Files in PHP.pptx g

Files in PHP
Web Design and Programming
5/8/2024
1 Department of Software Engineering

PHP File Handling
 Manipulating files is a basic for serious
programmers and PHP gives you a great deal of
tools for creating, uploading, and editing files.
 Before you can do anything with a file it has to be exist!
 In PHP, a file is created using a command that is also
used to open files.
 In PHP the fopen function is used to open files.
 However, it can also create a file if it does not find the
file specified in the function call.
 So if you use fopen on a file that does not exist, it will
create it, given that you open the file for writing or
appending.
5/8/2024
2 Department of Software Engineering

Opining a File
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Department of Software Engineering
3
 The fopen function needs two important
parameter.
 The first parameter of this function contains the
name of the file to be opened and the second
parameter specifies in which mode the file should
be opened(what we plan to do with that file read,
write… )
<html>
<body>
<?php
$file=fopen("welcome.txt","r");
?>
</body>
</html>

Modes of a file
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 The three basic ways to open a file and the corresponding
character that PHP uses.
Read: 'r'
 Open a file for read only use. The file pointer begins at the
front of the file.
Write: 'w'
 Open a file for write only. In addition, the data in the file is
erased and you will begin writing data at the beginning of
the file. This is also called truncating a file.
 The file pointer begins at the start of the file.
Append: 'a'
 Open a file for write only. However, the data in the file is
preserved and you begin writing data at the end of the file.
 The file pointer begins at the end of the file.
 ‘x’ - Write only. Creates a new file. Returns FALSE and an
error if file already exists

Opening a File-Example
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 If the fopen() function is unable to open the specified
file, it returns 0 (false).
Example
 The following example generates a message if the
fopen() function is unable to open the specified file:
<html>
<body>
<?php
$file=fopen("welcome.txt","r") or exit("Unable to open
file!");
?>
</body>
</html>

Closing a File
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6
 The fclose() function is used to close an open file:
 The function fclose requires the file handle that we want to close
down.
 After a file has been closed down with fclose it is impossible to
read, write or append to that file unless it is once more opened
up with the fopen function.
<?php
$file = fopen("test.txt","r");
//some code to be executed
fclose($file);
?>
Check End-of-file
 The feof() function checks if the "end-of-file" (EOF) has been
reached.
 The feof() function is useful for looping through data of unknown
length.
 Note: You cannot read from files opened in w, a, and x
mode!
if (feof($file)) echo "End of file";

Reading a File
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 The fread function is used to get data out of a file.
 The function requires a file handle, which we have,
and an integer to tell the function how much data, in
bytes, it is supposed to read.
 One character is equal to one byte. If you wanted to
read the first five characters then you would use five
as the integer.
<?php
$myFile = "testFile.txt";
$fh = fopen($myFile, 'r');
$theData = fread($fh, 5);
fclose($fh);
echo $theData;
?>

Reading a File…
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8
 If you wanted to read all the data from the file, then
you need to get the size of the file.
 The filesize function returns the length of a file, in
bytes, which is just what we need!
 The filesize function requires the name of the file that
is to be sized up.
<?php
$fh = fopen($myFile, 'r');
$theData = fread($fh, filesize($myFile));
fclose($fh);
echo $theData;
?>

Reading a File Line by Line
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 The fgets() function is used to read a single line from a file.
 The fgets function searches for the first occurrence of "n"
the newline character.
Example
 The example below reads a file line by line, until the end of
file is reached:
<?php
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file))
{
echo fgets($file). "<br />";
}
fclose($file);
?>

Reading a File Character by Character
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 The fgetc() function is used to read a single character from
a file.
 Note: After a call to this function the file pointer moves to
the next character.
Example
 The example below reads a file character by character,
until the end of file is reached:
<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
while (!feof($file))
{
echo fgetc($file);
}
fclose($file);
?>

Exercise
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1. Write a program that count the number
of words in the given text.
2. Write a program that display a word
with maximum character from a given
text.

