Limiting Form Submissions with Scripts

Expected Results

When developing a frontend page, you can add some submission restrictions to the form in the script to improve user experience and data security. For example, you can define a delay time in the script as shown in Figure 1. When a form is submitted within the specified time, the Submission failed: Not PortalUser! is displayed as shown in Figure 2. When the specified time is exceeded, the Submission failed: Submitted too late is displayed as shown in Figure 3.

Figure 1 Script restriction
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Figure 2 Submission failed: Not PortalUser!
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Figure 3 Submission failed: Submitted too late
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Implementation Methods

Create a low-code application.

Apply for a free trial or purchase a commercial instance by referring to Authorization of Users for Huawei Cloud Astro Zero Usage and Instance Purchases.
After the instance is purchased, click Access Homepage on Homepage. The application development page is displayed.
In the navigation pane, choose Applications. On the displayed page, click Low-Code or .
When you create an application for the first time, create a namespace as prompted. Once it is created, you cannot change or delete it, so check the details carefully. Use your company or team's abbreviation for the namespace.
In the displayed dialog box, choose Standard Applications and click Confirm.

Enter a label and name of the application, and click the confirm button. The application designer is displayed.

Figure 4 Creating a blank application
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**Table 1** Parameters for creating a blank application
Parameter	Description	Example
Label	The label for the new application; Max. 80 characters. A label uniquely identifies an application in the system and cannot be modified after creation.	My first application
Name	Name of the new application. After you enter the label value and click the text box of this parameter, the system automatically generates an application name and adds *Namespace*__ before the name. Naming rules: Max. characters: 31, including the prefix namespace. To prevent duplicate data names among different tenants, each tenant must define a unique namespace when first creating an application. A tenant can only create one namespace, and once it is created, it cannot be modified. Start with a letter and use only letters, digits, and underscores (_). Do not end with an underscore (_).	A

Create an object named product and add fields to the object.

In the navigation pane, choose Data, and click + next to Object.
Set Object Name and Unique ID of the object to product and click the confirm button.
Figure 5 Creating object product

**Table 2** Parameters for the created object product
Parameter	Description	Example
Object Name	Name of the new object, which can be changed after the object is created. Value: 1–80 characters.	product
Unique ID	ID of a new object in the system, which cannot be modified after being created. Naming rules: Max. 63 characters, including the prefix namespace. The content that is blurred in front of the ID is a namespace. To prevent duplicate data names among different tenants, each tenant must define a unique namespace when first creating an application. A tenant can only create one namespace, and once it is created, it cannot be modified. Start with a letter and use only letters, digits, and underscores (_). Do not end with an underscore (_).	product

Click to go to the object details page.

On the Fields tab page, click Add and add the ProName field for the object.

Figure 6 Adding the ProName field
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**Table 3** Parameters for adding the proName field
Parameter	Description	Example
Display Name	Name of the new field, which can be changed after the field is created. Value: 1–63 characters.	proName
Unique ID	ID of a new field in the system. The value cannot be changed after the field is created. Naming rules: Max. 63 characters, including the prefix namespace. Start with a letter and use only letters, digits, and an underscore (_). Do not end with an underscore (_).	proName
Field Type	Click . On the page that is displayed, select the type of the new field based on the parameter description.	Text

On the Fields tab, click Add again to add the proId field.
Figure 7 Adding the proId field

Create a script.

In the navigation pane, choose Logic and click + next to Script.
Create a script, set the name to submitLimit, and click Add.
Figure 8 Creating the submitLimit script

In the script editor, enter the sample code.

The sample code is used to obtain the input of the frontend page, verify the input parameters, and call the object API to add an object instance. In the example, Namespace __product__CST is the object created in 2.

