Oracle Application Express 18.1: Creating a Web Source Module (1 of 2)

Before You Begin

This 15-minute tutorial shows you how to create a Web Source Module and also create a calendar using Oracle Application Express 18.1. Web Source Modules act as a reference to one or multiple external web services. A module can contain one or many Web Source Operations which are the references to a concrete external web service.

This is the first tutorial in the Oracle Application Express 18.1: Creating a Web Source Module Series. Read the tutorials in sequence:

• Oracle Application Express 18.1: Creating a Web Source Module (1 of 2) 
  
• Oracle Application Express 18.1: Creating a Web Source Module (2 of 2)

Background

Web Source Modules enable developers to access Representational State Transfer (REST) services or generic JSON data feeds in applications and use the data in Application Express components such as reports, interactive reports, and interactive grids.

Unlike Web Service References, a Web Source Module contains metadata about the web service which can be used by Application Express Components or PL/SQL processes to invoke the service and to process the responses. Web Source Modules contain multiple operators that differ depending upon the Web service target. For REST services, an operation is a specific service handler (such as, GET, PUT, POST, or DELETE). Developers assign an operation on a database action, such as Fetch Multiple Rows, Fetch Single Row, Insert Row, Update Row, and Delete Row. However, you can assign each Database Operation only once to a Web Source Operation.

What Do You Need?

Accessing Your Development Environment

How you sign in and access Oracle Application Express depends upon where Oracle Application Express resides. Oracle Application Express may reside in a local on-premises Oracle Database or in a hosted environment, such as the Oracle Cloud. The sign in credentials you use to sign in differ depending upon the installation type.

• Free Workspace: Give Oracle Application Express a test run by signing up for a free workspace. To request an evaluation workspace, go to Database Cloud Service, and click Get Started.
• Oracle Cloud: Develop and deploy applications without worrying about infrastructure, repair, and downtime. Oracle Application Express is available in Exadata Express Cloud Service and Database Cloud Service. However, you need to manually customize your databases to install and enable Oracle Application Express. To learn more, see Database Cloud Service
• Oracle Application Express On-premises: Install Oracle Application Express directly within any Oracle Database and then sign in to your workspace using your sign in credentials. For details on your sign in credentials, contact your administrator or see Oracle Application Express Installation Guide.
• Oracle Application Express Pre-Built VM: Install a Pre-Built Virtual Machine (VM) which includes an Oracle Database and Oracle Application Express 18.1. To learn more, see Hands-On Labs.
  Once the VM is installed, start the VM:
• Click Start to start the browser.
• Click the APEX browser bookmark.
• When prompted to sign in, enter the sign in credentials (unless given other credentials to use):
• Workspace: obe
• Userame: obe
• Password: oracle

Create an Application

In this section you  create a new empty application with just a Global page, Home page, and a Login page. Later, you will add pages to it.

To create an application:

1. Sign in to Oracle Application Express 18.1 by entering the credentials (workspace, username, and password).
2. In the Workspace homepage, click App Builder.
   

   

3. Click Create.
4. Select New Application from the Create an Application window.

   

5. The Create an Application page opens. In the Name field, enter USGS Earthquake. This application will display the magnitude and time of when earthquakes occurred in the following sections. 
   

   

6. Select Create Application. The Application home page appears.

Create a Web Source Module

In this section you use the GeoJSON API to demonstrate steps for creating web source for your application.

To create a Web Source Module:

1. On the Application home page, click Shared Components.

   

2. Under Data Sources, select Web Source Modules.

   

3. The Web Source Modules page appears. Click Create.

   

4. On the Create Web Source Module - Method page, define the following attributes:
   •  Create Web Source Module: Select From Scratch.

