feat: fileParser validation handling, FileParsingExcpetion class created, Filetransform try catch added, tests and test data files added,,

Author: Warren-Pitterson

src/ServiceLayer.Mesh/FileTypes/NbssAppointmentEvents/FileParser.cs

@@ -1,6 +1,7 @@
 using CsvHelper;
 using CsvHelper.Configuration;
 using ServiceLayer.Mesh.FileTypes.NbssAppointmentEvents.Models;
+using ServiceLayer.Mesh.FileTypes.NbssAppointmentEvents.Validation;
 using System.Globalization;
 using System.Text;
 
@@ -31,6 +32,7 @@ public ParsedFile Parse(Stream stream)
 
         var rowNumber = 0;
         var fields = new List<string>();
+        var fieldsFound = false;
 
         while (csv.Read())
         {
@@ -44,9 +46,15 @@ public ParsedFile Parse(Stream stream)
 
                 case FieldsIdentifier:
                     fields = ParseFields(csv);
+                    fieldsFound = true;
                     break;
 
                 case DataIdentifier:
+                    if (!fieldsFound)
+                    {
+                        throw new FileParsingException(
+                        ErrorCodes.MissingFieldHeadings, "Field headings are missing");
+                    }
                     rowNumber++;
                     result.DataRecords.Add(ParseDataRecord(csv, fields, rowNumber));
                     break;
@@ -56,7 +64,10 @@ public ParsedFile Parse(Stream stream)
                     break;
 
                 default:
-                    throw new InvalidOperationException($"Unknown record identifier: {recordIdentifier}");
+                    recordIdentifier = recordIdentifier ?? "No Record Identifier found";
+                    throw new FileParsingException(
+                        ErrorCodes.UnknownRecordTypeIdentifier,
+                        $"Unknown Record Identifier {recordIdentifier}");
             }
         }
 
@@ -96,11 +107,6 @@ private static CsvReader CreateCsvReader(StreamReader reader)
 
     private static FileDataRecord ParseDataRecord(CsvReader csv, List<string> columnHeadings, int rowNumber)
     {
-        if (columnHeadings.Count == 0)
-        {
-            throw new InvalidOperationException("Field headers (NBSSAPPT_FLDS) must appear before data records.");
-        }
-
         const int dataFieldStartIndex = 1;
 
         var record = new FileDataRecord { RowNumber = rowNumber };
@@ -140,4 +146,3 @@ public FileHeaderRecordMap()
         }
     }
 }
-

src/ServiceLayer.Mesh/FileTypes/NbssAppointmentEvents/FileTransformer.cs

@@ -1,3 +1,4 @@
+using Microsoft.Extensions.Logging;
 using ServiceLayer.Data.Models;
 using ServiceLayer.Mesh.FileTypes.NbssAppointmentEvents.Validation;
 
@@ -6,22 +7,65 @@ namespace ServiceLayer.Mesh.FileTypes.NbssAppointmentEvents;
 public class FileTransformer(
     IFileParser fileParser,
     IValidationRunner validationRunner,
-    IStagingPersister stagingPersister)
+    IStagingPersister stagingPersister,
+    ILogger<FileTransformer> logger)
     : FileTransformerBase
 {
     protected override MeshFileType HandlesFileType => MeshFileType.NbssAppointmentEvents;
 
     public override async Task<IList<ValidationError>> TransformFileAsync(Stream stream, MeshFile metaData)
     {
-        // TODO - wrap this parsing in a try-catch and return a List<ValidationError> in case of any unforeseen parsing issues (file is totally unlike anything we expect)
-        var parsed = fileParser.Parse(stream);
+        try
+        {
+            var parsed = fileParser.Parse(stream);
+            var validationErrors = validationRunner.Validate(parsed);
+
+            if (!validationErrors.Any())
+            {
+                await stagingPersister.WriteStagedData(parsed, metaData);
+            }
 
-        var validationErrors = validationRunner.Validate(parsed);
-        if (!validationErrors.Any())
+            return validationErrors;
+        }
+        catch (FileParsingException ex)
         {
-            await stagingPersister.WriteStagedData(parsed, metaData);
+            return HandleFileParsingException(ex);
         }
+        catch (Exception ex)
+        {
+            return HandleUnexpectedException(ex, metaData);
+        }
+    }
+
+    private List<ValidationError> HandleFileParsingException(FileParsingException ex)
+    {
+        logger.LogError("File parsing failed with validation error. Code: {ErrorCode}, Message: {ErrorMessage}",
+            ex.Code, ex.ErrorMessage);
+
+        return
+        [
+            new ValidationError
+            {
+                Code = ex.Code,
+                Error = ex.ErrorMessage,
+                Scope = ValidationErrorScope.File
+            }
+        ];
+    }
+
+    private IList<ValidationError> HandleUnexpectedException(Exception ex, MeshFile metaData)
+    {
+        logger.LogError(ex, "System error occurred while parsing NBSS appointment file. File: {FileName}",
+            metaData?.FileId ?? "Unknown");
 
-        return validationErrors;
+        return
+        [
+            new ValidationError
+            {
+                Code = ErrorCodes.UnableToParseFile,
+                Error = "Unable to parse file",
+                Scope = ValidationErrorScope.File
+            }
+        ];
     }
 }

src/ServiceLayer.Mesh/FileTypes/NbssAppointmentEvents/Models/FileParsingException.cs

@@ -0,0 +1,21 @@
+namespace ServiceLayer.Mesh.FileTypes.NbssAppointmentEvents;
+
+public class FileParsingException : Exception
+{
+    public string Code { get; }
+    public string ErrorMessage { get; }
+
+    public FileParsingException(string code, string errorMessage)
+        : base(errorMessage)
+    {
+        Code = code;
+        ErrorMessage = errorMessage;
+    }
+
+    public FileParsingException(string code, string errorMessage, Exception innerException)
+        : base(errorMessage, innerException)
+    {
+        Code = code;
+        ErrorMessage = errorMessage;
+    }
+}

src/ServiceLayer.Mesh/Functions/FileExtractFunction.cs

@@ -109,7 +109,7 @@ private async Task ProcessFileExtraction(MeshFile file)
 
     private async Task HandleExtractionError(MeshFile file, FileExtractQueueMessage message, Exception ex)
     {
-        logger.LogError(ex, "An exception occurred during file extraction for fileId: {fileId}", message.FileId);
+        logger.LogError(ex, "An exception occurred during file extraction for fileId: {FileId}", message.FileId);
         file.Status = MeshFileStatus.FailedExtract;
         file.LastUpdatedUtc = DateTime.UtcNow;
         await serviceLayerDbContext.SaveChangesAsync();

src/ServiceLayer.Shared/Data/Models/MeshFileType.cs

@@ -2,5 +2,6 @@ namespace ServiceLayer.Data.Models;
 
 public enum MeshFileType
 {
-    NbssAppointmentEvents
+    NbssAppointmentEvents,
+    Unknown
 }