[json] Using curl POST with variables defined in bash script functions

When I echo I get this, which runs when I enter it into the terminal

curl -i \
-H "Accept: application/json" \
-H "Content-Type:application/json" \
-X POST --data '{"account":{"email":"[email protected]","screenName":"akdgdtk","type":"NIKE","passwordSettings":{"password":"Starwars1","passwordConfirm":"Starwars1"}},"firstName":"Test","lastName":"User","middleName":"ObiWan","locale":"en_US","registrationSiteId":"520","receiveEmail":"false","dateOfBirth":"1984-12-25","mobileNumber":"9175555555","gender":"male","fuelActivationDate":"2010-10-22","postalCode":"10022","country":"US","city":"Beverton","state":"OR","bio":"This is a test user","jpFirstNameKana":"unsure","jpLastNameKana":"ofthis","height":"80","weight":"175","distanceUnit":"MILES","weightUnit":"POUNDS","heightUnit":"FT/INCHES"}' https://xxx:[email protected]/xxxxx/xxxx/xxxx

But when run in the bash script file, I get this error

curl: (6) Could not resolve host: application; nodename nor servname provided, or not known
curl: (6) Could not resolve host: is; nodename nor servname provided, or not known
curl: (6) Could not resolve host: a; nodename nor servname provided, or not known
curl: (6) Could not resolve host: test; nodename nor servname provided, or not known
curl: (3) [globbing] unmatched close brace/bracket at pos 158

this is the code in the file

curl -i \
-H '"'Accept: application/json'"' \
-H '"'Content-Type:application/json'"' \
-X POST --data "'"'{"account":{"email":"'$email'","screenName":"'$screenName'","type":"'$theType'","passwordSettings":{"password":"'$password'","passwordConfirm":"'$password'"}},"firstName":"'$firstName'","lastName":"'$lastName'","middleName":"'$middleName'","locale":"'$locale'","registrationSiteId":"'$registrationSiteId'","receiveEmail":"'$receiveEmail'","dateOfBirth":"'$dob'","mobileNumber":"'$mobileNumber'","gender":"'$gender'","fuelActivationDate":"'$fuelActivationDate'","postalCode":"'$postalCode'","country":"'$country'","city":"'$city'","state":"'$state'","bio":"'$bio'","jpFirstNameKana":"'$jpFirstNameKana'","jpLastNameKana":"'$jpLastNameKana'","height":"'$height'","weight":"'$weight'","distanceUnit":"MILES","weightUnit":"POUNDS","heightUnit":"FT/INCHES"}'"'" "https://xxx:[email protected]/xxxxx/xxxx/xxxx"

I assume there's an issue with my quotation marks, but I've played with them a lot and I've gotten similar errors. All the variables are defined with different functions in the actual script

Here's what actually worked for me, after guidance from answers here:

export BASH_VARIABLE="[1,2,3]"
curl http://localhost:8080/path -d "$(cat <<EOF
{
  "name": $BASH_VARIABLE,
  "something": [
    "value1",
    "value2",
    "value3"
  ]
}
EOF
)" -H 'Content-Type: application/json'

• the info from Sir Athos worked perfectly !!

Here's how I had to use it in my curl script for couchDB. It really helped out a lot. Thanks!

bin/curl -X PUT "db_domain_name_:5984/_config/vhosts/$1.couchdb" -d '"/'"$1"'/"' --user "admin:*****"

A few years late but this might help someone if you are using eval or backtick substitution:

postDataJson="{\"guid\":\"$guid\",\"auth_token\":\"$token\"}"

Using sed to strip quotes from beginning and end of response

$(curl --silent -H "Content-Type: application/json" https://${target_host}/runs/get-work -d ${postDataJson} | sed -e 's/^"//' -e 's/"$//')

