Add local blob-triggered CSV validation with Azurite

src/ImportAssist.Cli/Program.cs

@@ -17,39 +17,19 @@ if (!File.Exists(path))
     return;
 }
 
-var lines = File.ReadAllLines(path);
+IReadOnlyList<InvoiceRow> rows;
 
-if (lines.Length == 0 ||
-    lines[0] != "InvoiceId;CustomerId;Amount;Currency")
+try
 {
-    Console.Error.WriteLine(
-        "Die Datei ist leer oder die Kopfzeile stimmt nicht.");
+    rows = InvoiceCsvParser.Parse(File.ReadAllText(path));
+}
+catch (FormatException exception)
+{
+    Console.Error.WriteLine(exception.Message);
     Environment.ExitCode = 1;
     return;
 }
 
-var rows = new List<InvoiceRow>();
-
-for (var index = 1; index < lines.Length; index++)
-{
-    var line = lines[index];
-    var columns = line.Split(';');
-
-    if (line.Contains('"') || columns.Length != 4)
-    {
-        Console.Error.WriteLine(
-            $"Zeile {index + 1}: Erwartet werden vier Spalten ohne Anführungszeichen.");
-        Environment.ExitCode = 1;
-        return;
-    }
-
-    rows.Add(new InvoiceRow(
-        columns[0],
-        columns[1],
-        columns[2],
-        columns[3]));
-}
-
 foreach (var row in rows)
 {
     var errors = InvoiceValidator.Validate(row);

src/ImportAssist.Core/InvoiceCsvParser.cs

@@ -0,0 +1,41 @@
+namespace ImportAssist.Core;
+
+public static class InvoiceCsvParser
+{
+    public static IReadOnlyList<InvoiceRow> Parse(string csv)
+    {
+        using var reader = new StringReader(csv);
+
+        var header = reader.ReadLine()?.TrimStart('\uFEFF');
+
+        if (header != "InvoiceId;CustomerId;Amount;Currency")
+        {
+            throw new FormatException(
+                "Die Datei ist leer oder die Kopfzeile stimmt nicht.");
+        }
+
+        var rows = new List<InvoiceRow>();
+        var lineNumber = 1;
+
+        while (reader.ReadLine() is { } line)
+        {
+            lineNumber++;
+
+            var columns = line.Split(';');
+
+            if (line.Contains('"') || columns.Length != 4)
+            {
+                throw new FormatException(
+                    $"Zeile {lineNumber}: Erwartet werden vier Spalten ohne Anführungszeichen.");
+            }
+
+            rows.Add(new InvoiceRow(
+                columns[0],
+                columns[1],
+                columns[2],
+                columns[3]));
+        }
+
+        return rows;
+    }
+}

src/ImportAssist.Functions/ImportAssist_Functions.csproj

@@ -11,6 +11,7 @@
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
     <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.52.0" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Storage.Blobs" Version="6.8.2" />
     <PackageReference Include="Microsoft.Azure.Functions.Worker.OpenTelemetry" Version="1.2.0" />
     <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3" />
     <PackageReference Include="Azure.Monitor.OpenTelemetry.Exporter" Version="1.7.0" />

src/ImportAssist.Functions/InvoiceBlobTrigger.cs

@@ -0,0 +1,66 @@
+using ImportAssist.Core;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Extensions.Logging;
+
+namespace ImportAssist_Functions;
+
+public sealed class InvoiceBlobTrigger(
+    ILogger<InvoiceBlobTrigger> logger)
+{
+    [Function("InvoiceBlobTrigger")]
+    public void Run(
+        [BlobTrigger(
+            "imports/{name}",
+            Connection = "AzureWebJobsStorage")]
+        string content,
+        string name)
+    {
+        IReadOnlyList<InvoiceRow> rows;
+
+        try
+        {
+            rows = InvoiceCsvParser.Parse(content);
+        }
+        catch (FormatException exception)
+        {
+            logger.LogWarning(
+                "Datei {BlobName} wegen CSV-Formatfehler abgewiesen: {Reason}",
+                name,
+                exception.Message);
+
+            return;
+        }
+
+        var validCount = 0;
+
+        foreach (var row in rows)
+        {
+            var errors = InvoiceValidator.Validate(row);
+
+            if (errors.Count == 0)
+            {
+                validCount++;
+            }
+
+            var invoiceId = string.IsNullOrWhiteSpace(row.InvoiceId)
+                ? "(ohne Rechnungsnummer)"
+                : row.InvoiceId;
+
+            logger.LogInformation(
+                "{BlobName}: {InvoiceId}: {Result}",
+                name,
+                invoiceId,
+                errors.Count == 0
+                    ? "Gültig"
+                    : string.Join("; ", errors));
+        }
+
+        logger.LogInformation(
+            "Dateiprüfung abgeschlossen: {BlobName}, " +
+            "{TotalCount} Rechnungen, {ValidCount} gültig, {InvalidCount} fehlerhaft.",
+            name,
+            rows.Count,
+            validCount,
+            rows.Count - validCount);
+    }
+}