5. Other Miscellaneous
5.1 Generating Images
PHP can manipulate image processing. If you have installed the GD library, you can even use PHP to generate images.
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Header ("Content-type:image/gif");
$string=implode ($ARGV, "");
$im = Imagecreatefromgif ("Images/button1.gif");
$orange = Imagecolorallocate ($im, 220, 210, 60);
$PX = (Imagesx ($im) -7.5*strlen ($string))/2;
Imagestring ($im,3,$px,9,$string,$orange);
Imagegif ($im);
Imagedestroy ($im);
?>
(Translator Note: The above code snippet is missing comments, please refer to the PHP Manual image processing function section)
This code is
5.2 Cookies
PHP supports cookies based on HTTP. You can use cookies as easily as you would use a generic variable when you need it. Cookies are pieces of information that the browser keeps in the client, so you can tell whether anyone on a particular PC has visited your site, the viewer's trail on your site, and so on. A typical example of using cookies is the screening of viewers ' preferences. Cookies are set by Function Setcookie (). As with the function header () of the output HTTP headers, Setcookie () must be invoked before any actual content cups are exported to the browser. Here's a simple example:
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if (empty ($visitedbefore))
{
If no cookie is set, the current time value is assigned to the cookie
The last parameter in the function declares the time the cookie was saved
In this case, 1 years.
The time () function returns the number of seconds since January 1, 1970
Setcookie ("Visitedbefore", Time (), Time () + (60*60*24*365));
}
Else
{
Visitors are welcome to visit again
echo "Hello there, welcome back<br>";
Read cookies and judge
if ((Time ()-$visitedbefore) >= "(60*60*24*7)")
echo "Why did you take a week to come back. You are here should to more often!? ";
}
?>
5.3 Based on HTTP authentication
HTTP-based authentication is not possible when PHP is running in CGI mode. We can use the function header () to send HTTP header enforcement authentication, and the client browser pops up a dialog box for entering a username and password. These two variables are stored in $php_auth_user and $PHP_AUTH_PW, and you can use these two variables to validate the legality and allow entry. The following example validates a user's login through a user name/password pair for tnc/nature:
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if (!isset ($php_auth_user))
{
Header ("Www-authenticate:basic realm=\" "My Realm\");
Header ("http/1.0 401 Unauthorized");
echo "Text to send if user hits Cancel button\n";
Exit
}
Else
{
if (!) ( $php_auth_user== "TNC" && $php_auth_pw== "nature"))
{
If the user name/password pair is incorrect, force re-verify
Header ("Www-authenticate:basic realm=\" "My Realm\");
Header ("http/1.0 401 Unauthorized");
echo "ERROR: $PHP_AUTH_USER/$PHP_AUTH_PW is invalid.";
Exit
}
Else
{
echo "Welcome tnc!";
}
?>
In fact, it is unlikely that the actual reference would be as obvious as the user name/password pair used in the code snippet above, but to access them using a database or encrypted password file.
5.4 File Upload
You can use PHP to implement the function of the file, note that the client's browser should be Netscape3 or above or IE3. Here's a simple demo of this feature:
(upload.html):
<HTML>
<HEAD>
<title>upload Your file</title>
</HEAD>
<BODY>
<form action= "Receiver.php3"
Enctype= "Multipart/form-data" method=post>
<input type= "HIDDEN"
Name= "max_file_size" value= "2000000" >
<input type= "FILE"
Name= "UploadFile" size= "maxlength=" >
<BR><BR>
<input type= "SUBMIT" value= "Upload file!"
Name= "Sendit" >
<input type= "SUBMIT" value= "Cancel"
Name= "Cancelit" ><BR>
</FORM>
<i><font size= "2" > (May notice a slight
Delay while we upload your file.) </FONT></I>
</BODY>
</HTML>
Here is the file to process the upload:
(RECEIVER.PHP3):
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function Do_upload ()
{
Global $uploadfile, $uploadfile_size;
Global $local_file, $error_msg;
if ($uploadfile = "None")
{
$error_msg = "You did is not specify a file for uploading."
Return
}
if ($uploadfile_size > 2000000)
{
$error_msg = "Sorry, your file is too large.";
Return
}
$the_time = time ();
You need to have write access to the following directory
$upload_dir = "/local/uploads";
$local_file = "$upload_dir/$the_time";
if (file_exists (' $local_file '))
{
$seq = 1;
while (File_exists ("$upload_dir/$the_time$seq")) {$seq++;}
$local_file = "$upload_dir/$the_time$seq";
};
Rename ($uploadfile, $local_file);
Display_page ();
}
function Display_page ()
{
Here is the content of your page
}
<HTML>
<HEAD>
<title>php3 receiving script</title>
</HEAD>
<BODY>
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if ($error_msg) {echo "<B>$error_msg</B><BR><BR>";}
if ($sendit)
{
Do_upload ();
}
ElseIf ($cancelit)
{
Header ("Location: $some_other_script");
Exit
}
Else
{
Some_other_func ();
}
?>
</BODY>
</HTML>
5.5 Common functions
Let's take a look at some of the commonly used functions.