//This script is used to submit forms and restrict the submission time and user type.
import * as db from 'db';//Import the standard library related to the object.
import * as context from 'context';//Import the standard library related to the context.
import { now } from 'date';
import { toDate } from 'date';

//Define the input parameter structure.
@action.object({ type: "param" })
export class ActionInput {
    @action.param({ type: 'String', required: true, label: 'String' })
    proId: string;
    @action.param({ type: 'String', required: true, label: 'String' })
    proName: string;
}
//Define the output parameter structure. The output parameter contains one parameter, that is, the record ID of workOrder.
@action.object({ type: "param" })
export class ActionOutput {
    @action.param({ type: 'String' })
    id: string;
}
//Use the data object namespace __product__CST.
@useObject(['Namespace__product__CST'])
@action.object({ type: "method" })
export class CreateWorkOrder {    //Define the API class. The input parameter of the API is ActionInput, and the output parameter is ActionOutput.
    @action.method({ input: 'ActionInput', output: 'ActionOutput' })
    public createWorkOrder(input: ActionInput): ActionOutput {
        let out = new ActionOutput();    //Create an instance of the ActionOutput type as the return value.
        let error = new Error();    //Create an instance of the error type to save the error information when an error occurs.
        try {
            let currentTime = now();
            let date = toDate('2024-04-08 20:08:08', 'yyyy-MM-dd HH:mm:ss');
            if (date.getTime() < currentTime.getTime()) { // Restrict the submission time
                error.name = "WOERROR";
                error.message = "Submitted too late";
                throw error;
            }
            let user = context.getUserType();
            if (user != "PortalUser") { // Restrict the submission user type. Only the PortalUser can submit data.
                error.name = "WOERROR";
                error.message = "Not PortalUser!";
                throw error;
            }

            let productData = new Object();
            productData['Namespace__proName__CST'] = input.proName;   //Assign value to input parameters.
            productData['Namespace__proId__CST'] = input.proId;
            let s = db.object('Namespace__product__CST');    //Obtain the operation instance of the Namespace__product__CST object.
            let id = s.insert(productData);
            if (id) {
                out.id = id;
            } else {
                error.name = "WOERROR";
                error.message = "Unable to create product!";
                throw error;
            }
        } catch (error) {
            console.error(error.name, error.message);
            context.setError(error.name, error.message);
        }
        return out;
    }
}

Click to save the script. After the script is saved, click to activate the script.

Create a form page to submit form data.
1. In the navigation pane, choose Page, and click + next to Standard Page.
2. Enter the label and name of the page and click Add to create a standard page.
3. Drag two Input widgets and one Button widget to page on the right.
4. Change the Label to name and id for these two Input widgets, and set the Button widget's Display Name to Add.
  Figure 9 Designing a form page
Create an object model.
1. At the bottom of the standard page, click Model View.
2. Click New, specify the Model Name (for example, submitLimit), select Services for Source, and click Next.
  Figure 10 Creating a model
3. Set Service Type to Script. On the displayed Select Service page, select the script created in 3 and click OK.
  Figure 11 Selecting the script
4. Click Next and then click OK.
Return to Designer View and bind the model with the widgets.
1. At the bottom of the standard page, click Designer View.
2. Select the name input widget, choose Properties > Data Binding and click next to Value Binding.
3. Select the model (proName) created in 5 and click OK.
  Figure 12 Selecting the model
  
  Figure 13 Binding effect
4. Repeat the preceding operations to bind the model (proId) created in 5 to the id input widget.
  Figure 14 Binding a model to the id input widget
Add an event for the Add button.
1. Select the Add button widget and click the Events tab on the right of the page.
2. Click + next to on-click. The page for adding an action is displayed.
3. Under Custom Action, enter the custom code and click Create.
  Figure 15 Customizing an action
  
  In this example, the custom JavaScript code is used to obtain the exception information thrown by the script and display the exception information on the page after the submit button is clicked.
```
$model.ref('submitLimit').run().then(function(data){
    context.$message.success('Submitted successfully.');
    console.log(data);
}).catch(function(error){
    context.$message.error('Submission failed: ' + error.resMsg);
});
```
Click in the upper part of the page to save the page settings.
After the settings are saved, click in the upper part of the page to preview the effect.