In jtrecenti/sabesp: Baixa dados da sabesp

require(httr)
require(rvest)
require(tidyr)
require(lubridate)
require(dplyr)
require(stringr)
require(ggplot2)
require(scales)
rm_accent <- function (x) gsub("`|\\'", "", iconv(x, to = "ASCII//TRANSLIT"))
renomear <- function(x, ...) {
  names(x) <- eval(substitute(c(...)))
  x
}

baixa_sabesp <- function(x) {
  link <- 'http://www2.sabesp.com.br/mananciais/DivulgacaoSiteSabesp.aspx'
  txt <- GET(link)
  viewstate <- txt %>% content('text') %>% html %>% html_node('#__VIEWSTATE') %>% html_attr('value')
  eventval <- txt %>% content('text') %>% html %>% html_node('#__EVENTVALIDATION') %>% html_attr('value')
  data <- as.Date(x)
  dados <- list(cmbDia=day(data), 
                cmbMes=month(data), 
                cmbAno=year(data), 
                Imagebutton1.x='0', 
                Imagebutton1.y='0', 
                '__VIEWSTATE'=viewstate, 
                '__EVENTVALIDATION'=eventval)
  r <- POST(link, body=dados, cookies=unlist(txt$cookies))
  try({
    nomes <- r %>% content('text') %>% html(encoding='UTF-8') %>% html_nodes('img') %>% html_attr('src')
    nomes <- nomes %>% `[`(!str_detect(nomes, 'jpg')) %>% str_match('/(.+)\\.gif') %>% `[`(,2) 
    d <- r %>% 
      content('text') %>% 
      html(encoding='UTF-8') %>% 
      html_node('#tabDados') %>% 
      html_table(fill=TRUE) %>%
      renomear('titulo', 'info') %>%
      select(1:2) %>%
      filter(titulo!='') %>%
      mutate(titulo=rm_accent(gsub(' +', '_', titulo)),
             lugar=rep(nomes, each=4),
             info=gsub('[^0-9.]', '', gsub(',', '.', info))) %>%
      spread(titulo, info, convert=TRUE) %>%
      mutate(volume_armazenado=volume_armazenado/100)
    return(d)
  })
  return(data.frame())
}

datas <- today() - days(0:3650)
d_sabesp <- datas %>% 
  as.character %>% 
  data.frame(data=., stringsAsFactors=F) %>% 
  group_by(data) %>% 
  do(baixa_sabesp(as.character(.))) %>%
  ungroup

save(d_sabesp, file='d_sabesp.RData')

load('d_sabesp.RData')
d_sabesp %>%
  ggplot(aes(x=as.Date(data), y=volume_armazenado, colour=lugar)) +
  geom_line() +
  scale_y_continuous(labels=percent, limits=c(0,1.1), breaks=0:11/10) +
  geom_hline(yintercept=0, colour='red') +
  theme_bw()

d_sabesp %>%
  mutate(data_date=as.Date(data),
         ano=year(data_date),
         data_mes=as.Date(sprintf('2014-%02d-%02d', month(data_date), day(data_date)))) %>%
  filter(ano >= 2010) %>%
  ggplot(aes(x=data_mes, y=volume_armazenado, colour=factor(ano), group=ano)) +
  geom_line(size=.6) +
  facet_wrap(~lugar) +
  theme_bw() +
  scale_x_date(breaks='1 month', labels = date_format("%b")) +
  theme(axis.text.x=element_text(angle=45, hjust=1)) +
  scale_colour_brewer(palette = 'Reds') +
  scale_y_continuous(labels=percent, breaks=0:12/10) +
  geom_hline(yintercept=0, colour='red')