Send file via cURL from form POST in PHP

Question

I'm writing an API and I'm wanting to handle file uploads from a form POST. The markup for the form is nothing too complex:

<form action="" method="post" enctype="multipart/form-data">
  <fieldset>
    <input type="file" name="image" id="image" />
    <input type="submit" name="upload" value="Upload" />
  </fieldset>
</form>

However, I'm having difficulties understanding how to handle this server-side and send along with a cURL request.

I'm familiar with sending POST requests with cURL with a data array, and resources I've read on uploading files tell me to prefix the filename with an @ symbol. But these same resources have a hard-coded file name, e.g.

$post = array(
    'image' => '@/path/to/myfile.jpg',
    ...
);

Well which file path is this? Where would I find it? Would it be something like $_FILES['image']['tmp_name'], in which case my $post array should look like this:

$post = array(
    'image' => '@' . $_FILES['image']['tmp_name'],
    ...
);

Or am I going about this the wrong way? Any advice would be most appreciated.

EDIT: If someone could give me a code snippet of where I would go with the following code snippets then I'd be most grateful. I'm mainly after what I would send as cURL parameters, and a sample of how to use those parameters with the receiving script (let's call it curl_receiver.php for argument's sake).

I have this web form:

<form action="script.php" method="post" enctype="multipart/form-data">
  <fieldset>
    <input type="file" name="image />
    <input type="submit" name="upload" value="Upload" />
  </fieldset>
</form>

And this would be script.php:

if (isset($_POST['upload'])) {
    // cURL call would go here
    // my tmp. file would be $_FILES['image']['tmp_name'], and
    // the filename would be $_FILES['image']['name']
}

Raybourne

Would the http extension be on topic? Unlike cURL (multi-protocol) it's better tailored to HTTP. – Viscacha

Answer 1

Here is some production code that sends the file to an ftp (may be a good solution for you):

// This is the entire file that was uploaded to a temp location.
$localFile = $_FILES[$fileKey]['tmp_name']; 

$fp = fopen($localFile, 'r');

// Connecting to website.
$ch = curl_init();

curl_setopt($ch, CURLOPT_USERPWD, "[email protected]:password");
curl_setopt($ch, CURLOPT_URL, 'ftp://@ftp.website.net/audio/' . $strFileName);
curl_setopt($ch, CURLOPT_UPLOAD, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 86400); // 1 Day Timeout
curl_setopt($ch, CURLOPT_INFILE, $fp);
curl_setopt($ch, CURLOPT_NOPROGRESS, false);
curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'CURL_callback');
curl_setopt($ch, CURLOPT_BUFFERSIZE, 128);
curl_setopt($ch, CURLOPT_INFILESIZE, filesize($localFile));
curl_exec ($ch);

if (curl_errno($ch)) {

    $msg = curl_error($ch);
}
else {

    $msg = 'File uploaded successfully.';
}

curl_close ($ch);

$return = array('msg' => $msg);

echo json_encode($return);

Whomp

how fast is FTP? Will it be much slower than HTTP uploads? – Dagney

@think123 FTP can be faster or slower sometimes. It depends upon your ftp server. If they put a throttle on ftp uploads that can slow it down, but otherwise ftp and http should be about equivalent. – Whomp

Ah, thanks. I've found this solution extremely useful. – Dagney

ftp should be faster than http due to the way http encodes everything. – Azrael

@Toby It's not really as simple as we would like, sometimes http is faster. See answers here #717700 – Whomp

You saved me a day of research! What's the BUFFERSIZE for and why 128? – Voyageur

The above works will with http/https as well, just change the url and you probably don't need the buffer size. This was particularly useful for me because the api I was using didn't support multipart, therefore CURLOPT_POSTFIELDS could not be used. – Judiejudith

@Voyageur Without it, it was not reporting any progress until it finished the upload. So that made it check in regularly so I could show a progress bar. – Whomp

what should be the value of $strFileName ? – Mauney

@BenjaminG Whatever you want the filename to be after you upload the file contents. – Whomp

Answer 2

For people finding this post and using PHP5.5+, this might help.

I was finding the approach suggested by netcoder wasn't working. i.e. this didn't work:

$tmpfile = $_FILES['image']['tmp_name'];
$filename = basename($_FILES['image']['name']);
$data = array(
    'uploaded_file' => '@'.$tmpfile.';filename='.$filename,
);
$ch = curl_init();   
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

I would receive in the $_POST var the 'uploaded_file' field - and nothing in the $_FILES var.

