Convert From-Json

Module:
Microsoft.PowerShell.Utility
Converts a JSON-formatted string to a custom object or a hash table.

Syntax 

ConvertFrom-Json
           [-InputObject] <String>
           [-AsHashtable][<CommonParameters>]

Description

The ConvertFrom-Json cmdlet converts a JavaScript Object Notation (JSON) formatted string to a custom PSCustomObject object that has a property for each field in the JSON string. JSON is commonly used by web sites to provide a textual representation of objects. The JSON standard does not prohibit usage that is prohibited with a PSCustomObject. For example, if the JSON string contains duplicate keys, only the last key is used by this cmdlet. See other examples below.

To generate a JSON string from any object, use the ConvertTo-Json cmdlet.

This cmdlet was introduced in PowerShell 3.0.

Examples

Example 1: Convert a DateTime object to a JSON object 

PS C:\> Get-Date | Select-Object -Property * | ConvertTo-Json | ConvertFrom-Json

DisplayHint : 2

DateTime    : Friday, January 13, 2012 8:06:31 PM

Date        : 1/13/2012 8:00:00 AM

Day         : 13

DayOfWeek   : 5

DayOfYear   : 13

Hour        : 20

Kind        : 2

Millisecond : 400

Minute      : 6

Month       : 1

Second      : 31

Ticks       : 634620819914009002

TimeOfDay   : @{Ticks=723914009002; Days=0; Hours=20; Milliseconds=400; Minutes=6; Seconds=31; TotalDays=0.83786343634490734; TotalHours=20.108722472277776; TotalMilliseconds=72391400.900200009; TotalMinutes=1206.5233483366667;TotalSeconds=72391.4009002}

Year        : 2012

This command uses the ConvertTo-Json and ConvertFrom-Json cmdlets to convert a DateTime object from the Get-Date cmdlet to a JSON object.

The command uses the Select-Object cmdlet to get all of the properties of the DateTime object. It uses the ConvertTo-Json cmdlet to convert the DateTime object to a JSON-formatted string and the ConvertFrom-Json cmdlet to convert the JSON-formatted string to a JSON object.

Example 2: Get JSON strings from a web service and convert them to PowerShell objects 

# Ensures that Invoke-WebRequest uses TLS 1.2

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$j = Invoke-WebRequest 'https://api.github.com/repos/PowerShell/PowerShell/issues' | ConvertFrom-Json

This command uses the Invoke-WebRequest cmdlet to get JSON strings from a web service and then it uses the ConvertFrom-Json cmdlet to convert JSON content to objects that can be managed in PowerShell.

You can also use the Invoke-RestMethod cmdlet, which automatically converts JSON content to objects.

Example 3: Convert a JSON string to a custom object 

(Get-Content JsonFile.JSON) -join '`n' | ConvertFrom-Json

This example shows how to use the ConvertFrom-Json cmdlet to convert a JSON file to a PowerShell custom object.

The command uses Get-Content cmdlet to get the strings in a JSON file. It uses the Join operator to join the lines in the file into a single string that is delimited by newline characters (`n). Then it uses the pipeline operator to send the delimited string to the ConvertFrom-Json cmdlet, which converts it to a custom object.

The Join operator is required, because the ConvertFrom-Json cmdlet expects a single string.

Example 4: Convert a JSON string to a hash table 

'{ "key":"value1", "Key":"value2" }' | ConvertFrom-Json -AsHashtable

This command shows an example where the -AsHashtable switch can overcome limitations of the command. The JSON string contains 2 key value pairs with keys that differ only in casing. Without the switch, the command would have thrown an error.

Required Parameters

-InputObject

Specifies the JSON strings to convert to JSON objects. Enter a variable that contains the string, or type a command or expression that gets the string. You can also pipe a string to ConvertFrom-Json .

The InputObject parameter is required, but its value can be an empty string. When the input object is an empty string, ConvertFrom-Json does not generate any output. The InputObject value cannot be $Null.

Type: String
Position: 1
Default value: None
Accept pipeline input: True (ByValue)
Accept wildcard characters: False

Optional Parameters

-AsHashtable

Converts the JSON to a hash table object. This switch was introduced in PowerShell 6.0. There are several scenarios where it can overcome some limitations of the ConvertFrom-Json cmdlet.

  • If the JSON contains a list with keys that only differ in casing. Without the switch, those keys would be seen as identical keys and therefore only the last one would get used.
  • If the JSON contains a key that is an empty string. Without the switch, the cmdlet would throw an error since a PSCustomObject does not allow for that but a hash table does. An example use case where this can occurs are project.lock.json files.
  • Hash tables can be processed faster for certain data structures.
Type: SwitchParameter
Position: named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

Inputs

System.String

You can pipe a JSON string to ConvertFrom-Json .

Outputs

PSCustomObject

Outputs

System.Collections.Hashtable

Notes

The ConvertFrom-Json cmdlet is implemented by using the JavaScriptSerializer class .