSJson.$LongNestedJsonPath"
An alternative approach that was mentioned is the use of multiple select statements ... but I've not been able to get that to work with multi-nested objects (Powershell seems to not resolve those properly for some reason).
So for instance in this scenario:
($MyComp | select $_.DoubleNestedJSON | select FirstLevel)
Powershell returns
FirstLevel
----------
... instead of the actual data value. So - for now, it seems that selects won't work with multi-level nested objects due to Powershell apparently not resolving them?
When you write something like
$MyPSJson.Name
this will attempt to retrieve the member named Name from the object $MyPSJson. If there is no such member, you'll get $null.
Now, when you do that with variables for the member name:
$MyPSJson.$ShortJsonPath
this works pretty much identical in that the member with the name stored in $ShortJsonPath is looked up and its value retrieved. No surprises here.
When you try that with a member that doesn't exist on the object, such as
$MyPSJson.$NestedJsonPath
# equivalent to
# $MyPSJson.'NestedJSON.Version'
you'll get $null, as detailed before. The . operator will only ever access a member of the exact object that is the result of its left-hand-side expression. It will never go through a member hierarchy in the way you seem to expect it to do. To be frank, I'm not aware of a language that works that way.
The reason it works with Invoke-Expression is, that you effectively converting the $NestedJsonPath string into part of an expression resulting in:
$MyPSJson.NestedJSON.Version
which Invoke-Expression then evaluates.
You can, of course, define your own function that works that way (and I'd much prefer that instead of using Invoke-Expression, a cmdlet that should rarely, if ever, used (heck, it's eval for PowerShell – few languages with eval advocate its use)):
function Get-DeepProperty([object] $InputObject, [string] $Property) {
$path = $Property -split '\.'
$obj = $InputObject
$path | %{ $obj = $obj.$_ }
$obj
}
PS> Get-DeepProperty $MyPSJson NestedJson.Version
5,0
You could even make it a filter, so you can use it more naturally on the pipeline:
filter Get-DeepProperty([string] $Property) {
$path = $Property -split '\.'
$obj = $_
$path | %{ $obj = $obj.$_ }
$obj
}
PS> $MyPSJson | Get-DeepProperty nestedjson.version
5,0
Why this doesn't work
When you provide the properties that you'd like within a string, like this
[string]$NestedJsonPath = "NestedJson.Version"
Powershell looks for a property called NestedJSon.Version. It's not actually traversing the properties, but looking for a string literal which contains a period. In fact, if I add a property like that to your JSON like so.
[object]$QuickJson = #'
{
"Name" : "I am a JSON",
"Version" : "1.2.3.4",
"SomeBool" : true,
"NULLValue" : null,
"ArrayOfVersions" : [1.0,2.0,3.0],
"MyInteger" : 69,
"NestedJSON.Version" : 69,
"NestedJSON" : {
"Version" : 5.0,
"IsReady" : false
}
}
I now get a value back, like so:
>$MyPSJson.$NestedJsonPath
69
The best way to get your values back is to use two separate variables, like this.
$NestedJson = "NestedJson"
$property = "Version"
>$MyPSJson.$NestedJson.$property
5.0
Or, alternatively, you could use select statements, as seen in the original answer below.
$MyPSJson | select $_.NestedJSON | select Version
Version
-------
1.2.3.4
If you use multiple Select-Object statements, they'll discard the other properties and allow you to more easily drill down to the value you'd like.
I followed Joey's filter example. However, I found it did not support accessing arrays.
Sharing the code that I got to work for this. Hopefully it will help others as well. Awesome thread!
filter Get-DeepProperty([string] $Property) {
$path = $Property -split '\.'
$obj = $_
foreach($node in $path){
if($node -match '.*\[\d*\]'){
$keyPieces = $node -split ('\[')
$arrayKey = $keyPieces[0]
$arrayIndex = $keyPieces[1] -replace ('\]','')
$obj = $obj.$arrayKey[$arrayIndex]
} else {
$obj = $obj.$node
}
}
$obj
}
Example usage:
$path = "nested.nestedtwo.steps[2]"
$payload | Get-DeepProperty $path
I had the same problem, so I wrote a function that does the trick.
