Issue on Reading .txt inside a Zipped File by PHP [duplicate] - php

I need to read the content of a single file, "test.txt", inside of a zip file. The whole zip file is a very large file (2gb) and contains a lot of files (10,000,000), and as such extracting the whole thing is not a viable solution for me. How can I read a single file?

Try using the zip:// wrapper:
$handle = fopen('zip://test.zip#test.txt', 'r');
$result = '';
while (!feof($handle)) {
$result .= fread($handle, 8192);
}
fclose($handle);
echo $result;
You can use file_get_contents too:
$result = file_get_contents('zip://test.zip#test.txt');
echo $result;

Please note #Rocket-Hazmat fopen solution may cause an infinite loop if a zip file is protected with a password, since fopen will fail and feof fails to return true.
You may want to change it to
$handle = fopen('zip://file.zip#file.txt', 'r');
$result = '';
if ($handle) {
while (!feof($handle)) {
$result .= fread($handle, 8192);
}
fclose($handle);
}
echo $result;
This solves the infinite loop issue, but if your zip file is protected with a password then you may see something like
Warning: file_get_contents(zip://file.zip#file.txt): failed to open
stream: operation failed
There's a solution however
As of PHP 7.2 support for encrypted archives was added.
So you can do it this way for both file_get_contents and fopen
$options = [
'zip' => [
'password' => '1234'
]
];
$context = stream_context_create($options);
echo file_get_contents('zip://file.zip#file.txt', false, $context);
A better solution however to check if a file exists or not before reading it without worrying about encrypted archives is using ZipArchive
$zip = new ZipArchive;
if ($zip->open('file.zip') !== TRUE) {
exit('failed');
}
if ($zip->locateName('file.txt') !== false) {
echo 'File exists';
} else {
echo 'File does not exist';
}
This will work (no need to know the password)
Note: To locate a folder using locateName method you need to pass it like folder/ with a
forward slash at the end.

Related

My php script won't open files that aren't in its root directory

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.

Open content.xml in a odt-file directly via php [duplicate]

I need to read the content of a single file, "test.txt", inside of a zip file. The whole zip file is a very large file (2gb) and contains a lot of files (10,000,000), and as such extracting the whole thing is not a viable solution for me. How can I read a single file?
Try using the zip:// wrapper:
$handle = fopen('zip://test.zip#test.txt', 'r');
$result = '';
while (!feof($handle)) {
$result .= fread($handle, 8192);
}
fclose($handle);
echo $result;
You can use file_get_contents too:
$result = file_get_contents('zip://test.zip#test.txt');
echo $result;
Please note #Rocket-Hazmat fopen solution may cause an infinite loop if a zip file is protected with a password, since fopen will fail and feof fails to return true.
You may want to change it to
$handle = fopen('zip://file.zip#file.txt', 'r');
$result = '';
if ($handle) {
while (!feof($handle)) {
$result .= fread($handle, 8192);
}
fclose($handle);
}
echo $result;
This solves the infinite loop issue, but if your zip file is protected with a password then you may see something like
Warning: file_get_contents(zip://file.zip#file.txt): failed to open
stream: operation failed
There's a solution however
As of PHP 7.2 support for encrypted archives was added.
So you can do it this way for both file_get_contents and fopen
$options = [
'zip' => [
'password' => '1234'
]
];
$context = stream_context_create($options);
echo file_get_contents('zip://file.zip#file.txt', false, $context);
A better solution however to check if a file exists or not before reading it without worrying about encrypted archives is using ZipArchive
$zip = new ZipArchive;
if ($zip->open('file.zip') !== TRUE) {
exit('failed');
}
if ($zip->locateName('file.txt') !== false) {
echo 'File exists';
} else {
echo 'File does not exist';
}
This will work (no need to know the password)
Note: To locate a folder using locateName method you need to pass it like folder/ with a
forward slash at the end.

PHP not writing to file from one source

I have an issue I can't seem to find the solution for. I am trying to write to a flat text file. I have echoed all variables out on the screen, verified permissions for the user (www-data) and just for grins set everything in the whole folder to 777 - all to no avail. Worst part is I can call on the same function from another file and it writes. I can't see to find the common thread here.....
function ReplaceAreaInFile($AreaStart, $AreaEnd, $File, $ReplaceWith){
$FileContents = GetFileAsString($File);
$Section = GetAreaFromFile($AreaStart, $AreaEnd, $FileContents, TRUE);
if(isset($Section)){
$SectionTop = $AreaStart."\n";
$SectionTop .= $ReplaceWith;
$NewContents = str_replace($Section, $SectionTop, $FileContents);
if (!$Handle = fopen($File, 'w')) {
return "Cannot open file ($File)";
exit;
}/*
if(!flock($Handle, LOCK_EX | LOCK_NB)) {
echo 'Unable to obtain file lock';
exit(-1);
}*/
if (fwrite($Handle, $NewContents) === FALSE) {
return "Cannot write to file ($File)";
exit;
}else{
return $NewContents;
}
}else{
return "<p align=\"center\">There was an issue saving your settings. Please try again. If the issue persists contact your provider.</p>";
}
}
Try with...
$Handle = fopen($File, 'w');
if ($Handle === false) {
die("Cannot open file ($File)");
}
$written = fwrite($Handle, $NewContents);
if ($written === false) {
die("Invalid arguments - could not write to file ($File)");
}
if ((strlen($NewContents) > 0) && ($written < strlen($NewContents))) {
die("There was a problem writing to $File - $written chars written");
}
fclose($Handle);
echo "Wrote $written bytes to $File\n"; // or log to a file
return $NewContents;
and also check for any problems in the error log. There should be something, assuming you've enabled error logging.
You need to check for number of characters written since in PHP fwrite behaves like this:
After having problems with fwrite() returning 0 in cases where one
would fully expect a return value of false, I took a look at the
source code for php's fwrite() itself. The function will only return
false if you pass in invalid arguments. Any other error, just as a
broken pipe or closed connection, will result in a return value of
less than strlen($string), in most cases 0.
Also, note that you might be writing to a file, but to a different file that you're expecting to write. Absolute paths might help with tracking this.
The final solution I ended up using for this:
function ReplaceAreaInFile($AreaStart, $AreaEnd, $File, $ReplaceWith){
$FileContents = GetFileAsString($File);
$Section = GetAreaFromFile($AreaStart, $AreaEnd, $FileContents, TRUE);
if(isset($Section)){
$SectionTop = $AreaStart."\n";
$SectionTop .= $ReplaceWith;
$NewContents = str_replace($Section, $SectionTop, $FileContents);
return $NewContents;
}else{
return "<p align=\"center\">There was an issue saving your settings.</p>";
}
}
function WriteNewConfigToFile($File2WriteName, $ContentsForFile){
file_put_contents($File2WriteName, $ContentsForFile, LOCK_EX);
}
I did end up using absolute file paths and had to check the permissions on the files. I had to make sure the www-data user in Apache was able to write to the files and was also the user running the script.

