Scrape website with R by navigating doPostBack

Question

I want to extract a table periodicaly from below site.

price list changes when clicked building block names(BLOK 16 A, BLOK 16 B, BLOK 16 C, ...) . URL doesn\'t cha

Answer 1

library(rvest)    
url<-"http://www.kentkonut.com.tr/tr/modul/projeler/daire_fiyatlari.aspx?id=44"
    pgsession<-html_session(url) 
    t<-html_table(html_nodes(read_html(pgsession), css = "#ctl00_ContentPlaceHolder1_DataList1"), fill= TRUE)[[1]]
    even_indices<-seq(2,length(t$X1),2)
    t<-t[even_indices,]
    t<-t[2:(length(t$X1)),]

EDITED CODE:

library(rvest)    
url<-"http://www.kentkonut.com.tr/tr/modul/projeler/daire_fiyatlari.aspx?id=44"
pgsession<-html_session(url)
pgform<-html_form(pgsession)[[1]]
page<-rvest:::request_POST(pgsession,"http://www.kentkonut.com.tr/tr/modul/projeler/daire_fiyatlari.aspx?id=44",
                           body=list(
                             `__VIEWSTATE`=pgform$fields$`__VIEWSTATE`$value,
                             `__EVENTTARGET`="ctl00$ContentPlaceHolder1$DataList2$ctl01$lnk_blok",
                             `__EVENTARGUMENT`="",
                             `__VIEWSTATEGENERATOR`=pgform$fields$`__VIEWSTATEGENERATOR`$value,
                             `__VIEWSTATEENCRYPTED`=pgform$fields$`__VIEWSTATEENCRYPTED`$value,
                             `__EVENTVALIDATION`=pgform$fields$`__EVENTVALIDATION`$value
                           ),
                           encode="form"
                           )
# in the above example change eventtarget as "ctl00$ContentPlaceHolder1$DataList2$ctl02$lnk_blok" to get different table

t<-html_table(html_nodes(read_html(page), css = "#ctl00_ContentPlaceHolder1_DataList1"), fill= TRUE)[[1]]
even_indices<-seq(2,length(t$X1),2)
t<-t[even_indices,]
t<-t[2:(length(t$X1)),]