Host and deploy ASP.NET Core Blazor

Publish the app

Apps are published for deployment in Release configuration.

Note

Publish hosted Blazor WebAssembly solutions from the Server project.

  1. Select Build > Publish {APPLICATION} from the navigation bar.
  2. Select the publish target. To publish locally, select Folder.
  3. Accept the default location in the Choose a folder field or specify a different location. Select the Publish button.

Publishing the app triggers a restore of the project's dependencies and builds the project before creating the assets for deployment. As part of the build process, unused methods and assemblies are removed to reduce app download size and load times.

Publish locations:

  • Blazor WebAssembly
    • Standalone: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder. To deploy the app as a static site, copy the contents of the wwwroot folder to the static site host.
    • Hosted: The client Blazor WebAssembly app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder of the server app, along with any other static web assets of the server app. Deploy the contents of the publish folder to the host.
  • Blazor Server: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish folder. Deploy the contents of the publish folder to the host.

The assets in the folder are deployed to the web server. Deployment might be a manual or automated process depending on the development tools in use.

App base path

The app base path is the app's root URL path. Consider the following ASP.NET Core app and Blazor sub-app:

  • The ASP.NET Core app is named MyApp:
    • The app physically resides at d:/MyApp.
    • Requests are received at https://www.contoso.com/{MYAPP RESOURCE}.
  • A Blazor app named CoolApp is a sub-app of MyApp:
    • The sub-app physically resides at d:/MyApp/CoolApp.
    • Requests are received at https://www.contoso.com/CoolApp/{COOLAPP RESOURCE}.

Without specifying additional configuration for CoolApp, the sub-app in this scenario has no knowledge of where it resides on the server. For example, the app can't construct correct relative URLs to its resources without knowing that it resides at the relative URL path /CoolApp/. This scenario also applies in various hosting and reverse proxy scenarios when an app isn't hosted at a root URL path.

To provide configuration for the Blazor app's base path of https://www.contoso.com/CoolApp/, set the relative root path.

Blazor WebAssembly (wwwroot/index.html):

<base href="/CoolApp/">

The trailing slash is required.

In a Blazor Server app, use either of the following approaches:

  • Option 1: Use the <base> tag in Pages/_Layout.cshtml to set the app's base path:

    <base href="/CoolApp/">
    

    The trailing slash is required.

  • Option 2: Call UsePathBase in the app's request pipeline (Program.cs):

    app.UsePathBase("/CoolApp");
    

    This approach (Option 2) is recommended when you also wish to run the Blazor Server app locally. For example, supply the launch URL in Properties/launchSettings.json:

    "launchUrl": "https://localhost:{PORT}/CoolApp",
    

    The {PORT} placeholder in the preceding example is the port that matches the secure port in the applicationUrl configuration path. The following example shows the full launch profile for an app at port 7279:

    "BlazorSample": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "https://localhost:7279;http://localhost:5279",
      "launchUrl": "https://localhost:7279/CoolApp",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
    }
    

Note

In typical configurations for Azure/IIS hosting, additional configuration usually isn't required. In some non-IIS hosting and reverse proxy hosting scenarios, additional Static File Middleware configuration might be required to serve static files correctly (for example, app.UseStaticFiles("/CoolApp");). The required configuration might require further configuration to serve the Blazor script (_framework/blazor.server.js or _framework/blazor.webassembly.js). For more information, see ASP.NET Core Blazor static files.

For third-party host support, check the host provider's documentation and interact with developers on public support forums to implement the correct configuration. Common general support forums include: Stack Overflow (tag: blazor), ASP.NET Core Slack Team, and Blazor Gitter. The preceding forums are not owned or controlled by Microsoft.

By providing the relative URL path, a component that isn't in the root directory can construct URLs relative to the app's root path. Components at different levels of the directory structure can build links to other resources at locations throughout the app. The app base path is also used to intercept selected hyperlinks where the href target of the link is within the app base path URI space. The Blazor router handles the internal navigation.