It turns out that for php5.5+ there is a new curl_file_create() function you need to use. So the above would become:

$data = array(
    'uploaded_file' => curl_file_create($tmpfile, $_FILES['image']['type'], $filename)
);

As the @ format is now deprecated.

Eastertide

I was looking for this command in the last 5 hrs!! NOBODY mentioned the curl_file_create() function, thanks a lot – Spermatic

now is 2019 and I was looking 6 Hrs for this... Thanks! – Apure

curl_file_create() <== this function is life savier. – Tris

The bottom of your answer is so clutch. – Comical

The best example of curl_file_create. You saved my life. ^^ – Tiki

Answer 3

This should work:

$tmpfile = $_FILES['image']['tmp_name'];
$filename = basename($_FILES['image']['name']);

$data = array(
    'uploaded_file' => '@'.$tmpfile.';filename='.$filename,
);

$ch = curl_init();   
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
// set your other cURL options here (url, etc.)

curl_exec($ch);

In the receiving script, you would have:

print_r($_FILES);
/* which would output something like
     Array (
        [uploaded_file] => Array (
            [tmp_name] => /tmp/f87453hf
            [name] => myimage.jpg
            [error] => 0
            [size] => 12345
            [type] => image/jpeg
        )
     )
*/

Then, if you want to properly handle the file upload, you would do something like this:

if (move_uploaded_file($_FILES['uploaded_file'], '/path/to/destination/file.zip')) {
   // do stuff
}

Erleena

Thanks. I got a derirative of this solution working, but when I change the request method to PUT it falls over (the $_FILES array is empty, yet is populated as expected when set to POST). Any idea why this would be? – Raybourne

PHP $_FILES array will not be populated on a PUT request ever, because PHP expected $_FILES to be uploaded via POST. If you want to accept file uploads on a PUT request, you will have to parse the php://input stream manually for the multipart format (which is not too hard, but can't be explained in a comment...). – Erleena

@netcoder, what if services are located at different services and tmp file needs to be passed as data via PUT request, what would be the approach then? – Bon

Answer 4

For my the @ symbol did not work, so I do some research and found this way and it work for me, I hope this help you.

    $target_url = "http://server:port/xxxxx.php";           
    $fname = 'file.txt';   
    $cfile = new CURLFile(realpath($fname));

        $post = array (
                  'file' => $cfile
                  );    

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $target_url);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;)");   
    curl_setopt($ch, CURLOPT_HTTPHEADER,array('Content-Type: multipart/form-data'));
    curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);   
    curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);  
    curl_setopt($ch, CURLOPT_TIMEOUT, 100);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

    $result = curl_exec ($ch);

    if ($result === FALSE) {
        echo "Error sending" . $fname .  " " . curl_error($ch);
        curl_close ($ch);
    }else{
        curl_close ($ch);
        echo  "Result: " . $result;
    }   

Anderton

thanks, I have try few days and finally try with your answer and it is works (PHP 5.6), it most important is use CURLFile() to enclose the realpath($file). – Vito

I'm glad I helped you – Anderton

Answer 5

It works for me when sending an attachment to Mercadolibre, through its messaging system.

The anwswer https://mcmap.net/q/153134/-send-file-via-curl-from-form-post-in-php

$target_url = "http://server:port/xxxxx.php";           
$fname = 'file.txt';   
$cfile = new CURLFile(realpath($fname));

    $post = array (
              'file' => $cfile
              );    

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;)");   
curl_setopt($ch, CURLOPT_HTTPHEADER,array('Content-Type: multipart/form-data'));
curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);   
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);  
curl_setopt($ch, CURLOPT_TIMEOUT, 100);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

$result = curl_exec ($ch);

if ($result === FALSE) {
    echo "Error sending" . $fname .  " " . curl_error($ch);
    curl_close ($ch);
}else{
    curl_close ($ch);
    echo  "Result: " . $result;
}   

Dandiprat

Answer 6

cURL file object in procedural method:

$file = curl_file_create('full path/filename','extension','filename');

cURL file object in Oop method:

$file = new CURLFile('full path/filename','extension','filename');

$post= array('file' => $file);

$curl = curl_init();  
//curl_setopt ... 
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
$response = curl_exec($curl);
curl_close($curl);

Impetuosity

$post should actually be $data – Neal

Answer 7

we can upload image file by curl request by converting it base64 string.So in post we will send file string and then covert this in an image.

