Specifying the URL source of a web component

The content of URL-based web components is defined by the form field value. It can only be set by program.

Setting the initial URL

When the current form defines a WEBCOMPONENT form item without the COMPONENTTYPE attribute, it is a URL-based web component. The program can set the URL dynamically in field value:

DISPLAY "wc-URL" TO wc-field

or with:

DEFINE wc_field STRING
LET wc_field = "wc-URL"
DISPLAY BY NAME wc_field

or by using the variable in an INPUT dialog with the UNBUFFERED option:

DEFINE rec RECORD
   name STRING,
   mymap STRING
 END RECORD
...
LET rec.mymap = "http://www.openstreetmap.org"
INPUT BY NAME rec.* WITHOUT DEFAULTS
      ATTRIBUTES(UNBUFFERED)
   ...

Once the URL of the web component is defined, the initial URL content is shown by the front-end, and the end user can interact with it.

Changing the URL

During program execution, you can assigning another URL to the web component field value. The content will be updated to show the new URL.

This example implements a MENU dialog with actions that set different URLs to the web component field, changing the content based on the selected action:

MENU "test"
   ON ACTION map_1
      DISPLAY "http://www.openstreetmap.org" TO wc_field
   ON ACTION map_2
      DISPLAY "http://www.wikimapia.org" TO wc_field
   ON ACTION map_3
      DISPLAY "http://maps.google.com" TO wc_field
END MENU

Source of the URL

The URL resource set by the program code is typically an URL that can be accessed and downloaded from a web server, on the internet or in a local network.

However, it is also possible to use a resource that is only available locally on the server where the program executes. The URL-based web components can consume URIs computed in programs by ui.Interface.filenameToURI(). In this case, no web server is required: The URL-based WEBCOMPONENT field content will be provided by the intrinsic file transfer:

-- mypage.html is in current fglrun working directory:
DISPLAY ui.Interface.filenameToURI("mypage.html") TO wc_field