powershell parse Json file with and wildcard in the key name

After your edits to the question that changed to /, your first question no longer applies, and your own answer is no longer needed.

• The only thing worth noting with respect to your first question is that you need quoting in order to access properties whose names contain unusual characters such as and /, as already shown in the code in your question:

  • $Workflow_Info.properties.files."$($WorkflowName)/workflow.json"

    • Note that it can be simplified to $Workflow_Info.properties.files."$WorkflowName/workflow.json", given that you don’t strictly need $(...) inside expandable (double-quoted) string ("...") for stand-alone variable references such as $WorkflowName – however, you do need $(...) for expressions, such as $Workflows[0] or $Workflow.Name

  • For verbatim names with unusual names, use verbatim (single-quoted) strings ('...'), e.g.. ([pscustomobject] @{ 'foobar' = 42 }).'foobar'

As for your second question:

• You cannot use wildcards such as * to represent a property / properties of unknown names in a property path.

• However, you can combine the intrinsic psobject property with its .Properties collection with member-access enumeration to achieve the same effect.

A simplified example:

# Get all .Parent property values, if any, from the values of all
# properties that the System.IO.FileInfo instance returned by Get-ChildItem has.
(Get-ChildItem $PROFILE).psobject.Properties.Value.Parent

• Note the psobject.Properties.Value part, which enumerates all
  property values and looks for a .Parent property on each.

  • That is, it is the equivalent of combining the results of (Get-ChildItem $PROFILE).Name, (Get-ChildItem $PROFILE).Length, …, over all properties that a FileInfo instance has.

• Situationally, there may be NO results ($null), ONE result, or an ARRAY of results.

  • In the case at hand, only the DirectoryInfo instances stored in the .Directory property has a .Parent property, so that a single result – another DirectoryInfo instance representing the parent directory of the directory in which the $PROFILE file is located – is returned.

  • By contrast, if you used .Name, you’d get three results, because the objects stored in the .PSDrive, .PSProvider, and .Directory properties all have a .Name property.

• Note that it is possible to use multiple .psobject.Properties.Value expressions in a single property path, one for each level of the object-graph hierarchy where the property name(s) are unknown.

  • However, you always need to know at what level of the hierarchy the target value is to be found and provide the appropriate number of path components.

  • If not known, you need a solution that walks an entire object graph (hierarchy of nested objects) to look for properties of interest, as shown in iRon’s answer.

Applied to your case (this is a self-contained example that can be run as-is):

$fromJson = ConvertFrom-Json @'
{"id":"/subscriptions/fcxxxx7/resourceGroups/xxxxxx/providers/Microsoft.Web/sites/xxxx/workflows/Test_email","name":"xxxxxxxxx/Test_email","type":"Microsoft.Web/sites/workflows","kind":"Stateful","location":"East Asia","properties":{"files":{"Test_email/workflow.json":{"definition":{"$schema":"https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#","actions":{"Send_an_email_from_a_shared_mailbox_(V2)":{"inputs":{"host":{"connection":{"referenceName":"TheValueIwant"}},"method":"post","path":"/v2/SharedMailbox/Mail"},"runAfter":{},"type":"ApiConnection"}},"contentVersion":"1.0.0.0","outputs":{}},"kind":"Stateful"}}}}
'@

$WorkflowName = 'Test_email'

# Again, note the `psobject.Properties.Value` part.
# -> 'TheValueIwant'
$fromJson.properties.files."$WorkflowName/workflow.json".definition.actions.
  psobject.Properties.Value.inputs.host.connection.referenceName