So I'm trying to create a file and write code into that file whenever a user submits a register and successfully moves on to the activation stage. I'm doing this so that I can store all of the variables and information in my registration php file into the file I create. This is relevant code of the signup form:
#$file is set in removed code
$filename = '../' . $file;
fopen($filename, "w") or die("<h1 style='text-align: center; color: red;'>There has been an error creating your user files. Try again later.</h1>");
$content = "
<?php
potato
?>
";
fwrite($filename, $content);
Everything works, except for the fwrite() function. I looked at the file I created, and nothing appears in it. What's going on?
fopen() returns a stream resource bound to $filename. When you call fwrite(), the first parameter it takes is the resource returned by fopen(). Not the filename.
So change the relevant part of your program to this:
$handle = fopen($filename, "w") or die("...");
$content = "foobar";
fwrite($handle, $content);
fclose($handle); // Don't forget to close when you're done.
Related
This is a php script for a user login system that I am developing.
I need it to read from, and write to, the /students/students.txt file, but it won't even read the content already contained in the file.
<?php
//other code
echo "...";
setcookie("Student", $SID, time()+43200, "/");
fopen("/students/students.txt", "r");
$content = fread("/students/students.txt", filesize("/students/students.txt"));
echo $content;
fclose("/students/students.txt");
fopen("/students/students.txt", "w");
fwrite("/students/students.txt", $content."\n".$SID);
fclose("/students/students.txt");
//other code
?>
You are not using fopen() properly. The function returns a handle that you then use to read or edit the file, for example:
//reading a file
if ($handle = fopen("/students/students.txt", "r"))
{
echo "info obtained:<br>";
while (($buffer = fgets($handle))!==false)
{ echo $buffer;}
fclose($handle);
}
//writing/overwriting a file
if ($handle = fopen("/students/students.txt", "w"))
{
fwrite($handle, "hello/n");
fclose($handle);
}
Let me know if that worked for you.
P.S.: Ty to the commentators for the constructive feedback.
There are many ways to read/write to file as others have demonstrated. I just want to illustrate the mistake in your particular approach.
fread takes a file handle as param, NOT a string that represents the path to the file.
So your line:
$content = fread("/students/students.txt", filesize("/students/students.txt")); is incorrect.
It should be:
$file_handle = fopen("/students/students.txt", "r");
$content = fread($file_handle, filesize("/students/students.txt"));
Same thing when you write contents to file using fwrite. Its reference to the file is a File Handle opened using fopen NOT the filepath. when opening a file using fopen() you can also check if the $file_handle returned is a valid resource or is false. If false, it means the fopen operation was not successful.
So your code:
fopen("/students/students.txt", "w");
fwrite("/students/students.txt", $content."\n".$SID);
fclose("/students/students.txt");
Needs to be re-written as:
$file_handle = fopen("/students/students.txt", "w");
fwrite($file_handle, $content."\n".$SID);
fclose($file_handle);
You can see that fclose operates on file handles as well.
File Handle (as per php.net):
A file system pointer resource that is typically created using fopen().
Here are a couple of diagnostic functions that allow you to validate that a file exists and is readable. If it is a permission issue, it gives you the name of the user that needs permission.
function PrintMessage($text, $success = true)
{
print "$text";
if ($success)
print " [<font color=\"green\">Success</font>]<br />\n";
else
print(" [<font color=\"red\">Failure</font>]<br />\n");
}
function CheckReadable($filename)
{
if (realpath($filename) != "")
$filename = realpath($filename);
if (!file_exists($filename))
{
PrintMessage("'$filename' is missing or inaccessible by '" . get_current_user() . "'", false);
return false;
}
elseif (!is_readable($filename))
{
PrintMessage("'$filename' found but is not readable by '" . get_current_user() . "'", false);
return false;
}
else
PrintMessage("'$filename' found and is readable by '" . get_current_user() . "'", true);
return true;
}
I've re-written your code with (IMO) a cleaner and more efficient code:
<?php
$SID = "SOMETHING MYSTERIOUS";
setcookie("Student", $SID, time()+43200, "/");
$file = "/students/students.txt"; //is the full path correct?
$content = file_get_contents($file); //$content now contains /students/students.txt
$size = filesize($file); //do you still need this ?
echo $content;
file_put_contents($file, "\n".$SID, FILE_APPEND); //do you have write permissions ?
file_get_contents
file_get_contents() is the preferred way to read the contents of a
file into a string. It will use memory mapping techniques if supported
by your OS to enhance performance.
file_put_contents
This function is identical to calling fopen(), fwrite() and
fclose() successively to write data to a file. If filename does not
exist, the file is created. Otherwise, the existing file is
overwritten, unless the FILE_APPEND flag is set.
Notes:
Make sure the full path /students/students.txt is
correct.
