I am trying to create API that can take in JSON data .

For example

```
#* Return the sum of two numbers
#* @post /sum
function(a, b) {
as.numeric(a) + as.numeric(b)
}
```

The above API for single value (http://host:port/sum?a=3&b=2 ) and below for JSON

```
#* Return the sum of two numbers given JSON input
#*
#* @post /sum/json
function(req,res) {
req$data <- tryCatch(jsonlite::fromJSON(req$postBody),
error = function(e) NULL)
....
req$sum_values <- sum(req$data)
}
sum<- function(df){
as.numeric(df$a) + as.numeric(df$b)
}
```

Input

```
[
{
"a": 5,
"b": 3
},
{
"a": 2,
"b": 6
}
]
```

Is it possible to use the dataframe alone directly in both cases with standard filters/serializers/de-serializers etc.

```
sum<- function(df){
as.numeric(df$a) + as.numeric(df$b)
}
```

Note : My attempt is be least intrusive into a given model/function (Example :sum<- function(df) ) and do the maximum with decorators or standards.

Thanks