exemplos_de_aula/18-esalq.R

In curso-r/202202-web-scraping: What the Package Does (One Line, Title Case)

library(magrittr)


r0 <- httr::GET("https://www.cepea.esalq.usp.br/br")

ua <- httr::user_agent("Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.141 Safari/537.36")

u_soja <- "https://www.cepea.esalq.usp.br/br/indicador/soja.aspx"
r_soja <- httr::GET(u_soja, ua)

ids_pesquisa <- r_soja |>
  xml2::read_html() |>
  xml2::xml_find_all("//a[contains(text(), 'Série de preços')]") |>
  xml2::xml_attr("href")

soja <- httr::GET(
  "https://www.cepea.esalq.usp.br/br/indicador/series/soja.aspx?id=92",
  ua
)

writeBin(soja$content, "output/soja.xls")





readxl::read_excel("output/soja.xls")
# openxlsx::read.xlsx("output/soja.xlsx")

readxl::read_xls("output/soja.xls")
gdata::read.xls("output/soja.xls")



u0 <- "https://www.cepea.esalq.usp.br/br/indicador/listar_especificacao.aspx"

body <- list(produto = "3,4,35,36,37,38,43,44,45,46,47,48,49,50")

r0 <- httr::POST(u0, body = body)

# scrapr::html_view(r0)

query <- list(
  "tabela_id" = "53",
  "data_inicial" = "01/07/2021",
  "periodicidade" = "1",
  "data_final" = "08/07/2021"
)

r1 <- httr::GET(
  "https://www.cepea.esalq.usp.br/br/consultas-ao-banco-de-dados-do-site.aspx",
  query = query
)

link <- r1 %>%
  xml2::read_html() %>%
  xml2::xml_text() %>%
  jsonlite::fromJSON() %>%
  purrr::pluck("arquivo")

httr::GET(link, httr::write_disk(paste0("output/", basename(link)), TRUE))