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Fetch Data from Public API to Your SAP Build Application

Configure your application to fetch records from a public API when a food item is scanned, using a Get Record command, which first needs to be configured.
You will learn
  • How to configure your application to fetch records from a public API
  • How to configure data variables.
thecodesterDaniel WrolewskiMarch 5, 2023
Created by
September 20, 2021

In the previous tutorial, you learned how to connect your application to a public API. From here, you now need to configure the application to read specific information from that API once a barcode has been scanned. This again uses the Get Record HTTPS request, but this time that request is triggered with a logic flow.

  • Step 1

    Open your draft application in your Composer account, displaying your barcode scanner app.

    As you no longer need your application to send an alert, as this was just used as a test, you need to start by removing the alert component in your logic flow.

    To do this, click your Scan button and then click Show Logic for Button1.

    Show logic for button 1

    Remove the Alert component from your logic panel, as this is no longer needed.

    Remove alert component
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  • Step 2

    You now need to add your new logic flow for what should happen after the barcode has been scanned. For your application, you want the barcode scanner to fetch data from the data resource you configured in the previous tutorial.

    To do this, using the core logic options, scroll down to Data – Get Record and then drag and drop this into the logic editor.

    Add Get Record component

    Add a connector from the top Scan QR/barcode option to the Get Record option, indicating the flow of logic in your application.

    Add connector
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  • Step 3

    Once the logic flow is set, you need to bind the information to the output of the scanner node.

    1. To do this, select the Get Record element and, using the properties panel, click Currently bound to: Static text, opening the binding options screen.

      Currently bound options
    2. Click Output value of another node.

      Output value edit

      Configure the binding to the following:

      • Select logic node – Scan QR/barcode
      • Select node output – Scan QR/barcode / QR barcode content
    3. Click Save.

    The Get Record flow function should now be able to fetch data for any food barcode you scan with your application.

    Edit binding
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  • Step 4

    You now need to configure your application to store the data it receives. To do this, you need to add data variables.

    1. To do this, switch to the Variables view.

      Switch to variables view
    2. Click Data Variables.

      Data variables
    3. Click Add Data Variable.

      Add data variables

      Select your Open Food Facts variable.

      Select open food facts

      As the barcode will be for a single product, select Data variable type – Single data record.

      Select single data record
    4. Data variables come with default logic that fetches new information every five seconds, however your app should only fetch information when a barcode is scanned. As a result, you need to remove the default logic.

      To do this, click Show Logic for Empty Page.

      Click show logic button

      Then delete the default logic by highlighting it and pressing the delete button on the keyboard.

      Delete default logic

      Click Save.

      Save logic

      Why did we delete default logic?

      Whenever you create a data variable, default logic is added to fetch the data when the page loads, and then again every 5 seconds. But we want to fetch data only when the user clicks the button and scans a barcode, so we removed the default logic and will later add logic on the button click.

    The data variables are now configured for your application.

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  • Step 5
    1. Click View to switch back to your application interface view.

      From here, you will need to add the final piece to your logic flow, storing the retrieved data into the data variable.

      Change view
    2. Click your Scan button to open the relevant logic panel.

      Scan button logic

      This is where we add the logic to scan a barcode and retrieve the data for that product.

    3. Using the core logic options, scroll down to Variables – Set Data Variables and then drag and drop this into the logic editor.

      Set Data Variable

      Add a connector from the top Get record option to the Set data variable option.

      Add connector
    4. Click the Set data variable element and click Currently bound to: object with properties.

      Currently bound

      Now you must store the data you just retrieved to the data variable.

      IMPORTANT: The following provides 2 ways to do this. The first way is the standard way, but for some people this may cause the SAP Build Apps editor to hang (you can click to exit). So we have provided a second way to store the data using a formula.

      • Select Output value of another node and then choose the following:

        • Select logic node: Get record
        • Select node output: Record
        Link text e.g., Destination screen
      • Instead, you can do the same thing with a formula. Most, if not all, bindings can be done with the UI or manually with a formula.

        Select Formula, and then enter for the formula the following:

        outputs["Get record"].record

      Click Save to save this logic (no matter how you entered it).

      Save the logic
    5. Click Save (upper right) to save your draft application.

      Link text e.g., Destination screen

    The logic has now been added to your draft application.

    When will your app fetch new information from the API?

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