Share Data Between Apps

Introduction

This how-to will demonstrate how easy it is to build apps using data from different sources using the Catalog. The steps describe the following:

• Create an app in Mendix Studio Pro
• Publish an entity from the app and register it in the Catalog
• Use the Catalog to explore the data sources from the organization that are registered as assets
• Connect to the registered asset that you published earlier and use it in a new app
• Change data in the original app and see it updated in the new or consuming app
• See the network of shared data in the Landscape

Prerequisites

Before starting this how-to, make sure you have completed the following prerequisites:

• Install Mendix Studio Pro 8.14.0 or above

Creating an App

Follow these steps to create a simple app in Studio Pro:

1. In Studio Pro, click New App and choose the Blank app template. Fill in the App Name as {yourname}CustomerServiceApp and select Create app.

2. In the App Explorer, double-click the Domain model in MyFirstModule.

3. In the Toolbox, select Entity and drag it into the domain model.

4. Double-click the entity to open its properties and set its Name to Customer.

5. In the Attributes tab, click New and do the following:

   1. In the Add Attribute dialog box, set Name to CustomerID and set to Type to Autonumber.
   2. Click OK to create the attribute.

6. Repeat steps 5a and 5b to create attributes FirstName, LastName, CompanyName, Address and set type to String for all of them.

   

7. Click OK to save your changes.

8. Right-click the entity and select Generate overview pages from the drop-down list.

9. In the Generate pages dialog box, make sure Atlas_Default (Atlas_Core) is selected as the Content layout and click OK.

10. In the Information pop-up dialog, click Close. Overview pages for the new entity are added in the OverviewPages folder of MyFirstModule.

    

11. In the App Explorer, double-click Home_Web to open the Home_Web page.

12. From the App Explorer, drag Customer_Overview into the empty Auto-fill container under the Home banner.

You have created a simple app with the entity Customer, and a web page where you can view and edit details for this entity.

Customize the home page further by changing the banner text.

Publishing to the Catalog

You need to register the Customer entity in the Catalog to use this entity in other apps. To do this, expose the Customer entity in a Published OData service in Studio Pro. OData v3 and OData v4 are REST-based protocols and standard formats for registering services in the Catalog.

Do the following:

1. In the App Explorer, right-click MyFirstModule. From the drop-down list, select Add folder and name it APIs.

   The published OData service functions as an API to your app. Some apps may have several published services, so it is good practice to keep them together in a folder for each module.

2. In the Domain model, right-click the Customer entity and select Publish in OData service….

   

3. In the Select Published OData Service dialog box, select the MyFirstModule > APIs folder and click New to add a new OData service to this folder.

   

4. Name the published OData service {yourname}CustomerODataService and click OK. The new {yourname}CustomerODataService is added to the module.

5. In the Choose key dialog box, move the attributes you want to be the key from Available attributes to Key attributes.

   

6. Click OK to see the Edit published entity dialog.

   

   Make a note of the Exposed set name. This defaults to the Exposed name with an “s” added to the end. When the service is registered in the Catalog, the Exposed set name will be displayed as the available Dataset.

7. Click OK to display the OData Service document that will be registered in the Catalog. In the General tab, notice the Version number.

   

   Under Entities, the Customer entity is listed. The details of the entity are displayed on the right. To expose more entities in the service, add them in this field.

8. Click Publish in the top bar to deploy the app and publish it. When prompted, click Save and continue to save any unsaved changes to the app.

9. The app is deployed and the OData service is automatically registered in the Catalog. Click View App to open the app in a browser.

10. On the app’s home page, click Customers Overview.

11. Add data to the app. Click New to add data for a customer entry.

    

When this entity set is consumed by another app via the Catalog, the other app will see the data entered here.

Using the Catalog and Curating Your Own Service

The {yourname}CustomerODataService from your app is now registered in the Catalog. The data can be used in other apps. The service is called a Data Source in the Catalog, and the exposed Customer entity is a Dataset.

Do the following:

1. Go to the Catalog.

2. Click Browse and enter the search term {yourname}. All services and datasets that satisfy this search string are displayed in the search results pane.

