Installing prerequisites for .NET Core projects

build.ps1

$Global:required = "netcore", "nuget", "docfx"
. $PSScriptRoot\tools\prerequisites.ps1

$tooldir = "$env:LOCALAPPDATA\.build"
$docs = "$PSScriptRoot\docs\docfx.json"
$projects =
    "$PSScriptRoot\src\projectA",
    "$PSScriptRoot\src\projectB"

$projects.ForEach({ & dotnet build $_ })
& $tooldir\docfx\docfx $docs

tools\download.ps1

<#
.Synopsis
    Converts a size in bytes to its upper most value.
.DESCRIPTION
    Converts a size in bytes to its upper most value.
.PARAMETER Size
    The size in bytes to convert
.NOTES
    Author: Boe Prox
    Date Created: 22AUG2012
#>
function Convert-Size {

    [CmdletBinding()]
    Param (
        [Parameter(ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$True)]
        [Alias("Length")]
        [Int64]$Size
    )
    Begin {
        If (-Not $ConvertSize) {
            Write-Verbose ("Creating signature from Win32API")
            $Signature =  @"
                 [DllImport("Shlwapi.dll", CharSet = CharSet.Auto)]
                 public static extern long StrFormatByteSize( long fileSize, System.Text.StringBuilder buffer, int bufferSize );
"@
            $Global:ConvertSize = Add-Type -Name SizeConverter -MemberDefinition $Signature -PassThru
        }
        Write-Verbose ("Building buffer for string")
        $stringBuilder = New-Object Text.StringBuilder 1024
    }
    Process {
        Write-Verbose ("Converting {0} to upper most size" -f $Size)
        $ConvertSize::StrFormatByteSize( $Size, $stringBuilder, $stringBuilder.Capacity ) | Out-Null
        $stringBuilder.ToString()
    }
}

<#
.Synopsis
    Download file.
.DESCRIPTION
    Downloads a file from a URL.
.PARAMETER Address
    The URL of the file.
.PARAMETER Destination
    The destination path of the file.
.PARAMETER Name
    An optional download name to display.
.NOTES
    Author: Marcus Schweda
#>
function Download-File {
    Param(
        [Parameter(Mandatory=$true)]
        [string]$Address,
        [Parameter(Mandatory=$true)]
        [string]$Destination,
        [string]$Name = "file"
    )
    Begin{
        $activity = "Downloading $Name..."
        $client = New-Object System.Net.WebClient
        $src = $client.OpenRead($Address)

        $completed = 0
        $total = $client.ResponseHeaders["Content-Length"]

        $dest = New-Object System.IO.FileStream -ArgumentList $Destination, Create
        $buffer = New-Object byte[] 10KB
        $read = $src.Read($buffer,0, $buffer.length)

        while ($read -gt 0) {
            $completedStr = Convert-Size $completed
            $completedP = ($completed / $total * 100)

            $dest.Write($buffer, 0, $read)
            $read = $src.Read($buffer, 0, $buffer.length)

            Write-Progress -Activity $activity -CurrentOperation $completedStr -PercentComplete $completedP
            $completed = $completed + $read
        }

        $dest.Flush()
        $dest.Dispose()
        $src.Dispose()
    }
}

<#
.Synopsis
    Latest version of a GitHub release.
.DESCRIPTION
    Retrieves the latest stable version of a GitHub release from the GitHub API.
.PARAMETER Owner
    The owner of the repository.
.PARAMETER Repo
    The name of the repository.
.NOTES
    Author: Marcus Schweda
#>
function Github-Latest {
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]$Owner,
        [Parameter(Mandatory=$true)]
        [string]$Repo
    )

    Begin {
        $url = "https://api.github.com/repos/$Owner/$Repo/releases/latest"
        Invoke-WebRequest $url | ConvertFrom-Json | Select -ExpandProperty tag_name
    }
}

<#
.Synopsis
    Latest download of a GitHub release.
.DESCRIPTION
    Retrieves the download url of the latest stable version of a GitHub release from the GitHub API.
.PARAMETER Owner
    The owner of the repository.
.PARAMETER Repo
    The name of the repository.
.NOTES
    Author: Marcus Schweda
#>
function Github-LatestUrl {
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]$Owner,
        [Parameter(Mandatory=$true)]
        [string]$Repo
    )

    Begin {
        $url = "https://api.github.com/repos/$Owner/$Repo/releases/latest"
        Invoke-WebRequest $url | ConvertFrom-Json | Select -ExpandProperty assets -first 1 | select -ExpandProperty browser_download_url
    }
}

<#
.Synopsis
    Date and time of NuGet GitHub release.
.DESCRIPTION
    Retrieves the publication date of a GitHub release from the GitHub API.
.PARAMETER Owner
    The owner of the repository.
.PARAMETER Repo
    The name of the repository.
.NOTES
    Author: Marcus Schweda
#>
function Github-When {
    [CmdletBinding()]
    [OutputType([datetime])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]$Owner,
        [Parameter(Mandatory=$true)]
        [string]$Repo
    )

    Begin {
        $url = "https://api.github.com/repos/$Owner/$Repo/releases/latest"
        $dt = Invoke-WebRequest $url | ConvertFrom-Json | Select -ExpandProperty published_at
        [datetime]::Parse($dt)
    }
}

