innomatrix / delivery-sdk-net

Kentico Cloud Delivery .NET SDK

Kentico Cloud Delivery .NET SDK

Paradigm	Package	Downloads	Documentation
Async			📖
Reactive			📖

Summary

The Kentico Cloud Delivery .NET SDK is a client library used for retrieving content from Kentico Cloud.

You can use it via any of the following NuGet packages:

• KenticoCloud.Delivery
• KenticoCloud.Delivery.Rx

The first package provides the DeliveryClient object to consume Kentico Cloud data via the traditional async way. The second one provides the DeliveryObservableProxy object that enables the reactive way of consuming the data.

The SDK targets the .NET Standard 2.0, which means it can be used in .NET Framework 4.6.1 projects and above, and .NET Core 2.0 projects and above.

Using the DeliveryClient

The IDeliveryClient interface is the main interface of the SDK. Using an implementation of this interface, you can retrieve content from your Kentico Cloud projects.

To initialize the client, use the DeliveryClientBuilder class and provide a project ID.

// Initializes an instance of the DeliveryClient client by building it with the DeliveryClientBuilder class
IDeliveryClient client = DeliveryClientBuilder.WithProjectId("<YOUR_PROJECT_ID>").Build();

You can also provide the project ID and other parameters by passing a function that returns the DeliveryOptions object to the DeliveryClientBuilder.WithOptions method.

We recommend creating the DeliveryOptions instance by using the DeliveryOptionsBuilder class. With the options builder, you can use the following parameters:

• ProjectId – sets the ID of your Kentico Cloud project. This parameter must always be set.
• UsePreviewApi – determines whether to use the Delivery Preview API and sets the Delivery Preview API key. See previewing unpublished content to learn more.
• UseProductionApi – determines whether to use the default production Delivery API.
• UseSecuredProductionApi – determines whether authenticate requests to the production Delivery API with an API key. See retrieving secured content to learn more.
• WaitForLoadingNewContent – forces the client instance to wait while fetching updated content, useful when acting upon webhook calls.
• EnableResilienceLogic – determines whether HTTP requests will use retry logic. By default, the resilience logic is enabled.
• MaxRetryAttempts – sets a custom number of retry attempts. By default, the SDK retries requests five times.
• WithCustomEndpoint - sets a custom endpoint for the specific API (preview, production, or secured production).

IDeliveryClient client = DeliveryClientBuilder
    .WithOptions(builder => builder
        .WithProjectId("<YOUR_PROJECT_ID>")
        .UseProductionApi
        .WithMaxRetryAttempts(maxRetryAttempts)
	.Build())
    .Build();

For advanced configuration options, see using dependency injection and ASP.NET Core Configuration API.

Basic querying

Once you have an instance of the IDeliveryClient, you can start querying your project by calling methods on the instance.

// Retrieves a single content item
DeliveryItemResponse response = await client.GetItemAsync("about_us");

// Retrieves a list of all content items
DeliveryItemListingResponse listingResponse = await client.GetItemsAsync();

Filtering retrieved data

The SDK supports full scale of the API querying and filtering capabilities as described in the API reference.

// Retrieves a list of the specified elements from the first 10 content items of
// the 'brewer' content type, ordered by the 'product_name' element value
DeliveryItemListingResponse response = await client.GetItemsAsync(
    new EqualsFilter("system.type", "brewer"),
    new ElementsParameter("image", "price", "product_status", "processing"),
    new LimitParameter(10),
    new OrderParameter("elements.product_name")
);

Getting localized items

The language selection is just a matter of specifying the LanguageParameter parameter with a codename of the required language.

// Retrieves a list of the specified elements from the first 10 content items of
// the 'brewer' content type, ordered by the 'product_name' element value
DeliveryItemListingResponse response = await client.GetItemsAsync(
    new LanguageParameter("es-ES"),
    new EqualsFilter("system.type", "brewer"),
    new ElementsParameter("image", "price", "product_status", "processing"),
    new LimitParameter(10),
    new OrderParameter("elements.product_name")
);

Strongly-typed responses

The IDeliveryClient also supports retrieving of strongly-typed models.

