My script tries to exec() wget but seems to fail (though, no error raises up). What could be the problem? Should I tune PHP somehow? I just installed Apache and PHP on Ubuntu...
Add third parameter to exec() to find out the exit code of wget.
Maybe wget is not in the (search) path of the apache/php process.
Did you try an absolute path to the wget executable?
What is your $_GET['one']? The name of a video file? A number? A url? What's $file? What' $one?
Obvious error sources:
Are all of those variables set? If $one is blank, then wget has nowhere to go to fetch your file. If $_GET['one'] and $file are blank, then your output file will most likely not exist, either because the directory can't be found ($_GET['one']) is empty, or $file is empty, causing wget to try and output to a directory name, which is not allowed.
'illegal' characters in any of the variables. Does $file contain shell meta-characters? Any of ;?*/\ etc...? Those will all screw up the command line.
Why are you using wget anyways? You're passing raw query parameters out to a shell, which is just asking for trouble. It would be trivial to pass in shell metacharacters, which would allow remote users to run ANYTHING on your webserver. Consider the following query:
http://example.com/fetch.php?one=;%20rm%20-rf%20/%20;
which in your script becomes:
wget -O /var/www/videos/; rm -rf / ;/$file $one
and now your script is happily deleting everything on the server which your web server's user has permissions for.
Related
I'm currently using the Pygments for PHP plugin that is located here: http://derek.simkowiak.net/pygments-for-php/.
The line that actually calls Pygments from that code is an exec() passed: pygmentize -f html $extra_opts -l $language $temp_name as the command. This all works fine, and I get back the output and it is formatted by the plugin.
What I would like to happen at the same time is for Pygments to create an image of it, so I pass exec() a similar command: pygmentize -f png $extra_opts -l $language -o $full_image_path/$output_file.png $temp_name This is where I run into a problem. The image never shows up in the expected folder.
However, if I var_dump() that command string before I exec() it and take it and run it straight from the command line, it works fine.
I have tried echoing exec('whoami') which tells me that the PHP user is www-data. I've tried giving permissions to www-data and changing ownership to www-data on the folder where I store the images. I've also tried changing permissions to 777 just to see what would happen, and the answer is nothing.
Is there something I'm missing? I'm running out of ideas to try. Thank you!
Edit: Another thing that I've checked is the output from the exec command, and the return value. It outputs an empty array, and it returns 1 as the return value.
Edit 2: After seeing that that directory should be writeable/readable for the PHP user, is it possible that pygments doesn't have permission to write it as a specific user? I'm not sure this makes sense, as when I run it myself it works fine, and in fact, when PHP runs it with the HTML lexer, it is able to run. I'm not very experienced in Python, so I don't know if this is a potential issue.
I guess you cannot do it like this.
$output_file.png
Try
$file = $output_file.".png"
and substitute in the exec
Ended up being an issue with the font that was installed for use by the www-root user. Apparently the one that is used by default for Pygments was installed only for the user that I was running as when I use the command line.
The way I was able to figure this out, was running
exec("$command 2>&1", $out, $code);.
The extra 2>&1 redirects stderr into the output for me to see the issue.
The $out parameter showed the FontNotFound error that pygments was throwing.
I changed the font that Pygments used via the command line using: full,style=manni,cssclass=pygmentize_kbOKBd,font_name='DejaVu Sans Mono' -l php -o /srv/www/path/to/images/uploads/2513732976ad4b7.02729290.png /tmp/pygmentize_kbOKBd after finding which fonts I had available to me.
To see which fonts I had available to me as the user running the script, I just ran fc-list in an exec() command for Ubuntu, and checked the output of that for the list of available fonts.
exec('wget --progress=bar http://technabob.com/blog/wp-
content/uploads/2011/04/light_up_pi_symbol_1.jpg');
echo "1";
output 1
ie the download is not working.I m sure that the command is correct. I believe it has something to do with my Apache.Any help will be appreciated.
The image is not getting downloaded.
I was wrong about Apache . I think it is about wget because I can run other commands on my server using
$output = `ls -al`;
echo "<pre>$output</pre>";
This has nothing to do with Apache. Also, read the documentation for exec(). Most likely you'll see that that function call replaces the current process with the one specified in the argument, meaning that the rest of your code won't get run.
UPDATE
Perhaps the PATH is incorrect? Try using the full path to the wget command instead. Also, the current working directory will be used as the download destination for your command and the process may not have permissions to write to that directory.
The mistake was that I didnot specify the download location so it was saved at some random location. But still the command was working right.
The correct method could be
$command="wget --output-document=/var/2 --progress=bar http:/"."/technabob.com/blog/wp-content/uploads/2011/04/light_up_pi_symbol_1.jpg";
I'm building a PHP web application that will run on my machine, and one of its purposes is to call HandBrakeCLI with an exec() or similar call. If I run the command
HandBrakeCLI -i path_to_dvd_drive -o output_file --preset preset_name
from a shell, it works fine. However, when I put the exact same command in an exec() php function (or similar), it doesn't work, and doesn't return anything, aside from a return status of 0. No errors, nothing else.
Is this just a simple permissions issue that I'm not seeing, due to the lack of errors being spit out? Or am I missing something else?
