How to prevent cURL joining multiple `--data` values by &-symbol?

Question

I'm using cURL to put some data onto a Redmine server. I want to use multiple --data-xxx options to build a valid XML request body. The command is like this:

curl -H "Content-Type: application/xml" \
  -H "X-Redmine-API-Key: $TOKEN" \
  -d "<?xml version=\"1.0\"?><wiki_page><text>" \
  --data-binary "@$FILE" \
  -d "</text></wiki_page>" \
  -X PUT http://some.redmine.site.com/projects/someproj/wiki/test.xml

However, as --data option documented:

If any of these options is used more than once on the same command line, the data pieces specified will be merged together with a separating &-symbol. Thus, using -d name=daniel -d skill=lousy would generate a post chunk that looks like name=daniel&skill=lousy.

I can understand the designer of cURL make it this way to help build a URL with query string. But in this situation, these added &-symbols will make my request XML body malformed. I can prepend "nbsp;" to the value to workaround this when it's after --data. But when it comes to the usage mixed with a file (--data-binary "@$FILE"), there are no way to work this out.

Answer 1

Just pass everything as a single --data value, then. There are several ways you could do it:

• For short files, 'include' the file's raw contents in the command:

  curl … -d "<?xml…?><wiki_page><text>$(cat "$FILE")</text></wiki_page>"
  

• For longer files, create a temporary file containing the required data:

  temp=$(mktemp /tmp/redmineXXXXXXXX.xml)
  {
      echo "<?xml…>"
      echo "<wiki_page><text>"
      cat "$FILE"
      echo "</text></wiki_page>"
  } > "$temp"
  curl … -d "@$temp"
  rm -f "$temp"