alchemyapitest.R

library(httr)

alchemy_url <- "http://access.alchemyapi.com/"
call <- "calls/text/TextGetRankedConcepts"
api_key <- "[your API key here]"

text <- "Indeed the Environment Agency inform us that these guidelines have been used as the basis of several hundred appraisals for the ongoing WaterIndustry Price Review process 10"

# The following doesn't work. 'Status: 404, Content-Type: <unknown>'
#
# q <- paste0(alchemy_url, call, "&apikey=", api_key, "&text=", URLencode(text))
#
# POST(q,     
#    add_headers("Content-type" = "application/x-www-form-urlencoded" ),
#    verbose())

# However, this works
# Thanks http://stackoverflow.com/questions/26001012/how-to-structure-httr-post-request-to-return-site-data
url <- paste0(alchemy_url, call)
r <- POST(url,     
          query = list(apikey = api_key,
                       text = URLencode(text)))

# But - actually I shouldn't URLencode text, so final version:
r <- POST(url,     
          query = list(apikey = api_key,
                       text = text))