Loop into JSON Array in Bash Script

Question

I make a curl request to an API and get a json return with jq.

The result

{
  "errors": [],
  "metadata": {
    "clientTransactionId": "",
    "serverTransactionId": "20190318164551347"
  },
  "responses": [
    {
      "comment": "",
      "keyData": {
        "algorithm": 13,
        "flags": 257,
        "protocol": 3,
        "publicKey": "a1"
      },
      "keyTag": 28430
    },
    {
      "comment": "",
      "keyData": {
        "algorithm": 13,
        "flags": 257,
        "protocol": 3,
        "publicKey": "a4"
      },
      "keyTag": 28430
    },
    {
      "comment": "",
      "keyData": {
        "algorithm": 13,
        "flags": 257,
        "protocol": 3,
        "publicKey": "fa4"
      },
      "keyTag": 33212
    }
  ],
  "status": "success",
  "warnings": []
}

Now i want have a loop to make a second api request with the four values frim keyData

But how can I make it? I search a half day and don't have found out it.

My request:

curl -v -X POST --data '{
    "authToken": ".......",
    "clientTransactionId": "",
}' https:/domain.tld/api/v1/json/keysList | jq .

With jq '.responses[]' I have a "array" with this, but I don't find the solution for a loop with my values.

Answer 1

You could use jq to retrieve the 'keyData' objects, and then pipe it to while read:

jq -c '.responses[].keyData' file.json

{"algorithm":13,"flags":257,"protocol":3,"publicKey":"a1"}
{"algorithm":13,"flags":257,"protocol":3,"publicKey":"a4"}
{"algorithm":13,"flags":257,"protocol":3,"publicKey":"fa4"}

And from there:

jq -c '.responses[].keyData' file.json | 
while read keydata; do curl --data "'$keydata'" http://example.com/service ; done

Putting in your original curl command, the whole pipeline would look like this:

curl -v -X POST --data '{ "authToken": ".......", "clientTransactionId": "",}' https:/domain.tld/api/v1/json/keysList | 
jq -c '.responses[].keyData' file.json | 
while read keydata; do curl --data "'$keydata'" http://example.com/service ; done

Do remember to modify the second curl command with the actual URL, options and so on before execution. If it is necessary, you can add an echo/printf statement before the curl command to see what your request would look like.

Answer 2

alternatively, you could use a unix utility jtc to walk keyData:

bash $ <file.json jtc -w'[responses][:][keyData]' -r
{ "algorithm": 13, "flags": 257, "protocol": 3, "publicKey": "a1" }
{ "algorithm": 13, "flags": 257, "protocol": 3, "publicKey": "a4" }
{ "algorithm": 13, "flags": 257, "protocol": 3, "publicKey": "fa4" }
bash $ 

and feed it to curl:

bash $ <file.json jtc -w'[responses][:][keyData]' -r | while read keydata; do curl --data "'$keydata'" http://example.com/service ; done