Writing in to a file
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 The fwrite function allows data to be written to any
type of file.
 It takes two parameters:- first parameter is the file
handler and its second parameter is the string of data
that is to be written.
 Below we are writing a couple of names into our test
file testFile.txt and separating them with a carriaged
return.
<?php
$file = fopen($myFile, 'w') or die("can't open file");
$stringData = “Abebe Derejen";
fwrite($file, $stringData);
$stringData = “Debela Hailen";
fwrite($file, $stringData);
fclose($fh);
?>

Deleting a File
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 If you unlink a file, you are effectively causing the
system to forget about it or delete it!
 Before you can delete (unlink) a file, you must
first be sure that it is not open in your program.
 Example
unlink($myFile);
 The testFile.txt should now be removed.

PHP Filesystem Functions
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 chmod() Changes the file mode
 chown() Changes the file owner
 copy() Copies a file
 delete() Deletes a file like that of unlink() or unset()
 dirname() Returns the directory name component
of a path
 disk_free_space() Returns the free space of a
directory
 disk_total_space() Returns the total size of a
directory
 fclose() Closes an open file
 feof() Tests for end-of-file on an open file

PHP Filesystem Functions…
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 fgetc() Returns a character from an open file
 fgets() Returns a line from an open file
 fgetss() Returns a line, with HTML and PHP tags
removed, from an open file
 file() Reads a file into an array
 file_exists() Checks whether or not a file or directory
exists
 file_get_contents() Reads a file into a string
 file_put_contents() Writes a string to a file
 fileatime() Returns the last access time of a file
 filectime() Returns the last change time of a file
 filemtime() Returns the last modification time of a file

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 fileowner() Returns the user ID (owner) of a file
 fileperms() Returns the permissions of a file
 filesize() Returns the file size
 filetype() Returns the file type
 flock() Locks or releases a file
 fnmatch() Matches a filename or string against a
specified pattern
 fopen() Opens a file or URL
 fpassthru() Reads from an open file, until EOF, and
writes the result to the output buffer
 fread() Reads from an open file

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 fwrite() Writes to an open file
 is_dir() Checks whether a file is a directory
 is_executable() Checks whether a file is executable
 is_file() Checks whether a file is a regular file
 is_link() Checks whether a file is a link
 is_readable() Checks whether a file is readable
 is_uploaded_file() Checks whether a file was
uploaded via HTTP POST
 is_writable() Checks whether a file is writeable
 mkdir() Creates a directory
 move_uploaded_file() Moves an uploaded file to a
new location

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 readfile() Reads a file and writes it to the output
buffer
 realpath() Returns the absolute pathname
 rename() Renames a file or directory
 rmdir() Removes an empty directory
 set_file_buffer() Sets the buffer size of an open
file
 stat() Returns information about a file
 umask() Changes file permissions for files
 unlink() Deletes a file

PHP File Upload
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19
 With PHP it is possible to upload files to the server.
Create an Upload-File Form
 To allow users to upload files from a form can be very
useful.
 Look at the following HTML form for uploading files:
<html>
<body>
<form action="upload_file.php" method="post"
enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file" />
<br />
<input type="submit" name="submit" value="Submit" />
</form>
</body>
</html>

PHP File Upload…
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 Notice the following about the HTML form above:
 The enctype attribute of the <form> tag specifies
which content-type to use when submitting the
form. "multipart/form-data" is used when a form
requires binary data, like the contents of a file, to
be uploaded.
 The type="file" attribute of the <input> tag
specifies that the input should be processed as a
file.
 For example, when viewed in a browser, there will
be a browse-button next to the input field.
 Note: Allowing users to upload files is a big
security risk. Only permit trusted users to perform
file uploads.

Create The Upload Script
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 The "upload_file.php" file contains the code for
uploading a file:
<?php
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br />";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
?>

Create The Upload Script…
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 By using the global PHP $_FILES array you can
upload files from a client computer to the remote
server.
 The first parameter is the form's input name and the
second index can be either "name", "type", "size",
"tmp_name" or "error". Like this:
 $_FILES["file"]["name"] - the name of the uploaded file
 $_FILES["file"]["type"] - the type of the uploaded file
 $_FILES["file"]["size"] - the size in bytes of the uploaded
file
 $_FILES["file"]["tmp_name"] - the name of the temporary
copy of the file stored on the server
 $_FILES["file"]["error"] - the error code resulting from the
file upload
 For security reasons, you should add restrictions on
what the user is allowed to upload.