It enables accessing any level of the json by variable path (string):
function getNestedJsonValue() {
param(
[Parameter(Mandatory = $true, ValueFromPipeline)] [PSCustomObject] $inputObj,
[Parameter(Mandatory = $true)] [string] $valuePath
)
if (($valuePath -eq $null) -or ($valuePath.length -eq 0) -or ($inputObj -eq $null)) {
return $inputObj
}
[System.Array] $nodes = "$valuePath" -split '\.'
foreach ($node in $nodes) {
if (($node -ne $null) -and ($node.length -gt 0) -and ($inputObj -ne $null)) {
$inputObj = $inputObj.$node
} else {
return $inputObj
}
}
return $inputObj
}
Usage: getNestedJsonValue -valuePath $nestedValuePath -inputObj $someJson
Pipe usage: $someJson | getNestedJsonValue -valuePath $nestedValuePath
An example nestedValuePath would be $nestedValuePath="some.nested.path"
Credit to wOxxOm for getting things on the right track.
Invoke-Expression does seem to work perfectly for this situation (if somewhat expensive, but that's fine in my personal example & situation), and it can cope with multiple levels of nesting.
So as examples for the above code snippet, the following will resolve just fine (Key point - pay attention to the initial back-tick. That caught me off guard):
Write-Host ("Single level JSON test ==> " + (iex "`$MyPSJson.$NestedJsonPath"))
Write-Host ("Double level JSON test ==> " + (iex "`$MyPSJson.$LongNestedJsonPath"))
That'll return our desired results:
Single level JSON test ==> 5.0
Double level JSON test ==> I am on the 2nd nested level
FoxDeploy's answer of using multi-level selects doesn't seem to work with 2+ levels of nesting, unfortunately for some bizarre reason.
Using:
($MyPSJson | select $_.DoubleNestedJSON | select FirstLevel)
We get the following back from Powershell:
FirstLevel
----------
... it seems that Powershell doesn't resolve nested objects in its entirety? We get a similar results if we intentionally use something that doesn't exist:
($MyPSJson | select $_.DoubleNestedJSON | select Doesnotexist)
... also simply returns:
Doesnotexist
------------
So - for now - it seems as if "Invoke-Expression" works most reliably (and most easily, as it's just a case of handing it a variable with the path'ed string).
I still can't explain the WHY of any of this so far (since I've used 'dotwalk'-ing with multiple variables through arrays quite happily), but at least there's a solution for now ... and that is Invoke-Expression !
The best (/least bad?) explanations for Invoke-Expression I've found so far are here (Microsoft's own description of the cmdlet doesn't really make a great job of hinting that it'd help in situations such as this):
http://ss64.com/ps/invoke-expression.html
https://www.adminarsenal.com/powershell/invoke-expression/
I have written following code to use ping command to ping multiple computers, I would like to capture following values it:
Reply from / Request timed out etc.
Actual IP Address of the remote host
This function is working fine however, if I am trying to get its returned values to a CSV I am unable to do so.
# Declaration of the function name and expected parameters
Function Ping-Check{
[cmdletbinding()]
PARAM (
[Parameter(Mandatory=$True,
ValueFromPipeline=$True,
ValueFromPipelineByPropertyName=$True,
HelpMessage='Enter the name of the remote host.')]
[String]$ObjCompName
)
Begin{
# Setup the Process startup info
$pinfo = New-Object System.Diagnostics.ProcessStartInfo
$pinfo.FileName = "ping.exe"
$pinfo.Arguments = " -a " + $ObjCompName + " -n 2"
$pinfo.UseShellExecute = $false
$pinfo.CreateNoWindow = $true
$pinfo.RedirectStandardOutput = $true
$pinfo.RedirectStandardError = $true
}
Process{
$p = New-Object System.Diagnostics.Process
$p.StartInfo = $pinfo
$p.Start() | Out-Null
$p.WaitForExit()
# Redirect the Output
$stdout = $p.StandardOutput.ReadToEnd()
$stderr = $p.StandardError.ReadToEnd()
}
End{
Write-Output "stdout: $stdout"
Write-Output "stderr: $stderr"
Write-Output "exit code: " + $p.ExitCode
}
}
There is a Test-Connection cmdlet available in powershell which returns an object array with properties you can use. If you wan't to stick with your attempt, be aware that you have to parse the output yourself.
I'm working with PowerShell to gather data from a list of remote servers which I then turn into a JSON object. Everything is working fine, but I get some really weird output that I can't seem to exclude.
