I’m replacing a function that downloads a file with cURL and returns its content in a variable, then outside the function the code writes this variable to a file with file_put_content. Because of requirements of the system I have to use wget now, so I’m using something like this:
function GetData($strdata,$wwwurl){ $content = exec("wget --post-data '".$strdata."' -qO- ".$wwwurl); return $content; }
But when I later use file_put_content to save the content of $content, the size of the file is way smaller than it should be (1kb when it should be around 480kb). I can’t remove file_put_content as it’s used in several places of the code (that would take us a very long time) and all I can edit must be into that function. If I launch wget with “-O test.zip” instead of “-O-” the file is downloaded and saved fine, the same happens if I launch the command from command line. Any ideas?
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Answer
Its because exec
doesn’t return the whole data. Take a look at the documentation
https://www.php.net/manual/en/function.exec.php :
Return Values: The last line from the result of the command.
But shell_exec
(or just backticks) returns whole data: https://www.php.net/manual/en/function.shell-exec.php .
Example:
<?php $url = 'https://file-examples-com.github.io/uploads/2017/02/zip_5MB.zip'; $content = exec("wget -qO- $url"); var_dump(strlen($content)); $content2 = shell_exec("wget -qO- $url"); var_dump(strlen($content2)); file_put_contents('1.zip', $content); file_put_contents('2.zip', $content2);
Output:
int(208) int(5452018)
2.zip works (all 5MB data), 1.zip obviously not (just some bytes from the end).
So don’t treat exec
‘s return value as the whole output of the command.