Creating session variable properly with application.cfc

Report · Sep 07, 2012

I haven't had the chance to use application.cfc when creating web application. Usually this is how I create session variable ,such as, session.userid after user validation. Here is an example:

First, on my application.cfm I did :

Then on my loginaction.cfm page, I validate user login with something like:

SELECT UserId, Username, Password FROM users

WHERE Username = <cfqueryparam cfsqltype="cf_sql_varchar" value="#Form.username#">

AND Password = <cfqueryparam cfsqltype="cf_sql_varchar" value="#Form.Password#">

</cfquery>

</CFIF>

Once this session.UserId is created then I can use it on any query throughout the application.

Now, I want to use Application.cfc instead of Application.cfm. From my reading Within Application.cfc I can create a Function called:

OnApplicationStart, OnSessionStart, etc

It is said that: OnSessionStart is the perfect place to define session-scoped variables (ex. SESSION.Cart for eCommerce cart data).

If this method is invoked manually, be sure to call StructClear() on the SESSION scope before you re-initialized the data values. HOWEVER! before clearing the scope, get a copy of the CFID/CFTOKEN values so that you can store them back into the session during re-initialization.

I don't quite understand this explanation and especially when I want to create my session.UserId using the logic I explain above.

Below is my test when trying to work with application.cfc:

On my loginaction.cfm:

<cfinvoke component="cfcomponents.application" method="OnSessionEnd" UserName ="#Trim(Form.MyUsername)#"

Password = "#Trim(Form.myPassword>

On Application.cfc:

<cfreturn true/

</cffunction>

SELECT UserId, Username, Password FROM users

WHERE Username = <cfqueryparam cfsqltype="cf_sql_varchar" value="#Form.username#">

AND Password = <cfqueryparam cfsqltype="cf_sql_varchar" value="#Form.Password#">

</cfquery>

</CFIF>

</cffunction>

</cfcomponent>

Report · Sep 07, 2012

GKiew,

No. The correct way to establish those settings in Application.cfc is to put them in the pseudo constructor (using the "this" scope), before any of the functions. Here is an example (with all of the functions omitted for simplicity):

<cfcomponent...>

</cffunction>

</cfcomponent>

See the following in the CF 9 Docs for more information:

http://help.adobe.com/en_US/ColdFusion/9.0/CFMLRef/WSc3ff6d0ea77859461172e0811cbec22c24-750b.html

Ben Nadel's classic blog post gives you a pretty complete explanation of how all the parts to Application.cfc work:

http://www.bennadel.com/blog/726-ColdFusion-Application-cfc-Tutorial-And-Application-cfc-Reference.h...

HTH,

-Carl V.

Report · Sep 09, 2012

Hi Carl, I did more reading and some questions of mine got answered, thanks for pointing out some of them.

One thing that I'm still confused is setting the session variable.

For example, When I need to create a session variable in my loginaction.cfm, such as, session.userId, HOW IS :

<CFSET session.userId = "#MyQueryName.UserId#"> in my loginaction.cfm and The OnSessionStart function included within an Application.cfc

Related to each other?

When using CFAPPLICATION, I have:

I only need to set sessionmanagement attribute to "yes" and then on my loginaction.cfm I'm ready to do :

<CFSET session.userId = "#MyQueryName.UserId#" without having to call OnSessionStart Function.

But when I use Application.cfc, If I already put:

Practically I'm ready to do <CFSET session.userId = "#MyQueryName.UserId#"> anywhere in my template so why should I call OnSession.Star()?

Report · Sep 09, 2012

You don't need to use onSessionStart() if you don't want to.

In the case above, I would use onSessionStart() to create the session.userid variable with an empty value. That way it is always there. Then in the login process I would populate it with a value.

There is nothing that says yo NEED to use onSessionStart() if you are using session management, but it is there in case you WANT to use it.

A great example is if you want every user who visits your site to have a shopping cart instantiated and ready to go (whether they are logged in or not). You would create that cart in onSessionStart() and stick it in the user session. Then later after the login process you would also populate the session with appropriate user details and associate that cart with that user.

Hope that makes sense.

Jason

Report · Sep 10, 2012

GKiew,

Jason (@12Robots) is spot on about onSessionStart() not being necessary if you don't need to use it. In fact, all of the functions/methods in Application.cfc are optional - just use the ones you need. Each provides a hook into the various events that occur during the lifecycle of a ColdFusion application. You don't have to use them.

-Carl V.

Report · Sep 12, 2012

OK it make sense and I do appreciate all the input. Base on what I read and your input I tried to use

OnSessionStart() in my app.cfc because I think I can set session.EntityId = 0 here and it'll come handy in a lot of places later.

So I did this:

</cffunction>

Then in one of the template, I have:

do something here

</CFIF>

It turns out I got an error:

It says, session.EntityId is not recognized!!

I thought I read, when using OnSessionStart() on Application.cfc and when a session.variable is set in here like the way I set my session.EntityId=0 then I do not have to use CFIF IsDefined("session.EntityId")> :

So this is unnecessary:

<cfiifsession.EntityId IS 0>

</cfif>

do something here

</CFIF>

But when I did not use IsDefined, I got that error.

I thought when user accessing in the beginning CF will call Application.cfc, then call OnApplicationStart() then calls OnSessionStart() and the session.variable will be created why it did not happened on my testing? Am I doing this wrong?

Report · Sep 12, 2012

Did you already have an existing session? When you added that code and attmepted to visit the page?

The best way to make sure that onSessionStart() fires is to delete your cookies for the site. My guess is you already had cookies for an established, valid session, so CF did not fire onSessionStart().

Jason

Report · Sep 13, 2012

Hi!

