char1iecha1k wrote:
> On 15 May, 13:54, Oisin Grehan <ois...@gmail.com> wrote:
>> On May 15, 5:11 am, char1iecha1k <charlesgarg...@gmail.com> wrote:
>>
>>
>>
>>> On 15 May, 09:09, RichS <R...@discussions.microsoft.com> wrote:
>>>> Is this for reading, writing or both
>>>> --
>>>> Richard Siddaway
>>>> Please note that all scripts are supplied "as is" and with no warranty
>>>> Blog:http://richardsiddaway.spaces.live.com/
>>>> PowerShell User Group:http://www.get-psuguk.org.uk
>>>> "char1iecha1k" wrote:
>>>>> Hi,
>>>>> I would like to open a file for exclusive access for the duration of a
>>>>> script. If the script fails or finishes the lock must be released.
>>>>> This is to prevent another user or process from accessing the same
>>>>> data file. I have googled to no avail.
>>>>> Thanks in advance
>>> I want to open file for reading, and when open disallow any other
>>> process from opening that file. So far I have this
>>> $test1=new-object System.IO.FileStream("test1.txt",
>>> [System.IO.FileMode]::Open)
>>> Now I need to know how to return the state of the file into a variable
>>> so that my script can move on to the next unopen file ie
>>> for each file in folder open file (if $file already open then return,
>>> else process job)
>>> hope that makes sense- Hide quoted text -
>>> - Show quoted text -
>> Do you have control of these other scripts? If so, why not use a
>> traditional ".lock" file - e.g. when you start up, create a file
>> called "mydatafile.lock," and delete it when you're finished. All
>> scripts should look for this while on start up, and quit if it already
>> exists.
>
> Thats the way I do it at the moment. If the script errors for some
> unkown reason then the lock file doesnt get removed.
>
> If I open a file in a script as soon as the script ends (due to an
> error or natural cause) the file will close.
>
> I have got a bit further, but there are some peculiarities. Here is
> the relevant bit of the script :
>
> &{
> trap { write-host "error"; exit }
> $script:test = new-object System.IO.FileStream("file.lck",
> [System.IO.FileMode]::Open)
> }
> write-host "success"
>
> if the file isnt opened anywhere else then there will be no error in
> the script block and the file is opened.
> if the file is opened in another process then creating the new object
> fails and and the trap handler exits the script.
> as soon as the script finishes or exits the filestream is closed
>
> this all works but if you run that piece of code in a test batch file
> and keep running it then some times it displays an error and sometimes
> not. here is a sample output below
>
> 1# gc test.ps1
> &{
> trap { write-host "error"; exit }
> $script:test = new-object System.IO.FileStream("cmdc.lck",
> [System.IO.FileMode]::Open)
> }
> write-host "success"
> 2# .\test.ps1
> success
> 3# .\test.ps1
> success
> 4# .\test.ps1
> success
> 5# .\test.ps1
> error
> 6# .\test.ps1
> success
> 7# .\test.ps1
> error
> 8# .\test.ps1
> success
> 9# .\test.ps1
> error
> 10# .\test.ps1
> success
> 11# .\test.ps1
> error
> 12# .\test.ps1
> success
> 13# .\test.ps1
> success
> 14# .\test.ps1
> error
> 15# .\test.ps1
> error
>
>
>
Sounds like you need to set your PSH script to continue even if there's
a failure of any sorts so the lock gets created, then removed even if
any commands within it fail?
http://blogs.msdn.com/powershell/arc...25/583241.aspx