Convert BloodHound graph files into CSV files

convert-bhgraph.ps1

function Convert-BHGraph
{
  <#
      .SYNOPSIS
      Convert BloodHound graph files into CSV files.
      .DESCRIPTION
      The PowerShell script Convert-BHGraph is designed to convert JSON files, specifically formatted as BloodHound graph exports, into CSV files. It accepts optional parameters for the source JSON file path and the destination CSV file path, defaulting to .\bh-graph.json and .\bh-graph.csv respectively. The script reads the JSON file, extracts nodes and edges data, and constructs a hashtable for nodes to facilitate quick lookups. It then processes the edges to create custom objects representing relationships, which include labels and kinds for both source and target nodes, as well as the type of edge. Finally, these relationship objects are exported to a CSV file at the specified destination path, providing a structured representation of the graph's relationships.
      .EXAMPLE
      Convert-BHGraph
      Converts the file bh-graph.json from the current directory into a CSV file named bh-graph.csv.
      .EXAMPLE
      Convert-BHGraph -Path my-bloodhound-graph.json -Destination my-bloodhound-relationships.csv
      Converts the file my-bloodhound-graph.json into a CSV file named my-bloodhound-relationships.csv.
  #>
  [CmdletBinding()]
  param
  (
    [Parameter(Mandatory = $false, Position = 0)]
    [String]
    $Path = '.\bh-graph.json',
    
    [Parameter(Mandatory = $false, Position = 1)]
    [String]
    $Destination = '.\bh-graph.csv'
  )
    
  # Ingest the bloodhound export
  $bhe = Get-Content -Raw -LiteralPath $Path| ConvertFrom-Json
  
  # Convert nodes from the export into a hashtable for quick lookups.
  $nodes = @{}
  $bhe.data.nodes.psobject.members|ForEach-Object -Process {
    $nodes.Add($_.name,$_.value)
  }
  
  # Put edges into an array
  $edges = @($bhe.data.edges)
  
  # Create custom objects with relationships
  $relationships = $edges | ForEach-Object -Process {
    [PSCustomObject] @{
      SourceLabel = $nodes.($_.source).label
      SourceKind  = $nodes.($_.source).kind
      EdgeKind    = $_.kind
      TargetLabel = $nodes.($_.target).label
      TargetKind  = $nodes.($_.target).kind
    }
  }
  
  # Export relationships to csv
  $relationships|Export-Csv -NoTypeInformation -LiteralPath $Destination
}