cURL - - digest command

Question

Please explain this curl command:

curl --digest \
    -u{username}:{password} \
    -v \
    -X PUT \
    -H 'Expect: ' \
    -H 'Content-type: application/xml' \
    -d @- \
    http://webapi.ebayclassifieds.com/webapi/partners/{username}/ads/{ext-reference-id} \
        < ad.xml 

What does the < sign mean?

What I understand:

[--digest] its a digest authentication
[-u{username}:{password}] obviously username and password
[-X PUT] method="put"
[-H 'Expect: '] header = 'Expect: '
[-H 'Content-type: application/xml'] additional header

This is probably what I don't get -d @- url < ad.xml [-d @- http://webapi.ebayclassifieds.com/webapi/partners/{username}/ads/{ext-reference-id} < ad.xml ]

What I found:

-d, --data

(HTTP) Sends the specified data in a POST request to the HTTP server, in the same way that a browser does when a user has filled in an HTML form and presses the submit button. This will cause curl to pass the data to the server using the content-type application/x-www-form-urlencoded. Compare to -F, --form.

-d, --data is the same as --data-ascii. To post data purely binary, you should instead use the --data-binary option. To URL-encode the value of a form field you may use --data-urlencode.

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'.

If you start the data with the letter @, the rest should be a file name to read the data from, or - if you want curl to read the data from stdin. The contents of the file must already be URL-encoded. Multiple files can also be specified. Posting data from a file named 'foobar' would thus be done with --data @foobar.

Leading question: If somebody knows how to translate this to cfhttp just dont mind the digest authentication and assume request is working with digest authentication.

Answer 1

The "-d@ -" option means that curl will send a POST request with the data it reads from stdin.

The '<' operator tells the shell to feed a file to stdin.

You could make a simpler command line by instead doing -d @ad.xml and not use stdin at all.