Wednesday, November 23, 2016

Setting item session state using AJAX in APEX 5

You probably know about the old way how to do this with htmldb_Get JS object:

  var get = new htmldb_Get(null, $v('pFlowId'), null, 0);
  get.add('F_APP_ITEM', vNewItemValue);
  gReturn = get.get();

You can find more about "the old way" here.

But If you've read APEX 5 Release Notes carefully you know that htmldb_Get object is deprecated and it's moved to legacy.js - and you don't what to use legacy JS in your new, modern and shiny APEX 5 applications. You should use apex.server.process or apex.server.plugin for plugins.

So, how can you do it in APEX 5?
It's easy if you want to set current page item values to session state. For this you have a parameter pageItems which can be of type jQuery selector, jQuery or DOM object or array of item names that identifies the page items:

apex.server.process ('MY_PROCESS', 
  {
     pageItems: '#P1_DEPTNO,#P1_EMPNO'
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

But if you want to do some calculations before request or if you want to set application item value to session state you have to dig a bit deeper into the documentation where you can find that with pData parameter of AJAX requests you can set additional parameters that the wwv_flow.show procedure provides.

If you need to set session state of only one item (page or application) you can use parameters p_arg_name and p_arg_value:

apex.server.process ('MY_PROCESS', 
  {
     p_arg_name: 'F_APP_ITEM',
     p_arg_value: vNewAppItemValue
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

If you need to set session state of more than one item (page or application) you have to use parameters p_arg_names and p_arg_values where you have to pass JS array as parameter:

apex.server.process ('MY_PROCESS', 
  {
     p_arg_names: ['F_APP_ITEM','P1_DEPTNO'],
     p_arg_values: [vNewAppItemValue, vNewItemValue]
  }, 
  {
    success: function(pData) { ... do something here ... }
  } 
);

Enjoy!


Tested on APEX 5.0.4.00.12

Tuesday, November 8, 2016

How to check ORDS version from APEX builder

Probably somebody blogged about this, but I couldn't find it.

So, if you need to check ORDS version and you only have access to APEX Builder you can do it by running following SQL query in SQL Workshop > SQL Commands:

select owa_util.get_cgi_env('APEX_LISTENER_VERSION') 
  from dual;

If you need to check other environment variables you can do it by running following PL/SQL block:

begin 
  owa_util.print_cgi_env;
end;


Edit no. 1 (thanks to Robert Schafer):

You can also query:

select ords.installed_version 
  from dual


Edit no. 2 (thanks to Christian Neumuller)

You can also open Help > About dialog in APEX to see the most important CGI variables and some additional info about APEX and database.

Tested on APEX 5.0.4.00.12 and ORDS 3.0.*

Thursday, November 3, 2016

APEX 4 to APEX 5 Migration Tip: Tree Regions

If you're moving your applications to APEX 5 you've probably read about deprecated features. One of the notes there is about the deprecation of jsTree Region.

It doesn't matter if you've turned on legacy JavaScript or jQuery Migrate you'll still get some errors by using old implementation so you have to move them to new APEX tree.

Most probably you'll get error in JS Console like this one:


The reason of this is that $.curCSS() method is removed in jQuery 1.8 and it's not added into jQuery Migrate library.

The next thing you'll probably notice is that there's no icons in new tree.

Old legacy tree:


New APEX tree:


FontAwsome Tree Icons


You can easily use FontAwsome icons there. To do this set Icon Type property to fa in Tree Attributes:


Next step is to modify SQL query of Tree region and set icon column to fa-folder-o



If you want a bit more, for example to have special icon for expanded folder you have to add additional CSS to you page (preferably to CSS file):


.a-TreeView .is-collapsible > .a-TreeView-content > span.fa:before{
  content:"\f115"
}


After those modifications your tree should look like this:



APEX Tree Icons


There's also a way to use APEX font icons for the new APEX tree. Unfortunately, CSS classes are not included by default so you have to add it manually.

In case that you want to use APEX font icons you have to set Icon Type property to a-Icon:


Also you have to modify CSS class in icon column of source SQL query to icon-tree-folder:


The last thing is to add CSS classes (preferably to CSS file and not to inline CSS code page property):

  /* line 583, ../scss/core/IconFont.scss */
  .a-Icon.icon-tree-folder:before,
  .a-TreeView-node.is-expandable > .a-TreeView-content > .a-Icon.icon-tree-folder:before {
    content: "\e0da";
  }

  /* line 588, ../scss/core/IconFont.scss */
  .a-Icon.icon-tree-folder-open:before,
  .a-TreeView-node.is-collapsible > .a-TreeView-content > .a-Icon.icon-tree-folder:before {
    content: "\e0d7";
  }

With APEX font icons your tree should look like this:

Returning selected node value dynamically


If you need to return node value dynamically without submitting page the easiest way to do it is to call $s function inside your SQL query:



Expand tree on page load

To expand tree on page load you have to call: 


apex.widget.tree.expand_all('treeID');

where treeID is value of attribute property Static Tree ID of tree region.
Just put this code into page property Execute when Page Loads.

Edit: You can expand/collapse tree declaratively by using Dynamic Actions Expand/Collapse tree.

Enjoy!

