nav[aria-label="Primary Navigation"] { padding: 0; & ul { list-style: none; width: 100%; display: flex; flex-direction: row; justify-content: start; align-items: start; gap: 30px; padding: 0; & li { margin: 0; } & ul li { list-style: none; } } }

callServer() question

niniti

I have never used callServer() before in a DCT. Now I may have to use it. I need some confusion cleared.

I am going through guide, but can not understand it.

The target server (which can be any process that can handle an HTTP request and make a response, such as a servlet or CGI) reads the request and returns JavaScript code embedded in an HTML page. This page is loaded into a hidden frame, distinct from the frame that contains the user script and FormAPI. FormsPublisher provides a special parent.getScriptFrame() function to this hidden frame that returns the user script frame. In this way, the code returned by the server coexists with the user script and has full access to its methods and data

1) a remote server call is made using callServer() , then remote server executes a CGI and returns an HTML page as response which contains Javascript code only. Why is there Javascript code only ? can this HTML page not containg any other HTML code ? As CGI can return any valid HTML code.

2) This page is loaded in hidden frame. What does this mean ? what is hidden frame ? Is it separate HTML page or is it a frame within DCT form used by user ? I did not see any attribute in frame element to make a frame hidden. When HTML page is returned by remote server that contains javascripot code, does it exist separately from DCT form or does it exist within DCT form ? It looks like this HTML that contains Javascript code exists within DCT form , but it is separate from already existing Javascript code.

3) FormsPublisher provides a special parent.getScriptFrame() function to this hidden frame that returns the user script frame.
Does it mean that page returned by the remote server stays in the DCT as a child page or sub page of existing DCT form ? and when we use parent.getScriptFrame(), does that get code from parent frame into the child frame ? Can we get javascript code from child frame into parent frame ?

4) How does the HTML page returned by remote server get converted to frame to exist within DCT form ?

5) What makes it necessary to get JavaScript code to be called using callServer() ? Can we just not write a JavaScript code in the DCT itself ?

thanks

Find more posts tagged with

Comments

RonaldV

Poeh,

that is a lot of questions. Let;s start with 5:

5: Using callserver() is only useful if you need some info that is not available in the dcr but only on the server (that you are calling). F.i. validate a field value against a database or so.

1+2+3+4: the callserver is "executed" in hidden iframe (hidden as in you will not see it in the browser). Thus any html that is in the cgi-result will not be shown. But won't throw any error either. And in order to have your "cgi-javascript" to communicate with you form/formapi you MUST use parent.getScriptFrame() as a hook. Their is no other way to talk back from you cgi to you form.

Hope this helps.....

ISCBorisB

Take a look at [post=165508]this[/post] post, review attached sample.

It illustrates one of the typical callServer practices, namely "Get something from the Server and Populate DCR Item with it".
It also shows getScriptFrame() usage to execute DCT-side "callback" Function, etc...

niniti

Thanks for replies.

I am understanding but still I dont understand following. Please help with that.

I am making a remote server call to invoke a CGI.

1) This CGI returns an HTML code , which contains JavaScript code only. Is this HTML code returned by remote server and hidden frame two different things or one and same thing ?

2) Now this HTML code is loaded in the original page as a hidden frame. How can HTML code returned by remote server be turned into a hidden frame ?

3) Once the JavaScript code is loaded in the hidden frame, which is separate from DCT Form making remote server call, does this code get called in the parent frame or does the javascript from parent DCT Form get called in this hidden frame ? It appears to me that script from parent DCT Form gets called in hidden frame by reading the manual. If thats the case, then how does this script in hidden frame act on DCT Form, because DCT form is a separate entity which is not available to hidden frame ?

If possible, please answer point wise.

Thanks

ISCBorisB

If possible, please answer point wise...

>>1. This CGI returns an HTML code, which contains JavaScript code only. Is this HTML code returned by remote
server and hidden frame two different things or one and same thing?
No, it's not one and the same. Frames are not some abstract concept. It's a mechanism and distinct HTML Syntax
to build Browser Page from multiple URLs. Take a look here for some details.

Data Capture Window that opens up when you edit a DCR is a multi-frame window. Frames naming, Layout, Visibility
and whatnot are defined by TS Front - End Code and are out of your control. One of these pre-existing Frames is
the frame that sends HTTP Request to the callServer and subsequently evaluates callServer generated CGI Output - in
case you've got a fancy to use callServer. If you don't - the frame is there regardless.

This Frame is hidden. It means that no matter what your CGI generates it will not be directly visible on the Form.
The key word here is "directly". After all, you've called it for a reason. So, your generated CGI output *may*
have JS code that makes visible changes in other Page Frame(s) - like for example populating certain
item in the visible "formframe" Frame. Or, it can set certain FomAPI Flag allowing "Save" later on. Or, it
can show some warning. Or, it can do nothing as far as DC Form is concerned. In other words, it should do what you
need - whatever that might be.

>>2) Now this HTML code is loaded in the original page as a hidden frame. How can HTML code returned by remote server be turned into a hidden frame?
It can't and it doesn't. I hope that's clear from the previous answer.

>>3) Once the JavaScript code is loaded in the hidden frame, which is separate from DCT Form making remote server call, does this code get
called in the parent frame or does the javascript from parent DCT Form get called in this hidden frame? It appears to me that script from
parent DCT Form gets called in hidden frame by reading the manual. If thats the case, then how does this script in hidden frame act on DCT
Form, because DCT form is a separate entity which is not available to hidden frame?
Absolutely nothing gets called automatically by DC Form Frames, hidden or otherwise. It is all yours (the developer)
responsibility to make sure that what you need gets called upon evaluation of the HTML that your callServer Script
generates. There are several ways to do it. One of the simplest is illustrated in the sample I've referred
above - head's JS script executed upon Page loading

niniti

Thanks.

That clears almost all the confusion.

From the link provided for w3schools.com, I can understand that each frame contains a separate HTML document and each frame is independent from each other, Its just they are grouped together by way of frameset.

So CGI generated output is evaluated by the hidden frame. And there is a separate frame displaying the DC Form and this is the frame which contains user script and FormAPI.
FormsPublisher provides a special parent.getScriptFrame() function to this hidden frame that returns the user script frame. Does it mean that user script (Script defined in script tag in DCT) gets loaded in hidden frame by parent.getScriptFrame() or is it other way ?
If this is the case, how will script in hidden frame access DCT fields , as its a separate frame meaning a separate document from the one in display frame ?

So how will script loaded in hidden frame can access DC fields in display frame. I can understand it if content from hidden frame is loaded in diplay frame.

I am doing the reading to clarify myself on the rest.

Adam Stoller

Are you trying to implement your own templating interface, or are you trying to learn how to use callServer to interact with a DCT form in FormsPublisher?

If the latter - you're digging way deeper than you need to do so - all you need is a conceptual understanding:

You've already been pointed to example code to do some of these things - do you really need to know the complete underlying architecture down to the individual semi-colons used in the code to implement it?I mean - it's great that you're interested in such technology (perhaps I should be) - but if you're trying to solve a problem with your code - explain what you've done and what's not working rather than trying to understand how the vendor's product was implemented. If you're not trying to solve a problem and are really just trying to understand the architecture so you could implement your own templating interface - say so - and then you'd probably be better off going through some technical courses at a school rather than trying to learn it all through a public forum.