Is there someway to get a list of activated sessions in classic ASP?
I want to limit the number of simultaneus activated sessions.
Here is a good article which shows a way to do that: Active User Count Without Global.asa by Josh Painter
I guess you have to change some details, but this is the way you could approach the problem. The author doesn't use global.asa.
A simpler way would be to hook the Sesssion_OnStart and Session_OnEnd events in global.asa and adding/removing the item from the list of sessions implemented as an Application variable.
If you just want the count of sessions, you could simply doing it this way:
Sub Session_OnStart
Application.Lock
Application("count") = Application("count") + 1
Application.Unlock
End Sub
Sub Session_OnEnd
Application.Lock
Application("count") = Application("count") - 1
If Application("count") < 0 then ' Could only happen if some other function interfers
Application("count")=0
End If
Application.Unlock
End Sub
In your ASP file
<%
Response.Write "There are currently " & Application("count") & "active sessions>"
%>
You can't access one session from another, so there's no built-in way to get a list of all the active sessions. However, you can use Session_OnStart and Session_OnEnd in global.asa to track the sessions by saving the relevant session info to the Application object, a log file, a database etc (depending on exactly what you want to do with the information).
We tend to track the number of active sessions in an Application object to get a rough idea of how many people are using a site at any given time (bearing in mind, of course, that people will typically have left the site long before their sessions time out). It's not 100% accurate but it's close enough for a guide to current activity.
If you just want the number of sessions, you can also use Perfmon to track the Sessions Current counter (and other related counters) for the Active Server Pages performance object. Obviously this assumes access to the server and probably isn't what you want in this case.
For more info on some options, try this article: How do I count the number of current users / sessions? (archived version)
Related
I am trying to build a system to list items within my Back office system on eBay via the eBay ASP.NET SDK.
Since loading eBay categories isn't terribly fast, and infrequently changing, I figured I'd cache the responses from the requests I'll make.
I have a function which returns a list of eBay categories as an eBay CategoryTypeCollection and I am trying to Cache it, then check for it and retrieve new if necessary:
Dim CategoryList As New CategoryTypeCollection
If HttpRuntime.Cache.Get("eBayCategories") Is Nothing Then
CategoryList = Categories.DisplayCategories()
HttpRuntime.Cache.Insert("eBayCategories", CategoryList, Nothing, DateTime.UtcNow.AddMinutes(30), TimeSpan.FromMinutes(0))
Else
CategoryList = HttpRuntime.Cache.Get("eBayCategories")
End If
However, it is always getting new data.
This is part of a much bigger project, and caching is working for other things, I can't see what I am doing wrong here?
The cache is expiring immediately because you specify 0 minutes to expire.
Change it to Cache.NoSlidingExpiration instead.
HttpRuntime.Cache.Insert("eBayCategories", connectionString, Nothing, DateTime.UtcNow.AddMinutes(30), Cache.NoSlidingExpiration)
See MSDN Cache.Insert.
I've a classic ASP page which call a en external webservice.
this is how the actual process works:
'[Part0 : Call the external webservice]
wsResponse = setConfirmation(...)
' [PART1: external webservice is responding]
if not wsResponse is Nothing then
'....Process the response from the webservice according to wsResponse
code =wsResponse.getCode
if code = 'C' then
'We confirm the transaction and call a storedprocedure in SqlServer
else
'if code is different from C, we assume, the transaction status is 'not confirmed' or 'cancelled'
'[PART2: no answer from external webservice]
Else
'so wsReponse is nothing..We don't get any answer from the external webservice
'transaction is not confirmed
'the transaction status is set to 'not confirmed' in database
So what I want to do is that in PART2 (when no answer is get from external webservice), wait 30 seconds before send 'not confirmed' status in database . So I will like to do PART0 again ie: Call again the external webservice at least 10 times and see if it responding or not. A kind of recursive process.
