Script that downloads custom fields for release notes from Azure DevOps work items and outputs markdown.

Get-ReleaseNotes.ps1

param (
    [string]$Pat = $env:AzureDevOpsReleaseNotesPat,
    [string]$Organization = $env:AzureDevOpsReleaseNotesOrganization,
    [string]$Project = $env:AzureDevOpsReleaseNotesProject,
    [string]$Query = 'My Queries/Release Notes',
    [string]$Header = 'Release Notes',
    [switch]$IncludeUrls
)

$ErrorActionPreference = 'Stop'

function Invoke-AzureDevopsGetMethod {
    param ($Uri)
    $patAsBase64 = [convert]::ToBase64String([System.Text.ASCIIEncoding]::ASCII.GetBytes(":$Pat"))
    $headers = @{ Authorization = "Basic $patAsBase64" }
    return Invoke-RestMethod -Uri $Uri -Headers $headers
}

function Load-Dlls {
    $html2MarkdownDllPath = Resolve-Path '.\Html2Markdown.*\lib\net45\Html2Markdown.dll'
    if ($null -eq $html2MarkdownDllPath) {
        nuget install Html2Markdown | Out-Null
        $html2MarkdownDllPath = Resolve-Path '.\Html2Markdown.*\lib\net45\Html2Markdown.dll'
    }
    $htmlAgilityPackDllPath = Resolve-Path '.\HtmlAgilityPack.*\lib\Net45\HtmlAgilityPack.dll'
    Add-Type -Path $htmlAgilityPackDllPath
    Add-Type -Path $html2MarkdownDllPath
}

function Get-WorkItemUrls {
    $query = Invoke-AzureDevopsGetMethod -Uri "https://dev.azure.com/$Organization/$Project/_apis/wit/queries/$($Query)?api-version=5.0"
    $results = Invoke-AzureDevopsGetMethod -Uri $query._links.wiql.href
    return $results.workItems | Select-Object -ExpandProperty url
}

function Get-HtmlInnerText {
    param ($Html)
    $doc = New-Object HtmlAgilityPack.HtmlDocument
    $doc.LoadHtml($Html)
    return $doc.DocumentNode.InnerText.Trim().Replace([char]160, [char]32) # Remove strange space char
}

function Get-PossiblyNotThereProperty {
    param ($Wi, $Property, $Backup, $Default)
    $value = $Wi.fields | Select-Object -ExpandProperty $Property -ErrorAction SilentlyContinue
    if ($null -eq $value) {
        $value = $value = $Wi.fields | Select-Object -ExpandProperty $Backup -ErrorAction SilentlyContinue
    }
    if ($null -eq $value) {
        $value = $Default
    }
    return $value.Trim()
}

function Get-PropertiesFromWorkItem {
    param ($Wi)
    $title = Get-PossiblyNotThereProperty -Wi $Wi -Property Custom.PbiReleaseNotesTitle -Backup Custom.BugReleaseNotesTitle -Default '{Title not set}'
    $type = Get-PossiblyNotThereProperty -Wi $Wi -Property Custom.PbiReleaseNotesType -Backup Custom.BugReleaseNotesType -Default 'Other'
    $descriptionHtml = Get-PossiblyNotThereProperty -Wi $Wi -Property Custom.PbiReleaseNotesDescription -Backup Custom.BugReleaseNotesDescription '{Description is missing}'
    $descriptionHtml = $descriptionHtml -replace '\n', ' ' -replace '<div>', '' -replace '</div>' # Remove new lines and divs
    $converter = New-Object Html2Markdown.Converter
    $descriptionMarkdown = Get-HtmlInnerText -Html $converter.Convert($descriptionHtml)
    return New-Object psobject -Property @{Title = $title; Type = $type; Description = $descriptionMarkdown; Url = "https://dev.azure.com/$Organization/$Project/_workitems/edit/$($Wi.id)" }
}

if ($IncludeUrls) {
    $sectionTemplate = @'
### [{0}]({2})

{1}
'@
}
else {
    $sectionTemplate = @'
### {0}

{1}
'@
}

$index = 0
Load-Dlls
$workItemUrls = @(Get-WorkItemUrls)
$sectionItems = $workItemUrls | ForEach-Object {
    $wi = Invoke-AzureDevopsGetMethod -Uri $_
    Write-Progress -Activity "Collecting work items" -Status "Id: $($wi.id)" -PercentComplete ($index / $workItemUrls.Count * 100)
    $index++
    return Get-PropertiesFromWorkItem -Wi $wi
}
$sections = $sectionItems | Group-Object -Property Type | ForEach-Object {
    $subTitle = $_.Name
    $items = $_.Group
    $subSections = $items | ForEach-Object {
        $sectionTemplate -f $_.Title, $_.Description, $_.Url
    }
    $content = [string]::Join([System.Environment]::NewLine + [System.Environment]::NewLine, $subSections)
    return @"
## $subTitle

$content
"@
}

$content = [string]::Join([System.Environment]::NewLine + [System.Environment]::NewLine, $sections)

# Return document
@"
# $Header

$content
"@