I tried it again this afternoon for the first time today since I posted my question yesterday. The session variable should be gone by now since I only set the session for 1 hr.

When I first get my website up just now, it looks OK but when I click a link to another cfm template, I got this:

The following information is meant for the website developer for debugging purposes.

Error Occurred While Processing Request

Element DSN is undefined in APPLICATION.


The error occurred in C:\inetpub\wwwroot\test\profile.cfm: line 6
4 : 5 : 6 : <cfquery name="GetProfile" datasource="#application.dsn#"> 7 : SELECT * FROM Entity 8 : WHERE EntityId = <cfqueryparam cfsqltype="cf_sql_numeric" value="#Trim(session.EntityId)#">

On top of my profile.cfm I have this query:

SELECT * FROM Entity WHERE EntityId = <cfqueryparam cfsqltype="cf_sql_numeric" value="#Trim(session.EntityId)#"></cfquery>

On my Application.cfc I have:

<cfscript>
this.name = "MyTestApp";
this.applicationTimeout = createTimeSpan(0,1,0,0);
this.clientManagement = false;
this.sessionManagement = true;
this.sessionTimeout = createTimeSpan(0,1,0,0);
this.setClientCookies = true;
this.setDomainCookies = false;
this.scriptProtect = false;
this.secureJSON = false;
this.secureJSONPrefix = "";
this.welcomeFileList = "";
</cfscript>

</cffunction>

My directory :

www

MyComp

all cfm files are under wwww but Application.cfc is within MyComp folder

Should I put Application.cfc under www together with all cfm files?

Report · Sep 13, 2012

If /MyComp is in a parallel directory to /www, then an Application.cfc must also be in /www for it to be called for *.cfm files that are in /www. Is /www the root folder for this application?

Report · Sep 13, 2012

I'm Sorry I did not write my directory correctly:

WWW is the root directory, under www I have the main application folder: MyTestSide where all my .cfm files are.

Then inside MyTestSide I have a few sub folders: MyComp to hold all my .cfc files and MyJSFiles to hold all my .js files

So it looks like this:

WWW

---MyTestSide

--------MyComp

--------MyJSFiles

My question is:

When I do : <cfset application.dsn = "MyDB"> inside OnApplicationStart() in Application.cfc

How come the application scope only recognized by files that are at the same directory as Application.cfc???

So when I place Application.cfc at MyTestSide, only .cfm files recognized #application.dsn#

.cfc files in the SubFolder don't know what #application.dsn# is??? It doesn't make sense.

I thought:

1. Application scope was recognized throughout the whole application

2. CF server first look for Application.cfm and/or Application.cfc before running the application so it doesn't matter

whether Application.cfc is located, am I wrong?

Report · Sep 14, 2012

Do you have any Application.cfc files in your sub-folders?

Are you running CF9 (or 10)? I believe CF9 added a new feature that allows you to change the default lookup order for the Application.cfc file. What is your's set to? In the admin under Server Settings > Settings. Scroll down and you should see these options:

Application.cfc/Application.cfm lookup order

	Default order
	Until webroot
	In webroot

Specify the option ColdFusion should use to search for an Application.cfc/Application.cfm if it is not found in the current folder. By default, ColdFusion will search until the system root.

Report · Sep 14, 2012

Your Application.cfc must be within a direct ancestor directory of the file currently being requested. It cannot be in an adjacent directory, or a directory adjacent to an ancestor. CF finds the Application.cfc by checking the current dir, then moving upwards towards to root of the drive (or the webroot, or the application root, depending on the setting).

EG: if you have this directory structure:

C:\path\to\my\coldfusionroot\then\my\webroot\and\then\the\file\being\requested.cfm, it will look in these directories:

C:\path\to\my\coldfusionroot\then\my\webroot\and\then\the\file\being\

C:\path\to\my\coldfusionroot\then\my\webroot\and\then\the\file\

C:\path\to\my\coldfusionroot\then\my\webroot\and\then\the\

C:\path\to\my\coldfusionroot\then\my\webroot\and\then\

C:\path\to\my\coldfusionroot\then\my\webroot\and\

C:\path\to\my\coldfusionroot\then\my\webroot\

C:\path\to\my\coldfusionroot\then\my\

C:\path\to\my\coldfusionroot\then\

C:\path\to\my\coldfusionroot\

C:\path\to\my\

C:\path\to\

C:\path\

C:\

(depending on a setting, it might stop looking at the indicated places).

It will not look in C:\path\to\my\coldfusionroot\some\subdirectory\

However if you want to organise your files to minimise the number of "non-browseable" files being in your web-browseable directories (which is the correct thing to do), then you can simply out a stub Application.cfc in the webroot, and have that extend another Application.cfc within your non-browseable CF files directory (if that makes sense).

--

Adam

Report · Sep 15, 2012

Hi all, thank you for helping.

I'm developing locally with CF9 and On my admin the Application.cfc/Application.cfm lookup order is set to "In webroot"

Shoul I change it to "Until webroot"?

I tried to read more about using extends attribute of Application.cfc and for some reason it did not work. Thanks for suggesting Adam!

Because of your suggestion, I googled more and I found Ben Nadel's posting about using cfinclude, including the root's Application.cfc in the subfolder's Application.cfc and it looks like everything works now.

All I did was:

Create Application.cfc inside my subfolder and then I just have the following:

</cfcomponent>

Report · Sep 13, 2012

I'm not sure what is causing that problem. But, seriously, I wasn't kidding. Delete the cookies for that site. It is the most reliable way to ensure that onSessionStart() fires. You could also restart the server, but I think deleting cookies is probably easier.

Jason

Creating session variable properly with application.cfc

Element DSN is undefined in APPLICATION.