diff --git a/ImportAssist.slnx b/ImportAssist.slnx
index 44ad562..559b508 100644
--- a/ImportAssist.slnx
+++ b/ImportAssist.slnx
@@ -3,4 +3,7 @@
+
+
+
diff --git a/src/ImportAssist.Functions/.gitignore b/src/ImportAssist.Functions/.gitignore
new file mode 100644
index 0000000..3c3f4e6
--- /dev/null
+++ b/src/ImportAssist.Functions/.gitignore
@@ -0,0 +1,264 @@
+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+
+# Azure Functions localsettings file
+local.settings.json
+
+# User-specific files
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+*.userprefs
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+
+# Visual Studio 2015 cache/options directory
+.vs/
+# Uncomment if you have tasks that create the project's static files in wwwroot
+#wwwroot/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+# NUNIT
+*.VisualState.xml
+TestResult.xml
+
+# Build Results of an ATL Project
+[Dd]ebugPS/
+[Rr]eleasePS/
+dlldata.c
+
+# DNX
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+*_i.c
+*_p.c
+*_i.h
+*.ilk
+*.meta
+*.obj
+*.pch
+*.pdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*.log
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.svclog
+*.scc
+
+# Chutzpah Test files
+_Chutzpah*
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opendb
+*.opensdf
+*.sdf
+*.cachefile
+*.VC.db
+*.VC.VC.opendb
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+*.sap
+
+# TFS 2012 Local Workspace
+$tf/
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# JustCode is a .NET coding add-in
+.JustCode
+
+# TeamCity is a build add-in
+_TeamCity*
+
+# DotCover is a Code Coverage Tool
+*.dotCover
+
+# NCrunch
+_NCrunch_*
+.*crunch*.local.xml
+nCrunchTemp_*
+
+# MightyMoose
+*.mm.*
+AutoTest.Net/
+
+# Web workbench (sass)
+.sass-cache/
+
+# Installshield output folder
+[Ee]xpress/
+
+# DocProject is a documentation generator add-in
+DocProject/buildhelp/
+DocProject/Help/*.HxT
+DocProject/Help/*.HxC
+DocProject/Help/*.hhc
+DocProject/Help/*.hhk
+DocProject/Help/*.hhp
+DocProject/Help/Html2
+DocProject/Help/html
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.[Pp]ublish.xml
+*.azurePubxml
+# TODO: Comment the next line if you want to checkin your web deploy settings
+# but database connection strings (with potential passwords) will be unencrypted
+#*.pubxml
+*.publishproj
+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
+# checkin your Azure Web App publish settings, but sensitive information contained
+# in these scripts will be unencrypted
+PublishScripts/
+
+# NuGet Packages
+*.nupkg
+# The packages folder can be ignored because of Package Restore
+**/packages/*
+# except build/, which is used as an MSBuild target.
+!**/packages/build/
+# Uncomment if necessary however generally it will be regenerated when needed
+#!**/packages/repositories.config
+# NuGet v3's project.json files produces more ignoreable files
+*.nuget.props
+*.nuget.targets
+
+# Microsoft Azure Build Output
+csx/
+*.build.csdef
+
+# Microsoft Azure Emulator
+ecf/
+rcf/
+
+# Windows Store app package directories and files
+AppPackages/
+BundleArtifacts/
+Package.StoreAssociation.xml
+_pkginfo.txt
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!*.[Cc]ache/
+
+# Others
+ClientBin/
+~$*
+*~
+*.dbmdl
+*.dbproj.schemaview
+*.jfm
+*.pfx
+*.publishsettings
+node_modules/
+orleans.codegen.cs
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+#bower_components/
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+
+# SQL Server files
+*.mdf
+*.ldf
+
+# Business Intelligence projects
+*.rdl.data
+*.bim.layout
+*.bim_*.settings
+
+# Microsoft Fakes
+FakesAssemblies/
+
+# GhostDoc plugin setting file
+*.GhostDoc.xml
+
+# Node.js Tools for Visual Studio
+.ntvs_analysis.dat
+
+# Visual Studio 6 build log
+*.plg
+
+# Visual Studio 6 workspace options file
+*.opt
+
+# Visual Studio LightSwitch build output
+**/*.HTMLClient/GeneratedArtifacts
+**/*.DesktopClient/GeneratedArtifacts
+**/*.DesktopClient/ModelManifest.xml