function covertImageInBase64()
{
    var imageFile = document.getElementById("imageFile").files;
    if (imageFile.length > 0)
    {
        var imageFileUpload = imageFile[0];
        var readFile = new FileReader();
        readFile.onload = function(fileLoadedEvent) 
        {
            var base64image = document.getElementById("image");
            base64image.value = fileLoadedEvent.target.result;
        };
        readFile.readAsDataURL(imageFileUpload);
    }
}

then send it in curl request

if(isset($_POST['image'])){
    $curlUrl='localhost/curlfile.php';  
    $ch = curl_init();
    curl_setopt($ch,CURLOPT_URL, $curlUrl);
    curl_setopt($ch,CURLOPT_POST, 1);
    curl_setopt($ch,CURLOPT_POSTFIELDS, 'image='.$_POST['image']);
    $result = curl_exec($ch);
    curl_close($ch);
}

see here http://technoblogs.co.in/blog/How-to-upload-an-image-by-using-php-curl-request/118

Domingodominguez

Answer 8

Here is my solution, i have been reading a lot of post and they was really helpfull, finaly i build a code for small files, with cUrl and Php, that i think its really usefull.

public function postFile()
{


        $file_url = "test.txt";  //here is the file route, in this case is on same directory but you can set URL too like "http://examplewebsite.com/test.txt"
        $eol = "\r\n"; //default line-break for mime type
        $BOUNDARY = md5(time()); //random boundaryid, is a separator for each param on my post curl function
        $BODY=""; //init my curl body
        $BODY.= '--'.$BOUNDARY. $eol; //start param header
        $BODY .= 'Content-Disposition: form-data; name="sometext"' . $eol . $eol; // last Content with 2 $eol, in this case is only 1 content.
        $BODY .= "Some Data" . $eol;//param data in this case is a simple post data and 1 $eol for the end of the data
        $BODY.= '--'.$BOUNDARY. $eol; // start 2nd param,
        $BODY.= 'Content-Disposition: form-data; name="somefile"; filename="test.txt"'. $eol ; //first Content data for post file, remember you only put 1 when you are going to add more Contents, and 2 on the last, to close the Content Instance
        $BODY.= 'Content-Type: application/octet-stream' . $eol; //Same before row
        $BODY.= 'Content-Transfer-Encoding: base64' . $eol . $eol; // we put the last Content and 2 $eol,
        $BODY.= chunk_split(base64_encode(file_get_contents($file_url))) . $eol; // we write the Base64 File Content and the $eol to finish the data,
        $BODY.= '--'.$BOUNDARY .'--' . $eol. $eol; // we close the param and the post width "--" and 2 $eol at the end of our boundary header.



        $ch = curl_init(); //init curl
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                         'X_PARAM_TOKEN : 71e2cb8b-42b7-4bf0-b2e8-53fbd2f578f9' //custom header for my api validation you can get it from $_SERVER["HTTP_X_PARAM_TOKEN"] variable
                         ,"Content-Type: multipart/form-data; boundary=".$BOUNDARY) //setting our mime type for make it work on $_FILE variable
                    );
        curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/1.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0'); //setting our user agent
        curl_setopt($ch, CURLOPT_URL, "api.endpoint.post"); //setting our api post url
        curl_setopt($ch, CURLOPT_COOKIEJAR, $BOUNDARY.'.txt'); //saving cookies just in case we want
        curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1); // call return content
        curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 1); navigate the endpoint
        curl_setopt($ch, CURLOPT_POST, true); //set as post
        curl_setopt($ch, CURLOPT_POSTFIELDS, $BODY); // set our $BODY 


        $response = curl_exec($ch); // start curl navigation

     print_r($response); //print response

}

With this we shoud be get on the "api.endpoint.post" the following vars posted You can easly test with this script, and you should be recive this debugs on the function postFile() at the last row

print_r($response); //print response

public function getPostFile()
{

    echo "\n\n_SERVER\n";
    echo "<pre>";
    print_r($_SERVER['HTTP_X_PARAM_TOKEN']);
    echo "/<pre>";
    echo "_POST\n";
    echo "<pre>";
    print_r($_POST['sometext']);
    echo "/<pre>";
    echo "_FILES\n";
    echo "<pre>";
    print_r($_FILEST['somefile']);
    echo "/<pre>";
}

Here you are it should be work good, could be better solutions but this works and is really helpfull to understand how the Boundary and multipart/from-data mime works on php and curl library,

My Best Reggards,

my apologies about my english but isnt my native language.

Gastroenterology

Trying to reverse-engineer HTTP without understanding it? – Adventuresome