Define array of file locations, parse and replace. Where's my error?

I'm trying to define an array with a list of file urls, and then have each file parsed and if a predefined string is found, for that string to be replaced. For some reason what I have isn't working, I'm not sure what's incorrect:
<?php
$htF = array('/home/folder/file.extension', '/home/folder/file.extension', '/home/folder/file.extension', '/home/folder/file.extension', '/home/folder/file.extension');
function update() {
global $htF;
$handle = fopen($htF, "r");
if ($handle) {
$previous_line = $content = '';
while (!feof($handle)) {
$current_line = fgets($handle);
if(stripos($previous_line,'PREDEFINED SENTENCE') !== FALSE)
{
$output = shell_exec('URL.COM');
if(preg_match('#([0-9]{1,3}\.){3}[0-9]{1,3}#',$output,$matches))
{
$content .= 'PREDEFINED SENTENCE '.$matches[0]."\n";
}
}else{
$content .= $current_line;
}
$previous_line = $current_line;
}
fclose($handle);
$tempFile = tempnam('/tmp','allow_');
$fp = fopen($tempFile, 'w');
fwrite($fp, $content);
fclose($fp);
rename($tempFile,$htF);
chown($htF,'admin');
chmod($htF,'0644');
}
}
array_walk($htF, 'update');
?>
Any help would be massively appreciated!
Do you have permissions to open the file?
Do you have permissions to write to /tmp ?
Do you have permissions to write to the destination file or folder?
Do you have permissions to chown?
Have you checked your regex? Try something like http://regexpal.com/ to see if it's valid.
Try adding error messages or throw Exceptions for all of the fail conditions for these.
there's this line:
if(stripos($previous_line,'PREDEFINED SENTENCE') !== FALSE)
and I think you just want a != in there. Yes?
You're using $htF within the update function as global, which means you're trying to fopen() an array.
$fh = fopen($htF, 'r');
is going to get parsed as
$fh = fopen('Array', 'r');
and return false, unless you happen to have a file named 'Array'.
You've also not specified any parameters for your function, so array_walk cannot pass in the array element it's dealing with at the time.

Unpack large files with gzip in PHP

I'm using a simple unzip function (as seen below) for my files so I don't have to unzip files manually before they are processed further.
function uncompress($srcName, $dstName) {
$string = implode("", gzfile($srcName));
$fp = fopen($dstName, "w");
fwrite($fp, $string, strlen($string));
fclose($fp);
}
The problem is that if the gzip file is large (e.g. 50mb) the unzipping takes a large amount of ram to process.
The question: can I parse a gzipped file in chunks and still get the correct result? Or is there a better other way to handle the issue of extracting large gzip files (even if it takes a few seconds more)?
gzfile() is a convenience method that calls gzopen, gzread, and gzclose.
So, yes, you can manually do the gzopen and gzread the file in chunks.
This will uncompress the file in 4kB chunks:
function uncompress($srcName, $dstName) {
$sfp = gzopen($srcName, "rb");
$fp = fopen($dstName, "w");
while (!gzeof($sfp)) {
$string = gzread($sfp, 4096);
fwrite($fp, $string, strlen($string));
}
gzclose($sfp);
fclose($fp);
}
try with
function uncompress($srcName, $dstName) {
$fp = fopen($dstName, "w");
fwrite($fp, implode("", gzfile($srcName)));
fclose($fp);
}
$length parameter is optional.
If you are on a Linux host, have the required privilegies to run commands, and the gzip command is installed, you could try calling it with something like shell_exec
SOmething a bit like this, I guess, would do :
shell_exec('gzip -d your_file.gz');
This way, the file wouldn't be unzip by PHP.
As a sidenote :
Take care where the command is run from (ot use a swith to tell "decompress to that directory")
You might want to take a look at escapeshellarg too ;-)
As maliayas mentioned, it may lead to a bug. I experienced an unexpected fall out of the while loop, but the gz file has been decompressed successfully. The whole code looks like this and works better for me:
function gzDecompressFile($srcName, $dstName) {
$error = false;
if( $file = gzopen($srcName, 'rb') ) { // open gz file
$out_file = fopen($dstName, 'wb'); // open destination file
while (($string = gzread($file, 4096)) != '') { // read 4kb at a time
if( !fwrite($out_file, $string) ) { // check if writing was successful
$error = true;
}
}
// close files
fclose($out_file);
gzclose($file);
} else {
$error = true;
}
if ($error)
return false;
else
return true;
}

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