Hi everyone,
I have developed a Dockerized R API that receives a JSON with multiple inputs, performs data operations, and returns a list as output.
The API works on a local machine and deployed on a workstation without any problem. However, when I deploy it on Azure Web App POST request returns: 'No JSON file is found in the request' error, while, I do not experience any issue with the GET (echo) endpoint.
The Web App allows inbound traffic, hence, I deduce the issue is most probably because of how I handle the request.
I have several questions:
-
How can I manipulate the code so that the JSON input is a parameter of a POST endpoint and will be processed under that?
-
What could be the other potential reasons of such strange behavior in Azure Web App?
Thanks
library(plumber)
library(jsonlite)
library(reprex)
source('./functions.R')
#* @apiTitle ...
#* @apiDescription ...
#* @apiDescription ...
#* @apiVersion 1.0
#* @plumber
function(pr) {
pr %>%
pr_set_debug(TRUE)
}
#* Echo back the input
#* @param msg The message to echo
#* @get /echo
function() {
list(Status = 'API is working properly!',
Time = Sys.time())
}
#* Log some information about the incoming request
#* @filter logger
function(req){
cat(as.character(Sys.time()), "-",
req$REQUEST_METHOD, req$PATH_INFO, "-",
req$HTTP_USER_AGENT, "@", req$REMOTE_ADDR, "\n")
forward()
}
#* Get model input
#* @filter /field_filter
function(req, res){
if(grepl("field_filter", req$PATH_INFO)){
req$data <- tryCatch(jsonlite::fromJSON(req$postBody),
error = function(x){
return(NULL)
})
if(is.null(req$data)){
res$status <- 400
return(
list(error = "No JSON file is found in the request")
)
}
list_of_inputs <- req$data
req$results <- main(input_1 = list_of_inputs[[1]],
input_2 = list_of_inputs[[2]],
input_3 = list_of_inputs[[3]])
}
forward()
}
#* ...
#* @post /field_filter/report
function(req){
res <- req$results
res
}