Array
Array-generating arrays
Count-Number of elements in an array
Sort-array ordering, and there are several other sort functions to use
List-list array elements
Each-returns the next Key/value pair
Current-Returns the present array element
Next,prev-Returns the pointer before and after the current array element
Date and time
Checkdate-Validate Date/time format
Date-Generate dates/time formats
Time-Current information
Strftime-Format Date/time
Directory, File system
ChDir-Change Directory
Dir-Directory Category
Opendir, Readdir, Closedir-open, read, close directory
fopen, fclose-Open, close file
Fgets, FGETSS-read content line by row
File-Reads an entire file into an array variable
Regular expressions
Ereg-Matching regular expressions
Eregi-case insensitive matching regular expressions
Ereg_replace-matches regular expressions and replaces
Eregi_replace-case insensitive match regular expression and replace
Split-cut the string by rule and store it in an array situation
String
Addslashes-use string after slash-plus
echo-outputs one or more strings
Join, implode-merging array elements into strings
Htmlentities, Htmlspecialchars-converts HTML special characters to HTML markup form
Split-cut the string by rule and store it in an array situation
5.6 Expansion of our example homepage
We will use some of the functions and ideas mentioned above to add more dynamic content to our example home page. We can add a navigation bar at the top of each page, and make the current page automatically not be linked to the display, but also can be added a user to verify the form to upload music, images and other files and automatically update the page.
Navigation bar
It's actually adding a piece of code to the Footer.inc file. Suppose that all files in your Web site with the suffix. PhP3 appear in the navigation bar, and the following is the code saved as Include/navbar.inc:
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/* Output the navigation bar, link all except the current page in the station. php3 File * *
# reading Directories
$d = Dir ("./");
echo "<p align=\" Center\ "> | \ n ";
while ($entry = $d->read ())
{
Ignore no file condition
if (!is_file ($entry))
Continue
/* Separate the file name from the extension. Because. is a regular expression special character, should be used to draw/
List ($filenm, $fileext) = Split ("\.", $entry, 2);
Ignore non. php3 file conditions
if ($fileext!= "PhP3")
Continue
/* Now we've selected the. php3 file, search for the first line (title) in the file below
Similar to $title= "something";
and separate the above headings to be used as link text * *
$LINKNM = "";
$fp=fopen ($entry, "R");
while ($buffer=fgets ($FP, 4096))
{
$buffer = Trim ($buffer);
We have placed the title of each file on the first line of the file to search
But when you change the name of the variable, it can be a big problem.
if (Ereg ("title *= *\", $buffer))
{
/* We have obtained the title content and can on this basis
To remove space and other processing.
Must be handled in the form of PHP code, such as $title = "blah blah" * *
eval ($buffer);
Then display the link text as the title text
$LINKNM = $title;
Break
}
}
Fclose ($FP);
if ($entry = = basename ($php_self))
echo "$LINKNM";
Else
echo "<a href=\" $entry\ ">$linknm</A>";
echo "|";
}
$d->close ();
echo "</p>\n";
?>
Photo Favorites
We will use HTTP based authentication, file system functions, and file upload functions to maintain the directory where image files are placed.
At the same time we need to create a page that lists all the photos in the directory.
File Upload
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Include ("Include/common.inc");
We're going to do this again. User authentication
if (!isset ($php_auth_user))
{
Header ("Www-authenticate:basic realm=\" $mysitename\ "");
Header ("http/1.0 401 Unauthorized");
echo "Sorry, you are not authorized to upload files\n";
Exit
}
Else
{
if (!) ( $php_auth_user==$myname && $php_auth_pw==$mypassword))
{
If it is the wrong user name/password pair, Force again authentication
Header ("Www-authenticate:basic realm=\" "My Realm\");
Header ("http/1.0 401 Unauthorized");
echo "ERROR: $PHP_AUTH_USER/$PHP_AUTH_PW is invalid.<p>";
Exit
}
}
if ($cancelit)
{
When the viewer presses the Cancel button, it turns to the first page.
Header ("Location:front_2.php3");
Exit
}
function Do_upload () {
Global $userfile, $userfile_size, $userfile_name, $userfile_type;
Global $local_file, $error_msg;
Global $http_referer;
if ($userfile = = "None") {
$error_msg = "You did is not specify a file for uploading."
Return
}
if ($userfile_size > 2000000)
{
$error_msg = "Sorry, your file is too large.";
Return
}
Wherever you have write permission below ...
$upload_dir = "Photos";
$local_file = "$upload_dir/$userfile_name";
if (file_exists ($local_file)) {
$error_msg = "Sorry, a file with that name already exists";
Return
};
You can also check the file name/type pairs to determine what file: Gif,jpg,mp3 ...
Rename ($userfile, $local_file);
echo "The file is uploaded<br>\n";
echo "<a href=\" $http_referer\ ">go back</a><br>\n";
}
$title = "Upload File";
Include ("Include/header.inc");
if (Empty ($userfile) | | | $userfile== "NONE")
{
Print the following form
?>
<form action= ". echo "$php_self";?> "enctype=" Multipart/form-data "method=post>"
<input type= "HIDDEN" name= "max_file_size" value= "2000000" >
<input type= "FILE" name= "UserFile" size= "" "Maxlength=" >
<BR><BR>
<input type= "SUBMIT" value= "Upload file!" Name= "Sendit" >
<input type= "SUBMIT" value= "Cancel" name= "Cancelit" ><BR>
</FORM>
<i><font size= "2" > (You'll notice a slight delay while we upload your file.) </FONT></I>
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} else {
if ($error_msg) {echo "<B>$error_msg</B><BR><BR>";}
if ($sendit) {
Do_upload ();
}
}
Include ("Include/footer.inc");
?>
Photo Gallery
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Include ("Include/common.inc");
$title = "Gallery";
Include ("Include/header.inc");
?>
<P>
This is are some of our family photos. This PHP script can really
be made better and by splitting into multiple pages.
</P>
?
$d = Dir ("photos");
while ($entry = $d->read ())
{
if (Is_file ("Photos/$entry"))
echo "\n";
}
$d->close ();
?>
?
Include ("Include/footer.inc");
?>
In addition, you can add an INPUT element to the file upload form to describe the uploaded file. This element will be stored in the file and then read and displayed by the code in the image gallery above.
