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rposthttr

R httr how to structure body

I have a curl code below that runs in a terminal and I want to convert it httr code in R.

curl -X POST "https://api.purpleair.com/v1/groups/zzz/members" -H "Content-Type: application/json" -H "X-API-Key: xxxxxxxxx" -d '{"sensor_index":"yyyyyy"}'

This R code doesn't quite work.

library(httr)
url <- "https://api.purpleair.com/v1/groups/zzz/members"
body <- list(sensor_index = "yyyyyy") 
headers <- c("Content-Type" = "application/json",
             "X-API-Key" = "xxxxxxxxx")

response <- POST(url, body = body, add_headers(.headers = headers))

It returns

"error" : "MissingIdentifierError",
  "description" : "Missing sensor_id or sensor_index value."

I can't figure out how to turn -d '{"sensor_index":"yyyyyy"}' into a body.

Solution

  • If you pass your body= as a list, by default POST() will use "multipart" encoding which more generally allows you to upload files and form data. But if you want POST to turn the list into a JSON string for you, you need to set encode="json". When you use that value, it will also set the correct content-type for you so you don't need to explicitly set it in a header.