Using cURL to upload POST data with files

Shell Problem Overview

I would like to use cURL to not only send data parameters in HTTP POST but to also upload files with specific form name. How should I go about doing that ?

HTTP Post parameters:

userid = 12345 filecomment = This is an image file

HTTP File upload: File location = /home/user1/Desktop/test.jpg Form name for file = image (correspond to the $_FILES['image'] at the PHP side)

I figured part of the cURL command as follows:

curl -d "userid=1&filecomment=This is an image file" --data-binary @"/home/user1/Desktop/test.jpg" localhost/uploader.php

The problem I am getting is as follows:

Notice: Undefined index: image in /var/www/uploader.php

The problem is I am using $_FILES['image'] to pick up files in the PHP script.

How do I adjust my cURL commands accordingly ?

Shell Solutions

Solution 1 - Shell

You need to use the -F option:
-F/--form <name=content> Specify HTTP multipart POST data (H)

Try this:

curl \
  -F "userid=1" \
  -F "filecomment=This is an image file" \
  -F "image=@/home/user1/Desktop/test.jpg" \
  localhost/uploader.php

Solution 2 - Shell

Catching the user id as path variable (recommended):

curl -i -X POST -H "Content-Type: multipart/form-data" 
-F "[email protected]" http://mysuperserver/media/1234/upload/

Catching the user id as part of the form:

curl -i -X POST -H "Content-Type: multipart/form-data" 
-F "[email protected];userid=1234" http://mysuperserver/media/upload/

or:

curl -i -X POST -H "Content-Type: multipart/form-data" 
-F "[email protected]" -F "userid=1234" http://mysuperserver/media/upload/

Solution 3 - Shell

Here is my solution, I have been reading a lot of posts and they were really helpful. Finally I wrote some code for small files, with cURL and PHP that I think its really useful.

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 should be get on the "api.endpoint.post" the following vars posted. You can easily test with this script, and you should be receive 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>";
}

It should work well, they may be better solutions but this works and is really helpful to understand how the Boundary and multipart/from-data mime works on PHP and cURL library.

Solution 4 - Shell

if you are uploading binary file such as csv, use below format to upload file

curl -X POST \
    'http://localhost:8080/workers' \
    -H 'authorization: eyJhbGciOiJIUzI1NiIsInR5cCI6ImFjY2VzcyIsInR5cGUiOiJhY2Nlc3MifQ.eyJ1c2VySWQiOjEsImFjY291bnRJZCI6MSwiaWF0IjoxNTExMzMwMzg5LCJleHAiOjE1MTM5MjIzODksImF1ZCI6Imh0dHBzOi8veW91cmRvbWFpbi5jb20iLCJpc3MiOiJmZWF0aGVycyIsInN1YiI6ImFub255bW91cyJ9.HWk7qJ0uK6SEi8qSeeB6-TGslDlZOTpG51U6kVi8nYc' \
    -H 'content-type: application/x-www-form-urlencoded' \
    --data-binary '@/home/limitless/Downloads/iRoute Masters - Workers.csv'

Solution 5 - Shell

After a lot of tries this command worked for me:

curl -v -F filename=image.jpg -F [email protected] http://localhost:8080/api/upload

Solution 6 - Shell

The issue that lead me here turned out to be a basic user error - I wasn't including the @ sign in the path of the file and so curl was posting the path/name of the file rather than the contents. The Content-Length value was therefore 8 rather than the 479 I expected to see given the legnth of my test file.

The Content-Length header will be automatically calculated when curl reads and posts the file.

curl -i -H "Content-Type: application/xml" --data "@test.xml" -v -X POST https://<url>/<uri/

... < Content-Length: 479 ...

Posting this here to assist other newbies in future.

Solution 7 - Shell

As an alternative to curl, you can use HTTPie, it'a CLI, cURL-like tool for humans.

Installation instructions: https://github.com/jakubroztocil/httpie#installation

Then, run:

 http -f POST http://localhost:4040/api/users username=johnsnow photo@images/avatar.jpg

 HTTP/1.1 200 OK
 Access-Control-Expose-Headers: X-Frontend
 Cache-control: no-store
 Connection: keep-alive
 Content-Encoding: gzip
 Content-Length: 89
 Content-Type: text/html; charset=windows-1251
 Date: Tue, 26 Jun 2018 11:11:55 GMT
 Pragma: no-cache
 Server: Apache
 Vary: Accept-Encoding
 X-Frontend: front623311

 ...

Solution 8 - Shell

cat test.txt

file test.txt content.

curl -v -F "hello=word" -F "file=@test.txt" https://httpbin.org/post

> POST /post HTTP/2
> Host: httpbin.org
> user-agent: curl/7.68.0
> accept: */*
> content-length: 307
> content-type: multipart/form-data; boundary=------------------------78a9f655d8c87a53
> 
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
* We are completely uploaded and fine
< HTTP/2 200 
< date: Mon, 15 Nov 2021 06:18:47 GMT
< content-type: application/json
< content-length: 510
< server: gunicorn/19.9.0
< access-control-allow-origin: *
< access-control-allow-credentials: true
< 
{
  "args": {}, 
  "data": "", 
  "files": {
    "file": "file test.txt content.\n"
  }, 
  "form": {
    "hello": "word"
  }, 
  "headers": {
    "Accept": "*/*", 
    "Content-Length": "307", 
    "Content-Type": "multipart/form-data; boundary=------------------------78a9f655d8c87a53", 
    "Host": "httpbin.org", 
    "User-Agent": "curl/7.68.0", 
    "X-Amzn-Trace-Id": "Root=1-6191fbc7-6c68fead194d943d07148860"
  }, 
  "json": null, 
  "origin": "43.129.xx.xxx", 
  "url": "https://httpbin.org/post"
}

Solution 9 - Shell

Here is how to correctly escape arbitrary filenames of uploaded files with bash:

#!/bin/bash
set -eu

f="$1"
f=${f//\\/\\\\}
f=${f//\"/\\\"}
f=${f//;/\\;}

curl --silent --form "uploaded=@\"$f\"" "$2"

Solution 10 - Shell

I got it worked with this command curl -F 'filename=@/home/yourhomedirextory/file.txt' http://yourserver/upload

Content Type	Original Author	Original Content on Stackoverflow
Question	thotheolh	View Question on Stackoverflow
Solution 1 - Shell	jimp	View Answer on Stackoverflow
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