PHP-language, files

Teppo RäisänenPrincipal Lecturer

Oulu University of Applied SciencesSchool of Business and Information Management

teppo.raisanen@oamk.fi, 050 382 6587

Why files?

• To store data• Simple to use• No database available• When storing complex data - use database

Basic steps using files from application

1. Open file2. (Lock file while reading)3. Read from/write to file4. (Release locking)5. Close file

Opening file

• Usually it is wise that applications don’t create file (necessary files are created manually during application setup)

• Files must be NEVER stored under public_html

fopen()

$filehandle=fopen(”../somefile.csv”,”w”);…

• Opening modesr=readw=writea=append• Check for more modes on PHP-manual

fwrite()

$filehandle=fopen(”../somefile.csv”,”w”);flock($filehandle,LOCK_EX);fwrite($filehandle,”Content to be added to file.”);flock($filehandle,LOCK_UN);fclose($filehandle);

Reading a file<?php$filehandle=fopen(”…/../data.csv”,”r”);while (!feof($filehandle)) //Check if we have reached end of file{

$row=fgets($filehandle); //Read current row from fileprint ”$row<br>”; //Print row without any formatting

}fclose($filehandle);?>

Note that $row=fread($filehandle, 1024) works also

fclose()

$filehandle=fopen(”../somefile.csv”,”r”);fclose($filehandle);

• You’ll have to ALWAYS remember to close to used file!

Using files in Applications

• Data is stored to file using e.g. delimeter character

• For example csv-file (Comma separated value)

Exercise

• Implement simple guestbook which stores messages to csv-file