|
Description
resourcefalse fopen( string $filename , string $mode , bool $use_include_path = false , resourcenull $context = null )
Parameters
-
filename
-
If filename is of the form "scheme://...", it
is assumed to be a URL and PHP will search for a protocol handler
(also known as a wrapper) for that scheme. If no wrappers for that
protocol are registered, PHP will emit a notice to help you track
potential problems in your script and then continue as though
filename specifies a regular file.
If PHP has decided that filename specifies
a local file, then it will try to open a stream on that file.
The file must be accessible to PHP, so you need to ensure that
the file access permissions allow this access.
If you have enabled
open_basedir further
restrictions may apply.
If PHP has decided that filename specifies
a registered protocol, and that protocol is registered as a
network URL, PHP will check to make sure that
allow_url_fopen is
enabled. If it is switched off, PHP will emit a warning and
the fopen call will fail.
Note:
The list of supported protocols can be found in Supported Protocols and Wrappers. Some protocols (also referred to as
wrappers ) support context
and/or php.ini options. Refer to the specific page for the
protocol in use for a list of options which can be set. (e.g.
php.ini value user_agent used by the
http wrapper).
On the Windows platform, be careful to escape any backslashes
used in the path to the file, or use forward slashes.
-
mode
-
The mode parameter specifies the type of access
you require to the stream. It may be any of the following:
A list of possible modes for fopen
using mode
mode |
Description |
'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; otherwise it has the
same behavior as 'w' .
|
'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.
In this mode, fseek has no effect, writes are always appended.
|
'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. In this mode, fseek only affects
the reading position, writes are always appended.
|
'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_EXCL|O_CREAT flags for the
underlying open(2) system call.
|
'x+' |
Create and open for reading and writing; otherwise it has the
same behavior as 'x' .
|
'c' |
Open the file for writing only. If the file does not exist, it is
created. If it exists, it is neither truncated (as opposed to
'w' ), nor the call to this function fails (as is
the case with 'x' ). The file pointer is
positioned on the beginning of the file. This may be useful if it's
desired to get an advisory lock (see flock)
before attempting to modify the file, as using
'w' could truncate the file before the lock
was obtained (if truncation is desired,
ftruncate can be used after the lock is
requested).
|
'c+' |
Open the file for reading and writing; otherwise it has the same
behavior as 'c' .
|
'e' |
Set close-on-exec flag on the opened file descriptor. Only
available in PHP compiled on POSIX.1-2008 conform systems.
|
Note:
Different operating system families have different line-ending
conventions. When you write a text file and want to insert a line
break, you need to use the correct line-ending character(s) for your
operating system. Unix based systems use \n as the
line ending character, Windows based systems use \r\n
as the line ending characters and Macintosh based systems (Mac OS Classic) used
\r as the line ending character.
If you use the wrong line ending characters when writing your files, you
might find that other applications that open those files will "look
funny".
Windows offers a text-mode translation flag ('t' )
which will transparently translate \n to
\r\n when working with the file. In contrast, you
can also use 'b' to force binary mode, which will not
translate your data. To use these flags, specify either
'b' or 't' as the last character
of the mode parameter.
The default translation mode is 'b' .
You can use the 't'
mode if you are working with plain-text files and you use
\n to delimit your line endings in your script, but
expect your files to be readable with applications such as old versions of notepad. You
should use the 'b' in all other cases.
If you specify the 't' flag when working with binary files, you
may experience strange problems with your data, including broken image
files and strange problems with \r\n characters.
Note:
For portability, it is also strongly recommended that
you re-write code that uses or relies upon the 't'
mode so that it uses the correct line endings and
'b' mode instead.
Note:
The mode is ignored for php://output,
php://input, php://stdin,
php://stdout, php://stderr and
php://fd stream wrappers.
-
use_include_path
-
The optional third use_include_path parameter
can be set to true if you want to search for the file in the
include_path, too.
-
context
-
A context stream
resource.
Return Values
Returns a file pointer resource on success,
or false on failure
Errors/Exceptions
Upon failure, an E_WARNING is emitted.
Examples
Example #1 fopen examples
<?php
$handle = fopen("/home/rasmus/file.txt", "r");
$handle = fopen("/home/rasmus/file.gif", "wb");
$handle = fopen("http://www.example.com/", "r");
$handle = fopen("ftp://user:password@example.com/somefile.txt", "w");
?>
Notes
WarningWhen using SSL, Microsoft IIS
will violate the protocol by closing the connection without sending a
close_notify indicator. PHP will report this as "SSL: Fatal
Protocol Error" when you reach the end of the data. To work around this, the
value of error_reporting should be
lowered to a level that does not include warnings.
PHP can detect buggy IIS server software when you open
the stream using the https:// wrapper and will suppress the
warning. When using fsockopen to create an
ssl:// socket, the developer is responsible for detecting
and suppressing this warning.
Note:
If you are experiencing problems with reading and writing to files and
you're using the server module version of PHP, remember to make sure that
the files and directories you're using are accessible to the server
process.
Note:
This function may also succeed when filename is a
directory. If you are unsure whether filename is a
file or a directory, you may need to use the is_dir
function before calling fopen.
See Also
- Supported Protocols and Wrappers
- fclose
- fgets
- fread
- fwrite
- fsockopen
- file
- file_exists
- is_readable
- stream_set_timeout
- popen
- stream_context_create
- umask
- SplFileObject
|