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C
Cold_Fish
Participant
July 22, 2014
Answered

Writing to a file

  • July 22, 2014
  • 4 replies
  • 914 views

hi everyone,

I have a file that only contains a number in it (invoice number).  Every time someone submits a form, it should increase the value of the number in the file by one. 

It's my understanding that the file should be "locked" while it is being written to, so it does not give a duplicate amount if two people submit at the same time.  Upon updating the file, it would then unlock the file, so it could then be written to by the next transaction.

The file would exist in the same folder as the form. 

That's just my speculation as to how I think it should work. Basically, Open file, Lock file, write to file, unlock file.

Does anyone know of any tutorials that would show how to do this?

Thanks!

This topic has been closed for replies.
Correct answer BKBK

<cfset fileName = expandPath("counter.txt")>

<cflock name="fileReadLock" type="exclusive" timeout="20" throwontimeout="yes">

<cfif fileExists(fileName)>

    <cffile action="read" file="#fileName#" variable="fileContent">

    <cfif not isNumeric(fileContent)>

        <cfthrow message="Content of file counter.txt is non-numerical.">

        <cfabort>

    </cfif>

    <cfset fileContent = fileContent+1>

    <cffile action="write" file="#expandpath('counter.txt')#" output="#fileContent#">

<cfelse>

    <cfthrow message="Counting file counter.txt is in the wrong location or does not exist.">

    <cfabort>

</cfif>

Current count: <cfoutput>#fileContent#</cfoutput>

</cflock>

4 replies

C
Cold_FishAuthor
Participant
July 24, 2014

Thank-you for your concerns.

I am open to other methods to accomplish the same thing, but need a little more help than simply "write it to a database".  I would likely need use MSAccess as the database for this counter if I'm going to go this method.

I'm willing to learn!

Graham.

Dave Ferguson
Dave Ferguson
Participating Frequently
July 24, 2014

Your application doesn't use a database at all?  I find that a little strange and at the same time Interesting.  First, don't use MS Access for well, anything.  If you don't have a DB use something like Mysql.  It is free and works very well.

S
Scott Stroz
Participating Frequently
July 24, 2014

This is an incredibly bad way to manage this information - so bad it cannot be measured with existing technology.

Store the number in a DB, not in a file to be read/written to frequently. Too many factors that can cause this to go belly up.

Dave Ferguson
Dave Ferguson
Participating Frequently
July 24, 2014

While BKBK does give you a way that it will work I am wondering why you would even do this?  This has more ways it could fail than I can count.  Among them, you could easily have a lock left behind on the file thus making it unreadable.  You should really be storing this data in a database not a file.

--Dave

    BKBK
    Community Expert
    BKBKCommunity ExpertCorrect answer
    Community Expert
    July 23, 2014

    <cfset fileName = expandPath("counter.txt")>

    <cflock name="fileReadLock" type="exclusive" timeout="20" throwontimeout="yes">

    <cfif fileExists(fileName)>

        <cffile action="read" file="#fileName#" variable="fileContent">

        <cfif not isNumeric(fileContent)>

            <cfthrow message="Content of file counter.txt is non-numerical.">

            <cfabort>

        </cfif>

        <cfset fileContent = fileContent+1>

        <cffile action="write" file="#expandpath('counter.txt')#" output="#fileContent#">

    <cfelse>

        <cfthrow message="Counting file counter.txt is in the wrong location or does not exist.">

        <cfabort>

    </cfif>

    Current count: <cfoutput>#fileContent#</cfoutput>

    </cflock>

      C
      Cold_FishAuthor
      Participant
      July 24, 2014

      BKBK!!!

      That was exactly what I needed!  I implemented it into my current code and it worked perfectly!  Thank-you so much for your help with this!  It is very much appreciated!


      Graham.

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