So I was thinking of 2 way of doing this:
In PART2, put ASP to sleep for 30s and to PART0 again (Call the webservice) and if still no response, write in DB, transaction not confirmed, but if response, then do PART1.
In PART2, Call repeat PART0 at least 10 times, if after 10 trials, there is no response, then write in DB, transaction is not confirmed.
So my question is: is there a better way to do this or which or 1 or 2 will be better? and also, for 1, how can we put ASP to sleep like in dotnet or PHP?
Thanks for your answers.
Regards
Here is a simple subroutine that will delay for as many seconds as you need
Sub MyDelay(NumberOfSeconds)
Dim DateTimeResume
DateTimeResume= DateAdd("s", NumberOfSeconds, Now())
Do Until (Now() > DateTimeResume)
Loop
End Sub
Just call this subroutine in Part 2
Call MyDelay(30)
I don't know any way to put ASP to sleep. Especially when you are on a hosted web. So what I would do is this: I would have a service like Pingdom.com to request an ASP page every say 10 seconds. The requested ASP page will then attend to any pending transactions (logged in a tabel).
I have a classic ASP CRM that was built by a third party company. Currently, I have access to the source code and am able to make any changes required.
Randomly throughout the day, usually after some prolonged usage by users, most of my pages start getting an Out of Memory error.
The way that the application is built, is all the pages and scripts pull core functions from a Global.asp file. In that file are embeds to other global files as well, but the error presented shows
Out Of Memory
WhateverScriptYouTriedToRun.asp Line 0
Line 0 is the include for the global.asp file. Once the error occurs, after an unspecified amount of time the error occurence subsides for some time but then begins to reoccur again. With how the application is written, and the functions it uses, and the "diagnostics" I've already done - it seems to be a common used function that is withholding data such as recordset or something of that nature and then not releasing it properly. Other users then try to use the same function and eventually it just fills up causing the error. The only way for me to effectively clear the error is to actually restart IIS, Recycle the App Pool, and Restart the SQL Server Services.
Needless to say, myself and my users are getting annoyed....
I can't pinpoint the error due to the actual error message presented being Line 0 - but from there I have no idea where in the 20K lines of code it could be hanging up. Any thoughts or ideas on how to isolate or at least point me in the right direction to begin clearing this up? Is there a way for me to increase "memory" size for VBScript? I know there is a limitation but is it set at say...512K and you can increase it to 1GB?
Here are things I have tried:
Removing SQL Inline statements into Views
Going through several hundred scripts and ensuring that every OpenConnection & OpenRecordSet is followed by an appropriate Close.
Going through the Global File and commenting out any large SQL statements such as ApplicationLog (A function that writes the executed query into a table).
Some smaller script edits.
Common Memory Leak
You say you are closing all recordsets and connections which is good.
But are you deleting objects?
For example:
Set adoCon = new
Set rsCommon = new
'Do query stuff
'You do this:
rsCommon.close
adocon.close
'But do you do this?
Set adoCon = nothing
Set rsCommon = nothing
No garbage collection in classic ASP, so any objects not destroyed will remain in memory.
Also, ensure your closes/nothings are run in every branch. For example:
adocon.open
rscommon.open etc
'Sql query
myData = rscommon("condition")
if(myData) then
response.write("ok")
else
response.redirect("error.asp")
end if
'close
rsCommon.close
adocon.close
Set adoCon = nothing
Set rsCommon = nothing
Nothing is closed/destroyed before the redirect so it will only empty memory some of the time as not all branches of logic lead to the proper memory clearance.
Better Design
Also unfortunately it sounds like the website wasn't designed well. I always structure my classic ASP as:
<%
Option Explicit
'Declare all vars
Dim this
Dim that
'Open connections
Set adoCon...
adocon.open()
'Fetch required data
rscommon.open strSQL, adoCon
this = rsCommon.getRows()
rsCommon.close
'Fetch something else
rscommon.open strSQL, adoCon
that = rsCommon.getRows()
rsCommon.close
'Close connections and drop objects
adoCon.close
set adoCon = nothing
set rscommon = nothing
'Process redirects
if(condition) then
response.redirect(url)
end if
%>
<html>
<body>
<%
'Use data
for(i = 0 to ubound(this,2)
response.write(this(0, i) & " " & this(1, i) & "<br />")
next
%>
</body>
</html>
Hope some of this helped.
