在单个页面加载中传输（相当）大量的数据

Question

I have an application that generates an array of statistics based on a greyhounds racing history. This array is then used to generate a table which is then output to the browser. I am currently working on creating a function that will generate an excel download based on these statistics. However, this excel download will only be available after the original processing has been completed. Let me explain.

1. The user clicks on a race name
2. The data for that race is then processed and displayed in a table.
3. Underneath the table is a link for an excel download.

However, this is where I get stuck. The excel download exists within another method within the same controller like so...

function view($race_id) {
    //Process race data and place in $stats
    //Output table & excel link
}

function view_excel($race_id) {
    //Process race data <- I don't want it to have to process all over again!
    //Output excel sheet
}

As you can see, the data has already been processed in the "view" method so it seems like a massive waste of resources having it processed again in the "view_excel" method.

Therefore, I need a method of transferring $stats over to the excel method when the link is clicked to prevent it having to be reproduced. The only methods I can think of are as follows.

• Transferring $stats over to the excel method using a session flash
  • The variable may end up being too big for a session variable. Also, if for some reason the excel method is refreshed, the variable will be lost.
• Transferring $stats over to the excel method using an ordinary session variable
  • As above, the variable may end up being too big for a session variable. This has the benefit that it wont be lost on a page refresh but I'm not sure how I would go about destroying old session variables, especially if the user it processing alot of races in a short period of time.
• Storing $stats in a database and retrieving it in the excel method
  • This seems like the most viable method. However, it seems like a lot of effort to just transfer one variable across. Also, I would have to implement some sort of cron job to remove old database entries.

An example of $stats :

Array
(
    [1] => Array
        (
            [fcalc7] => 
            [avgcalc7] => 
            [avgcalc3] => 86.15
            [sumpos7] => 
            [sumpos3] => 9
            [sumfin7] => 
            [sumfin3] => 8
            [total_wins] => 0
            [percent_wins] => 0
            [total_processed] => 4
            [total_races] => 5
        )

    [2] => Array
        (
            [fcalc7] => 28.58
            [avgcalc7] => 16.41
            [avgcalc3] => 28.70
            [sumpos7] => 18
            [sumpos3] => 5
            [sumfin7] => 23
            [sumfin3] => 7
            [total_wins] => 0
            [percent_wins] => 0
            [total_processed] => 7
            [total_races] => 46
        )

    [3] => Array
        (
            [fcalc7] => 28.47
            [avgcalc7] => 16.42
            [avgcalc3] => 28.78
            [sumpos7] => 28
            [sumpos3] => 11
            [sumfin7] => 21
            [sumfin3] => 10
            [total_wins] => 0
            [percent_wins] => 0
            [total_processed] => 7
            [total_races] => 63
        )
)

Would be great to hear your ideas.

Dan

Answer 1

You could serialize the array into a file in sys_get_temp_dir() with a data-dependet file name. The only problem left is cleaning up old files.

Putting it into the database is also possible as you said, and deleting old data is easier than on the file system if you track the creation time.