Cocatenate 2 variables to put inside json is not working - json

Question

I need to concatenate 2 variables, but when i execute the bash code i get this error filters.api.malformed_request_body.
I need to get the current IPs, to be able to add a new IP to the filter, that's because i need to use two variables, $a is the current IP that is in my firewall rule, and $b is the new IP that i will add.
From Cloudflare
To preserve existing values, issue a GET request and based on the response, determine which fields (and respective values) to include in your PUT request and that way, avoid any undesired overwrites.
Code:
a=122.16.89.10
b=137.77.77.77
curl -X PUT \
-H "X-Auth-Email: EMAIL" \
-H "X-Auth-Key: KEY" \
-H "Content-Type: application/json" \
-d '[
{
"id": "ID",
"paused": false,
"expression": "(ip.src in {'$a'" "'$b'})",
"description": "Block IP"
}
]' "https://api.cloudflare.com/client/v4/zones/ZONE/filters"
I also tried: "(ip.src in {'$a $b'})" and:
new_filter="$a $b"
...
...
"(ip.src in {'$new_filter'})"
If i echo $new_filter it shows the correct result:
new_filter="$a $b"
echo $new_filter
#122.16.89.10 137.77.77.77
When i use the variable $new_filter it also show this error curl: (3) [globbing] unmatched close brace/bracket in column 13 line 13 is this one -H "Content-Type: application/json" \.
None worked, why? I get this error:
{
"result": null,
"success": false,
"errors": [
{
"code": 10014,
"message": "filters.api.malformed_request_body"
}
],
"messages": []
}
This works: "(ip.src in {'$a'})".

Answer 1

Well, let's take your first example and modify it to print the JSON body:
export a=122.16.89.10
export b=137.77.77.77
echo '[
{
"id": "ID",
"paused": false,
"expression": "(ip.src in {'$a'" "'$b'})",
"description": "Block IP"
}
]'
The output is this:
{
"id": "ID",
"paused": false,
"expression": "(ip.src in {122.16.89.10" "137.77.77.77})",
"description": "Block IP"
}
]
You can see that JSON is not valid. The double quotes are unbalanced in expression.
Try "expression": "(ip.src in {'$a' '$b'})", instead -- that will produce valid JSON.