Check if you've read/write permissions on /students/students.txt
Learn more about linux file/folder permissions or, if you don't access to the shell, how to change file or directory permissions via ftp
Try to do this:
fopen("students/students.txt", "r");
And check to permissions read the file.
I wonder, why PHP file_put_contents() function works in a weird way.
I used it in a loop to write some logs to file and all was fine (new lines were appended even if no flag was specified). When I started the script again, it re-created my file.
From PHP doc:
If filename does not exist, the file is created. Otherwise, the
existing file is overwritten, unless the FILE_APPEND flag is set.
OK, so my question is: Why (when used in one loop) it doesn't overwrite my file (without FILE_APPEND flag of course)? Bug or feature? :)
Edit: Example context of use when this happened:
$logFile = dirname ( __FILE__ ) . '/example.log';
foreach($something1 as $sth1) {
$logData .= "Something\n";
foreach($something2 as $sth2) {
if($something_else) {
$logData .= "Line: \t" . $sth2 . "\n";
file_put_contents($logFile, $logData);
}
}
}
As it has been very clearly mentioned in this link under the flags content(which you should have read) it clearly states that if file filename already exists, append the data to the file instead of overwriting it(when this flag is set). So when the flag for FILE_APPEND is set it appends and when not it rewrites. Hope this helped you.
Alternative Way
<?php
$file = 'file.txt';
$append = true;
if (file_exists($file)) {
if ($append) {
// append file
$file = fopen($file, 'a+');
} else {
// overwrite file
$file = fopen($file, 'a');
}
} else {
// create file
$file = fopen($file, 'a');
}
fwrite($file, 'text');
fclose($file);
?>
here is a php fopen documentation
and php file
and read on its related topics
ok, when you are run the script each time try to rename the log file with random number or currentdate timestamp and try to save it in your DB
by this when you again run the script and can take the log file name from DB and update it when you needed
This is quite a long-winded question as im completely lost!
The concept: User inputs a text file they wish to write to, upon submitting they are sent to a page where users can create shapes and submit them to the text file, this data is then used to work out the shapes area, colour that was selected etc...
Issue is how do i write to a text file that is in the session?
This is what i have on the home page:
<?php
// This line starts the session
session_start();
//The below calls the file
$txtFile = $_POST['submittedTxtFile'];
$_SESSION['submittedTxtFile']= $txtFile;
$file = fopen($txtFile, "r") or exit("That file does not exist");
include_once 'classShapeCollection.php';
//Creates the shapecollection
$shapes = new ShapeCollection();
//These lines get the called file, unserialize the $shapes and serialize them again before entering them into the session.
$buffer = fgets($file);
//Checking if there are any contents in the file
if($buffer)
{
$shapes = unserialize($buffer); //unserialize takes Text and turns it into an object
$_SESSION['serial']= serialize($shapes); //Serialize takes the objects and converts them into Text
}
else //if there is nothing in the file, the session serialises the new ShapeCollection
{
$_SESSION['serial']= serialize($shapes);
}
// Closes the called file
fclose($file);
?>
Opening the file as "r" means read only you should open it as write
fopen($txtFile, 'r+')
Or replace 'r+' with 'w+' if you want file to be truncated when opened
After closing the file handler, use file_put_contents() function to update the file. Like this:
fclose($file);
file_put_contents($txtfile, $_SESSION['serial']);
Make sure the file is writable.
Give this a try.
The following will write to a file called TEST.txt taken from the $write_session = "TEST"; session variable.
Base yourself on it, am sure you will get it to work the way you want it to, but that's basically how it will work.
<?php
session_start();
$_POST['submittedTxtFile'] = "file.txt"; // generic filename
$txtFile = $_POST['submittedTxtFile'];
$_SESSION['submittedTxtFile']= $txtFile;
$write_session = "TEST";
$_SESSION['write_session_write'] = $write_session;
$file = fopen($txtFile, "r") or exit("That file does not exist");
echo $_SESSION['submittedTxtFile'];
$file2 = $_SESSION['write_session_write'] . ".txt";
file_put_contents($file2, $write_session);
I have this script on one free PHP-supporting server:
<html>
<body>
<?php
$file = fopen("lidn.txt","a");
fclose($file);
?>
</body>
</html>
It creates the file lidn.txt, but it's empty.
How can I create a file and write something into it,
for example the line "Cats chase mice"?
You can use a higher-level function like:
file_put_contents($filename, $content);
which is identical to calling fopen(), fwrite(), and fclose() successively to write data to a file.
