fix #167: create new option to provide server deployment sub-path

samples/WebApp/Program.cs

@@ -36,12 +36,14 @@
 app.UseAuthentication();
 app.UseAuthorization();
 
+var serverSubPath = bool.Parse(builder.Configuration["SerilogUi:AddServerSubPath"] ?? "false") ? "logs/" : "";
 app.UseSerilogUi(options => options
     .WithHomeUrl("/#Test")
+    .WithServerSubPath(serverSubPath)
     .WithAuthenticationType(AuthenticationType.Jwt)
     .WithExpandedDropdownsByDefault()
     .EnableAuthorizationOnAppRoutes()
-    .InjectJavascript("/js/serilog-ui/custom.js")
+    .InjectJavascript($"/{serverSubPath}js/serilog-ui/custom.js")
 );
 
 app.MapControllerRoute(

samples/WebApp/Properties/launchSettings.json

@@ -4,7 +4,7 @@
     "windowsAuthentication": false,
     "anonymousAuthentication": true,
     "iisExpress": {
-      "applicationUrl": "http://localhost:40034",
+      "applicationUrl": "http://localhost:40034/logs",
       "sslPort": 44304
     }
   },
@@ -23,7 +23,8 @@
       "commandName": "IISExpress",
       "launchBrowser": true,
       "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "SerilogUi:AddServerSubPath": "true"
       }
     }
   }

samples/WebApp/appsettings.json

@@ -17,12 +17,11 @@
   },
   "SerilogUi": {
     "UserName": "BasicSampleUser",
-    "Password": "BasicSamplePwd"
+    "Password": "BasicSamplePwd",
+    "AddServerSubPath": false
   },
   "Serilog": {
-    "Using": [
-      "Serilog.Sinks.MongoDB"
-    ],
+    "Using": ["Serilog.Sinks.MongoDB"],
     "MinimumLevel": "Debug",
     "WriteTo": [
       {

src/Serilog.Ui.Web/Endpoints/SerilogUiAppRoutes.cs

@@ -51,7 +51,7 @@ public Task RedirectHomeAsync()
 
     private async Task<string> LoadStream(Stream stream, UiOptions options)
     {
-        StringBuilder htmlStringBuilder = new StringBuilder(await new StreamReader(stream).ReadToEndAsync());
+        StringBuilder htmlStringBuilder = new(await new StreamReader(stream).ReadToEndAsync());
         string authType = options.Authorization.AuthenticationType.ToString();
 
         var feOpts = new
@@ -63,7 +63,7 @@ private async Task<string> LoadStream(Stream stream, UiOptions options)
             options.ShowBrand,
             options.HomeUrl,
             BlockHomeAccess,
-            options.RoutePrefix,
+            RoutePrefix = ConstructRoutesPrefix(options),
             options.ExpandDropdownsByDefault
         };
         string encodeAuthOpts = Uri.EscapeDataString(JsonSerializer.Serialize(feOpts, JsonSerializerOptionsFactory.GetDefaultOptions));
@@ -75,4 +75,16 @@ private async Task<string> LoadStream(Stream stream, UiOptions options)
 
         return htmlStringBuilder.ToString();
     }
+
+    private static string ConstructRoutesPrefix(UiOptions options)
+    {
+        var safeHostPath = string.IsNullOrWhiteSpace(options.ServerSubPath) ? "" : options.ServerSubPath;
+        var hostPathWithoutInitialSlash = safeHostPath.StartsWith("/", StringComparison.OrdinalIgnoreCase) ? safeHostPath[1..] : safeHostPath;
+        var hostPathWithDivider = !string.IsNullOrWhiteSpace(hostPathWithoutInitialSlash) &&
+                                  !hostPathWithoutInitialSlash.EndsWith('/')
+            ? $"{hostPathWithoutInitialSlash}/"
+            : hostPathWithoutInitialSlash;
+
+        return $"{hostPathWithDivider}{options.RoutePrefix}";
+    }
 }

src/Serilog.Ui.Web/Models/UiOptions.cs

@@ -27,6 +27,12 @@ public class UiOptions(ProvidersOptions options)
     /// <value>The route prefix.</value>
     public string RoutePrefix { get; private set; } = "serilog-ui";
 
+    /// <summary>
+    /// Gets the server sub-path deployment.
+    /// </summary>
+    /// <value>The server sub path.</value>
+    public string ServerSubPath { get; private set; } = string.Empty;
+
     /// <summary>
     /// Get the option to auto-expand dropdowns in the log viewer.
     /// </summary>
@@ -126,6 +132,23 @@ public UiOptions WithRoutePrefix(string routePrefix)
         return this;
     }
 
