![\"001\"](\"https:\/\/blog.sharedove.com\/adisjugo\/wp-content\/uploads\/2016\/11\/001.png\" "\\"001\\"")
<\/a><\/p>\nSince the main purpose of our API App will be to make a restful service wrapper around a database, let\u2019s add some data to it. I will choose here ADO.NET Entity Data model and Code First from Database, but it can really be anything. I am going to call it BeerDataModel.<\/p>\n So let\u2019s use my beers database. I will need to create a connection string in Visual Studio\u2026<\/p>\n \u2026and to choose table(s) which I want to publish through this restful API. In this case, we will keep it simple, and take only one table \u2013 \u201callbeers\u201d. <\/p>\n Once we have added the data model to our service, we need to add some controllers to wrap that data. In my case, Scaffolded Item will do fine:<\/p>\n I will say that it is Web API 2 Controller with actions around Entity Framework data:<\/p>\n Visual Studio will be nice enough, to immediately offer me model and data context classes.<\/p>\n Once when it is all done, my project looks like this: Model Class, Data Context class, my new controller, and default controller (\u201cValuesController\u201d) which was created initially with the project. We can delete that one, since we will not need it.<\/p>\n Now, we need to enable swagger UI. Swagger is service definition format, used for restful services, much as WSDL was used with SOAP. Visual Studio offers us instant enabling of swagger UI in the SwaggerConfig.cs file in App_Start. In short, you can just uncomment the .EnableSwaggerUi part. But, it is worthwhile to take look at that file, much of the how swagger works with your service can be understood from there.<\/p>\n Once it has been done, you can actually just press F5 and look the magic happen. Since we didn\u2019t define any startup document, IIS Express will just return 403 error. No problem, since we have the swagger interface enabled, let\u2019s just append \u201c\/swagger\u201d to your service url, and voila\u2026 There is your service! With service description, and options to test all the methods.<\/p>\n For example, click on GET allbeers operation, and then click on \u201cTry it out!\u201d \u2013 you\u2019ll get all your beers as bunch of JSON.<\/p>\n The next we need to do, is to deploy this Web API it as an API App. This is a fairly simple process form Visual Studio, you will need to select or create new Azure web application, and to publish it as an App Service.<\/p>\n Now let\u2019s go to our Azure management portal, and check if the API App has been properly created:<\/p>\n Also, test it through the swagger UI of the deployed API:<\/p>\n Once you are sure it all works, open the swagger API definition from swagger UI, and save it is a JSON file:<\/p>\n <\/p>\n <\/p>\n Once you have done that, go to the PowerApps portal, in the connections section, and click on add new connection, New Custom API.<\/p>\n In the dialog that you will get after it, you will have to name your custom API, to upload the swagger API definition and icon.<\/p>\n We will talk about authentication a bit later, but for the moment, in the authentication dialog, choose the only possible option \u2013 No authentication.<\/p>\n And there is your new custom API! Now, let\u2019s create a PowerApp from it.<\/p>\n In the early version of PowerApps, when the Enterprise plan was still available, it was possible to use a wizard generate an app from the custom API. That feature hit the dust at some point of time, and it seems that it is not coming back. So, you will have to wire the controls to your custom data source manually. Which is not difficult, but not something you would let your power users (intended audience here) do. A practical workaround is to create a PowerApp from any data source, and then to change wirings manually. In my case, I created a dummy PowerApp from an existing SharePoint list, and through the Data sources dialog in PowerApps app for Windows 10, added my custom API as a new connection:<\/p>\n <\/p>\n In the screens that PowerApps wizard created for me, I just changed the existing item sources with my RESTful API methods (get all, get one, put, post, delete), and I was good to go:<\/p>\n <\/p>\n That\u2019s it \u2013 this is your PowerApp, which is using custom API as a data source! Pretty cool, huh? Well\u2026<\/p>\n \u2026well, only partly. As you have probably noticed, there is zero security around this API, and in this App. When we already speak about the features which have bit the dust, passing authentication tokens to API Apps was one of them. That \u201cAuthentication\u201d dialog was not always empty \u2013 \u201cAzure Active Directory\u201d was there earlier. When that option was selected, and when Azure API App\u2019s authentication was set to AAD (screenshot below), PowerApp (actually, an AAD App created in background) was passing tokens to API App, and user was properly impersonated.<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n I am hosting it in Azure, but it can be really anywhere.<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\nSecurity<\/h3>\n