// Retrieving a single content item
DeliveryItemResponse<Article> response = await client.GetItemAsync<Article>("latest_article");

// Retrieving all content items
DeliveryItemListingResponse<Article> listingResponse = await client.GetItemsAsync<Article>();

See Working with Strongly Typed Models to learn how to generate models and adjust the logic to your needs.

Previewing unpublished content

To retrieve unpublished content, you need to create an instance of the IDeliveryClient with both Project ID and Preview API key. Each Kentico Cloud project has its own Preview API key.

// Note: We recomend that you work with only either the production OR preview Delivery API within a single project.
IDeliveryClient client = DeliveryClientBuilder
    .WithOptions(builder => builder
        .WithProjectId("<YOUR_PROJECT_ID>")
        .UsePreviewApi("<YOUR_PREVIEW_API_KEY>")
        .Build())
    .Build();

Learn more about previewing unpublished content using the Delivery API in our Developer Hub.

Response structure

For full description of single and multiple content item JSON response formats, see our API reference.

Single content item response

When retrieving a single content item, you get an instance of the DeliveryItemResponse class. This class represents the JSON response from the Delivery API endpoint and contains the requested ContentItem as a property.

Multiple content items response

When retrieving a list of content items, you get an instance of the DeliveryItemListingResponse. This class represents the JSON response from the Delivery API endpoint and contains:

• Pagination property with information about the following:
  • Skip: requested number of content items to skip
  • Limit: requested page size
  • Count: the total number of retrieved content items
  • NextPageUrl: the URL of the next page
• A list of the requested content items

ContentItem structure

The ContentItem class provides the following:

• System property with metadata such as code name, display name, type, or sitemap location.
• Elements as a dynamically typed property containing all the elements included in the response structured by code names.
• Methods for easier access to certain types of content elements such as linked items, or assets.

Getting content item properties

You can access information about a content item (such as its ID, codename, name, location in sitemap, date of last modification, and its content type codename) by using the System property.

// Retrieves name of an article content item
articleItem.System.Name

// Retrieves codename of an article content item
articleItem.System.Codename

// Retrieves name of the content type of an article content item
articleItem.System.Type

Getting element values

The SDK provides methods for retrieving content from content elements such as Asset, Text, Rich Text, Multiple choice, etc.

Text

For Text elements, you can use the GetString method.

// Retrieves an article text from the 'body_copy' Text element
articleItem.GetString("body_copy")

Rich text

• The Rich text element can contain links to other content items within your project. See Resolving links to content items for more details.
• The Rich text element can contain components and other content items. See Structured Rich text rendering for more details. To learn more about components and linked content, visit our API Reference.

Asset

// Retrieves a teaser image URL
articleItem.GetAssets("teaser_image").First().Url

Multiple choice

To get a list of options defined in a Multiple choice content element, you first need to retrieve the content element itself. For this purpose, you can use the GetContentElementAsync method, which takes the codename of a content type and the codename of a content element.

// Retrieves the 'processing' element of the 'coffee' content type
ContentElement element = await client.GetContentElementAsync("coffee", "processing");

After you retrieve the Multiple choice element, you can work with its list of options. Each option has the following properties:

Property	Description	Example
Name	The display name of the option.	Dry (Natural)
Codename	The codename of the option.	dry__natural_

To put the element's options in a list, you can use the following code:

List<SelectListItem> items = new List<SelectListItem>();

foreach (var option in element.Options)
{
    items.Add(new SelectListItem {
        Text = option.Name,
        Value = option.Codename,
        Selected = (option.Codename == "semi_dry")
    });
}

Linked items

// Retrieves related articles
articleItem.GetLinkedItems("related_articles")

Using the Image transformations

The ImageUrlBuilder class exposes methods for applying image transformations on the Asset URL.

string assetUrl = articleItem.GetAssets("teaser_image").First().Url;
ImageUrlBuilder builder = new ImageUrlBuilder(assetUrl);
string transformedAssetUrl = builder.WithFocalPointCrop(560, 515, 2)
                                    .WithDPR(3)
                                    .WithAutomaticFormat(ImageFormat.Png)
                                    .WithCompression(ImageCompression.Lossy)
                                    .WithQuality(85)
                                    .Url;

For list of supported transformations and more information visit the Kentico Delivery API reference at https://developer.kenticocloud.com/v1/reference?#image-transformation.