Docs: file_put_contents
Consider fwrite():
<?php
$fp = fopen('lidn.txt', 'w');
fwrite($fp, 'Cats chase mice');
fclose($fp);
?>
$fp = fopen('lidn.txt', 'w');
fwrite($fp, 'Cats chase');
fwrite($fp, 'mice');
fclose($fp);
http://php.net/manual/en/function.fwrite.php
$text = "Cats chase mice";
$filename = "somefile.txt";
$fh = fopen($filename, "a");
fwrite($fh, $text);
fclose($fh);
You use fwrite()
It is easy to write file :
$fp = fopen('lidn.txt', 'w');
fwrite($fp, 'Cats chase mice');
fclose($fp);
Here are the steps:
Open the file
Write to the file
Close the file
$select = "data what we trying to store in a file";
$file = fopen("/var/www/htdocs/folder/test.txt", "w");
fwrite($file, $select->__toString());
fclose($file);
I use the following code to write files on my web directory.
write_file.html
<form action="file.php"method="post">
<textarea name="code">Code goes here</textarea>
<input type="submit"value="submit">
</form>
write_file.php
<?php
// strip slashes before putting the form data into target file
$cd = stripslashes($_POST['code']);
// Show the msg, if the code string is empty
if (empty($cd))
echo "Nothing to write";
// if the code string is not empty then open the target file and put form data in it
else
{
$file = fopen("demo.php", "w");
echo fwrite($file, $cd);
// show a success msg
echo "data successfully entered";
fclose($file);
}
?>
This is a working script. be sure to change the url in the form action and the target file in fopen() function if you want to use it on your site.
In order to write to a file in PHP you need to go through the following steps:
Open the file
Write to the file
Close the file
$select = "data what we trying to store in a file";
$file = fopen("/var/www/htdocs/folder/test.txt", "a");
fwrite($file , $select->__toString());
fclose($file );
fwrite() is a smidgen faster and file_put_contents() is just a wrapper around those three methods anyway, so you would lose the overhead.
Article
file_put_contents(file,data,mode,context):
The file_put_contents writes a string to a file.
This function follows these rules when accessing a file.If FILE_USE_INCLUDE_PATH is set, check the include path for a copy of filename
Create the file if it does not exist then Open the file and Lock the file if LOCK_EX is set and If FILE_APPEND is set, move to the end of the file. Otherwise, clear the file content
Write the data into the file and Close the file and release any locks.
This function returns the number of the character written into the file on success, or FALSE on failure.
fwrite(file,string,length):
The fwrite writes to an open file.The function will stop at the end of the file or when it reaches the specified length,
whichever comes first.This function returns the number of bytes written or FALSE on failure.
I have:
<?php
$file=fopen(date("Y-m-d").".txt","r+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
?>
but it overwrites the beginning of the file. How do I make it insert?
I'm not entirely sure of your question - do you want to write data and not have it over-write the beginning of an existing file, or write new data to the start of an existing file, keeping the existing content after it?
To insert text without over-writing the beginning of the file, you'll have to open it for appending (a+ rather than r+)
$file=fopen(date("Y-m-d").".txt","a+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
If you're trying to write to the start of the file, you'll have to read in the file contents (see file_get_contents) first, then write your new string followed by file contents to the output file.
$old_content = file_get_contents($file);
fwrite($file, $new_content."\n".$old_content);
The above approach will work with small files, but you may run into memory limits trying to read a large file in using file_get_conents. In this case, consider using rewind($file), which sets the file position indicator for handle to the beginning of the file stream.
Note when using rewind(), not to open the file with the a (or a+) options, as:
If you have opened the file in append ("a" or "a+") mode, any data you write to the file will always be appended, regardless of the file position.
A working example for inserting in the middle of a file stream without overwriting, and without having to load the whole thing into a variable/memory:
function finsert($handle, $string, $bufferSize = 16384) {
$insertionPoint = ftell($handle);
// Create a temp file to stream into
$tempPath = tempnam(sys_get_temp_dir(), "file-chainer");
$lastPartHandle = fopen($tempPath, "w+");
// Read in everything from the insertion point and forward
while (!feof($handle)) {
fwrite($lastPartHandle, fread($handle, $bufferSize), $bufferSize);
}
// Rewind to the insertion point
fseek($handle, $insertionPoint);
// Rewind the temporary stream
rewind($lastPartHandle);
// Write back everything starting with the string to insert
fwrite($handle, $string);
while (!feof($lastPartHandle)) {
fwrite($handle, fread($lastPartHandle, $bufferSize), $bufferSize);
}
// Close the last part handle and delete it
fclose($lastPartHandle);
unlink($tempPath);
// Re-set pointer
fseek($handle, $insertionPoint + strlen($string));
}
$handle = fopen("file.txt", "w+");
fwrite($handle, "foobar");
rewind($handle);
finsert($handle, "baz");
// File stream is now: bazfoobar
Composer lib for it can be found here
You get the same opening the file for appending
<?php
$file=fopen(date("Y-m-d").".txt","a+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
?>
If you want to put your text at the beginning of the file, you'd have to read the file contents first like:
<?php
$file=fopen(date("Y-m-d").".txt","r+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
$existingText = file_get_contents($file);
fwrite($file, $existingText . $_POST["lastname"]."\n");
}
fclose($file);
?>