php upload files through CURL

p>PHP uses CURL to upload files. Just send a POST request. Set a field in the request to the full path of the file to be uploaded, starting with "@", and then use CURL to POST the variable. method is sent to the server, and the corresponding uploaded file information can be obtained from the super global variable $_FILES on the server side.

<br>

Below we use an example to show this process.

<br>

Assume that there is a local text file log.txt, its path is "/www/test/log.txt", and the content is as follows:

this is a file for test
hello PythonTab!

For Upload this file to the server-side script http://www.pythontab.com/upload.php. We wrote a local script named curl_file.php with the following content:

<php?
//要上传的本地文件地址
"upload" = > "@/www/test/log.txt"
);
$ch = curl_init();
curl_setopt($ch , CURLOPT_URL , $url);
curl_setopt($ch , CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch , CURLOPT_POST, 1);
curl_setopt($ch , CURLOPT_POSTFIELDS, $post_data);
$output = curl_exec($ch);
curl_close($ch);
echo $output;
 ?>

curl_file.php The logic is very simple, set the POST variable $post_data, where upload points to the file that needs to be sent. It should be noted here that when we used POST before, we sent a string, and then used file_get_contents("php//input") on the server side to obtain the string. This is different from the usage here. In fact, POST can also be like GET. Send key-value pairs. There is a super global variable $_POST on the server side that can obtain the value of the corresponding POST data just like $_GET. It should be noted that the variable for uploading files does not exist in $_POST, but in $_FILES.

<br>

In order to show the logic of the server receiving the file upload request from the above code, we wrote the following code in upload.php:

<br>

upload. PHP first uses var_export to output the $_FILES variable to the standard output, then uses file_get_contents to read the contents of the file pointed to by $_FILES['upload']['tmp_name'], and outputs it to the standard output, and then puts $_FILES['upload' The file pointed to by ]['tmp_name'] is copied to the log_copy.txt file in the current directory. The standard output of the script is as follows:

array(
 'upload' =>
     array(
     'name' => 'log.txt',
     'type' => 'application/octet-stream',
     'tmp_name' => '/tmp/phpLUB59F',
     'error' => 0,
     'size' => 36,
     )
 )
 this is a file for test
 hello PythonTab!

You can see that there is an upload array in the $_FILES variable, which corresponds to the uploaded file description information, where name and type represent the name and type respectively. tmp_name is more critical. After the server receives the uploaded file, it will write the file in a temporary file. The name of this temporary file is the value of tmp_name. This is why we can get the file contents of a log.txt by reading the file. . Generally, after the server receives the uploaded file, it needs to read the file immediately or copy the file to another file, because the temporary file pointed to by tmp_name will be deleted after the server script is executed. The upload.php script The last line is to copy the temporary file to our target file.

<br>