How to reuse a variable in shell script when used in curl? - bash

Question

Depending on certain conditions I want to use JWT else I want to provide path to certs. Thus in my shell script this is the code:
if /* some condition */
authorization='-H "'Authorization': 'Bearer' ${JWT}"'
else
authorization="--cert "${ADMIN_CERT_PATH}" --key "${ADMIN_KEY_PATH}""
Now the curl request should be:
curl -H "Authorization: Bearer 348129" for if condition
curl --cert /Users/.../admin_cert --key /Users/../admin_key .. for else path
In order to get that output I need to use the following format in my shell script for if condition
response_code="$(curl -s -o /dev/null -w "%{http_code}" "$authorization" "$status_url")"
and following format for else code:
response_code="$(curl -s -o /dev/null -w "%{http_code}" $authorization "$status_url")"
Note:
I need $authorization variable quoted in first case and unquoted in the else case.
I do not want to write 2 different curl commands instead reuse the authorization variable.
Thus, i need to modify the way I have declared my authorization variable such that I can write any one of the curl commands only once which works for both if and else cases.

Answer 1

curl supports a way to pass command line parameters in a file that I have used before when I have complex parameters. The idea is to place the complex command-line parameters into a simple text file and instruct curl to read parameters from it using --config parameter.
In this case the shell script would look something like the following.
#!/bin/sh
## "safely" create a temporary configuration file
curlctl=$(mktemp -q -t $(basename "$0"))
if test $? -ne 0
then
echo "$0: failed to create temporary file, exiting."
exit 75 # EX_TEMPFAIL
fi
trap 'rm "$curlctl"' 0
## write parameters used in all cases
cat>>"$curlctl" <<EOF
output = /dev/null
silent
write-out = %{http_code}
EOF
## append conditional parameters
if test "$some" = 'condition'
then
printf 'header = "Authorization: Bearer %s"\n' "$JWT" >> "$curlctl"
else
echo "cert = $ADMIN_CERT_PATH" >> "$curlctl"
echo "key = $ADMIN_KEY_PATH" >> "$curlctl"
fi
# uncomment to see what the config file looks like
# cat "$curlctl" | sed 's/^/curl config: /'
response_code=$(curl --config "$curlctl" http://httpbin.org/get)
echo "response code: $response_code"
The first few lines set up a temporary file that is deleted when the shell script exits. If you are already using trap then your cleanup will probably be more complex.

Answer 2

When you are using a shell that supports arrays, you can avoid the need for a temporary configuration file.
curl_opts=(-s -o /dev/null -w "%{http_code}")
if /* some condition */
curl_opts+=(-H "Authorization: Bearer $JWT")
else
curl_opts+=(--cert "$ADMIN_CERT_PATH" --key "$ADMIN_KEY_PATH")
fi
...
response_code="$(curl "${curl_opts[#]}" "$status_url")"