Php i basic chapter 4

PHP Workshop 1

File Handling with PHP

PHP Workshop 2

Files and PHP

• File Handling– Data Storage

• Though slower than a database

– Manipulating uploaded files• From forms

– Creating Files for download

PHP Workshop 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.

PHP Workshop 4

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.

PHP Workshop 5

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);

?>

PHP Workshop 6

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..

PHP Workshop 7

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.

PHP Workshop 8

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.

PHP Workshop 9

Data Reading Example

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

while (!feof($handle)) {

echo fgets($handle, 1024);

echo ' ';

}

fclose($handle);

PHP Workshop 10





echo ' ';

}

fclose($handle);

Open the file and assign the resource to $handle


PHP Workshop 11





echo ' ';

}

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 ' ';}

PHP Workshop 12





echo ' ';

}

fclose($handle);

Close the file

fclose($handle);

PHP Workshop 13

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.

PHP Workshop 14

Writing Data

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

– Write $data to the file.

PHP Workshop 15

Data Writing Example

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

fwrite($handle, “\nFred:Male”);

fclose($handle);

PHP Workshop 16

Data Writing Example


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

fclose($handle);


Open file to append data (mode 'a')

fwrite($handle, “\nFred:Male”);

Write new data (with line break after previous data)

PHP Workshop 17

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

PHP Workshop 18

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'

PHP Workshop 19

Directory Example

$handle = opendir('./');

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

{

echo "$file ";

}

closedir($handle);

PHP Workshop 20

Directory Example



{

echo "$file ";

}

closedir($handle);

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

PHP Workshop 21

Directory Example



{

echo "$file ";

}

closedir($handle);

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

results


{

echo "$file ";

}

PHP Workshop 22

Directory Example



{

echo "$file ";

}

closedir($handle);Close the directory stream

closedir($handle);

PHP Workshop 23

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

PHP Workshop 24

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.

PHP Workshop 25

Review all

• Create a File

$my_file = 'file.txt';

$handle = fopen($my_file, 'w') or die('Cannot open file: '.$my_file); //implicitly creates file

PHP Workshop 26

Review all

• Open a File


$handle = fopen($my_file, 'w') or die('Cannot open file: '.$my_file); //open file for writing ('w','r','a')...

PHP Workshop 27

Review all

• Read a File


$handle = fopen($my_file, 'r');

$data = fread($handle,filesize($my_file));

PHP Workshop 28

Review all

• Write to a File


$handle = fopen($my_file, 'w') or die('Cannot open file: '.$my_file);

$data = 'This is the data';

fwrite($handle, $data);

PHP Workshop 29

Review all

• Append to a File


$handle = fopen($my_file, 'a') or die('Cannot open file: '.$my_file);

$data = 'New data line 1';

fwrite($handle, $data);

$new_data = "\n".'New data line 2';

fwrite($handle, $new_data);

PHP Workshop 30

Review all

• Close a File


$handle = fopen($my_file, 'w') or die('Cannot open file: '.$my_file);

//write some data here

fclose($handle);

PHP Workshop 31

Review all

• Delete a File


unlink($my_file);

PHP Workshop 32

Review all

PHP Workshop 33

Review all

Technology

Php i basic chapter 4