Have you looked at using a memory monitoring tool to see how much memory fragmentation is happening? My guess at a possible cause is that some object of a size is trying to be created but there isn't enough room in the memory to store it as one contiguous chunk. Imagine needing room to store an object that would take 100 MB and while there may be several hundred megabytes free, the largest contiguous chunk is 90MB then this doesn't fit.
Debug Diagnostic Tool v1.1 would be a tool where Bernard's articles may help in understanding how to use the tool.
Another thought is the question of how much string concatenation is there in the code? I remember where I used to work had problems with doing a lot of string concatenation operations that sucked up memory that may be another idea to consider.
Yeah, I could see some shock at that kind of number the first few times you see it but then if you understand what the code is doing it may make sense for why so much space gets reserved right off the bat at times.
I haven't used that debug tool specifically but I did have a tool that took a snapshot of memory when pages were hung so I couldn't tell if there was a performance impact of the tool or not. Course in my case I used a similar tool in 2004 so it has been a few years since I've had to research this kind of issue.
Just going to throw this in here, but this problem has taken a long time to solve. Here's a breakdown of what we did:
We took all the inline SQL and made SQL Views, every SELECT statement is now handled with a VIEW first.
I took every single SQL INSERT and UPDATE (as much as I could without breaking the system) and put them into Stored Procedures.
#2 was the one item that really made the biggest difference
Went through several thousand scripts, and ensured that variables were properly disposed of, and all the DB Open Connections were followed correctly with a Close Connection and same with Open/Close RecordSet.
One of the slow killers was doing something like:
ID = Request.QueryString("ID)
at the top of the page. Before redirecting, or closing a page, there is always a:
Set ID = Nothing
or the complete removal of the inference.
My ASP.NET intranet web application uses Windows Authentication, and I would like to record the following details:
1) Windows ID
2) Session Start Time
3) Session Stop Time
4) URL being browsed to (optional)
I've got some basic code setup in "Session_Start" method of the Global.ASAX to log session start times (seen below), but that's it so far. I have the feeling this is a primitive approach and there are "better" ways of doing this. So I really have two questions:
1) Is this the right way to go about doing this? If not what are some other options?
2) If this is the right way, do I just need to drop some code in the "Session_End" method to record the time they exit, and thats a complete solution? Does this method always get called when they close the browser tab they have the site open in, or do they have to close the entire browser (I don't have logout functionality)? Any way users can skip over this session end method (or start for that case)?
Dim connsql As New System.Data.SqlClient.SqlConnection(ConfigurationManager.ConnectionStrings("MyConnectionstring").ConnectionString)
Dim cmdsql As System.Data.SqlClient.SqlCommand = connsql.CreateCommand
cmdsql.CommandText = "BeginUserSession"
cmdsql.CommandType = Data.CommandType.StoredProcedure
Try
cmdsql.Parameters.Add("#windowsid", System.Data.SqlDbType.VarChar, 30, "windowsid")
cmdsql.Parameters("#windowsid").Value = Session("UserInfo").identity.name
If connsql.State <> System.Data.ConnectionState.Open Then connsql.Open()
cmdsql.ExecuteNonQuery()
connsql.Close()
Catch ex As Exception
Finally
If connsql.State <> Data.ConnectionState.Closed Then connsql.Close()
End Try
'Stored Proc records start time
Session_End is not reliable.
What I would suggest is on Session_Start you create a record that notes the time the Session was created, and in Session_End you update the record with the time it was ended.
To handle the majority of sessions which are passively abandoned, use Application_BeginRequest to update the record to note when the user was "last seen".
