How to use regex to parse this json: { "success" : true }? - json

Question

I am using a shell script to make an API call and I need to verify that the json response is this:
{ "success" : true }
I am able to echo the call response to see that it has that value but I need to validate the response in an if statement so that the script can continue, I have tried to do this a number of ways with no success
Regex - I have used regex to extract values from other json responses, but I have not found a regex pattern that can extract the value of "success" with this json
String Comparison - I thought of simply using this condition to attempt to match the strings:
if [ "$callResponse" = '{ "success" : true }' ]
However I quickly ran into issues with the script reading the json due to its special characters, I tried using sed to add a backslash before each special character but sed could not read the json either
Lastly I tried to pipe the response to python but got the error "ValueError: No JSON object could be decoded" when using this command:
status=${$callResponse | python -c "import sys, json; print(json.load(sys.stdin)['success'])"}
Does anyone know a regex pattern that could find that specific json string? Is there another simple solution to this issue?
(Note that it is not possible to download jq or any other utilities for this PC)

Answer 1

Since the caller knows that the response is { "success" : true }, I can't think of any reason to not use jq in this case. For instance, you can try something like this:
if echo '{ "success" : true }' | jq --exit-status '.success == true' >/dev/null; then
echo "success"
# Do something success is true in the response.
else
echo "not success" response.
# Do something else success is not true or absent in the
fi
If you want to make an API call and get the response, you can easily pass the JSON response directly from wget to jq instead of going the roundabout way of storing it in an intermediate variable by tweaking it like this:
if wget --timeout 10 -O - -q -t 1 https://your.api.com/endpoint | jq --exit-status '.success == true' >/dev/null; then
echo "success"
else
echo "not success"
fi

Answer 2

To match when the value of success is true in a flexible way:
"success"\s*:\s*"?true"?
This will match all of these:
{ "success" : true }
{ "success" : "true" }
{ "success":true}
To be strict and match the above, but not imbalanced quotes like { "success" : "true }, use this:
"success"\s*:\s*("?)true\1

Answer 3

I would highly recommend not doing it that way.
We used to do it this way long ago and got into trouble when the response code is "200 OK" but receiving {"success": false} seemed to contradict each other.
A better approach is to use the response status codes instead.
Simply return 200 OK if success is true otherwise return the appropriate error status code if its not.
https://www.restapitutorial.com/httpstatuscodes.html
EDIT:
Bash script to help:
COOKIE_FILE="cookies.txt"
SERVER_IP="172.1.2.3"
LOGFILE="logs/api-calls.log"
WGETLOGFILE="logs/last-api-call.log"
#Helper function
on_wget_err ( )
{
EXITCODE=${1}
case ${EXITCODE} in
0) RESULT="OK";;
*) cat ${WGETLOGFILE} >> ${LOGFILE};
grep "HTTP/1.1" ${WGETLOGFILE} | gawk '{print substr($0,16)}'
exit 0;;
esac
}
if wget -O - -qT 4 -t 1 ${SERVER_IP} > /dev/null; then
echo "Server is up"
wget -S -O - --load-cookies ${COOKIE_FILE} "http://${SERVER_IP}${SERVER_ADDRESS}/my/api?param=$1" 2> ${WGETLOGFILE}
on_wget_err ${?}
echo "API was successfull"
else
echo "Server or network down"
exit 1;
fi

Answer 4

Your Python attempt was close. Here's a working one:
callResponse='{ "success" : true }'
status=$(echo "$callResponse" |
python -c "import sys, json; print(json.load(sys.stdin)['success'])")
echo "$status"
Or alternatively, rewritten to go straight in an if statement:
callResponse='{ "success" : true }'
if echo "$callResponse" | python -c "import sys, json; sys.exit(0 if json.load(sys.stdin)['success'] else 1)"
then
echo "Success"
fi