cross-doi-register.sh

#!/usr/bin/env bash

PREFIX='10.00000'; 
USERNAME='username'
PASSWORD='password'
TESTMODE=true;
FILE='path/to/file.xml'

if $TESTMODE 
then
URL='https://test.crossref.org/servlet/deposit'
else
URL='https://doi.crossref.org/servlet/deposit'
fi

curl -F \
  'operation=doQueryUpload' \
  -F "login_id=${USERNAME}" \
  -F "login_passwd=${PASSWORD}" \
  -F "fname=@${FILE}" \
  $URL 

Hmm. Not sure what to say. Just tested and both of these work (replace username/password):

curl --location --request POST 'https://test.crossref.org/servlet/deposit' \
--form 'operation=doMDUpload' \
--form 'login_id=<username>' \
--form 'login_passwd=<password>' \
--form 'fname=@/tmp/deposit.xml'

As does this PHP (curl):

<?php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => "https://test.crossref.org/servlet/deposit",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 0,
  CURLOPT_FOLLOWLOCATION => true,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => array('operation' => 'doMDUpload','login_id' => '<username>','login_passwd' => '<password>','fname'=> new 
  CURLFILE('/tmp/deposit.xml')),
  
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;