Sample input JSON is given below: I want the code to construct the JSON object static/dynamically in KSH/BASH

Example : 
```{
    "param1": "value1", 
    "param2": "value2", 
    "param3": "value3"
}```

Nested JSON:
```{
    "param1": "value1", 
    "param2": "value2", 
    "param3": {
                "param4": "value4", 
                "param5": "value5"
              }
}```

CodePudding user response：

Using jq to generate your JSON will save you when the input data contains things like quotation marks.

1. simple JSON object

   json=$(
       jq -n \
           --arg "$param1" "$value1" \
           --arg "$param2" "$value2" \
           --arg "$param3" "$value3" \
           '$ARGS.named'
   )
   

2. nested

   nestedJson=$(
       jq -n \
           --arg     "$param1" "$value1" \
           --arg     "$param2" "$value2" \
           --arg     "$param3" "$value3" \
           --argjson "nested"  "$json" \
           '$ARGS.named'
   )
   

3. dynamic: use bash associative arrays

   declare -A data=([param4]="value4" [param5]="value5")
   
   jq_args=(
       -n 
       --arg "$param1" "$value1"
       --arg "$param2" "$value2"
   )
   for key in "${!data[@]}"; do
       jq_args =( --arg "$key" "${data[$key]}" )
   done
   
   dynamicJson=$( jq "${jq_args[@]}" '$ARGS.named'
   

CodePudding user response：

1. Preparing the JSON in KSH/Bash

   json=$(cat <<-END
       {
           "${param1}": "${value1}", 
           "${param2}": "${value2}", 
           "${param3}": "${value3}"
       }
       END
   )
   

2. Preparing the Nested-JSON in KSH/Bash

   nestedJson=$(cat <<-END
   {
       "${param1}": "${value1}", 
       "${param2}": "${value2}", 
       "${param3}": "${value3}", 
       "nested" : ${json}
   }
   END
   )
   

3. Dynamic JSON:

   array=("param4:value4", "param5:value5")
   dynamicJSON=$(cat <<-END
       {
           "${param1}": "${value1}", 
           "${param2}": "${value2}"
       }
   END
   )
   
   for element in ${array[@]}
   do
        key="$(cut -d":" -f1 <<<"$element")"
        val="$(cut -d":" -f2 <<<"$element")"
        dynamicJSON=$( sed  '$s/}/,\n'"\"$key\""':'"\"$val\""'}/' <<<"$dynamicJSON")
   done
   

CodePudding user response：

You can reference environment variables directory in your jq program using env.varname

$ export fname="foo"
$ export lname="bar"
$ export location="baz"
    
$ SAMPLE_JSON='{
  "first_name": "",
  "last_lname": "",
  "location": "",
  "key": "value"
}'

$ jq '{
    "first_name":env.fname, 
    "last_lname":env.lname, 
    "location":env.location,
    "key": .key
}' <<<"$SAMPLE_JSON"

{
  "first_name": "foo",
  "last_lname": "bar",
  "location": "baz",
  "key": "value"
}

Nested

SAMPLE_JSON='{
    "param1": "value1", 
    "param2": "value2", 
    "param3": {
                "param4": "value4", 
                "param5": "value5"
              }
}'

jq '{
    "param1": env.fname, 
    "param2": env.lname, 
    "param3": {
                "param4": .param3.param4, 
                "param5": env.location
              }
}' <<<"$SAMPLE_JSON"

{
  "param1": "foo",
  "param2": "bar",
  "param3": {
    "param4": "value4",
    "param5": "baz"
  }
}