For debugging, try running the command from the console but as the user PHP runs as. Here are some pointers how to find out which user that is.
Then use sudo to run the command as the Apache user. You will probably get more helpful information from that.
try to exec your script using absolute path (type which HandBrakeCLI in terminal to find it) and append 2>&1 to the end of command, like:
exec('HandBrakeCLI -i path_to_dvd_drive -o output_file --preset preset_name 2>&1')
this way if command outputs anything to stderr you will see it.
is handbrake in the path of whatever shell PHP is invoking when it does the exec()? Does whatever account PHP/webserver is running under have access to the directory where handbrak.exe is, and have permission to execute handbrake.exe? Does the webserver account have permissions to access the dvd drive, etc...
Many things to check, and without better diagnostic information, this is about the best you'll be able to get here.
I am using PHP on Windows machin. I also use Dev C++. I can perfectly compile .cpp file on CMD using this command:
g++ hello.cpp -O3 -o hello.exe
Now what I am trying to do is running the same command using php system() function, so it looks like this:
system("g++ c:\wamp\www\grader\hello.cpp -O3 -o C:\wamp\www\grader\hello.exe");
but it doesn't compile. I am lost, please tell me what am I missing?
I also looked up at this question and thats exactly what I need, but I couldnt find a usefull solution for my case there:
Php script to compile c++ file and run the executable file with input file
Use the PHP exec command.
echo exec('g++ hello.cpp -O3 -o hello.exe');
should work.
There's a whole family of different exec & system commands in PHP, see here:
http://www.php.net/manual/en/ref.exec.php
If you want the output into a variable, then use :
$variable = exec('g++ hello.cpp -O3 -o hello.exe');
If that doesn't work, then make sure that g++ is available in your path, and that your logged in with sufficient enough privliges to allow it to execute.
You may find also that it's failing beacuse PHP is essentially being executed by your web server (Unless your also running PHP from the cmd prompt) , and the web server user ID may not have write access to the folder where G++ is trying to create the output file.
Temporarily granting write access to 'Everybody' on the output folder will verify if that is the case.
Two things:
You are using double quotes and are not escaping the \ inside the path.
You are not using a full path to g++.
The first one is important as \ followed by something has a special meaning in such a string (you might know \n as new line), the second one is relevant since the PHP environment might have a different search path.
A solution might be
system("c:\\path\\to\\g++ c:\\wamp\\www\\grader\\hello.cpp -O3 -o C:\\wamp\\www\\grader\\hello.exe");
Alternatively you can use single quotes, intead of double quotes, they use diffeent,less strict escaping rules
system('c:\path\to\g++ c:\wamp\www\grader\hello.cpp -O3 -o C:\wamp\www\grader\hello.exe');
or use / instead of \, which is supported by windows, too.
system("c:/path/to/g++ c:/wamp/www/grader/hello.cpp -O3 -o C:/wamp/www/grader/hello.exe");
What you do is your choice, while many might consider the first one as ugly, and the last one as bad style on Windows ;-)
Thanks to everyone. I tried to run the codes given in above posts and it worked like a charm.
I ran the following code using my browser
$var = exec("g++ C:/wamp/www/cpp/hello.cpp -O3 -o C:/wamp/www/cpp/hello.exe");
echo $var;
The exe file is created. I am able to see the result when i run the exe file but the problem is when i run the above code in the browser, the result is not displayed on the webpage. I gave full access permission to all users but still give does not show the result on the webpage.
I really need help on this since i am doing a project on simulated annealing where i want to get the result from compiled c++ program and display it in the webpage with some jquery highcharts.
Thanks again to all, it has helped me alot and i have learnt alot as well.
I am trying to automate the download of a file using wget and calling the php script from cron, the filename always consists of filename and date, however the date changes depending on when the file is uploaded. The trouble is there is no certainty of when the file is updated, and hence the final name can never really be known until the directory is checked.
An example filename is file20100818.tbz
I tried using wildcards within wget but they have failed, both using * and %
Thanks in advance,
Greg
Assuming the file type is constant then from the wget man page:
You want to download all the GIFs from
a directory on an HTTP server. You
tried wget
http://www.server.com/dir/*.gif, but
that didn't work because HTTP
retrieval does not support globbing.
In that case, use:
wget -r -l1 --no-parent -A.gif http://www.server.com/dir/
So, you want to use the -A flag, something like:
wget -r -l1 --no-parent -A.tbz http://www.mysite.com/path/to/files/
For the sake of clarity, because this threads shows up in google search when searching "wget and wildcards" and because the answers above don't bring sensitive solution and there doesn't seem to be anything else on SO answering this:
According to the wget manual, you can use the wildcards when using ftp and using the option -g on (--glob=on), however, wget will return an error unless you are using all the -r -np -nd options. Thanks to Wiseman20#ubuntuforums for showing us the way.
Samplecode:
wget -r -np -nd --glob=on ftp://ftp.ncbi.nlm.nih.gov/blast/db/nt.*.tar.gz
You can for loop each date like this:
<?php
for($i=0;$i<30;$i++)
{
$filename = "file".date("Ymd", time() + 86400 * $i).".tbz";
//try file download, if successful, break out of loop.
?>
You can increase number of tries in for loop.