<#
.Synopsis
    Latest version of a NuGet package.
.DESCRIPTION
    Retrieves the latest stable version of a NuGet package from NuGet v3 API.
.PARAMETER PackageId
    The exact Id of the package. The default value is "NuGet.CommandLine" (nuget.exe).
.NOTES
    Author: Marcus Schweda
#>
function NuGet-Latest {
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter()]
        [string]$PackageId = "NuGet.CommandLine"
    )
    Begin {
        $url = "https://api-v2v3search-0.nuget.org/query?q=packageid:$PackageId"
        Invoke-WebRequest $url | ConvertFrom-Json | Select -ExpandProperty data -first 1 | Select -ExpandProperty version
    }
}

<#
.Synopsis
    Date and time of NuGet package publication.
.DESCRIPTION
    Retrieves the publication date of a NuGet package from NuGet v3 API.
.PARAMETER PackageId
    The exact Id of the package. The default value is "NuGet.CommandLine" (nuget.exe).
.PARAMETER Version
    The version of the package.
.NOTES
    Author: Marcus Schweda
#>
function NuGet-When {
    [CmdletBinding()]
    [OutputType([datetime])]
    Param
    (
        [Parameter()]
        [string]$PackageId = "NuGet.CommandLine",
        [Parameter(Mandatory=$true)]
        [string]$Version
    )
    Begin {
        $url = "https://api.nuget.org/v3/registration0/$PackageId/$Version.json"
        $dt = Invoke-WebRequest $url | ConvertFrom-Json | Select -ExpandProperty published
        [datetime]::Parse($dt)
    }
}

<#
.Synopsis
    Create or update timestamp file.
.DESCRIPTION
    Creates or updates a file with a timestamp for version checks.
.PARAMETER Directory
    The directory to create the file in.
.PARAMETER Date
    The date and time to save within the file.
.PARAMETER FileName
    The name of the file. The default value is ".ver".
.NOTES
    Author: Marcus Schweda
#>
function TimeStamp-Set {
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]$Directory,
        [Parameter(Mandatory=$true)]
        [datetime]$Date = [datetime]::Now,
        [string]$FileName = ".ver"
    )
    Begin {
        $path = [System.IO.Path]::Combine($Directory, $FileName)
        if ([System.IO.File]::Exists($path)) {
            [System.IO.File]::SetAttributes($path, [System.IO.FileAttributes]::Normal)
        }
        [System.IO.File]::WriteAllText($path, $Date.ToString("o"))
        [System.IO.File]::SetAttributes($path, [System.IO.FileAttributes]::Hidden)
    }
}

<#
.Synopsis
    Read timestamp file.
.DESCRIPTION
    Reads a tmestamp from a file previously created with TimeStamp-Set.
.PARAMETER Directory
    The directory of the file.
.PARAMETER FileName
    The name of the file. The default value is ".ver".
.NOTES
    Author: Marcus Schweda
#>
function TimeStamp-Get {
    [CmdletBinding()]
    [OutputType([datetime])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]$Directory,
        [string]$FileName = ".ver"
    )
    Begin {
        $path = [System.IO.Path]::Combine($Directory, $FileName)
        if (Test-Path $path) {
            $dt = [System.IO.File]::ReadAllText($path)
            [datetime]::ParseExact($dt, "o", [cultureinfo]::InvariantCulture)
        } else {
            [datetime]::MinValue
        }
    }
}

tools\prerequisites.ps1

if ($Global:required -ne $null) {

    . $PSScriptRoot\download.ps1

    $tooldir = "$env:LOCALAPPDATA\.build"

    if (!(Test-Path $tooldir)) {
        New-Item $tooldir -ItemType Directory | %{ $_.Attributes = "Hidden" }
    }

    ## .NET Core ##############################################################

    if ($Global:required.Contains("netcore")) {

        if ((Get-Command "dotnet" -ErrorAction SilentlyContinue) -eq $null) {
            Write-Host .NET Core not instaled.
            & $PSScriptRoot\tools\dotnet-install.ps1
        }

    }

    ## NuGet ##################################################################

    if ($Global:required.Contains("nuget")) {

        $dir = "$tooldir\nuget"
     
        if (!(Test-Path $dir)) {
            New-Item $dir -ItemType Directory | Out-Null
        }
     
        $ver = Nuget-Latest nuget.commandline
        $published = NuGet-When nuget.commandline $ver
        $update = $false
     
        if (-not(Test-Path $dir\nuget.exe)) {
            $update = $true
            Write-Host NuGet not installed.
        } else {
            $installed = TimeStamp-Get $dir
            if ($published -gt $installed) {
                Write-Host New NuGet version available.
                $update = $true
            }
        }
     
        if ($update) {
            $url = "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe"
            Download-File $url $dir\nuget.exe nuget.exe
            TimeStamp-Set $dir $published
        }

     }

    ## DocFX ##################################################################

    if ($Global:required.Contains("docfx")) {

        $dir = "$tooldir\docfx"
        
        if (!(Test-Path $dir)) {
            New-Item $dir -ItemType Directory | Out-Null
        }
        
        $published = Github-When dotnet docfx

        if (-not(Test-Path $dir\docfx.exe)) {
            $update = $true
            Write-Host DocFX not installed.
        } else {
            $installed = TimeStamp-Get $dir
            if ($published -gt $installed) {
                Write-Host New DocFX version available.
                $update = $true
            }
        }

        if ($update) {
            Get-ChildItem -Path $dir *.* | Remove-Item -Force

            $url = Github-LatestUrl dotnet docfx
            Download-File $url $dir\docfx.zip docfx.zip
            TimeStamp-Set $dir $published

            Write-Host Extracting...
            Add-Type -AssemblyName System.IO.Compression.FileSystem
            [System.IO.Compression.ZipFile]::ExtractToDirectory("$dir\docfx.zip", "$dir")
            Remove-Item "$dir\docfx.zip"
        }

    }

}