In many hosting scenarios, the relative URL path to the app is the root of the app. In these cases, the app's relative URL base path is a forward slash (<base href="/" /> for Blazor WebAssembly or <base href="~/" /> for Blazor Server), which is the default configuration for a Blazor app. In other hosting scenarios, such as GitHub Pages and IIS sub-apps, the app base path must be set to the server's relative URL path of the app.

For a Blazor WebAssembly app with a non-root relative URL path (for example, <base href="/CoolApp/">), the app fails to find its resources when run locally. To overcome this problem during local development and testing, you can supply a path base argument that matches the href value of the <base> tag at runtime. Don't include a trailing slash. To pass the path base argument when running the app locally, execute the dotnet run command from the app's directory with the --pathbase option:

dotnet run --pathbase=/{RELATIVE URL PATH (no trailing slash)}

For a Blazor WebAssembly app with a relative URL path of /CoolApp/ (<base href="/CoolApp/">), the command is:

dotnet run --pathbase=/CoolApp

The Blazor WebAssembly app responds locally at http://localhost:port/CoolApp.

Blazor Server MapFallbackToPage configuration

In scenarios where an app requires a separate area with custom resources and Razor components:

  • Create a folder within the app's Pages folder to hold the resources. For example, an administator section of an app is created in a new folder named Admin (Pages/Admin).

  • Create a root page (_Host.cshtml) for the area. For example, create a Pages/Admin/_Host.cshtml file from the app's main root page (Pages/_Host.cshtml). Don't provide an @page directive in the Admin _Host page.

  • Add a layout to the area's folder (for example, Pages/Admin/_Layout.razor). In the layout for the separate area, set the <base> tag href to match the area's folder (for example, <base href="/Admin/" />). For demonstration purposes, add ~/ to the static resources in the page. For example:

    • ~/css/bootstrap/bootstrap.min.css
    • ~/css/site.css
    • ~/BlazorSample.styles.css (the example app's namespace is BlazorSample)
    • ~/_framework/blazor.server.js for the Blazor script
  • If the area should have its own static asset folder, add the folder and specify its location to Static File Middleware in Program.cs (for example, app.UseStaticFiles("/Admin/wwwroot")).

  • Razor components are added to the area's folder. At a minimum, add an Index component to the area folder with the correct @page directive for the area. For example, add a Pages/Admin/Index.razor file based on the app's default Pages/Index.razor file. Indicate the Admin area as the route template at the top of the file (@page "/admin"). Add additional components as needed. For example, Pages/Admin/Component1.razor with an @page directive and route template of @page "/admin/component1.

  • In Program.cs, call MapFallbackToPage for the area's request path immediately before the fallback root page path to the _Host page:

    ...
    app.UseRouting();
    
    app.MapBlazorHub();
    app.MapFallbackToPage("~/Admin/{*clientroutes:nonfile}", "/Admin/_Host");
    app.MapFallbackToPage("/_Host");
    
    app.Run();
    

Host multiple Blazor WebAssembly apps

For more information on hosting multiple Blazor WebAssembly apps in a hosted Blazor solution, see Host and deploy ASP.NET Core Blazor WebAssembly.

Deployment

For deployment guidance, see the following topics:

Publish the app

Apps are published for deployment in Release configuration.

  1. Select Build > Publish {APPLICATION} from the navigation bar.
  2. Select the publish target. To publish locally, select Folder.
  3. Accept the default location in the Choose a folder field or specify a different location. Select the Publish button.

Publishing the app triggers a restore of the project's dependencies and builds the project before creating the assets for deployment. As part of the build process, unused methods and assemblies are removed to reduce app download size and load times.

Publish locations:

  • Blazor WebAssembly
    • Standalone: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder. To deploy the app as a static site, copy the contents of the wwwroot folder to the static site host.
    • Hosted: The client Blazor WebAssembly app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder of the server app, along with any other static web assets of the server app. Deploy the contents of the publish folder to the host.
  • Blazor Server: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish folder. Deploy the contents of the publish folder to the host.

The assets in the folder are deployed to the web server. Deployment might be a manual or automated process depending on the development tools in use.

