bash - Curl with multiline of JSON

Question

Consider the curl command below, is it possible to allow newline in JSON (without the minify) and execute directly in bash (Mac/Ubuntu)

curl -0 -v -X POST http://www.example.com/api/users 
-H "Expect:" 
-H 'Content-Type: text/json; charset=utf-8' 
-d 
'
{
    "field1": "test",
    "field2": {
        "foo": "bar"
    }
}'

When I run the command above, seems error occurred at the second { How to fix the above command?

Updated: actually I was able to run the command without issue previously, not sure why problem happen recently.

Answer 1

I remembered another way to do this with a "Here Document" as described in the Bash man page and detailed here. The @- means to read the body from STDIN, while << EOF means to pipe the script content until "EOF" as STDIN to curl. This layout may be easier to read than using separate files or the "echo a variable" approach.

curl -0 -v -X POST http://www.example.com/api/users 
-H "Expect:" 
-H 'Content-Type: application/json; charset=utf-8' 
--data-binary @- << EOF
{
    "field1": "test",
    "field2": {
        "foo": "bar"
    }
}
EOF

NOTE: Use the --trace <outfile> curl option to record exactly what goes over the wire. For some reason, this Here Document approach strips newlines. (Update: Newlines were stripped by curl -d option. Corrected!)