I've tried piping the Invoke-Command results and excluding properties. I've also tried removing the items manually from the returned hash file, but I can't seem to make them go away.
What am I missing?
EDIT:
For the sake of figuring out what's wrong here is a simplified, but still broken, script:
$returnedServer = #{}
$pass = cat "C:\...\securestring.txt" | convertto-securestring
$mycred = new-object -typename System.Management.Automation.PSCredential -argumentlist "UserName",$pass
$s = #("xx.xxx.xxx.xxx","xx.xxx.xxx.xxx")
foreach($server in $s)
{
$returnedServer.$server += ,(Invoke-Command -ComputerName $server -ScriptBlock
{
1
}-credential $mycred | select -ExcludeProperty PSComputerName,RunSpaceID,PSShowComputerName)
$returnedServer| ConvertTo-Json
Which outputs:
{
"xx.xxx.xxx.xxx": [
{
"value": 1,
"PSComputerName": "xx.xxx.xxx.xxx",
"RunspaceId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
"PSShowComputerName": xxxx
}
],
"xx.xxx.xxx.xxx": [
{
"value": 1,
"PSComputerName": "xx.xxx.xxx.xxx",
"RunspaceId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"",
"PSShowComputerName": xxxx
}
]
}
This post is really old, but I was unable to find an acceptable answer 6 years later, so I wrote my own.
$invokeCommandResults | ForEach-Object {
$_.PSObject.Properties.Remove('PSComputerName')
$_.PSObject.Properties.Remove('RunspaceId')
$_.PSObject.Properties.Remove('PSShowComputerName')
}
You need to use Select-Object to limit the result to just the properties you want to show up in the JSON output:
$returnedServers.$server += ,(Invoke-Command -ComputerName $server -ScriptBlock
{
...$serverHash = various look ups and calculations...
$serverHash
} | select PropertyA, PropertyB, ...)
For a more thorough answer you need to go into far more detail about your "various look ups and calculations" as well as the actual conversion to JSON.
After some testing, it seems the problem is the object type. I was able to get your test script to work by explicitly casting the returned result.
$returnedServer = #{}
$pass = cat "C:\...\securestring.txt" | convertto-securestring
$mycred = new-object -typename System.Management.Automation.PSCredential -argumentlist "UserName",$pass
$s = #("xx.xxx.xxx.xxx","xx.xxx.xxx.xxx")
foreach($server in $s)
{
$returnedServer.$server += ,[int](Invoke-Command -ComputerName $server -ScriptBlock {1} -credential $mycred)
}
$returnedServer| ConvertTo-Json
You could try this... instead of attempting to exclude extraneous property values, just be specific and "call" or "grab" the one(s) you want.
Quick Code Shortcut Tip! BTW, the Invoke-Command -Computer $server -Scriptbock {command} can be greatly simplified using: icm $server {command}
Now, getting back on track...
Using your original post/example, it appears that you are attempting to utilize one "value" by excluding all other values, i.e. -ExcludeProperty (which it is ultra-frustrating).
Let's start by removing and replacing the only exclusion section:
select -ExcludeProperty PSComputerName,RunSpaceID,PSShowComputerName
And instead, attempt to use one of the following:
1st Method: using the modified original command...
$returnedServer.$server += ,(Invoke-Command -ComputerName $server -ScriptBlock {1}-credential $mycred).value
2nd Method: using the "icm" version...
$returnedServer.$server += ,(icm $server {1} -credential $mycred).value
Essentially, you are "picking out" the value(s) you need (vs. excluding property values, which is, again, pretty frustrating when it does NOT work).
Related Example(s) follows:
Here is a typical system Powershell/WMIC command call:
icm ServerNameGoesHere {Get-CimInstance -ClassName win32_operatingsystem}
But what if I only want the "version" from the object glob:
(icm ServerNameGoesHere {Get-CimInstance -ClassName win32_operatingsystem}).version
But, hold on, now I only want the "lastbootuptime" from the object glob:
(icm ServerNameGoesHere {Get-CimInstance -ClassName win32_operatingsystem}).lastbootuptime
Indecisively, I want to be more flexible:
$a=icm ServerNameGoesHere {Get-CimInstance -ClassName win32_operatingsystem}
$a.version
$a.lastbootuptime
$a.csname
(Makes sense?)
Good luck,
~PhilC