Disabling Cache for CRUD/FI OData scenarios for a UI5 Application on Internet Explorer

This Blog attempts to make its audience understand the way to disable the cache content for UI5 Applications using SAP Netweaver Gateway/OData. It should be noted that there are mechanisms to disable the cache in a UI5 development environment but the blog focusses on disabling them using SAP Netweaver Gateway Implementation.

Understanding the Scenario – I’m Curious 😕

Q: What is the need to disable the CACHE in a UI5 Application that consumes OData Services ?

A: While performing a specific change/functionality in a UI5 application, it is desired that the Application loads fresh data from the backend and does not display stale/unchanged data.

Q: When does this happen ?

A: Specifically, When an OData service is called to perform an UPDATE operation, A Read is not enforced to fetch the updated DATA.

Q: So Why use GATEWAY/OData to disable cache on a service layer, Why not UI5 environment on an application layer ? 😕

A: UI5 applications are browser specific applications. For some of the browsers: IE, Firefox – The browser engine does not force a cache READ and has its limitations when trying to READ the data after an update is performed.

Q: Is this a restriction on only CRUD Services ?

A: This behaviour is exhibited for CRUD and Function Import/Non CRUD Operations as well.

Q: Is this a common development to adapt for for all the browsers ?

A: IE specifically, Firefox and Chrome are scenario centric.

Feeling contented…. 😐 Read Further … 🙂

~~ How do I do it ?

Ok, Let’s get down to some Business. What OData scenario am I looking at ?

How about a CRUD Operation : Let’s say an Update !

Navigate to your DPC Ext Implementation and locate the CORE_SRV_RUNTIME~READ_ENTITYSET Implementation.
Redefine the method by clicking on the icon as shown in the snapshot.
Copy the code from below into the redefined method !

Code Snippet

data: ls_header type ihttpnvp.

ls_header–name = ‘Cache-Control’.

ls_header–value = ‘no-cache, no-store’.

APPEND ls_header TO ct_headers.

ls_header–name = ‘Pragma’.

ls_header–value = ‘no-cache’.

APPEND ls_header TO ct_headers.

CALL METHOD SUPER->/IWBEP/IF_MGW_CORE_SRV_RUNTIME~READ_ENTITYSET

EXPORTING

iv_entity_name = iv_entity_name

iv_source_name = iv_source_name

is_paging = is_paging

it_order = it_order

it_filter_select_options = it_filter_select_options

is_request_details = is_request_details

CHANGING

ct_headers = ct_headers

cr_entityset = cr_entityset .

Looks Simple ? Does it solve my problem…….? 😕

Wait !! 😐 This is a READ ENTITYSET Implementation.

What if the Data that I’m trying to update is expected from an Entity and not an Entity Set ?? 😕 😕 .

As every problem has a solution so does this one ! 🙂 😎

4. Navigate to your DPC Ext implementation and Locate the CORE_SRV_RUNTIME~READ_ENTITY Implementation.

5. Redefine the method by clicking on the icon in the first snapshot as shown above.

6. Next, copy the code from below into the redefined method !

Code Snippet

data: ls_header type ihttpnvp.

ls_header–name = ‘Cache-Control’.

ls_header–value = ‘no-cache, no-store’.

APPEND ls_header TO ct_headers.

ls_header–name = ‘Pragma’.

ls_header–value = ‘no-cache’.

APPEND ls_header TO ct_headers.

CALL METHOD SUPER->/IWBEP/IF_MGW_CORE_SRV_RUNTIME~READ_ENTITY

EXPORTING

iv_entity_name = iv_entity_name

iv_source_name = iv_source_name

is_request_details = is_request_details

CHANGING

ct_headers = ct_headers

cr_entity = cr_entity.

Hmmm…..What If I’m calling a Function Import Service to update the Data ? Does the above Read Entity/Read Entity Set implementation takes care of the behaviour as well ? 😕

Not Really. We need to implement something more now ! 😎

7. Navigate to your DPC Ext implementation and Locate the CORE_SRV_RUNTIME~EXEC_SERVICE_OPERATION Implementation.

8. Redefine the method by clicking on the icon in the first snapshot as shown above..

9. Copy the code from below into the redefined method !

Code Snippet

data: ls_header type ihttpnvp.

ls_header–name = ‘Cache-Control’.

ls_header–value = ‘no-cache, no-store’.

APPEND ls_header TO ct_headers.

ls_header–name = ‘Pragma’.

ls_header–value = ‘no-cache’.

APPEND ls_header TO ct_headers.

