[AJAX] a simple way to do it

Question

I can see lot of question about AJAX in portal and the difficulty to implements it quickly.
Many Oracle documentations about AJAX are too complex and sometimes we want to do things just simply and quickly.
I were confronted to the same problem and I'll give you here a "ready to use" solution.
Scenario :
We want to have a link called "who I am ?" on a page.
This links will make an asynchronous call to a stored procedure that will give the userID of the current user.
Steps :
1/ Create a simple page and put an HTML portlet
2/ edit the HTML portlet
3/ paste this code in it :
----------------------------------------------------START OF COPY HERE >
<script type="text/javascript">
// call of XmlHttpRequest
function ajaxCallRemotePage(url) {
    if (window.XMLHttpRequest) { // Non-IE browsers
           req = new XMLHttpRequest();
            req.onreadystatechange = processStateChange;
        req.open("GET", url, true);
        req.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT");
          req.send(null);
     else if (window.ActiveXObject) { // IE
           req = new ActiveXObject("Microsoft.XMLHTTP");
            req.onreadystatechange = processStateChange;
            req.open("GET", url, true);
            req.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT");
          req.send();
     else {
          return; // Navigateur non compatible     
  // process the return of the "ajaxCallRemotePage"
function processStateChange() {
    if (req.readyState == 4) { // Complete
      if (req.status == 200) { // OK response
        alert("connected user is :" + req.responseText);
      } else {
     alert("your error message here");
</script>
&lt;a href="javascript:ajaxCallRemotePage('/portal/pls/portal/MYSCHEMA.MYPACKAGE.MYMETHOD')"&gt;Who am I ?&lt;/a&gt;
< END OF COPY HERE ----------------------------------------------------
4/ In the DB create this procedure
--------------------------------START OF COPY HERE >
procedure giveUserId is
begin            
htp.p (portal.wwctx_api.get_user ) ;
end giveUserId ;
< END OF COPY HERE ---------------------------------
5/ check if the execute access is granted to public users
6/ test it
workarounds :
You can put the javascript in a file and embed it in a HTML template of your page.
Procedures can be replaced by JSPs
Target url can contain parameters like : /portal/pls/portal/MYSCHEMA.MYPACKAGE.MYMETHOD?param1=X&param2=Y
Parameters can be used in JSPs and in procedures
Processing the return of the call isn't mandatory.
Javascript calls can be triggered on events of the page (start, load, unload ... )
Javascript calls can be triggered on a javascript timer (so you can perform the action every N seconds)
And more and more .....
Here am I. So this the example that you can do AJAX in portal in only 60 lines of javascript code.
I hope it will help you to enhance your portal apps.
any suggestions/remarks are welcome.
cheers

Answer 1

Thank for your example.
I have a question about it.
Is it possible for the javascript to contact a URL that is hosted by the provider. Because in your example the js contact a url that is a plsql procedure hosted in a specific schema. So the problem here is that this procedure is not aware of the session of the provider.
I firstly think about connecting directly to the provider with its complete url but in this case too the session will not be kept.
I my opinion the ideal way would be to contact a url of the portal that will be redriected to the provider.
Do you have any idea on how to do this ?