App base path

The app base path is the app's root URL path. Consider the following ASP.NET Core app and Blazor sub-app:

  • The ASP.NET Core app is named MyApp:
    • The app physically resides at d:/MyApp.
    • Requests are received at https://www.contoso.com/{MYAPP RESOURCE}.
  • A Blazor app named CoolApp is a sub-app of MyApp:
    • The sub-app physically resides at d:/MyApp/CoolApp.
    • Requests are received at https://www.contoso.com/CoolApp/{COOLAPP RESOURCE}.

Without specifying additional configuration for CoolApp, the sub-app in this scenario has no knowledge of where it resides on the server. For example, the app can't construct correct relative URLs to its resources without knowing that it resides at the relative URL path /CoolApp/. This scenario also applies in various hosting and reverse proxy scenarios when an app isn't hosted at a root URL path.

To provide configuration for the Blazor app's base path of https://www.contoso.com/CoolApp/, set the relative root path.

Blazor WebAssembly (wwwroot/index.html):

<base href="/CoolApp/">

The trailing slash is required.

In a Blazor Server app, use either of the following approaches:

  • Option 1: Use the <base> tag in Pages/_Host.cshtml to set the app's base path:

    <base href="/CoolApp/">
    

    The trailing slash is required.

  • Option 2: Call UsePathBase in the app's request pipeline (Program.cs):

    app.UsePathBase("/CoolApp");
    

Note

In typical configurations for Azure/IIS hosting, additional configuration usually isn't required. In some non-IIS hosting and reverse proxy hosting scenarios, additional Static File Middleware configuration might be required to serve static files correctly (for example, app.UseStaticFiles("/CoolApp");). The required configuration might require further configuration to serve the Blazor script (_framework/blazor.server.js or _framework/blazor.webassembly.js). For more information, see ASP.NET Core Blazor static files.

For third-party host support, check the host provider's documentation and interact with developers on public support forums to implement the correct configuration. Common general support forums include: Stack Overflow (tag: blazor), ASP.NET Core Slack Team, and Blazor Gitter. The preceding forums are not owned or controlled by Microsoft.

By providing the relative URL path, a component that isn't in the root directory can construct URLs relative to the app's root path. Components at different levels of the directory structure can build links to other resources at locations throughout the app. The app base path is also used to intercept selected hyperlinks where the href target of the link is within the app base path URI space. The Blazor router handles the internal navigation.

In many hosting scenarios, the relative URL path to the app is the root of the app. In these cases, the app's relative URL base path is a forward slash (<base href="/" /> for Blazor WebAssembly or <base href="~/" /> for Blazor Server), which is the default configuration for a Blazor app. In other hosting scenarios, such as GitHub Pages and IIS sub-apps, the app base path must be set to the server's relative URL path of the app.

For a Blazor WebAssembly app with a non-root relative URL path (for example, <base href="/CoolApp/">), the app fails to find its resources when run locally. To overcome this problem during local development and testing, you can supply a path base argument that matches the href value of the <base> tag at runtime. Don't include a trailing slash. To pass the path base argument when running the app locally, execute the dotnet run command from the app's directory with the --pathbase option:

dotnet run --pathbase=/{RELATIVE URL PATH (no trailing slash)}

For a Blazor WebAssembly app with a relative URL path of /CoolApp/ (<base href="/CoolApp/">), the command is:

dotnet run --pathbase=/CoolApp

The Blazor WebAssembly app responds locally at http://localhost:port/CoolApp.

Blazor Server MapFallbackToPage configuration

In scenarios where an app requires a separate area with custom resources and Razor components:

  • Create a folder within the app's Pages folder to hold the resources. For example, an administator section of an app is created in a new folder named Admin (Pages/Admin).

  • Create a root page (_Host.cshtml) for the area. For example, create a Pages/Admin/_Host.cshtml file from the app's main root page (Pages/_Host.cshtml). Don't provide an @page directive in the Admin _Host page.

