GET और POST एंडपॉइंट बनाना

# #* Get a user by ID
# #* @get /users/<id:int>
# function(id) {
#   # id is already an integer
#   list(
#     user_id = id,
#     name    = paste('User', id)
#   )
# }
#
# GET /users/42  =>  {"user_id":42, "name":"User 42"}

# #* Search users by name
# #* @param name The name to search for
# #* @param limit Maximum results to return
# #* @get /users/search
# function(name = '', limit = '10') {
#   limit <- as.integer(limit)
#   # query string: /users/search?name=Alice&limit=5
#   list(query = name, max = limit)
# }

# #* Create a new user
# #* @post /users
# function(req) {
#   body <- jsonlite::fromJSON(req$postBody)
#   # body$name, body$email are now available
#   list(
#     status  = 'created',
#     user_id = sample(1000:9999, 1),
#     name    = body$name
#   )
# }

# #* @post /orders
# function(req, res) {
#   body <- jsonlite::fromJSON(req$postBody)
#   if (is.null(body$product_id)) {
#     res$status <- 400L
#     return(list(error = 'product_id is required'))
#   }
#   list(
#     order_id   = as.integer(Sys.time()),
#     product_id = body$product_id,
#     quantity   = body$quantity %||% 1
#   )
# }

# #* @get /items/<id:int>
# function(id, res) {
#   items <- list(
#     list(id=1, name='Widget'),
#     list(id=2, name='Gadget')
#   )
#   found <- Filter(function(x) x$id == id, items)
#   if (length(found) == 0) {
#     res$status <- 404L
#     return(list(error = paste('Item', id, 'not found')))
#   }
#   found[[1]]
# }

# Named list => JSON object
# list(id=1, name='Alice')  => {"id":1, "name":"Alice"}
#
# Unnamed list => JSON array
# list(1, 2, 3)  =>  [1, 2, 3]
#
# Nested structures work too:
# list(
#   user   = list(id=1, name='Alice'),
#   orders = list(list(id=101), list(id=102))
# )
# => {"user":{"id":1,"name":"Alice"}, "orders":[{"id":101},{"id":102}]}

# Standard plumber startup in api_start.R:
# library(plumber)
# pr <- plumb('api.R')
# pr$run(port = 8000, host = '0.0.0.0')
#
# Or with pipe style:
# plumb('api.R') |> pr_run(port = 8000)
#
# Test with:
# curl http://localhost:8000/hello

# #* List all products
# #* @get /products
# function() {
#   list(products = list(list(id=1, name='Widget')))
# }
#
# #* Create a product
# #* @post /products
# function(req) {
#   body <- jsonlite::fromJSON(req$postBody)
#   list(created = TRUE, name = body$name)
# }

# From terminal:
# curl http://localhost:8000/users/42
# curl -X POST http://localhost:8000/users \
#      -H 'Content-Type: application/json' \
#      -d '{"name":"Alice","email":"alice@example.com"}'
#
# From R:
# library(httr2)
# resp <- request('http://localhost:8000/users/42') |> req_perform()
# resp_body_json(resp)