Solution tested with https://httpbin.org/ and inline bash script
1. For variables without spaces in it i.e. 1:
Simply add ' before and after $variable when replacing desired string

for i in {1..3}; do \
  curl -X POST -H "Content-Type: application/json" -d \
    '{"number":"'$i'"}' "https://httpbin.org/post"; \
done

2. For input with spaces:
Wrap variable with additional " i.e. "el a":

declare -a arr=("el a" "el b" "el c"); for i in "${arr[@]}"; do \
  curl -X POST -H "Content-Type: application/json" -d \
    '{"elem":"'"$i"'"}' "https://httpbin.org/post"; \
done

Wow works :)

Existing answers point out that curl can post data from a file, and employ heredocs to avoid excessive quote escaping and clearly break the JSON out onto new lines. However there is no need to define a function or capture output from cat, because curl can post data from standard input. I find this form very readable:

curl -X POST -H 'Content-Type:application/json' --data '$@-' ${API_URL} << EOF
{
  "account": {
    "email": "$email",
    "screenName": "$screenName",
    "type": "$theType",
    "passwordSettings": {
      "password": "$password",
      "passwordConfirm": "$password"
    }
  },
  "firstName": "$firstName",
  "lastName": "$lastName",
  "middleName": "$middleName",
  "locale": "$locale",
  "registrationSiteId": "$registrationSiteId",
  "receiveEmail": "$receiveEmail",
  "dateOfBirth": "$dob",
  "mobileNumber": "$mobileNumber",
  "gender": "$gender",
  "fuelActivationDate": "$fuelActivationDate",
  "postalCode": "$postalCode",
  "country": "$country",
  "city": "$city",
  "state": "$state",
  "bio": "$bio",
  "jpFirstNameKana": "$jpFirstNameKana",
  "jpLastNameKana": "$jpLastNameKana",
  "height": "$height",
  "weight": "$weight",
  "distanceUnit": "MILES",
  "weightUnit": "POUNDS",
  "heightUnit": "FT/INCHES"
}
EOF

Curl can post binary data from a file so I have been using process substitution and taking advantage of file descriptors whenever I need to post something nasty with curl and still want access to the vars in the current shell. Something like:

curl "http://localhost:8080" \
-H "Accept: application/json" \
-H "Content-Type:application/json" \
--data @<(cat <<EOF
{
  "me": "$USER",
  "something": $(date +%s)
  }
EOF
)

This winds up looking like --data @/dev/fd/<some number> which just gets processed like a normal file. Anyway if you wanna see it work locally just run nc -l 8080 first and in a different shell fire off the above command. You will see something like:

POST / HTTP/1.1
Host: localhost:8080
User-Agent: curl/7.43.0
Accept: application/json
Content-Type:application/json
Content-Length: 43

{  "me": "username",  "something": 1465057519  }

As you can see you can call subshells and whatnot as well as reference vars in the heredoc. Happy hacking hope this helps with the '"'"'""""'''""''.

Putting data into a txt file worked for me

bash --version
GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)
curl --version
curl 7.29.0 (x86_64-redhat-linux-gnu)
 cat curl_data.txt 
 {  "type":"index-pattern", "excludeExportDetails": true  }

curl -X POST http://localhost:30560/api/saved_objects/_export -H 'kbn-xsrf: true' -H 'Content-Type: application/json' -d "$(cat curl_data.txt)" -o out.json

We can assign a variable for curl using single quote ' and wrap some other variables in double-single-double quote "'" for substitution inside curl-variable. Then easily we can use that curl-variable which here is MERGE.

Example:

# other variables ... 
REF_NAME="new-branch";

# variable for curl using single quote => ' not double "
MERGE='{
    "repository": "tmp",
    "command": "git",
    "args": [
        "pull",
        "origin",
        "'"$REF_NAME"'"
    ],
    "options": {
        "cwd": "/home/git/tmp"
    }
}';

notice this line:

    "'"$REF_NAME"'"

and then calling curl as usual:

curl -s -X POST localhost:1365/M -H 'Content-Type: application/json' --data "$MERGE"