  • Add a layout to the area's folder (for example, Pages/Admin/_Layout.razor). In the layout for the separate area, set the <base> tag href to match the area's folder (for example, <base href="/Admin/" />). For demonstration purposes, add ~/ to the static resources in the page. For example:

    • ~/css/bootstrap/bootstrap.min.css
    • ~/css/site.css
    • ~/BlazorSample.styles.css (the example app's namespace is BlazorSample)
    • ~/_framework/blazor.server.js for the Blazor script
  • If the area should have its own static asset folder, add the folder and specify its location to Static File Middleware in Program.cs (for example, app.UseStaticFiles("/Admin/wwwroot")).

  • Razor components are added to the area's folder. At a minimum, add an Index component to the area folder with the correct @page directive for the area. For example, add a Pages/Admin/Index.razor file based on the app's default Pages/Index.razor file. Indicate the Admin area as the route template at the top of the file (@page "/admin"). Add additional components as needed. For example, Pages/Admin/Component1.razor with an @page directive and route template of @page "/admin/component1.

  • In Startup.Configure, call MapFallbackToPage for the area's request path immediately before the fallback root page path to the _Host page:

    ...
    app.UseRouting();
    
    app.MapBlazorHub();
    app.MapFallbackToPage("~/Admin/{*clientroutes:nonfile}", "/Admin/_Host");
    app.MapFallbackToPage("/_Host");
    
    app.Run();
    

Host multiple Blazor WebAssembly apps

For more information on hosting multiple Blazor WebAssembly apps in a hosted Blazor solution, see Host and deploy ASP.NET Core Blazor WebAssembly.

Deployment

For deployment guidance, see the following topics:

Publish the app

Apps are published for deployment in Release configuration.

  1. Select Build > Publish {APPLICATION} from the navigation bar.
  2. Select the publish target. To publish locally, select Folder.
  3. Accept the default location in the Choose a folder field or specify a different location. Select the Publish button.

Publishing the app triggers a restore of the project's dependencies and builds the project before creating the assets for deployment. As part of the build process, unused methods and assemblies are removed to reduce app download size and load times.

Publish locations:

  • Blazor WebAssembly
    • Standalone: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder. To deploy the app as a static site, copy the contents of the wwwroot folder to the static site host.
    • Hosted: The client Blazor WebAssembly app is published into the /bin/Release/{TARGET FRAMEWORK}/publish/wwwroot folder of the server app, along with any other static web assets of the server app. Deploy the contents of the publish folder to the host.
  • Blazor Server: The app is published into the /bin/Release/{TARGET FRAMEWORK}/publish folder. Deploy the contents of the publish folder to the host.

The assets in the folder are deployed to the web server. Deployment might be a manual or automated process depending on the development tools in use.

App base path

The app base path is the app's root URL path. Consider the following ASP.NET Core app and Blazor sub-app:

  • The ASP.NET Core app is named MyApp:
    • The app physically resides at d:/MyApp.
    • Requests are received at https://www.contoso.com/{MYAPP RESOURCE}.
  • A Blazor app named CoolApp is a sub-app of MyApp:
    • The sub-app physically resides at d:/MyApp/CoolApp.
    • Requests are received at https://www.contoso.com/CoolApp/{COOLAPP RESOURCE}.

Without specifying additional configuration for CoolApp, the sub-app in this scenario has no knowledge of where it resides on the server. For example, the app can't construct correct relative URLs to its resources without knowing that it resides at the relative URL path /CoolApp/. This scenario also applies in various hosting and reverse proxy scenarios when an app isn't hosted at a root URL path.

To provide configuration for the Blazor app's base path of https://www.contoso.com/CoolApp/, set the relative root path.

Blazor WebAssembly (wwwroot/index.html):

<base href="/CoolApp/">

The trailing slash is required.

In a Blazor Server app, use either of the following approaches:

  • Option 1: Use the <base> tag in Pages/_Host.cshtml to set the app's base path:

    <base href="/CoolApp/">
    

    The trailing slash is required.

