05-May-2007 : [1]BBK P1 ModuleSession 3

File Handling with PHP

05-May-2007 : [2]BBK P1 ModuleSession 3

Files and PHP

• File Handling– Data Storage

• Though slower than a database

– Manipulating uploaded files• From forms

– Creating Files for download

05-May-2007 : [3]BBK P1 ModuleSession 3

Open/Close a File

• A file is opened with fopen() as a “stream”, and PHP returns a ‘handle’ to the file that can be used to reference the open file in other functions.

• Each file is opened in a particular mode.

• A file is closed with fclose() or when your script ends.

05-May-2007 : [4]BBK P1 ModuleSession 3

File Open Modes‘r’ Open for reading only. Start at beginning of

file.

‘r+’ Open for reading and writing. Start at beginning of file.

‘w’ Open for writing only. Remove all previous content, if file doesn’t exist, create it.

‘a’ Open writing, but start at END of current content.

‘a+’ Open for reading and writing, start at END and create file if necessary.

05-May-2007 : [5]BBK P1 ModuleSession 3

File Open/Close Example

<?php

// open file to read

$toread = fopen(‘some/file.ext’,’r’);

// open (possibly new) file to write

$towrite = fopen(‘some/file.ext’,’w’);

// close both files

fclose($toread);

fclose($towrite);

?>

05-May-2007 : [6]BBK P1 ModuleSession 3

Now what..?

• If you open a file to read, you can use more in-built PHP functions to read data..

• If you open the file to write, you can use more in-built PHP functions to write..

05-May-2007 : [7]BBK P1 ModuleSession 3

Reading Data

• There are two main functions to read data:• fgets($handle,$bytes)

– Reads up to $bytes of data, stops at newline or end of file (EOF)

• fread($handle,$bytes) – Reads up to $bytes of data, stops at EOF.

05-May-2007 : [8]BBK P1 ModuleSession 3

Reading Data

• We need to be aware of the End Of File (EOF) point..

• feof($handle) – Whether the file has reached the EOF point.

Returns true if have reached EOF.

05-May-2007 : [9]BBK P1 ModuleSession 3

Data Reading Example

$handle = fopen('people.txt', 'r');

while (!feof($handle)) {

echo fgets($handle, 1024);

echo '<br />';

}

fclose($handle);

05-May-2007 : [10]BBK P1 ModuleSession 3

Data Reading Example

$handle = fopen('people.txt', 'r');

while (!feof($handle)) {

echo fgets($handle, 1024);

echo '<br />';

}

fclose($handle);

Open the file and assign the resource to $handle

$handle = fopen('people.txt', 'r');

05-May-2007 : [11]BBK P1 ModuleSession 3

Data Reading Example

$handle = fopen('people.txt', 'r');

while (!feof($handle)) {

echo fgets($handle, 1024);

echo '<br />';

}

fclose($handle);

While NOT at the end of the file, pointed to by $handle,

get and echo the data line by line

while (!feof($handle)) {echo fgets($handle, 1024);echo '<br />';}

05-May-2007 : [12]BBK P1 ModuleSession 3

Data Reading Example

$handle = fopen('people.txt', 'r');

while (!feof($handle)) {

echo fgets($handle, 1024);

echo '<br />';

}

fclose($handle);

Close the file

fclose($handle);

05-May-2007 : [13]BBK P1 ModuleSession 3

File Open shortcuts..

• There are two ‘shortcut’ functions that don’t require a file to be opened:

• $lines = file($filename) – Reads entire file into an array with each line a

separate entry in the array.

• $str = file_get_contents($filename) – Reads entire file into a single string.

05-May-2007 : [14]BBK P1 ModuleSession 3

Writing Data

• To write data to a file use:• fwrite($handle,$data)

– Write $data to the file.

05-May-2007 : [15]BBK P1 ModuleSession 3

Data Writing Example

$handle = fopen('people.txt', 'a');

fwrite($handle, “\nFred:Male”);

fclose($handle);

05-May-2007 : [16]BBK P1 ModuleSession 3

Data Writing Example

$handle = fopen('people.txt', 'a');

fwrite($handle, '\nFred:Male');

fclose($handle);

$handle = fopen('people.txt', 'a');

Open file to append data (mode 'a')

fwrite($handle, “\nFred:Male”);

Write new data (with line break after previous data)

05-May-2007 : [17]BBK P1 ModuleSession 3

Other File Operations

• Delete file– unlink('filename');

• Rename (file or directory)– rename('old name', 'new name');

• Copy file– copy('source', 'destination');

• And many, many more!– www.php.net/manual/en/ref.filesystem.php

05-May-2007 : [18]BBK P1 ModuleSession 3

Dealing With Directories

• Open a directory– $handle = opendir('dirname');

• $handle 'points' to the directory

• Read contents of directory– readdir($handle)

• Returns name of next file in directory• Files are sorted as on filesystem

• Close a directory– closedir($handle)

• Closes directory 'stream'

05-May-2007 : [19]BBK P1 ModuleSession 3

Directory Example

$handle = opendir('./');

while(false !== ($file=readdir($handle)))

{

echo "$file<br />";

}

closedir($handle);

05-May-2007 : [20]BBK P1 ModuleSession 3

Directory Example

$handle = opendir('./');

while(false !== ($file=readdir($handle)))

{

echo "$file<br />";

}

closedir($handle);

Open current directory$handle = opendir('./');

05-May-2007 : [21]BBK P1 ModuleSession 3

Directory Example

$handle = opendir('./');

while(false !== ($file=readdir($handle)))

{

echo "$file<br />";

}

closedir($handle);

Whilst readdir() returns a name, loop through directory contents, echoing

results

while(false !== ($file=readdir($handle)))

{

echo "$file<br />";

}

05-May-2007 : [22]BBK P1 ModuleSession 3

Directory Example

$handle = opendir('./');

while(false !== ($file=readdir($handle)))

{

echo "$file<br />";

}

closedir($handle);Close the directory stream

closedir($handle);

05-May-2007 : [23]BBK P1 ModuleSession 3

Other Directory Operations

• Get current directory– getcwd()

• Change Directory– chdir('dirname');

• Create directory– mkdir('dirname');

• Delete directory (MUST be empty)– rmdir('dirname');

• And more!– www.php.net/manual/en/ref.dir.php

05-May-2007 : [24]BBK P1 ModuleSession 3

HOE 6 : Managing Files with PHP

05-May-2007 : [25]BBK P1 ModuleSession 3

Review

• Can open and close files.

• Can read a file line by line or all at one go.

• Can write to files.

• Can open and cycle through the files in a directory.