Suggestion? Write to file - changing header line each time $_POST changes

sherry

Hello.

I'm looking for a suggestion(s):

I'm writing form data to a file that includes a delimiter. The data originates from $_POST so the number of vars (form fields) can change at anytime in the future.

In order to make collecting data with minimal fuss, therefore, I want to add a header line upon these conditions using a single flat file:

1) when there is an empty or new file, make the 1st line the header followed by the data line entry - this can occur when the file reaches a certain size then create anew with the appropriate file permissions e.g. 620;
2) whenever the $POST vars change, add a blank line (skip a line) followed by the new header line followed by the data line. The $POST var changes either more or less as fields on the form changes;
3) repeat as changes to $_POST structure changes.

The header line is already constructed to be fluid (adapt to changes to the $POST var). How to create the writing to the file is the issue for Step 1 & 2 above - how the script knows that the $POST array structure has changed and to write the new header line after skipping a line is the challenge.

Thanks.

DaveRandom

You could add the structure of the $_POST array to the header line using serialize(), and when it changes add another value to the header line which states what line the next (new) header line is on when it has changed?

You would probably have to read the file using file(), so beware of making your files too large and eating all your memory on every request...

sherry

Thanks DaveRandom.

I'll have to do a little reading up on serialize to adapt to this situation.

Q: What might a max file size be for this?

Thanks.

DaveRandom

sherry wrote:
What might a max file size be for this?

That really depends on how much RAM you have available to use on your server. I don't like to read a whole file into the memory that's larger than 100MB, but that's just a personal thing...

I can't help wondering if you would be better using a DB for this job though, then you can be alot more intelligent about which data your working with at any given time...

sherry

Thanks for your reply, DaveRandom.

Under normal circumstances, I use MySQL but for this project, it calls for a flat file. 🙂

DaveRandom

Fair enough

The alternative would be to create another file that tracks the structure of the $_POST array (I still think serialize()/unserialize() is the best way to do this) and which line in the main file the current header line is on.

sherry

Thanks DaveRandom.

I agree that another file can serve as a cross reference. Adding a ref param of some kind to the header line that refers to the serialized data is one way to do it (using a db would have been nicer, though). Given a little more thought, maybe there is an even better way. The serialized method seems the most appropriate, too.

Thanks again.

sherry

Hello again, DaveRandom.

UPDATE:

I created cross-reference file which stores the serialized values. When needed, I read that file via file() which puts the data into an array (I also tried file_get_contents with end() to get the value from the last element). Then, I could manipulate or search the array as needed. It works GREAT!

Thanks again!