You will then need to determine a way of marking sessions that have been passively abandoned. This will be site/app specific. It could be as simple as picking a number of minutes that must pass before the session is considered abandoned - like 10 minutes.
So then you have a query:
SELECT Username,
SessionStart,
SessionEnd,
LastSeenOn,
DATEDIFF(mi, SessionStart, ISNULL(SessionEnd, LastSeenOn)) DurationMinutes
FROM SessionAudit
WHERE SessionEnd IS NOT NULL
OR DATEDIFF(mi, LastSeenOn, getdate()) > 10
Which will bring back your session audit log.
Your approach could be described as simple, but that could be totally fine - it comes down to what the requirements are. If you need to log a full suite of application errors and warnings, look at implementing something like Log4Net. Otherwise I wouldn't say there is anything wrong with what you are doing.
Sessions are ended when there has been no user activity for the amount of time specified in the timeout value, or when you explicitly call Session.Abandon() in your code. Because of the stateless nature of HTTP, there is no way to tell if a user has left your site, closed the browser or otherwise stopped being interactive with their session.
I am not sure you can catch the end of the session accurately because
The user can close their browser and that will not necessarily end the session.
They can then go back to your site and thus may have multiple sessions.
You can try messing with setting in IIS to kill the session very quickly after inactivity but its not a good idea.
Also... If the users are not all on an internal network you will have no control as to whether they have a "Windows ID" or not.
When I call this function, everything works, as long as I don't try to recursively call the function again. In other words if I uncomment the line:
GetChilds rsData("AcctID"), intLevel + 1
Then the function breaks.
<%
Function GetChilds(ParentID, intLevel)
Set rsData= Server.CreateObject("ADODB.Recordset")
sSQL = "SELECT AcctID, ParentID FROM Accounts WHERE ParentID='" & ParentID &"'"
rsData.Open sSQL, conDB, adOpenKeyset, adLockOptimistic
If IsRSEmpty(rsData) Then
Response.Write("Empty")
Else
Do Until rsData.EOF
Response.Write rsData("AcctID") & "<br />"
'GetChilds rsData("AcctID"), intLevel + 1
rsData.MoveNext
Loop
End If
rsData.close: set rsData = nothing
End Function
Call GetChilds(1,0)
%>
*Edited after feedback
Thanks everyone,
Other than the usual error:
Error Type: (0x80020009) Exception occurred.
I wasn't sure what was causing the problems. I understand that is probably due to a couple of factors.
Not closing the connection and attempting to re-open the same connection.
To many concurrent connections to the database.
The database content is as follows:
AcctID | ParentID
1 Null
2 1
3 1
4 2
5 2
6 3
7 4
The idea is so that I can have a Master Account with Child Accounts, and those Child Accounts can have Child Accounts of their Own. Eventually there will be Another Master Account with a ParentID of Null that will have childs of its own. With that in mind, am I going about this the correct way?
Thanks for the quick responses.
Thanks everyone,
Other than the usual error:
Error Type: (0x80020009) Exception
occurred.
I wasn't sure what was causing the problems. I understand that is probably due to a couple of factors.
Not closing the connection and attempting to re-open the same connection.
To many concurrent connections to the database.
The database content is as follows:
AcctID | ParentID
1 Null
2 1
3 1
4 2
5 2
6 3
7 4
The idea is so that I can have a Master Account with Child Accounts, and those Child Accounts can have Child Accounts of their Own. Eventually there will be Another Master Account with a ParentID of Null that will have childs of its own. With that in mind, am I going about this the correct way?
Thanks for the quick responses.
Look like it fails because your connection is still busy serving the RecordSet from the previous call.
One option is to use a fresh connection for each call. The danger there is that you'll quickly run out of connections if you recurse too many times.
Another option is to read the contents of each RecordSet into a disconnected collection: (Dictionary, Array, etc) so you can close the connection right away. Then iterate over the disconnected collection.
