No global variables on the application server?

[LukeS]

I have a logical global variable that works when I use it on the application server built into A5 development software but does not work on the stand-alone application server. The logical global variable is set from the view menu -> global variables when editing code on the code tab of the control panel. I tried using the application global variables set in the project properties (the ones with a AppVar prefix) but they are read-only. Is there any way to use a global variable on the application server? I am thinking at this point I will have to use a temporary file as the logic variable, if file present flag is set, if not flag is not set.

Every night when a scheduled update of many databases from a legacy system is running I want to lock out users from logging on. I created a global variable flag that I set when the update process is running and cleared when it is finished. When users login or tries to do any critical task that pulls data from the databases being updated this flag is checked. The only problem is it does not work now that I have moved it over to the stand-alone app server. It pops up a 500 error, variable not found.

[Keith Hubert]

Re: No global variables on the application server?

How about you put it into the Autoexec and restart the application?

[glenschild]

Re: No global variables on the application server?

The equivalent of a desktop global variable on the application server would be a session variable. These can be set in the project properties area of the web control panel.

[LukeS]

Re: No global variables on the application server?

Thanks for the responses.

How about you put it into the Autoexec and restart the application?

I just tried defining a global var in the autoexec with the code below but that did not work; it is still not found. Also if I try to define a global variable using the below code it is not accessable globally, only within the scope of the function or a5w page it was declared in.

 DIM GLOBAL lGV_DB_CRITIAL_TASK_RUNNING AS L = .F.

I was looking at the A5_DEFINE_GLOBAL_VARS() function but it can only be used in desktop applications.

The equivalent of a desktop global variable on the application server would be a session variable. These can be set in the project properties area of the web control panel.

Session variables do not have a global scope, they are only global to the current logged in user not all users.

[glenschild]

Re: No global variables on the application server?

Hi Luke

As in my first post

These can be set in the project properties area of the web control panel

See attached image

[LukeS]

Re: No global variables on the application server?

Thanks for the suggestion Glen. I mentioned this in my first post but probably did not go into enough detail. The problem with the application global variables, AppVar variables, is they are read only. The "AppVar." variables can be set locally but changes are not made globally. What they are initialized to in the project properties is what they stay set as.

From the A5 wiki page on application global variables:

You can not persistently modify the value of an Application Global Variable in your code. On the next page request, the Application Global Variable will revert to its original value.

[glenschild]

Re: No global variables on the application server?

Hi Luke, yep re-read your original post....

A value set in a small table that is checked at login should achieve this for you. This could be tested via an included header file on each page of the site or at least the "critical" pages.

[LukeS]

Re: No global variables on the application server?

I ended up using a file as a marker, a field in a table is a really good idea though. If the global var was anything other then a boolean value I would go that route.

Here's how I did it; I created a global helper function to set and clear the "variable" (file) and a global helper function to check its state
Function to set the state of the "global variable"

'Date Created: 05-Jun-2012 07:48:53 PM
'Last Updated: 06-Jun-2012 02:36:15 PM
'Created By  : Luke
'Updated By  : Luke
' ---== Global Xbasic Helper Function, Set or clear global variable marker for DB critical task running ==---
'---------------------------------------------------------------------------------------------------------
' A5 does not have a method to create global variables on the application server so a temporary file will
' be uses as boolean variable (L).  If the temp file is present the var is set, if the file does not exist
' then the var is cleared.  This function creates a file to store the state of a boolean \ logical flag. 
'---------------------------------------------------------------------------------------------------------
FUNCTION Gh_lSet_DB_Critical_Task AS V (lState AS L )
	
	ON ERROR GOTO ERR_HANDLER
	
	DIM cTMPmarkerFile	AS C
	IF variable_exists("AppVar.cGav_Path_DB_CRITICAL_TASK") then
		'Variable defined in the web project control panel -> project properties -> application global variables
		cTMPmarkerFile = filename_decode(AppVar.cGav_Path_DB_CRITICAL_TASK)
	else
		'Else just dump the file on the c drive
		cTMPmarkerFile = filename_decode("c:\a5v11\DB_CRITICAL_TASK_RUNNING.txt")
	end if
	
	
	'If setting state of DB critical task running to true, create file as marker
	IF lState THEN
		'If file does not exist, create it
		IF (.NOT. file.exists(cTMPmarkerFile)) THEN
			FILE.APPEND_LINE(cTMPmarkerFile, "TRUE")
		END IF
	ELSE 'If clearing state of DB critical task running to false, delete temp marker file
		'If file exist, delete it
		IF file.exists(cTMPmarkerFile) then
			file.remove(cTMPmarkerFile)
		END IF
	END IF
	
	
	GOTO CONTINUE_1
	'-----------------------------------
	' - Error handler
	'-----------------------------------
	ERR_HANDLER:
		ON ERROR GOTO 0

		' ==== Setup Error handling file ====
		Dim Error_Log_File as C
		IF variable_exists("AppVar.cGav_Path_GeneralError_log") then
			'Variable defined in the web project control panel -> project properties -> application global variables
			Error_Log_File = filename_decode(AppVar.cGav_Path_GeneralError_log)
		else
			'Else just dump the file on the d drive
			Error_Log_File = filename_decode("C:\a5v11\Error_Log.txt")
		end if
		' ====
		
		File.Append_Line(Error_Log_File, now() + " ---- Error running Gh_lSet_DB_Critical_Task ----" )
		File.Append_Line(Error_Log_File, "Error text: " + error_text_get() )
		File.Append_Line(Error_Log_File, "Error code: " + error_code_get() )
		File.Append_Line(Error_Log_File, "Error script: " + error_script_get() )
		File.Append_Line(Error_Log_File, "Error line: " + error_line_number_get() )
		
		END
	'-----------------------------------
	' - END Error handler
	'-----------------------------------
	CONTINUE_1:

END FUNCTION

Function that is used to check the state of the global variable, if returns a logical value so it can be used in a IF statement in place of a actual global variable.

' ---== Global Xbasic Helper Function, Get state of global variable marker for DB critical task running ==---
'---------------------------------------------------------------------------------------------------------
' A5 does not have a method to create global variables on the application server so a temporary file will
' be uses as boolean variable (L).  If the temp file is present the var is set, if the file does not exist
' then the var is cleared.  This function checks for the presence of this temporary marker file and returns
' true if it is present, false if it is not.
'---------------------------------------------------------------------------------------------------------
FUNCTION Gh_isDBCriticalTaskActiv AS L ( )
	DIM cTMPmarkerFile	AS C
	IF variable_exists("AppVar.cGav_Path_DB_CRITICAL_TASK") then
		'Variable defined in the web project control panel -> project properties -> application global variables
		cTMPmarkerFile = filename_decode(AppVar.cGav_Path_DB_CRITICAL_TASK)
	else
		'Else just dump the file on the c drive
		cTMPmarkerFile = filename_decode("c:\a5v11\DB_CRITICAL_TASK_RUNNING.txt")
	end if
	
	Gh_isDBCriticalTaskActiv = file.exists(cTMPmarkerFile)

END FUNCTION