Tested on APEX 5.0.4.00.12 



Thursday, October 27, 2016

APEX4 to APEX5 Migration Tip: AJAX calls

If you're moving your APEX applications from APEX 4 to APEX 5 and you've decided that you don't want to include jQuery Migrate Plugin* (to reduce overall size of the JavaScript files loaded) as a result of your AJAX requests you may suddenly see messages like this one:


The reason of this is that there's changed behaviour of AJAX calls from jQuery version 1.9 (APEX 5 is on version 2.1.3, APEX 4 on 1.8.22). Prior to version 1.9 AJAX call that expected a return data type of JSON or JSONP would consider a return value of an empty string to be a success case, but return a null to the success handler or promise. As of 1.9, an empty string returned for JSON data is considered to be malformed JSON and it will throw an error.  

If you're using apex.server.process or apex.server.plugin for your AJAX calls by default expected return data type is JSON. So, if your AJAX callback is not returning JSON object or it's returning empty string you will get the error message like the one above.

There are two solutions to this problem:

1) Explicitly define data type in AJAX calls (for example dataType: 'text')



2) Put dummy return on end of your AJAX callback. It should be: 

  • empty JSON object - sys.htp.prn('{}')
  • or null string - sys.htp.prn('null')




Enjoy!

*jQuery Migrate Plugin: c/p from APEX help:
The plug-in restores deprecated features and behaviors of jQuery so that old JavaScript code and jQuery plug-ins will still run properly with the jQuery version loaded by Application Express.
If you are confident your application and any used jQuery plug-in does not contain any references to deprecated jQuery features, set this to No to reduce the overall size of the JavaScript files loaded.

Tested on APEX 5.0.4.00.12 

Tuesday, October 25, 2016

Changed behaviour in APEX5: APEX_PLUGIN_UTIL.CLEANUP_PAGE_ITEM_NAMES

Unfortunately some things have to be learned in a hard way.

As I'm doing another APEX 4.2 to APEX 5 migration I just learned that there's changed behaviour in function apex_plugin_util.cleanup_page_item_names. Unfortunately, not documented.

If you take a closer look at function source you may see that there's additional call to REPLACE function that replaces double commas with single one:



So, in APEX 4.2 query


will result with
P1_ITEM1,,P1_ITEM2

and in APEX 5
P1_ITEM1,P1_ITEM2

Hope that this will save some debug time to somebody! :)

Friday, July 8, 2016

ODTUG KSCOPE 2016...

...was the place to be, at least if you are PL/SQL or APEX developer. Numbers say it all: 350+ presentations, 50+ APEX presentations, Sunday symposium, open mic night, Thursday's deep dive session and many more - all of that in only 4 and a half days. Amazing!

One thing was special there - the APEX community. It look like all those 8 years that I'm working with APEX where gathered in one place - APEX dev team and all popular presenters, bloggers and tweeters that you can find out there when you google about APEX and all of them so kind, friendly and eager to share knowledge.

Also, it was great to see that all those rooms with APEX presentations (at least the ones that I've attended) where so full. I don't have anything against ADF, but it was so sad to see 5-10 people on their presentations while APEX rooms where so packed. It reminded me of many projects in which we needed to prove that APEX is the next step when you want to get rid off Oracle Forms. If only I had that picture then. :)

And the content? It wasn't all about the APEX 5.1 as I've expected. It was on the first day on the Sunday symposium when APEX team talked about the new features in 5.1, but that was only a great introduction for the rest of the week. The only problem was that you have to choose only one presentation per session and sometimes it was really hard. There were 3 to 4 parallel APEX presentations + PL/SQL + ORDS and always something interesting.


I had my presentation on Tuesday at 8:30am, first session of the day. I got some great feedbacks so I suppose it went well. If you want to take a look at the slides you can find them here and you are free to contact me anytime if you need some additional information or explanation.

On the last day we had this deep dive sessions that I've really liked. I liked the content and concept because it was a two hour session divided in 10 minute presentations by some of the best and well known APEX speakers. Short and interesting...and there was a hidden gem from Joel, a feature long awaited, about session isolation across multiple browser tabs. From my perspective one of top features in APEX 5.1.

During KSCOPE I wrote some notes on stuff that I want to explore a bit more so if you want to take a look:
  • Electron.js - extending your APEX apps to desktop
  • Camunda - workflow solutions for APEX apps
  • FlowControl - PL/SQL Open Source workflow solution
  • Nightmarejs - high-level automation library
  • Service Workers - a method that enables applications to take advantage of persistent background processing, including hooks to enable bootstrapping of web applications while offline.


And don't forget to take a look at OraOpenSource project. It was mentioned so many times there. Great project with really nice free products that can be very useful in every APEX app.

To conclude, it's time to plan KSCOPE2017, you'll not regret it.




Friday, May 6, 2016

Query APEX dictionary views from non-parsing schema

You may have noticed that if you query any of the APEX's dictionary views (APEX_*) outside the parsing schema you won't get any rows. There's quick solution for this. You only have to grant APEX_ADMINISTRATOR_ROLE to this schema.


    grant APEX_ADMINISTRATOR_ROLE to your_nonparsing_schema;


Be careful, user with this role can execute APEX_INSTANCE_ADMIN package procedures and functions.

Enjoy!

Tested in APEX 5.0.3.00.03