added backend for storing extra fields.

External/Implementations/Postgres/ExtraFieldDataAccess.cs

@@ -0,0 +1,75 @@
+using CarCareTracker.External.Interfaces;
+using CarCareTracker.Models;
+using Npgsql;
+using System.Text.Json;
+
+namespace CarCareTracker.External.Implementations
+{
+    public class PGExtraFieldDataAccess : IExtraFieldDataAccess
+    {
+        private NpgsqlDataSource pgDataSource;
+        private readonly ILogger<PGExtraFieldDataAccess> _logger;
+        private static string tableName = "extrafields";
+        public PGExtraFieldDataAccess(IConfiguration config, ILogger<PGExtraFieldDataAccess> logger)
+        {
+            pgDataSource = NpgsqlDataSource.Create(config["POSTGRES_CONNECTION"]);
+
+            _logger = logger;
+            try
+            {
+                //create table if not exist.
+                string initCMD = $"CREATE TABLE IF NOT EXISTS app.{tableName} (id INT primary key, data jsonb not null)";
+                using (var ctext = pgDataSource.CreateCommand(initCMD))
+                {
+                    ctext.ExecuteNonQuery();
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex.Message);
+            }
+        }
+        public RecordExtraField GetExtraFieldsById(int importMode)
+        {
+            try
+            {
+                string cmd = $"SELECT data FROM app.{tableName} WHERE id = @id";
+                var results = new RecordExtraField();
+                using (var ctext = pgDataSource.CreateCommand(cmd))
+                {
+                    ctext.Parameters.AddWithValue("id", importMode);
+                    using (NpgsqlDataReader reader = ctext.ExecuteReader())
+                        while (reader.Read())
+                        {
+                            RecordExtraField result = JsonSerializer.Deserialize<RecordExtraField>(reader["data"] as string);
+                            results = result;
+                        }
+                }
+                return results;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex.Message);
+                return new RecordExtraField();
+            }
+        }
+        public bool SaveExtraFields(RecordExtraField record)
+        {
+            try
+            {
+                string cmd = $"INSERT INTO app.{tableName} (id, data) VALUES(@id, CAST(@data AS jsonb))";
+                using (var ctext = pgDataSource.CreateCommand(cmd))
+                {
+                    ctext.Parameters.AddWithValue("id", record.Id);
+                    ctext.Parameters.AddWithValue("data", JsonSerializer.Serialize(record));
+                    return ctext.ExecuteNonQuery() > 0;
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex.Message);
+                return false;
+            }
+        }
+    }
+}