Restrictions on Upload
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In this script we add some restrictions to
the
file upload. The user may only upload .gif
or
.jpeg files and the file size must be under
20 kb.
<?php
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg"))
&& ($_FILES["file"]["size"] < 20000))
{
{
echo "Error: " . $_FILES["file"]["error"] . "<br
/>";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br
/>";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . "
Kb<br />";
echo "Stored in: " .
$_FILES["file"]["tmp_name"];
}
}
else
{
echo "Invalid file";
}
?>

Saving the Uploaded File
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 The examples above create a temporary copy of
the uploaded files in the PHP temp folder on the
server.
 The temporary copied files disappears when the
script ends.
 To store the uploaded file we need to copy it to a
different location:
 The script below checks if the file already exists, if
it does not, it copies the file to the specified folder.
 Note: This example saves the file to a new folder
called "upload"

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<?php
if (($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/pjpeg")
&& ($_FILES["file"]["size"] < 20000))
{
{
echo "Return Code: " .
$_FILES["file"]["error"] . "<br />";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] .
"<br />";
echo "Type: " . $_FILES["file"]["type"] .
"<br />";
echo "Size: " . ($_FILES["file"]["size"] /
1024) . " Kb<br />";
echo "Temp file: " .
$_FILES["file"]["tmp_name"] . "<br />";
$_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already
exists. ";
}
else
{
move_uploaded_file($_FILES["file"]["tmp_
name"],
"upload/" . $_FILES["file"]["name"]);
echo "Stored in: " . "upload/" .
$_FILES["file"]["name"];
}
}
}
else
{
echo "Invalid file";
}
?>

Server Side Includes
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 You can insert the content of a file into a PHP file
before the server executes it, with the include() or
require() function.
 The two functions are identical in every way, except
how they handle errors.
 The include() function generates a warning (but the
script will continue execution) while
 The require() function generates a fatal error (and
the script execution will stop after the error).
 These two functions are used to create functions,
headers, footers, or elements that can be reused
on multiple pages.
 This can save the developer a considerable
amount of time.

The include() Function
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 The include() function takes all the text in a specified
file and copies it into the file that uses the include
function.
Example
 Assume that you have a standard header file, called
"header.php". To include the header file in a page, use
the include() function, like this:
<html>
<body>
<?php include("header.php"); ?>
<h1>Welcome to my home page</h1>
<p>Some text</p>
</body>
</html>

The require() Function
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 The require() function is identical to include(), they
only handle errors differently.
 If you include a file with the include() function and an
error occurs, you might get an error message like the
one below.
 Example
<html>
<body>
<?php
include("wrongFile.php");
echo "Hello World!";
?>
</body>
</html>

The require() Function…
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 Error message:
Warning: include(wrongFile.php) [function.include]:
failed to open stream:
No such file or directory in C:homewebsitetest.php on line 5
Warning: include() [function.include]:
Failed opening 'wrongFile.php' for inclusion
(include_path='.;C:php5pear')
in C:homewebsitetest.php on line 5
Hello World!
 Notice that the echo statement is still executed!
This is because a Warning does not stop the
script execution.

The require() Function…
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30
 Now, let's run the same example with the require()
function.
<?php
require("wrongFile.php");
echo "Hello World!";
?>
 Error message:
Warning: require(wrongFile.php) [function.require]:
failed to open stream:
No such file or directory in C:homewebsitetest.php on line 5
Fatal error: require() [function.require]:
Failed opening required 'wrongFile.php'
(include_path='.;C:php5pear')
in C:homewebsitetest.php on line 5
 The echo statement was not executed because the
script execution stopped after the fatal error.

The End
Questions
5/8/2024
Compiled By: Melkamu D.
31

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