CALL METHOD SUPER->/IWBEP/IF_MGW_CORE_SRV_RUNTIME~EXEC_SERVICE_OPERATION

EXPORTING

iv_action_name = iv_action_name

iv_return_type = iv_return_type

iv_multiplicity = iv_multiplicity

is_request_details = is_request_details

CHANGING

ct_headers = ct_headers

cr_data = cr_data.

10. Lastly, Remember to activate all the implementations.

That’s it. That’s all you need to implement. 😆

You can access your UI5 OData application on Internet Explorer without pondering over – Why the Data was not getting updated ? !!! 😎

Thank you for spending time on this space. Glad if it helped you !! 🙂

20 Comments

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Former Member June 20, 2014 at 6:42 am

Exactly what I was looking for 🙂 Works fine!

like (0)
1. Vivek Vishal Post authorJune 20, 2014 at 7:20 am
  
  Thanks Robbe. Glad it helped you !
  
  like (0)
Arno Kristel October 2, 2014 at 10:29 pm

This only partially worked for us. Is there anything else we can do?

like (0)
1. Vivek Vishal Post authorOctober 27, 2014 at 5:08 am
  
  Hi Arno,
  
  Could you please describe your scenario in more detail and what could not work with the above solution ?
  
  Regards, Vivek
  
  like (0)
Stefan Heitzer October 15, 2014 at 2:05 pm

Great Blogpost!

This was exactly what we were looking for!

Thx a lot!!!

like (0)
1. Vivek Vishal Post authorOctober 27, 2014 at 5:09 am
  
  Thanks Stefan !
  
  like (0)
Matt Harding February 27, 2015 at 6:27 am

Thanks Stefan. Saved me today and very suprised this is not automatically there inside the framework with the option to selectively change (if you do want to do caching) as this causes all sorts of grief when people use IE and you’ve been testing using Chrome because IE is horrible to do UI5 development/testing in.

Cheers,

Matt

like (0)
1. Vivek Vishal Post authorMarch 11, 2015 at 5:33 am
  
  Thanks Matt.
  
  Not sure, but hopefully – It will be a part of the framework soon !
  
  Br, Vivek
  
  like (0)
Former Member June 7, 2016 at 2:35 pm

Great. Thank you.

like (0)
1. Vivek Vishal Post authorDecember 2, 2016 at 7:31 am
  
  Thanks !
  
  like (0)
Wolfgang Röckelein October 13, 2016 at 9:11 am

Are you sure this is needed for actions besides GET? IMHO a intermediate cache or a browser will not cache POST/PUT/MERGE/DELETE requests, so the header need only to be added to GET_ENTITY and GET_ENTITYSET?

like (0)
1. Vivek Vishal Post authorDecember 2, 2016 at 7:35 am
  
  Thanks,
  
  The FI READ/GET does work with the EXEC_SERVICE_OPERATION. For all other kinds of operation that does not involve a READ, the browser generally does not cache.
  
  like (0)
Patrick Dean November 2, 2016 at 8:16 am

Excellent blog – really detailed, and I like the attitude with all the smileys! Others need to learn from this example.

like (1)
1. Vivek Vishal Post authorDecember 2, 2016 at 7:36 am
  
  Thanks Patrick !
  
  like (0)
Bilen Cekic May 10, 2017 at 5:38 pm

you are the guy who saved my ass 😀 thx man

like (0)
1. Vivek Vishal Post authorJuly 21, 2017 at 8:48 am
  
  Good to know that it helped you ! 🙂
  
  like (0)
Ankit Garg June 1, 2017 at 12:16 pm

Hi Vivek ,

Great blog you have write ,

but can you elaborate for some parameter as you mention ls_header–name = ‘Pragma’. what does it mean ‘Pragma’ . is this program name any extension class name or method name .

please reply

like (0)
1. Vivek Vishal Post authorJuly 21, 2017 at 8:59 am
  
  Hi Ankit,
  
  Pragma or No Cache are identical to metadata tags that are inserted in the HTML or OData response to prevent caching. Pragma is applicable for the HTTP/1.0 implementation and Cache-Control is for the HTTP/1.1 implementations.
  
  The Method or the Class Names are mentioned above in the snapshots.
  
  Thanks.
  
  like (0)
Former Member February 10, 2018 at 8:13 am

Hi Vivek

We have implemented the solution and it works fine except dumps are getting generated. Is this a known issue and can it be fixed ?

like (0)
1. Vivek Vishal Post authorFebruary 28, 2018 at 5:19 am
  
  Hi Shajitha,
  
  What is the sources of these dumps and can you provide more technical information on this ?
  
  i did not encounter any dump scenarios yet for this use case.
  
  Regards, Vivek
  
  like (0)