Resilience capabilities

By default, the SDK uses a retry policy, asking for requested content again in case of an error. You can disable the retry policy by setting the DeliveryOptions.EnableResilienceLogic parameter to false. The default policy retries the HTTP requests if the following status codes are returned:

• 408 - RequestTimeout
• 500 - InternalServerError
• 502 - BadGateway
• 503 - ServiceUnavailable
• 504 - GatewayTimeout

The default policy retries requests 5 times, totaling 6 overall attempts to retrieve content before throwing a DeliveryException. You can configure the number of attempts using the DeliveryOptions.MaxRetryAttempts property. The consecutive attempts are delayed exponentially: 400 milliseconds, 800 milliseconds, 1600 milliseconds, etc.

The default resilience policy is implemented using Polly. You can also implement your own Polly policy wrapped in an IResiliencePolicyProvider instance. The instance can be set to IDeliveryClient implementation through the DeliveryClientBuilder class or by registering it to the ServiceCollection.

Using the KenticoCloud.Delivery.Rx reactive library

The DeliveryObservableProxy class provides a reactive way of retrieving Kentico Cloud content.

The DeliveryObservableProxy class constructor accepts an IDeliveryClient instance, therefore you are free to create the IDeliveryClient implementation (or its derivatives) in any of the supported ways.

public IDeliveryClient DeliveryClient => DeliveryClientBuilder.WithProjectId("975bf280-fd91-488c-994c-2f04416e5ee3").Build();
public DeliveryObservableProxy DeliveryObservableProxy => new DeliveryObservableProxy(DeliveryClient);

The DeliveryObservableProxy class exposes methods that mirror the public methods of the IDeliveryClient. The methods have the same names, with an Observable suffix. They call the IDeliveryClient methods in the background.

IObservable<Article> articlesWithBaristaPersona =
	DeliveryObservableProxy.GetItemsObservable<Article>(new ContainsFilter("elements.personas", "barista"));

Unlike most of the IDeliveryClient methods that return data wrapped in Delivery*Response objects, their *Observable counterparts always return sequences of the Kentico Cloud artifacts themselves (not wrapped). Should an error response be returned by the IDeliveryClient implementation, the observable sequence will terminate with the conventional OnError call.

Using SourceLink for debugging

This repository is configured to generate a SourceLink tag in the NuGet package that allows debugging this repository's source code when it is referenced as a Nuget package. The source code is downloaded directly from GitHub to Visual Studio.

How to configure SourceLink

1. Open a solution with a project referencing the KenticoCloud.Delivery (or KenticoCloud.Delivery.RX) Nuget package.
2. Open Tools -> Options -> Debugging -> General.
   • Clear Enable Just My Code.
   • Select Enable Source Link Support.
   • (Optional) Clear Require source files to exactly match the original version.
3. Build your solution.
4. Add a symbol server https://symbols.nuget.org/download/symbols

• 

5. Run a debugging session and try to step into the KenticoCloud.Delivery code.
6. Allow Visual Studio to download the source code from GitHub.

• 

Now you are able to debug the source code of our library without needing to download the source code manually!

Further information

For more developer resources, visit the Kentico Cloud Developer Hub at https://developer.kenticocloud.com.

Building the sources

Prerequisites:

Required: .NET Core SDK.

Optional:

• Visual Studio 2017 for full experience
• or Visual Studio Code

Feedback & Contributing

Check out the contributing page to see the best places to file issues, start discussions, and begin contributing.

Wall of Fame

We would like to express our thanks to the following people who contributed and made the project possible:

• Jarosław Jarnot - Vimanet
• Varinder Singh - Kudos Web
• Charith Sooriyaarachchi - 99X Technology

Would you like to become a hero too? Pick an issue and send us a pull request!