More on Functions

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More on Functions

• PHP mod 4 B

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Simple Mail Transfer Protocol (SMTP)

• mail(to, subject, msg, mailheaders)
• m08/8-1simple_form.html
• m08/8-1send_simpleform.php

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File operations

• dir opendir(dir_name)
• http//php.net/manual/en/function.opendir.php
• Opens up a directory handle to be used in
  subsequent closedir(), readdir(), and rewinddir()
  calls.
• readdir(dir)
• http//php.net/manual/en/function.readdir.php
• Returns the filename of the next file from the
  directory. The filenames are returned in the
  order in which they are stored by the filesystem.
  
• closedir(dir)
• http//php.net/manual/en/function.closedir.php
• Closes the directory stream indicated by
  dir_handle . The stream must have previously been
  opened by opendir().

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Example

• m09/9-1listfiles.php
• filetype()
• string filetype ( string filename )
• Returns the type of the given file.

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Opening/closing a file

• fopen Opens file or URL
• http//php.net/manual/en/function.fopen.php
• resource fopen ( string filename , string mode
  , bool use_include_path false , resource
  context )
• fopen() binds a named resource, specified by
  filename , to a stream.
• fclose()

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Modes of fopen()

• 'r' Open for reading only place the file
  pointer at the beginning of the file.
• 'r' Open for reading and writing place the
  file pointer at the beginning of the file.
• 'w' Open for writing only place the file
  pointer at the beginning of the file and truncate
  the file to zero length. If the file does not
  exist, attempt to create it.
• 'w Open for reading and writing place the file
  pointer at the beginning of the file and truncate
  the file to zero length. If the file does not
  exist, attempt to create it.
• 'a' Open for writing only place the file
  pointer at the end of the file. If the file does
  not exist, attempt to create it.
• 'a' Open for reading and writing place the
  file pointer at the end of the file. If the file
  does not exist, attempt to create it.
• 'x' Create and open for writing only place the
  file pointer at the beginning of the file. If the
  file already exists, the fopen() call will fail
  by returning FALSE and generating an error of
  level E_WARNING. If the file does not exist,
  attempt to create it. This is equivalent to
  specifying O_EXCLO_CREAT flags for the
  underlying open(2) system call.
• 'x' Create and open for reading and writing
  place the file pointer at the beginning of the
  file. If the file already exists, the fopen()
  call will fail by returning FALSE and generating
  an error of level E_WARNING. If the file does not
  exist, attempt to create it. This is equivalent
  to specifying O_EXCLO_CREAT flags for the
  underlying open(2) system call.

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Example

• M09/9-2newfile.php

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Since w truncates the length to 0

• file_exists Checks whether a file or directory
  exists
• http//php.net/manual/en/function.file-exists.php
• Example m09/9-3newfile_checkfirst.php
• To suppress PHP warnings
• precede PHP functions with _at_

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To write to a file

• fwrite Binary-safe file write
• Syntax int fwrite ( resource handle , string
  string , int length )
• fwrite() writes the contents of string to the
  file stream pointed to by handle .
• Return value fwrite() returns the number of
  bytes written, or FALSE on error.
• Example m09/9-4writedata.php
• die(String message) function

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To read from a file

• fread Binary-safe file read
• Syntac string fread ( resource handle , int
  length )
• fread() reads up to length bytes from the file
  pointer referenced by handle . Reading stops as
  soon as one of the following conditions is met
• length bytes have been read
• EOF (end of file) is reached
• a packet becomes available (for network streams)
• 8192 bytes have been read (after opening
  userspace stream)
• Return Returns the read string or FALSE in case
  of error.
• http//php.net/manual/en/function.fread.php for
  warnings - difference between text and binary

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Examples

• m09/9-5readdata.php
• Wait a minute! Compare textfile.txt and the
  printout. Any difference?
• m09/9-5Breaddata.php
• To deal with the missing line break, use the
  nl2br() function
• nl2br() - newline_to_break function

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email contents of a file

• M09/9-6emailcontents.php

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Copy file

• copy Copies file
• bool copy ( string source , string dest ,
  resource context )
• m09/9-7copyfile.php

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rename()

• rename Renames a file or directory
• bool rename ( string oldname , string newname
  , resource context )
• Attempts to rename oldname to newname .
• Return Values
• Returns TRUE on success or FALSE on failure.
• Example m09/9-8renamefile.php

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unlink Deletes a file

• bool unlink ( string filename , resource
  context )
• Deletes filename . Similar to the Unix C unlink()
  function.
• Return Values Returns TRUE on success or FALSE
  on failure.

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Uploading a file
How to produce an input element with a Browse
button in HTML?
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To get a Browse button

• ltinput type"file" name"img1" size"30 /gt
• m10/10-1upload_form.html

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Superglobal _FILES

• _FILES
• The _FILES Superglobal represents data available
  to a PHP script from HTTP POST file uploads.
• Using _FILES is the currently preferred way to
  handle uploaded files in PHP.

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_FILES userfile, where userfile is name of
input element

• _FILES'userfile''name' (Specifies the
  original name of the file being uploaded on the
  client computer).
• _FILES'userfile''type' (Specifies the MIME
  type of the file being uploaded, for instance,
  "image/jpeg").
• _FILES'userfile''size' (Indicates the size
  in bytes of the file being uploaded).
• _FILES'userfile''tmp_name' (Indicates the
  temporary name used by the web server to store
  the uploaded file).
• _FILES'userfile''error' (Specifies the error
  code associated with a specific file upload).

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• Variables automatically placed in the _FILES
  superglobal
• img1 is name of input element in the original
  html form
• _FILESimg1tmp_name - refers to the temporary
  file on the web server
• _FILESimg1name - Actual name of the file
  that was uploaded
• _FILESimg1size - size of uploaded file in
  bytes
• _FILESimg1type - The MIME type of the
  uploaded file, such as image/jpg

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if (_FILES"img1" ! "")
_at_copy(_FILESimg1tmp_name ,
"C/wamp/www/m10/"._FILESimg1name )
or die("Couldn't copy the file.") else
die("No input file specified") See
m10/10-1do_upload.php
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