+    /// <summary>
+    /// Sets the server hosting base-path.
+    /// If the application is deployed under a server sub-path, this property provides the additional sub-path to
+    /// the dashboard to help the client-side routing.<br/>
+    /// If provided, the final routing result will be:<br/><c>{server-base-path}/{UiOptions.ServerSubPath}/{UiOptions.RoutePrefix}</c>.
+    /// </summary>
+    /// <example>
+    /// Server root: "server.com"
+    /// IF the application is deployed at root level ("server.com/{my-app}") => NOT set ServerSubPath
+    /// IF the application is deployed at sub-path level ("server.com/{additional-path}/{my-app}") => MUST set ServerSubPath
+    /// </example>
+    public UiOptions WithServerSubPath(string serverSubPath)
+    {
+        ServerSubPath = serverSubPath;
+        return this;
+    }
+
     internal void Validate()
     {
         if (RoutePrefix.EndsWith('/')) throw new ArgumentException($"{nameof(RoutePrefix)} can't end with a slash.");

tests/Serilog.Ui.Web.Tests/Endpoints/SerilogUiAppRoutesTest.cs

@@ -39,18 +39,25 @@ public SerilogUiAppRoutesTest()
             _sut = new SerilogUiAppRoutes(_contextAccessor, _streamLoaderMock);
         }
 
-        [Fact]
-        public async Task It_gets_app_home()
+        [Theory]
+        [InlineData(null, "test")]
+        [InlineData("", "test")]
+        [InlineData(" ", "test")]
+        [InlineData("sub-path", "sub-path/test")]
+        [InlineData("sub-path/", "sub-path/test")]
+        [InlineData("/sub-path/", "sub-path/test")]
+        public async Task It_gets_app_home(string? serverSubPath, string expectedRoutePrefix)
         {
             // Arrange
-            _sut.SetOptions(new UiOptions(new ProvidersOptions())
-            {
-                BodyContent = "<div>body-test</div>",
-                HeadContent = "<div>head-test</div>"
-            }
-                .WithAuthenticationType(AuthenticationType.Jwt)
-                .WithRoutePrefix("test")
-                .WithHomeUrl("home-url")
+            var body = "<div>body-test</div>";
+            var head = "<div>head-test</div>";
+            var baseOpts = new UiOptions(new()) { BodyContent = body, HeadContent = head };
+            _sut
+                .SetOptions(baseOpts
+                    .WithAuthenticationType(AuthenticationType.Jwt)
+                    .WithRoutePrefix("test")
+                    .WithServerSubPath(serverSubPath!)
+                    .WithHomeUrl("home-url")
             );
             _testContext.Request.Path = "/serilog-ui-url/";
             _testContext.Response.Body = new MemoryStream();
@@ -75,9 +82,8 @@ public async Task It_gets_app_home()
                 "<body><div id=\"serilog-ui-app\"></div>" +
                 "<script>const config = '%7B%22authType%22%3A%22Jwt%22%2C%22columnsInfo%22%3A%7B%7D%2C%22" +
                 "disabledSortOnKeys%22%3A%5B%5D%2C%22renderExceptionAsStringKeys%22%3A%5B%5D%2C%22showBrand%22%3Atrue%2C%22homeUrl%22%3A%22home-url" +
-                "%22%2C%22blockHomeAccess%22%3Afalse%2C%22routePrefix%22%3A%22" +
-                "test%22%2C%22expandDropdownsByDefault%22%3Afalse%7D';</script><div>body-test</div></body></html>"
-            );
+                "%22%2C%22blockHomeAccess%22%3Afalse%2C%22routePrefix%22%3A%22" + Uri.EscapeDataString(expectedRoutePrefix) +
+                "%22%2C%22expandDropdownsByDefault%22%3Afalse%7D';</script><div>body-test</div></body></html>");
         }
 
         [Fact]

tests/Serilog.Ui.Web.Tests/Models/UiOptionsTest.cs

@@ -16,6 +16,7 @@ public void It_gets_default_options()
 
         sut.HomeUrl.Should().Be("/");
         sut.RoutePrefix.Should().Be("serilog-ui");
+        sut.ServerSubPath.Should().BeEmpty();
         sut.BodyContent.Should().BeEmpty();
         sut.HeadContent.Should().BeEmpty();
         sut.ShowBrand.Should().BeTrue();
@@ -33,12 +34,14 @@ public void It_sets_options()
             .WithHomeUrl("test")
             .WithAuthenticationType(AuthenticationType.Basic)
             .WithRoutePrefix("prefix")
+            .WithServerSubPath("log")
             .HideSerilogUiBrand()
             .WithExpandedDropdownsByDefault()
             .EnableAuthorizationOnAppRoutes();
 
         sut.HomeUrl.Should().Be("test");
         sut.RoutePrefix.Should().Be("prefix");
+        sut.ServerSubPath.Should().Be("log");
         sut.ShowBrand.Should().BeFalse();
         sut.ExpandDropdownsByDefault.Should().BeTrue();
         sut.Authorization.AuthenticationType.Should().Be(AuthenticationType.Basic);