If you're using SQL Server 2005 or later there's an even better option. You can use a CTE (common table expression) to write a recursive sql query. Then you can move everything to the database and you only need to execute one query.
Some other notes:
ID fields are normally ints, so you shouldn't encase them in ' characters in the sql string.
Finally, this code is probably okay because I doubt the user is allowed to input an id number directly. However, the dynamic sql technique used is very dangerous and should generally be avoided. Use query parameters instead to prevent sql injection.
I'm not too worried about not using intLevel for anything. Looking at the code this is obviously an early version, and intLevel can be used later to determine something like indentation or the class name used when styling an element.
Running out of SQL Connections?
You are dealing with so many layers there (Response.Write for the client, the ASP for the server, and the database) that its not surprising that there are problems.
Perhaps you can post some details about the error?
hard to tell without more description of how it breaks, but you are not using intLevel for anything.
How does it break?
My guess is that after a certain number of recursions you're probably getting a Stack Overflow (ironic) because you're not allocating too many RecordSets.
In each call you open a new connection to the database and you don't close it before opening a new one.
Not that this is actually a solution to the recursion issue, but it might be better for you to work out an SQL statement that returns all the information in a hierarchical format, rather than making recursive calls to your database.
Come to think of it though, it may be because you have too many concurrent db connections. You continually open, but aren't going to start closing until your pulling out of your recursive loop.
try declaring the variables as local using a DIM statement within the function definition:
Function GetChilds(ParentID, intLevel)
Dim rsData, sSQL
Set ...
Edit: Ok, I try to be more explicit.
My understanding is that since rsData is not declared by DIM, it is not a local variable, but a global var. Therefore, if you loop through the WHILE statement, you reach the .Eof of the inner-most rsData recordset. You return from the recursive function call, and the next step is again a rsData.MoveNext, which fails.
Please correct me if rsData is indeed local.
If you need recursion such as this I would personally put the recursion into a stored procedure and handle that processing on the database side in order to avoid opening multiple connections. If you are using mssql2005 look into something called Common Table Expressions (CTE), they make recursion easy. There are other ways to implement recursion with other RDBMS's.
Based on the sugestions I will atempt to move the query into a CTE (common table expression) when I find a good tutorial on how to do that. For now and as a quick and dirty fix, I have changed the code as follows:
Function GetChilds(ParentID, intLevel)
'Open my Database Connection and Query the current Parent ID
Set rsData= Server.CreateObject("ADODB.Recordset")
sSQL = "SELECT AcctID, ParentID FROM Accounts WHERE ParentID='" & ParentID &"'"
rsData.Open sSQL, conDB, adOpenKeyset, adLockOptimistic
'If the Record Set is not empty continue
If Not IsRSEmpty(rsData) Then
Dim myAccts()
ReDim myAccts(rsData.RecordCount)
Dim i
i = 0
Do Until rsData.EOF
Response.Write "Account ID: " & rsData("AcctID") & " ParentID: " & rsData("ParentID") & "<br />"
'Add the Childs of the current Parent ID to an array.
myAccts(i) = rsData("AcctID")
i = i + 1
rsData.MoveNext
Loop
'Close the SQL connection and get it ready for reopen. (I know not the best way but hey I am just learning this stuff)
rsData.close: set rsData = nothing
'For each Child found in the previous query, now lets get their childs.
For i = 0 To UBound(myAccts)
Call GetChilds(myAccts(i), intLevel + 1)
Next
End If
End Function
Call GetChilds(1,0)
I have working code with the same scenario.
I use a clientside cursor
...
rsData.CursorLocation = adUseClient
rsData.Open sSQL, conDB, adOpenKeyset, adLockOptimistic
rsData.ActiveConnectcion = Nothing
...
as pointed out in other responses, this is not very efficient, I use it only in an admin interface where the code is called infrequently and speed is not as critical.
I would not use such a recursive process in a regular web page.
Either rework the code to get all data in one call from the database, or make the call once and save it to a local array and save the array in an application variable.