3. In this scenario, your app was deployed to the Sandbox environment. To search within this environment, click Filter > Check Sandbox > Apply.

   

4. From the new search results list on the left, select the {yourname}CustomerODataService service. Full details from the OData contract for the service are displayed on the right.

You have permissions edit the metadata for this service in the Catalog and are a Technical Owner. To edit the metadata, click the edit icon in the top-right corner of the Data Source field.

For more details on searching in the Catalog and the Search Details screen, see Search in the Catalog. You can also explore registered services in the Landscape. For more information, see Landscape View.

Using the Customer Dataset in Another App

You are going to create a second app and consume the Customer dataset from the {yourname}CustomerODataService service.

To do this, follow the steps below:

1. In Mendix Studio Pro, create a new app using the Blank app template and call it {yourname}CustomerActionsApp.

2. Go to the domain model > Integration pane (if you do not see the Integration pane, click View > Integration to display it).

3. In the Integration pane, enter the search string {yourname}.

4. By default, search in the Integration pane only shows services in Production environments. Your app was deployed as a Sandbox app. Click the Filter icon next to the search and check Show development environments.

   

   The search results now include {yourname}CustomerOData_service from your Mendix Cloud Sandbox environment.

5. From {yourname}CustomerODataService, drag the Customer entity into the domain model. The consumed service and entity have green check marks in the Integration pane now.

6. This entity is different from the blue entity container from the first app. This purple colored entity is called an external entity. The name of the OData service it is exposed in is displayed above it. Click the information icon for the consumed service in the Integration pane to see further information about the service, and follow the link to View in Catalog.

7. In the App Explorer, notice the service and location documents for your external entity. These documents specify the metadata for the service and provide the links for connecting to the shared data.

8. Right-click the entity and select Generate overview pages for this entity. In the Generate pages dialog box, for Content layout select Atlas_Default(Atlas_Core) and click OK. Accept the Information box by clicking Close. Overview pages for the new entity are added in the OverviewPages folder of MyFirstModule.

9. From the App Explorer, open Home_Web and drag Customer_Overview into the empty Auto-fill container.

10. Click Publish to deploy the app and pull in the data you added to the Customer entity in the publishing app ({yourname}CustomerServiceApp) through the ({yourname}CustomerODataService).

Viewing the Shared Data in Your New App

To view the consumed data in your new app, follow these steps:

1. When the app has successfully been deployed, click View App to open the app in the browser.

2. Click Customer Overview.

   The overview page displays the list of the customers that you entered in the {yourname}CustomerServiceApp app. The data is shared from another app, so there are no options for adding or changing the data.

Seeing Changes in Data in the Consuming App

To see an example of consumed data being updated when data is changed in the originating app, follow these steps:

1. Make sure both apps are published in Mendix Studio Pro, then open both apps in separate browser windows.
2. Make a change to the customer list in {yourname}CustomerServiceApp, such as adding a few more customers or editing some existing entries.
3. Refresh the {yourname}CustomerActionsApp window and search to see the changes in the data displayed.

Congratulations, you have successfully used the Catalog to share data between Mendix apps! You can now see your new apps in your Landscape.

Viewing Your Apps in the Landscape

You can view the two apps that you have created in the Landscape and see how they are connected:

1. Open the Catalog home page.

2. Find your service using the search pane. Remember to use the filter to ensure you can see Sandbox apps.

3. Click Landscape View to see a visual representation of your apps (rounded squares), services (circles), and connections (lines). The number of entity sets/datasets that have been exposed appears beneath the service.

   

   The service {yourname}CustomerODataAPI is linked by a solid line to the running instance of {yourname}CustomerCustomerServiceApp, which is deployed as a Free App.

   The service is also linked by a dotted grey line to {yourname}CustomerActionsApp. The arrow indicates that {yourname}CustomerActionsApp is making a call to {yourname}CustomerODataAPI for data. If you click 1 Dataset on this dotted line, the datasets that are being consumed will be listed in the metadata panel on the right.