   

   • Click Next.
5. On the Create Web Source - General page, define the following attributes:
   • Web Source Type - Select Simple HTTP.
   • Name - Enter a descriptive name for this Web Source Module, USGS_Earthquake_WS.
   • URL Endpoint - Enter https://earthquake.usgs.gov/earthquakes/feed/

     

   • Click Next.
     Note that Application Express tests the URL endpoint once you click Next. If the URL is incorrect, an error message displays. If that is the case, click Back and correct the URL. If the URL works, Remote Server page appears.
6.  On the Create Web Source - Remote Server page, define the following attributes:
   • Remote Server: Select Create New
   • Base URL - Enter the Base URL of the chosen Remote Server object: https://earthquake.usgs.gov/earthquakes/feed/
   • Service URL Path - Enter the service-specific URL Path for the Web Source Module:
     v1.0/summary/4.5_month.geojson

   

   • Click Next.
7. On the Authentication page, define the following attributes:
   • Select No (as we are using a public API)

     

   • Click Discover.
8. The Web Source Discovery page opens. You can see that different columns are populated, for example, Place, Magnitude, and Time of the Earthquake.

   

   • Click Create Web Source. The Web Source Module is created.

     

Edit a Web Source Module

To edit the Web Source and add standard date/time for use in the charts or reports:

1. On the Web Source Modules page, select the Module Name. Choose Edit Data Profile at the bottom of the page.

   

2. Click Add Column.

   

3. On the Data Profile Column page, define the following attributes:
   
   • Name: Enter Time_As_Date
   • Column Type: Select Derived
   • SQL Expression: Enter DATE'1970-01-01'+TIME/86400000
   • Data Type: Select Date

   

   • Click Create. The Data Profile page appears.
   • Click Apply Changes to save your changes.

Add a Calendar Page

To update the web source and include a new calendar page:

1. Click the Application ID USGS Earthquake to navigate to the application home page.
2. Click Create Page.
3. Select Calendar.
   

   

4. On the Create Page - Page Attributes page, define the following attributes:
   
   • Page Name: Enter Latest_Earthquakes
   • Additional attributes appear. Accept the defaults.

   

   • Click Next.
5. On the Create Page - Navigation Menu page, define the following attributes:
   
   • Navigation Preference: Select Create a new navigation menu entry
   • Additional attributes appear. Accept the defaults.

   

   • Click Next.
6. On the Create Page - Source
   • Data Source: Select Web Source
   • Web Source Module: Select USGS_Earthquake_WS

     

   • Click Next.
7. On the Create Page - Settings page, define the following attributes:
   
   • Display Column: Select TITLE
   • Start Date Column: This is populated by default. Ensure it shows  Time_As_Date.
   • Show Time: Select Yes  

   

   • Click Create. The new Calendar Page (Latest_Earthquakes) is created.
   • Click Save and Run page.
   • Enter your sign in credentials (workspace,username, and password). You can see the calendar entries for all the days of the Month/Week.

     

Edit Calendar Page

To highlight in a different color the earthquakes with magnitude greater than 5:

1. From the runtime environment, return to the App Builder by clicking Edit Page Latest_Earthquakes in the Developer Toolbar. The Page Designer opens.
   
2. In the Rendering tab, select the Latest_Earthquakes calendar region.
   
3. In the Property Editor, edit the following:
   
   • Local Post Processing: Type - Select SQL Query
     
   • Local Post Processing: SQL Query - Click the Code Editor and add the following SQL statement after Time_As_Date,:

     case when mag > 5 then 'apex-cal-red'
        else 'apex-cal-orange'
        end css_class

     

4. In the Rendering tab, select Latest_Earthquakes calendar region. Select Attributes.
5. In the property editor, edit the following:
   • Enter css in the search filter.
   • Settings: CSS Class - Enter CSS_CLASS.
     

     

   • Click Save and Run page. You can see that the calendar displays different colors on the basis of the earthquake magnitudes.

     

Next Tutorial

Oracle Application Express 18.1: Creating a Web Source Module (2 of 2)

Want to Learn More?

• Managing Web Source Modules