POST Form Data with cURL

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cURL is the magical utility that allows developers to download a URL's contentexplore response headers, get stock quotes, confirm our GZip encoding is working, and much more.  One more great usage of cUrl for command line is POSTing form data to a server, especially while testing moderate to advanced form processing.  And just like other cURL commands, POSTing form data is incredibly simple.

POSTing Form Data with cURL

Start your cURL command with curl -X POST and then add -F for every field=value you want to add to the POST:

curl -X POST -F 'username=davidwalsh' -F 'password=something' http://domain.tld/post-to-me.php

If you were using PHP, you could use print_r on the $_POST variable to see that your server received the POST data as expected:

  'username' => 'davidwalsh',
  'password' => 'something'

If you need to send a specific data type or header with cURL, use -H to add a header:

# -d to send raw data
curl -X POST -H 'Content-Type: application/json' -d '{"username":"davidwalsh","password":"something"}' http://domain.tld/login

POSTing Files with cURL

POSTing a file with cURL is slightly different in that you need to add an @ before the file location, after the field name:

curl -X POST -F 'image=@/path/to/pictures/picture.jpg' http://domain.tld/upload

Using PHP to explore the $_FILES variable array would show file data as though it was uploaded via a form in browser:

  "image": array(
    "name" => "picture.jpg"
    "type" => "image/jpeg",
    "tmp_name" => "/path/on/server/to/tmp/phprj5rkG",
    "error" => 0,
    "size" => 174476

POSTing file contents with cURL is Probably easier than you thought, right?

The first time I needed to POST file data from command line I thought I was in for a fight; instead I found that cURL made the process easy!

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  1. zhat

    Very nice artice.! But can you explaint more about different from -d option and -F option in cURL.
    I was read in manual cURL is -d stand for --data, data when send to form will be endcode. But with -F ( stand for form ), it was really be encode ?
    Sorry my english.

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