What is the functionality of callserver on the background?

Hi,

How callserver is working in the background.I mean to say, why it is running asynchronously?.what is the functionality behind that?.

Many Thanks
~Sasi

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kaalraa

Hi,

How callserver is working in the background.I mean to say, why it is running asynchronously?.what is the functionality behind that?.

Many Thanks
~Sasi

For Synchronous execution they already have provided CGICallouts, however CallServer() superseded them in many ways.

1. It gets executed either using GET or POST method.
2. Uses HTTP session
3. Can return the values to DCR, which is similar to CGI callout.

I guess, there are many more... but these are which comes to my mind at first.

ISCBorisB

For Synchronous execution they already have provided CGICallouts, however CallServer() superseded them in many ways.

1. It gets executed either using GET or POST method.
2. Uses HTTP session
3. Can return the values to DCR, which is similar to CGI callout.

True, you can use either get or post in callServer case

I guess, there are many more... but these are which comes to my mind at first.

Almost all of that is incorrect. CGI Callout is asynchronous - just like callServer. HTTP protocol is stateless, there is
no such animal as "HTTP Session". Neither CGI nor callServer *return* anything. In the CGI case you use 'opener' properties
to find/modify DC Form components. callServer generated Page is rendered into DC Form's hidden Frame. Once again,
it is your (the developer) responsibility to generate JS Components to execute Form's *call-back* Functions from there, etc.

Granted, you can use either post or get with callServer request

ISCBorisB

Hi,

How callserver is working in the background.I mean to say, why it is running asynchronously?.what is the functionality behind that?.

Many Thanks
~Sasi

CGI Callouts are used to provide User Interface to extend standard DC Form items and Data Capturing mechanisms.

callServer is similar to AJAX, it provides developers with the mechanisms to communicate to Servers from DC Form Java Script.
All that is (usually) transparent to Content Contributors

sasikumarg

Actually I would like to know how callserver() works..For example if we are having multiple call server () request in a template,we dont have control over that.How ever we can control the same through some workaround.My question is , what are the things happening in the background when a form invokes call server()...Is there anything happening in the semphore locking??why the call server threads are not waiting for other one to complete...I hope you all got my question...

ISCBorisB

Actually I would like to know how callserver() works..For example if we are having multiple call server () request in a template,we dont have control over that.How ever we can control the same through some workaround.My question is , what are the things happening in the background when a form invokes call server()...Is there anything happening in the semphore locking??why the call server threads are not waiting for other one to complete...I hope you all got my question...

"Why the call server threads are not waiting for other one to complete" is a rhetorical question. callServer Method does not wait, period.
There are serious reasons for that IWOV architectural decision, but - parallel computing principles are way out of scope of
this thread.

callSerer works by sending asynchronous http request from the single Data Capture Form hidden Frame.
Subsequent callServer requests override the existing one, whether current call is still in progress or not.

As far as I can tell, you have two options here:
a) You can re-synchronize parallel threads yourself or
b) You can try to leverage Jeff/Jonathan Library to do it for you.

Either option requires some coding from your side

nipper

Thoe code Bo pointed you to is very good, however you really need to understand the issues. I would try to find the presentation they gave, because it shows some very good examples.

Andy

sasikumarg

Thanks very much Boris..