+**/*.Server/GeneratedArtifacts
+**/*.Server/ModelManifest.xml
+_Pvt_Extensions
+
+# Paket dependency manager
+.paket/paket.exe
+paket-files/
+
+# FAKE - F# Make
+.fake/
+
+# JetBrains Rider
+.idea/
+*.sln.iml
+
+# CodeRush
+.cr/
+
+# Python Tools for Visual Studio (PTVS)
+__pycache__/
+*.pyc
\ No newline at end of file
diff --git a/src/ImportAssist.Functions/.vscode/extensions.json b/src/ImportAssist.Functions/.vscode/extensions.json
new file mode 100644
index 0000000..dde673d
--- /dev/null
+++ b/src/ImportAssist.Functions/.vscode/extensions.json
@@ -0,0 +1,5 @@
+{
+ "recommendations": [
+ "ms-azuretools.vscode-azurefunctions"
+ ]
+}
\ No newline at end of file
diff --git a/src/ImportAssist.Functions/ImportAssist_Functions.csproj b/src/ImportAssist.Functions/ImportAssist_Functions.csproj
new file mode 100644
index 0000000..f3b163d
--- /dev/null
+++ b/src/ImportAssist.Functions/ImportAssist_Functions.csproj
@@ -0,0 +1,25 @@
+
+
+
+ net10.0
+ v4
+ Exe
+ enable
+ enable
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/src/ImportAssist.Functions/Program.cs b/src/ImportAssist.Functions/Program.cs
new file mode 100644
index 0000000..cd308f9
--- /dev/null
+++ b/src/ImportAssist.Functions/Program.cs
@@ -0,0 +1,20 @@
+using Azure.Monitor.OpenTelemetry.Exporter;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Builder;
+using Microsoft.Azure.Functions.Worker.OpenTelemetry;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using OpenTelemetry;
+
+var builder = FunctionsApplication.CreateBuilder(args);
+
+builder.ConfigureFunctionsWebApplication();
+
+if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("APPLICATIONINSIGHTS_CONNECTION_STRING")))
+{
+ builder.Services.AddOpenTelemetry()
+ .UseFunctionsWorkerDefaults()
+ .UseAzureMonitorExporter();
+}
+
+builder.Build().Run();
diff --git a/src/ImportAssist.Functions/Properties/launchSettings.json b/src/ImportAssist.Functions/Properties/launchSettings.json
new file mode 100644
index 0000000..bba629d
--- /dev/null
+++ b/src/ImportAssist.Functions/Properties/launchSettings.json
@@ -0,0 +1,9 @@
+{
+ "profiles": {
+ "ImportAssist_Functions": {
+ "commandName": "Project",
+ "commandLineArgs": "--port 7230",
+ "launchBrowser": false
+ }
+ }
+}
\ No newline at end of file
diff --git a/src/ImportAssist.Functions/ValidateInvoice.cs b/src/ImportAssist.Functions/ValidateInvoice.cs
new file mode 100644
index 0000000..5353d8e
--- /dev/null
+++ b/src/ImportAssist.Functions/ValidateInvoice.cs
@@ -0,0 +1,57 @@
+using System.Text.Json;
+using ImportAssist.Core;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Extensions.Logging;
+
+namespace ImportAssist_Functions;
+
+public sealed class ValidateInvoice(ILogger logger)
+{
+ private static readonly JsonSerializerOptions JsonOptions =
+ new(JsonSerializerDefaults.Web);
+
+ [Function("ValidateInvoice")]
+ public async Task Run(
+ [HttpTrigger(AuthorizationLevel.Function, "post")] HttpRequest request)
+ {
+ InvoiceRow? row;
+
+ try
+ {
+ row = await JsonSerializer.DeserializeAsync(
+ request.Body,
+ JsonOptions,
+ request.HttpContext.RequestAborted);
+ }
+ catch (JsonException)
+ {
+ return new BadRequestObjectResult(new
+ {
+ error = "Der Request muss ein Rechnungsobjekt mit Textfeldern enthalten."
+ });
+ }
+
+ if (row is null)
+ {
+ return new BadRequestObjectResult(new
+ {
+ error = "Ein Rechnungsobjekt ist erforderlich."
+ });
+ }
+
+ var errors = InvoiceValidator.Validate(row);
+
+ logger.LogInformation(
+ "Rechnungsprüfung abgeschlossen: {ErrorCount} Fehler.",
+ errors.Count);
+
+ return new OkObjectResult(new
+ {
+ invoiceId = row.InvoiceId,
+ isValid = errors.Count == 0,
+ errors
+ });
+ }
+}
\ No newline at end of file
diff --git a/src/ImportAssist.Functions/host.json b/src/ImportAssist.Functions/host.json
new file mode 100644
index 0000000..29667ea
--- /dev/null
+++ b/src/ImportAssist.Functions/host.json
@@ -0,0 +1,4 @@
+{
+ "version": "2.0",
+ "telemetryMode": "OpenTelemetry"
+}