Build Google Cloud Storage-Connected Apps in Mendix

Mendix is a high-productivity app platform that allows you to build and maintain both mobile and web applications at-scale. When paired with CData Connect AI, Mendix provides instant, cloud-to-cloud access to Google Cloud Storage data for applications. This article demonstrates how to connect to a CData Connect AI data source from within Mendix.

CData Connect AI provides a pure cloud-to-cloud interface for Google Cloud Storage, allowing you to import data from live Google Cloud Storage data in Mendix — without replicating the data to a natively supported database. As you build web and mobile applications from within Mendix, CData Connect AI pushes all supported SQL operations (filters, JOINs, etc.) directly to Google Cloud Storage, leveraging server-side processing to return the requested Google Cloud Storage data quickly.

Configure Google Cloud Storage Connectivity for Mendix

To work with Google Cloud Storage data from Mendix, we need to connect to Google Cloud Storage from Connect AI, provide user access to the connection, and create a Workspace for the Google Cloud Storage data.

Connect to Google Cloud Storage from Connect AI

CData Connect AI uses a straightforward, point-and-click interface to connect to data sources.

1. Log into Connect AI, click Sources, and then click Add Connection

2. Select "Google Cloud Storage" from the Add Connection panel

3. Enter the necessary authentication properties to connect to Google Cloud Storage.

   Authenticate with a User Account

   You can connect without setting any connection properties for your user credentials. After setting InitiateOAuth to GETANDREFRESH, you are ready to connect.

   When you connect, the Google Cloud Storage OAuth endpoint opens in your default browser. Log in and grant permissions, then the OAuth process completes

   Authenticate with a Service Account

   Service accounts have silent authentication, without user authentication in the browser. You can also use a service account to delegate enterprise-wide access scopes.

   You need to create an OAuth application in this flow. See the Help documentation for more information. After setting the following connection properties, you are ready to connect:

   • InitiateOAuth: Set this to GETANDREFRESH.
   • OAuthJWTCertType: Set this to "PFXFILE".
   • OAuthJWTCert: Set this to the path to the .p12 file you generated.
   • OAuthJWTCertPassword: Set this to the password of the .p12 file.
   • OAuthJWTCertSubject: Set this to "*" to pick the first certificate in the certificate store.
   • OAuthJWTIssuer: In the service accounts section, click Manage Service Accounts and set this field to the email address displayed in the service account Id field.
   • OAuthJWTSubject: Set this to your enterprise Id if your subject type is set to "enterprise" or your app user Id if your subject type is set to "user".
   • ProjectId: Set this to the Id of the project you want to connect to.

   The OAuth flow for a service account then completes.

   
4. Click Save & Test
5. Navigate to the Permissions tab in the Add Google Cloud Storage Connection page and update the User-based permissions.

Add a Personal Access Token

When connecting to Connect AI through the REST API, the OData API, or the Virtual SQL Server, a Personal Access Token (PAT) is used to authenticate the connection to Connect AI. It is best practice to create a separate PAT for each service to maintain granularity of access.

1. Click on the Gear icon () at the top right of the Connect AI app to open the settings page.
2. On the Settings page, go to the Access Tokens section and click Create PAT.
3. Give the PAT a name and click Create.
4. The personal access token is only visible at creation, so be sure to copy it and store it securely for future use.

Configure Google Cloud Storage Endpoints for Mendix

After connecting to Google Cloud Storage, create a workspace for your desired table(s).

1. Navigate to the Workspaces page and click Add to create a new Workspace (or select an existing workspace).
2. Click Add to add new assets to the Workspace.
3. Select the Google Cloud Storage connection (e.g. GoogleCloudStorage1) and click Next.
4. Select the table(s) you wish to work with and click Confirm.
5. Make note of the OData Service URL for your workspace, e.g. https://cloud.cdata.com/api/odata/{workspace_name}

With the connection, PAT, and Workspace configured, you are ready to connect to Google Cloud Storage data from Mendix.

Build a Google Cloud Storage-Connected App

Downloading the OData Metadata File

When creating a connection in Mendix, the connection flow requires a Data Source Contract File. Follow these steps to download the OData metadata file for CData Connect AI using curl, a command line tool:

1. Open a command-line window for your operating system. On Windows, open the start menu, type cmd, and press the Enter key to open a command prompt. On macOS and Linux, open a Terminal window.
2. To check if curl is installed on your system, type curl -help and press the enter key. If it is not installed, install it from the curl website.
3. Issue the following curl command, replacing USER with your CData Connect AI username and PAT with the PAT you generated above:

   curl -u USER:PAT https://cloud.cdata.com/api/odata/{workspace_name}/$metadata -o metadata.xml

4. Locate the metadata.xml file that the curl command created and move it to an accessible location.

Connecting to CData Connect AI in Mendix

Follow these steps to establish a connection from Mendix to CData Connect AI:

1. Login to Mendix and open the Data Hub page.

2. In the Register a Data Source section, select OData.

3. Upload the metadata.xml file from the steps above and click Next.

4. Enter your desired values for Data Source Name and Data Source Version. In the Data Source Relative Path field, enter /api/odata/{workspace_name} and click Next.

5. On the Application information page, click Register a new application.

6. Enter a name in Application Name and select a technical owner (by default, this is the user who is currently logged in).

7. Click Next. In the Environment Name field, enter a desired name (for example, CData Connect AI). In the Environment Location field, enter https://cloud.cdata.com and select the appropriate Environment Type (e.g. Production), depending on what is needed.

8. Click Done! to create your connection.

You can now use your connection in Mendix Studio Pro to easily create applications with access to live Google Cloud Storage data.

Get CData Connect AI

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