Add method to retrieve transaction data (#16)

src/Axepta.SDK/Entities/Response/TransactionResponse.cs

@@ -0,0 +1,7 @@
+namespace Axepta.SDK;
+
+public sealed record TransactionResponse
+{
+    [JsonPropertyName("data")]
+    public required Data Data { get; init; }
+}

src/Axepta.SDK/Extensions.cs

@@ -58,6 +58,39 @@ IConfiguration cfg
         return services;
     }
 
+    internal static async Task<T> GetAsync<T>(
+        this HttpClient http,
+        string url,
+        CancellationToken ct = default
+    )
+    {
+        HttpResponseMessage? httpRes = null;
+
+        var httpResContentAsJson = async () => httpRes is null ?
+            string.Empty :
+            await httpRes.Content.ReadAsStringAsync(ct);
+
+        try
+        {
+            httpRes = await http.GetAsync(
+                url,
+                ct
+            );
+
+            httpRes.EnsureSuccessStatusCode();
+
+            return (T)JsonSerializer.Deserialize(
+                await httpResContentAsJson().ConfigureAwait(false),
+                typeof(T),
+                _sourceGenOptions
+            )!;
+        }
+        catch (HttpRequestException)
+        {
+            throw new AxeptaException(await httpResContentAsJson().ConfigureAwait(false));
+        }
+    }
+
     internal static async Task<K> PostAsync<T, K>(
         this HttpClient http,
         string url,

src/Axepta.SDK/Services/Abstractions/IAxepta.cs

@@ -29,4 +29,17 @@ Task<ResponseRoot> CreateRefundAsync(
         Refund refund,
         CancellationToken ct = default
     );
+
+    /// <summary>
+    /// Retrieves the details of a specific transaction asynchronously.
+    /// </summary>
+    /// <param name="transactionId">The unique identifier of the transaction to retrieve.</param>
+    /// <param name="ct">An optional cancellation token to cancel the request.</param>
+    /// <returns>
+    /// A task that represents the asynchronous operation. The task result contains the <see cref="Transaction"/> object with the details of the requested transaction.
+    /// </returns>
+    Task<Transaction> GetTransactionAsync(
+        Guid transactionId,
+        CancellationToken ct = default
+    );
 }

src/Axepta.SDK/Services/Axepta.cs

@@ -22,4 +22,13 @@ public Task<ResponseRoot> CreateRefundAsync(
             refund,
             ct
         );
+
+    public async Task<Transaction> GetTransactionAsync(
+        Guid transationId,
+        CancellationToken ct = default
+    )
+        => (await http.GetAsync<TransactionResponse>(
+            $"transaction/{transationId}",
+            ct
+        )).Data.Transaction!;
 }