如何将 bash 变量插入到 cURL 请求的 JSON 正文中？

Question

I am trying to run the following cURL command (taken from the ArgoCD documentation ).

$ curl $ARGOCD_SERVER/api/v1/session -d $'{"username":"admin","password":"password"}'

With the proper credentials entered manually, it runs fine, but I have my password stored in an environment variable ( $PASSWORD ) and with the both the ' and " quotes it does not insert the password correctly.

$ curl $ARGOCD_SERVER/api/v1/session -d $'{"username":"admin","password":"$PASSWORD"}'

I suspect it uses the string literal $PASSWORD as the actual password, rather than the variable's content. How would I insert this variable correctly?

Answer 1

Like this:

curl $ARGOCD_SERVER/api/v1/session -d '{"username":"admin","password":"'$PASSWORD'"}'

or this:

curl $ARGOCD_SERVER/api/v1/session -d "{\"username\":\"admin\",\"password\":\"$PASSWORD\"}"

this'll probalby works too:

curl $ARGOCD_SERVER/api/v1/session -d "{'username':'admin','password':'$PASSWORD'}"

or:

printf -v data '{"username":"admin","password":"%s"}' "$PASSWORD"
curl $ARGOCD_SERVER/api/v1/session -d "$data"

Answer 2

You can use jq to create the JSON:

json=$(jq -c -n --arg username admin --arg password "$password" '$ARGS.named')

curl $ARGOCD_SERVER/api/v1/session -d "$json"

Using jq ensures that the JSON is properly formulated, no matter the contents of the variable:

$ password=$'with\'both"quotes'
$ declare -p password
declare -- password="with'both\"quotes"
$ jq -cn --arg username admin --arg password "$password" '$ARGS.named'
{"username":"admin","password":"with'both\"quotes"}