Sample webhook and build/deploy script for .NET back end server

gatewaysettings.env

GITHUB_WEBHOOK_SECRET="[SOME_GUID_THAT_MUST_MATCH_GITHUB_SETTING]"

Update-and-BuildProject.ps1

#!/usr/bin/env pwsh

param (
    [Parameter(Mandatory = $true)]
    [string]$refBranch
)

function Update-and-BuildProject {
    param (
        [string]$repoUrl,
        [string]$localPath,
        [string]$branch
    )

    try {
        Write-Host "repoUrl: $repoUrl"
        Write-Host "localPath: $localPath"
        Write-Host "branch: $branch"
        Write-Host "refBranch: $refBranch"

        # Ensure we're in the correct directory
        Set-Location $localPath
        
        # Use existing git remote
        Write-Host "Pulling and checking out branch: $refBranch"
        git pull origin $refBranch
        git checkout $refBranch

        # Build and publish the project
        dotnet run Publish
        $publishExitCode = $LASTEXITCODE

        if ($publishExitCode -eq 0) {
            # Restart services only if the build was successful
            sudo systemctl restart rex-server.service
            sudo systemctl restart rex-app.service
            Write-Host "Project updated and services restarted successfully."
        } else {
            Write-Error "Build failed with exit code $publishExitCode. Services were not restarted."
        }
    } catch {
        Write-Error "An error occurred: $_"
    }
}

# Setting up the HTTP listener
$listener = New-Object System.Net.HttpListener
$listener.Prefixes.Add("http://+:8081/")
$listener.Start()
Write-Host "Listening for connections on http://+:8081/..."

while ($listener.IsListening) {
    $context = $listener.GetContext()
    try {
        $request = $context.Request
        $response = $context.Response
        $body = New-Object System.IO.StreamReader($request.InputStream)
        $data = $body.ReadToEnd()
        $body.Close()

        # Log the received data
        Write-Host "Received Data: $data"

        $secret = [Environment]::GetEnvironmentVariable("GITHUB_WEBHOOK_SECRET")
        $receivedSignature = $request.Headers["X-Hub-Signature"]

        if (-not $receivedSignature) {
            Write-Host "No signature provided"
            $response.StatusCode = 400
            $response.Close()
            continue
        }

        # Compute HMAC hash on the raw data without any modifications
        $hmac = New-Object System.Security.Cryptography.HMACSHA1
        $hmac.Key = [Text.Encoding]::UTF8.GetBytes($secret)
        $hashBytes = $hmac.ComputeHash([Text.Encoding]::UTF8.GetBytes($data))
        $expectedSignature = "sha1=" + ([BitConverter]::ToString($hashBytes) -replace '-', '').ToLower()

        if ($expectedSignature -eq $receivedSignature) {
            Write-Host "Signatures match"
            try {
                # Extract the Content-Type header
                $contentType = $request.Headers["Content-Type"]

                # If the content type is application/x-www-form-urlencoded, extract and decode the payload
                if ($contentType -eq "application/x-www-form-urlencoded") {
                    # Extract the 'payload' parameter
                    $formFields = [System.Web.HttpUtility]::ParseQueryString($data)
                    $payloadJson = $formFields["payload"]
                } else {
                    # Assume the data is the raw JSON payload
                    $payloadJson = $data
                }

                # Parse the JSON payload
                $payload = $payloadJson | ConvertFrom-Json

                # Extract necessary information
                $repoUrl = $payload.repository.clone_url
                $branch = $payload.ref -replace 'refs/heads/', ''
                $localPath = "/home/rexuser/Rex"

                # Check if the branch is 'dev'
                if ($branch -eq $refBranch) {
                    Update-and-BuildProject -repoUrl $repoUrl -localPath $localPath -branch $branch -refBranch $refBranch
                } else {
                    Write-Output "No build triggered as the branch is not '{$refBranch}'."
                }
            } catch {
                Write-Host "Failed to parse JSON payload. Error: $_"
                $response.StatusCode = 400
                $response.Close()
                continue
            }
        } else {
            Write-Host "Invalid secret"
            $response.StatusCode = 403
            $response.Close()
            continue
        }

        $response.StatusCode = 200
        $response.StatusDescription = "OK"
        $response.Close()
    } catch {
        Write-Error "An error occurred: $_"
        if ($response -and !$response.HasExited) {
            $response.StatusCode = 500
            $response.Close()
        }
    }
}

webhooklistener.service

[Unit]
Description=GitHub Webhook Listener Service
After=network.target

[Service]
ExecStart=/opt/microsoft/powershell/7/pwsh -NoProfile -File /cicd/Update-and-BuildProject.ps1 -refBranch '*YOUR_BRANCH*'
WorkingDirectory=/cicd
Restart=on-failure
RestartSec=10
StartLimitInterval=0
StartLimitBurst=5
User=*YOUR_USER*
EnvironmentFile=/root/gatewaysettings.env

[Install]