fix: include request URL in NetworkException (#31)

NetworkException previously surfaced only the status code and response
body, so callers wrapping the SDK could not tell whether a 401 came
from PKG (MPK / signing-key fetch) or one of the three Cryptify upload
phases without digging through stack traces. Add a Url property,
include the URL in the message, and propagate it from both
EnsureSuccessAsync helpers via response.RequestMessage.RequestUri.

Closes #26

Co-authored-by: dobby-yivi-agent[bot] <275734547+dobby-yivi-agent[bot]@users.noreply.github.com>

Author: dobby-coder[bot]

src/Api/CryptifyClient.cs

@@ -130,7 +130,8 @@ private static async Task EnsureSuccessAsync(HttpResponseMessage response)
         if (!response.IsSuccessStatusCode)
         {
             var body = await response.Content.ReadAsStringAsync();
-            throw new NetworkException((int)response.StatusCode, body);
+            var url = response.RequestMessage?.RequestUri?.ToString() ?? "<unknown>";
+            throw new NetworkException((int)response.StatusCode, body, url);
         }
     }
 }

src/Api/PkgClient.cs

@@ -73,7 +73,8 @@ private static async Task EnsureSuccessAsync(HttpResponseMessage response)
         if (!response.IsSuccessStatusCode)
         {
             var body = await response.Content.ReadAsStringAsync();
-            throw new NetworkException((int)response.StatusCode, body);
+            var url = response.RequestMessage?.RequestUri?.ToString() ?? "<unknown>";
+            throw new NetworkException((int)response.StatusCode, body, url);
         }
     }
 }

src/Exceptions/PostGuardException.cs

@@ -10,12 +10,14 @@ public class NetworkException : PostGuardException
 {
     public int StatusCode { get; }
     public string Body { get; }
+    public string Url { get; }
 
-    public NetworkException(int statusCode, string body)
-        : base($"HTTP {statusCode}: {body}")
+    public NetworkException(int statusCode, string body, string url)
+        : base($"HTTP {statusCode} at {url}: {body}")
     {
         StatusCode = statusCode;
         Body = body;
+        Url = url;
     }
 }
 

tests/E4A.PostGuard.Tests/NetworkExceptionTests.cs

@@ -0,0 +1,35 @@
+using E4A.PostGuard.Exceptions;
+
+namespace E4A.PostGuard.Tests;
+
+public class NetworkExceptionTests
+{
+    [Fact]
+    public void Ctor_PopulatesUrlProperty()
+    {
+        var ex = new NetworkException(401, "Unauthorized", "https://pkg.postguard.eu/v2/irma/sign/key");
+
+        Assert.Equal(401, ex.StatusCode);
+        Assert.Equal("Unauthorized", ex.Body);
+        Assert.Equal("https://pkg.postguard.eu/v2/irma/sign/key", ex.Url);
+    }
+
+    [Fact]
+    public void Ctor_IncludesUrlAndStatusInMessage()
+    {
+        var ex = new NetworkException(500, "boom", "https://cryptify.postguard.eu/fileupload/init");
+
+        Assert.Contains("500", ex.Message);
+        Assert.Contains("https://cryptify.postguard.eu/fileupload/init", ex.Message);
+        Assert.Contains("boom", ex.Message);
+    }
+
+    [Fact]
+    public void Ctor_AllowsEmptyBody()
+    {
+        var ex = new NetworkException(204, "", "https://pkg.postguard.eu/v2/parameters");
+
+        Assert.Equal("", ex.Body);
+        Assert.Equal("https://pkg.postguard.eu/v2/parameters", ex.Url);
+    }
+}