variables / application[]-object

[Patrick]

Hi

I have the following problem. When starting my asp.net application, i read a
encrypted string from a file, decrypt it and want this values to be
available in the complete application. they should be stored in a global
variable, but it shouldn't be possible to modify this variable.

so what i tried first was using the application object to store that string.
that was fine, but the problem is, that it can be modified from outside, so
it's not good for my use.

next idea was to create a public string that returns the private string with
the get{} method. this works fine, but the problem is, where do i store the
string, that i don't lose it. i mean, how can i store the decrypted string
in the variable, without reading it each time from the file and decrypting
it. i want to store it in the private variable and it should always be
there, as long as the application is running.

any ideas?

Thanks

 

[Patrick]

Karl, thnanks for your answer. but as I see in your example, you add the
secret string to the application object? so that was what i was thinking,
that i have to add it there. there is no way to keep it in memory as
readonly. in the application_start i want to read the file, decrypt that
info, store it to a read-only global variable, that i can access from every
aspx page.

as i understand you, in the application_start i load the string to the
session variable (crypted) and each time i request the public readonly
variable, it will be decrypted.

right?

but in that case, people still can modify the application object and clear
the crypted string.

or do i missunderstand you?

thanks for your help

 

[Karl Seguin]

you don't load the string in the application variable, you load the entire
object...which means the string is still private (or readonly via the
property). However, the object can still be removed...or replaced with
something else - as you've pointed out.

You could implement a readonly static field...but then you could get into
threading issues.

How about this:

implement a class with a single shared/statis function. something like
this:

public function GetSecret() as string
dim secret as string = cstr(cache("mysecretstring"))
if secret is nothing then
secret = DECRYPTSTRING() 'some private shared function
cache.add("mysecretstring", secret, New
System.Web.Caching.CacheDependency("FILETHATHOLDSYOURSTRING"),
Caching.Cache.NoAbsoluteExpiration, Caching.Cache.NoSlidingExpiration,
CacheItemPriority.Normal, Nothing)
end if
return string
end function


Yes, people can still manipulate teh cache and screw around with it...as far
as I know..there's no way to create a readonly cache...though atleast it's a
bit obfuscated. You've also moved the string away from the application and
into the cache..which I think is good.

There are callback methods you can use whenever the cache drops an
item..never used them..,maybe the could come in handy...dunno.

Karl

 

[Patrick]

Karl, thanks for your help. The caching solution works fine for my needs and
was just a quick thing to implement.

So thanks for your great help

Patrick