short script to send sms using gosms.cz (czech numbers)

send_gosms.R

# the following script worked Feb-2024, not sure, whether the API wont change
# it is pretty cheap - 1CZK per message (again, this could be cheaper with better pricing plan)
library(tidyverse)
library(httr2)

# you need to register for gosms.eu
# you will need your client_id, client_secret and channel_id

# store those in variables
client_id     <- "your client id"
client_secret <- "your secret"
channel_id    <- "your channel id"

# authenticate ------------------------------------------------------------

## Get the authorization code

# url for authentication
url <- "https://app.gosms.eu/oauth/v2/token"

# Set up the request
request <- request(url) %>%
  req_method("POST") %>%
  req_body_form(
    client_id = client_id ,
    client_secret = client_secret,
    grant_type = "client_credentials"
  )

# Perform the request
response <- req_perform(request)

# get access token
access_token_raw <- response %>% resp_body_json() 
access_token <- access_token_raw$access_token

# now, we are authenticated for 1 hour

# send message ------------------------------------------------------------


# this is a message that you want to send
sms_data <- list(
  message = "Hello World!", # here is the messaage
  recipients = c("+420000000000"), # here is a list of numbers
  channel = channel_id # this is channel
)

# url for sending messages
url <- "https://app.gosms.eu/api/v1/messages"

# Set up the request
request <- request(url) %>%
  req_method("POST") %>%
  req_headers(`Authorization` = sprintf("Bearer %s", access_token),
              `Content-Type` = "application/json") %>%
  req_body_json(sms_data)

req_perform(request)

# and that it is!