PHP-language, files Teppo Räisänen Principal Lecturer Oulu University of Applied Sciences School of Business and Information Management

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 file 2.(Lock file while reading) 3.Read from/write to file 4.(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 modes r=read w=write a=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 file print ”$row ”; //Print row without any formatting } fclose($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