  • Option 2: Call UsePathBase in the app's request pipeline (Program.cs):

    app.UsePathBase("/CoolApp");
    

Note

In typical configurations for Azure/IIS hosting, additional configuration usually isn't required. In some non-IIS hosting and reverse proxy hosting scenarios, additional Static File Middleware configuration might be required to serve static files correctly (for example, app.UseStaticFiles("/CoolApp");). The required configuration might require further configuration to serve the Blazor script (_framework/blazor.server.js or _framework/blazor.webassembly.js). For more information, see ASP.NET Core Blazor static files.

For third-party host support, check the host provider's documentation and interact with developers on public support forums to implement the correct configuration. Common general support forums include: Stack Overflow (tag: blazor), ASP.NET Core Slack Team, and Blazor Gitter. The preceding forums are not owned or controlled by Microsoft.

By providing the relative URL path, a component that isn't in the root directory can construct URLs relative to the app's root path. Components at different levels of the directory structure can build links to other resources at locations throughout the app. The app base path is also used to intercept selected hyperlinks where the href target of the link is within the app base path URI space. The Blazor router handles the internal navigation.

In many hosting scenarios, the relative URL path to the app is the root of the app. In these cases, the app's relative URL base path is a forward slash (<base href="/" /> for Blazor WebAssembly or <base href="~/" /> for Blazor Server), which is the default configuration for a Blazor app. In other hosting scenarios, such as GitHub Pages and IIS sub-apps, the app base path must be set to the server's relative URL path of the app.

For a Blazor WebAssembly app with a non-root relative URL path (for example, <base href="/CoolApp/">), the app fails to find its resources when run locally. To overcome this problem during local development and testing, you can supply a path base argument that matches the href value of the <base> tag at runtime. Don't include a trailing slash. To pass the path base argument when running the app locally, execute the dotnet run command from the app's directory with the --pathbase option:

dotnet run --pathbase=/{RELATIVE URL PATH (no trailing slash)}

For a Blazor WebAssembly app with a relative URL path of /CoolApp/ (<base href="/CoolApp/">), the command is:

dotnet run --pathbase=/CoolApp

The Blazor WebAssembly app responds locally at http://localhost:port/CoolApp.

Blazor Server MapFallbackToPage configuration

In scenarios where an app requires a separate area with custom resources and Razor components:

  • Create a folder within the app's Pages folder to hold the resources. For example, an administator section of an app is created in a new folder named Admin (Pages/Admin).

  • Create a root page (_Host.cshtml) for the area. For example, create a Pages/Admin/_Host.cshtml file from the app's main root page (Pages/_Host.cshtml). Don't provide an @page directive in the Admin _Host page.

  • Add a layout to the area's folder (for example, Pages/Admin/_Layout.razor). In the layout for the separate area, set the <base> tag href to match the area's folder (for example, <base href="/Admin/" />). For demonstration purposes, add ~/ to the static resources in the page. For example:

    • ~/css/bootstrap/bootstrap.min.css
    • ~/css/site.css
    • ~/BlazorSample.styles.css (the example app's namespace is BlazorSample)
    • ~/_framework/blazor.server.js for the Blazor script
  • If the area should have its own static asset folder, add the folder and specify its location to Static File Middleware in Program.cs (for example, app.UseStaticFiles("/Admin/wwwroot")).

  • Razor components are added to the area's folder. At a minimum, add an Index component to the area folder with the correct @page directive for the area. For example, add a Pages/Admin/Index.razor file based on the app's default Pages/Index.razor file. Indicate the Admin area as the route template at the top of the file (@page "/admin"). Add additional components as needed. For example, Pages/Admin/Component1.razor with an @page directive and route template of @page "/admin/component1.

  • In Startup.Configure.cs, call MapFallbackToPage for the area's request path immediately before the fallback root page path to the _Host page:

    ...
    app.UseRouting();
    
    app.MapBlazorHub();
    app.MapFallbackToPage("~/Admin/{*clientroutes:nonfile}", "/Admin/_Host");
    app.MapFallbackToPage("/_Host");
    
    app.Run();
    

Host multiple Blazor WebAssembly apps

For more information on hosting multiple Blazor WebAssembly apps in a hosted Blazor solution, see Host and deploy ASP.NET Core Blazor WebAssembly.

Deployment

For deployment guidance, see the following topics: