This component allows iterating on the different options provided by a specific web form, executing a different query on each iteration.
The Form Iterator requires the following elements as input parameters:
- The input page, where the form on which to iterate is located.
- Zero or more lists of records, zero or more values, zero or more records that can be used to parameterize the search and run sequences of the specific form.
As a return value, this component returns the page obtained after each iteration.
Information is required on vacations in the US through a source of real estate offers. This source offers a search form where a group of search terms can be entered in a text box. There is also a combo box, where the type of house required for the summer season can be chosen (apartment, summerhouse, sublet, sale, etc.). With ITPilot, it would be possible to create a process that accepts the type of house to be searched as the input argument. However, if the search is to be made on several house types, an input list provided by the user must be created. The Form Iterator component allows doing this in a simpler form by allowing to iterate on the options provided by the form. In each iteration, the component will assign one of the possible combinations of form input arguments and will run it.
Use of the Form Iterator component shows part of the described process. A Sequence component navigates to the page containing the form. A Form Iterator component is then added. In each iteration, it returns a page used by an Extractor to obtain the required data.
To configure the Form Iterator component follow these steps:
- The component receives as an input the output page of the Sequence component. It may also receive lists, records or values that may be used as input values on the required form.
The component wizard is divided into five tabs:
“Values”: This allows specifying the desired form fields and values on which to iterate. To do so, you must first specify the target form. For this, the following steps are taken:
Open a browser from the Browser->New Browser menu option and navigate to the form page.
Highlight the required form on the page. To do so, simply select part of the text or elements associated with that form (see the figure below).
Click on the “Import Selected Form” button. The wizard editor will display information on each of the form fields and their values (see the figure below).
- It is now possible to choose the different values to be used in the iterations for each field with an enumerated list of possible values (selection lists, check boxes, etc.). For text fields, constant values (between quotes) can be typed or attribute values can be drag&dropped (see the figure below). Through these steps, ITPilot is informed of the values to be used in the different iterations. The number of iterations is equal to the total combinations of these data (e.g. if two possible values are entered in a drop-down and two values in a text field, the component will iterate four times).
On the next tab (“Navigation”) the searching and submitting sequences for the selected form are configured (this is usually already defined after importing the form). The sequence can be loaded from files or imported from the browser, as explained in section Web Browsing Automation, or ITPilot can automatically generate the sequence using the “Suggest submit sequence” button (see the figure below).
The “Configuration” tab is used for configuring the total number of iterations, whether to run parallel iterations or not, the maximum number of parallel iterations that can be run and whether to reuse the current connection (so that the same browser is used for each iteration (which, as explained in section Access to the Details Page: Using Extractor Sequence, may be inadequate for parallel iterations) or not. The order in which the attributes are used may also be configured, affecting the order of the combinations. On this tab it is also possible to configure the number of retries that can be run when an error is detected in the navigation sequence.
The tabs ‘Advanced’ and ‘Denodo Browser’ contain the advanced configuration for the navigation sequence. For more information please see section Advanced Configuration of the Sequence and Next Interval Iterator Components.
- Now the component is configured and it can be independently tested using the “Test” button (in this case a browser must be located in the imported form page. See section Individual Test of Extractor Sequence, Next Interval Iterator and Form Iterator Components).