Download mp3 file - r

Question

I would like to use a website from R. The website is http://soundoftext.com/ where I can download WAV. files with audios from a given text and a language (voice).
There are two steps to download the voice in WAV:
1) Insert text and Select language. And Submit
2) On the new window, click Save and select folder.
Until now, I could get the xml tree, convert it to list and modify the values of text and language. However, I don't know how to convert the list to XML (with the new values) and execute it. Then, I would need to do the second step too.
Here is my code so far:
require(RCurl)
require(XML)
webpage <- getURL("http://soundoftext.com/")
webpage <- readLines(tc <- textConnection(webpage)); close(tc)
pagetree <- htmlTreeParse(webpage, error=function(...){}, useInternalNodes = TRUE)
x<-xmlToList(pagetree)
# Inserting word
x$body$div$div$div$form$div$label$.attrs[[1]]<-"Raúl"
x$body$div$div$div$form$div$label$.attrs[[1]]
# Select language
x$body$div$div$div$form$div$select$option$.attrs<-"es"
x$body$div$div$div$form$div$select$option$.attrs
I have follow this approach but there is an error with "tag".
UPDATED: I just tried to use rvest to download the audio file, however, it does not respond or trigger anything. What am I doing wrong (missing)?
url <- "http://soundoftext.com/"
s <- html_session(url)
f0 <- html_form(s)
f1 <- set_values(f0[[1]], text="Raúl", lang="es")
attr(f1, "type") <- "Submit"
s[["fields"]][["submit"]] <- f1
attr(f1, "Class") <- "save"
test <- submit_form(s, f1)

Answer 1

I see nothing wrong with your approach and it was worth a try.. that's what I'd write too.
The page is somewhat annoying in that uses jquery to append new divs at each request. I still think that should be possible to do with rvest, but I found a fun workaround using the httr package:
library(httr)
url <- "http://soundoftext.com/sounds"
fd <- list(
submit = "save",
text = "Banana",
lang="es"
)
resp<-POST(url, body=fd, encode="form")
id <- content(resp)$id
download.file(URLencode(paste0("http://soundoftext.com/sounds/", id)), destfile = 'test.mp3')
Essentially when it send the POST request to the server, an ID come back, if we simply GET that id when can download the file.

Answer 2

Creator of Sound of Text here. Sorry it took so long for me to find this post.
I just redesigned Sound of Text, so your html parsing probably won't work anymore.
However, there is now an API that you can use which should make things considerably easier for you.
You can find the documentation here: https://soundoftext.com/docs
I apologize if it's not very good. Please let me know if you have any questions.