Structured (XML / YAML / CSV)

Return alternative serializations for interoperability, configuration and exports.

Full source

File: pwsh/tutorial/examples/9.2-Structured-Xml-Yaml-Csv.ps1


<#
    Sample: Structured Formats (XML / YAML / CSV)
    Purpose: Demonstrate XML, YAML, and CSV responses in a Kestrun server.
    File:    9.2-Structured-Xml-Yaml-Csv.ps1
    Notes:   Shows alternative serialization formats for objects.
#>
param(
    [int]$Port = 5000,
    [IPAddress]$IPAddress = [IPAddress]::Loopback
)
# 1. Logging
New-KrLogger | Add-KrSinkConsole | Register-KrLogger -Name 'console' -SetAsDefault

# 2. Server
New-KrServer -Name 'Responses 9.2'

# 3. Listener
Add-KrEndpoint -IPAddress $IPAddress -Port $Port

# 4. Runtime


# Finalize configuration
Enable-KrConfiguration

# XML route
Add-KrMapRoute -Pattern '/xml' -Verbs GET -ScriptBlock {
    Write-KrXmlResponse -InputObject @{ Id = 1; Name = 'Alpha'; Nested = @{ X = 10; Y = 20 } }
}

# YAML route
Add-KrMapRoute -Pattern '/yaml' -Verbs GET -ScriptBlock {
    @{ env = 'dev'; enabled = $true; tags = @('one', 'two') },
    @{ Id = 1; Name = 'Alpha'; Nested = @{ X = 10; Y = 20 } } | Write-KrYamlResponse -ContentType 'application/x-yaml'
}

# CSV route
Add-KrMapRoute -Pattern '/csv' -Verbs GET -ScriptBlock {
    $data = 1..5 | ForEach-Object { @{ Id = $_; Square = ($_ * $_) } }
    Write-KrCsvResponse -InputObject $data
}

# Start the server
Start-KrServer -CloseLogsOnExit

Step-by-step

  1. Logging: Register console logger as default.
  2. Server: Create server named ‘Responses 9.2’.
  3. Listener: Listen on 127.0.0.1:5000.
  4. /xml: serialize object with nested property to XML.
  5. /yaml: serialize object with array property to YAML.
  6. /csv: build collection, output CSV text.
  7. Enable configuration and start server.

Try it 

curl http://127.0.0.1:5000/xml
curl http://127.0.0.1:5000/yaml
curl http://127.0.0.1:5000/csv

PowerShell equivalents:

Invoke-RestMethod -Uri http://127.0.0.1:5000/xml
Invoke-RestMethod -Uri http://127.0.0.1:5000/yaml
Invoke-WebRequest -Uri http://127.0.0.1:5000/csv  | Select -ExpandProperty Content

Example routes 

# Logging
New-KrLogger | Add-KrSinkConsole | Register-KrLogger -Name 'console' -SetAsDefault

# Server
New-KrServer -Name 'Responses 9.2'

# Listener
Add-KrEndpoint -IPAddress '127.0.0.1' -Port 5000

# Enable configuration
Enable-KrConfiguration

# XML route
Add-KrMapRoute -Pattern '/xml' -Verbs GET -ScriptBlock {
    @{ Id = 1; Name = 'Alpha'; Nested = @{ X = 10; Y = 20 } } | Write-KrXmlResponse -ContentType 'application/xml'
}

# YAML route
Add-KrMapRoute -Pattern '/yaml' -Verbs GET -ScriptBlock {
    @{ env = 'dev'; enabled = $true; tags = @('one','two') } | Write-KrYamlResponse -ContentType 'application/x-yaml'
}

# CSV route
Add-KrMapRoute -Pattern '/csv' -Verbs GET -ScriptBlock {
    $data = 1..5 | ForEach-Object { @{ Id = $_; Square = ($_ * $_) } }
    $data | Write-KrCsvResponse -ContentType 'text/csv'
}

# Start the server
Start-KrServer

Tips

  • Prefer JSON for public APIs; use XML/YAML when clients require it.
  • For very large tabular exports consider streaming (see Binary & Stream chapter).

Troubleshooting

Symptom Cause Fix
Wrong content type Default type overridden Pass explicit -ContentType
YAML not formatted Input not object/hashtable Ensure proper object is piped
CSV missing headers Inconsistent properties Use uniform hashtables/objects

References

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