将对象转换为键值对数组

Question

I have a file where every line is a json (not formatted) as follows:

{
  "callID": "xxxxxxxxxxxxxx",
  "authType": "xxxxxxxxxxxxxx",
  "timestamp": "xxxxxxxxxxxxxx",
  "errCode": "0",
  "errMessage": "xxxxxxxxxxxxxx",
  "endpoint": "xxxxxxxxxxxxxx",
  "userKey": "xxxxxxxxxxxxxx",
  "httpReq": {
    "key1": "value1",
    "key2": "value2",
    "key3": "value3"
  },
  "ip": "xxxxxxxxxxxxxx",
  "params": {
    "key1": "value1",
    "key2": "value2",
    "key3": "value3"
  },
  "uid": "xxxxxxxxxxxxxx",
  "apikey": "xxxxxxxxxxxxxx",
  "userAgent": {
    "key1": "value1",
    "key2": "value2",
    "key3": "value3"
  },
  "userKeyDetails": {
    "name": "xxxxxxxxxxxxxx"
  }
}

I need to perform a conversion where every object ( httpReq , params , userAgent , userKeyDetails ) need to be converted as array of objects, with key and value properties. Every key is not mandatory, a single json may NOT have all given keys.

Here is a partial output of the structure:

{
  "httpReq": [
    {
      "key": "key1",
      "value": "value1"
    },
    {
      "key": "key2",
      "value": "value2"
    }
  ]
}

Using jq command line I understand that to_entries operator is the one I'm looking for, so I created this command

cat test.json | jq -c '.userAgent = (.userAgent | to_entries) | .userKeyDetails = (.userKeyDetails | to_entries) | .params = (.params | to_entries) | .httpReq= (.
httpReq | to_entries)' > out.json

It works, but it's failing on rows where one of the given key is missing, with following error:

jq: error (at <stdin>:2): null (null) has no keys
jq: error (at <stdin>:3): null (null) has no keys
jq: error (at <stdin>:4): null (null) has no keys
jq: error (at <stdin>:5): null (null) has no keys

So I need a selector which works handling the possibility of a key to be missing, can this be obtained directly with a jq selector?

Answer 1

If you want to perform the conversion on all the objects you don't need to specify every one of them; following should do the trick.

map_values(if type == "object" then to_entries else . end)

^{REPL demo}

Answer 2

Your initial filter can be shortened to

(.userAgent |= to_entries) |
(.userKeyDetails |= to_entries) | 
(.params |= to_entries) | 
(.httpReq |= to_entries)

and we can abstract the common behavior to a function:

def f(key):
  .[key] |= to_entries
;
f("userAgent") | f("userKeyDetails") | f("params") | f("httpReq")

Now we just need to update f so that it doesn't fail if the requested key doesn't exist. To do that, we can replace . with select(has(key)) .

def f(key):
    [key] |= to_entries
;
f("userAgent") | f("userKeyDetails") | f("params") | f("httpReq")