# Modularity & Providers

## Providers

A provider is a design pattern to integrate and swap a code extension more easily and flexibly. A good example are payment methods. If a developer wants to implement multiple payment methods of one payment company, he can create a single module (representing the payment company), which contains a provider for each payment method. Besides [IPaymentMethod](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Checkout/Payment/Service/IPaymentMethod.cs), there are other providers like [IExportProvider](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Platform/DataExchange/Export/IExportProvider.cs), [IShippingRateComputationMethod](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Checkout/Shipping/Services/IShippingRateComputationMethod.cs), [IExchangeRateProvider](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Common/Services/IExchangeRateProvider.cs), [IExternalAuthenticationMethod](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Platform/Identity/Services/IExternalAuthenticationMethod.cs) etc.

Each of these provider interfaces is derived from the marker interface [IProvider](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore/Engine/Modularity/IProvider.cs) in order to be able to identify it uniformly as a provider. The [generic provider class](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Platform/Modularity/Provider.cs) encapsulates the respective interface and enriches it with general properties like [ProviderMetadata](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Platform/Modularity/ProviderMetadata.cs). As a result you get an abstract, handy and API friendly construct such as `Provider<IPaymentMethod>`.

### Metadata

<table><thead><tr><th width="202">Name</th><th width="219">Implement</th><th>Description</th></tr></thead><tbody><tr><td><strong>FriendlyName</strong></td><td>FriendlyNameAttribute</td><td>The English name of the provider. Localizable by using resource key <em>Plugins.FriendlyName.&#x3C;ProviderSystemName></em></td></tr><tr><td><strong>Description</strong></td><td>FriendlyNameAttribute</td><td>The English description of the provider. Localizable by using resource key <em>Plugins.Description.&#x3C;ProviderSystemName></em></td></tr><tr><td><strong>DisplayOrder</strong></td><td>OrderAttribute</td><td>The display order in the providers list.</td></tr><tr><td><strong>DependentWidgets</strong></td><td>DependentWidgetsAttribute</td><td>Widgets which are automatically (de)activated when the provider gets (de)activated. Useful in scenarios where separate widgets are responsible for displaying provider data.</td></tr><tr><td><strong>ExportFeatures</strong></td><td>ExportFeaturesAttribute</td><td>Data processing types supported by an export provider.</td></tr><tr><td><strong>IsConfigurable</strong></td><td>IConfigurable</td><td>A value indicating whether the provider is <a href="#configuration">configurable</a>.</td></tr><tr><td><strong>IsEditable</strong></td><td>IUserEditable</td><td>A value indicating whether the metadata is editable by the user.</td></tr><tr><td><strong>IsHidden</strong></td><td>IsHiddenAttribute</td><td>A value indicating whether the provider is hidden. A hidden provider can only be used programmatically but not by the user through the user interface.</td></tr><tr><td><strong>SystemName *</strong></td><td>SystemNameAttribute</td><td>Unique SystemName of the provider, e.g. <em>Payments.AmazonPay.</em></td></tr></tbody></table>

{% hint style="info" %}
A provider can be activated or deactivated using the provider list. For example, a deactivated payment provider does not appear in the checkout payment method list.
{% endhint %}

### Configuration

Providers are configurable via `IConfigurable`. It specifies a `RouteInfo` that points to an action method used for configuration.

```csharp
public RouteInfo GetConfigurationRoute()
    => new(nameof(MyModuleAdminController.Configure), "MyModuleAdmin", new { area = "Admin" });
```

Typically the configuration consists of two *Configure* methods, one called by `HttpGet` to load the configuration and one called by `HttpPost` to save it. Since we are configuring a provider and its configuration view is just a portion of the actual Razor layout page, we need to tell it what provider we are configuring. This is done via the metadata and `ViewBag.Provider`.

```csharp
private readonly IProviderManager _providerManager;

[LoadSetting]
public IActionResult Configure(MyProviderSettings settings)
{
    var model = MiniMapper.Map<MyProviderSettings, MyConfigurationModel>(settings);
    
    ViewBag.Provider = _providerManager.GetProvider("MyProviderSystemName").Metadata;
    
    return View(model);
}
```

Use [IProviderManager](https://github.com/smartstore/Smartstore/blob/main/src/Smartstore.Core/Platform/Modularity/IProviderManager.cs) to load any provider (including its metadata) or all providers of a certain type. Since we are configuring settings inherited from `ISetting`, we can use the `LoadSettingAttribute` to load an instance of our settings as an action parameter. The `HttpPost` method for saving may look like this:

```csharp
[HttpPost, SaveSetting]
public IActionResult Configure(MyConfigurationModel model,
    MyProviderSettings settings)
{
    if (!ModelState.IsValid)
    {
        return Configure(settings);
    }

    MiniMapper.Map(model, settings);
    
    return RedirectToAction(nameof(Configure));
}
```

The `SaveSettingAttribute` automatically saves the updated settings to database. The configuration view may look like this:

```cshtml
@model MyConfigurationModel

@{
    Layout = "_ConfigureProvider";
}

<widget target-zone="admin_button_toolbar_before">
    <button id="SaveConfigButton" type="submit" name="save" value="save"
        class="btn btn-warning">
        <i class="fa fa-check"></i>
        <span>@T("Admin.Common.Save")</span>
    </button>
</widget>

@await Component.InvokeAsync("StoreScope")

<form asp-action="Configure">
    <div asp-validation-summary="All"></div>
    @* TODO: multi-store configuration using setting-editor tag helper. *@
</form>
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://dev.smartstore.com/framework/platform/modularity-and-providers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.