R/funcoes.R

In rdurl0/spcrimr: spcrimr: tidy data from SSP-SP.

#'Extract data from SSP
#'
#'Extract data avaliable in SSP's website: (1) number of criminal ocurrencies
#' (2) police productivity indicators, by month and by municipalities.
#'
#'
#'@param ano is a number between 2002 e 2018 indicating the year,
#'
#'@param municipio is a number between 1 and 645 indicating the municipality
#' (organized by alphabetical order)
#'
#'@param type a character string indicating the data resquested to the
#' SSP's website. Use
#' \code{'ctl00$conteudo$btnMensal'} if you want to extract criminal ocurrencies
#' \code{'ctl00$conteudo$btnPolicial'} to request police indicators.
#'
#'@return a tibble
#'
#'@references Web scraping do site da
#'Secretaria de Seguranca Publica de Sao Paulo.
#' \link[www.curso-r.com/blog/2017/05/19/2017-05-19-scrapper-ssp/]{Blog do
#' Curso R}. 2017. ultimo acesso em: 11/07/2018
#'
#'@references \link[www.ssp.sp.gov.br/Estatistica/Pesquisa.aspx]{Secretaria de
#'Seguranca Publica do estado de Sao Paulo}
#'
#'@export
download_table_sp <- function(
  ano,
  municipio,
  type = c("ctl00$conteudo$btnPolicial", "ctl00$conteudo$btnMensal")
  ) {

  url <- "http://www.ssp.sp.gov.br/Estatistica/Pesquisa.aspx"

  pivot <- httr::GET(url)

  view_state <- pivot %>%
    xml2::read_html() %>%
    rvest::html_nodes("input[name='__VIEWSTATE']") %>%
    rvest::html_attr("value")

  event_validation <- pivot %>%
    xml2::read_html() %>%
    rvest::html_nodes("input[name='__EVENTVALIDATION']") %>%
    rvest::html_attr("value")

  params <- list(`__EVENTTARGET` = type,
                 `__EVENTARGUMENT` = "",
                 `__LASTFOCUS` = "",
                 `__VIEWSTATE` = view_state,
                 `__EVENTVALIDATION` = event_validation,
                 `ctl00$conteudo$ddlAnos` = ano,
                 `ctl00$conteudo$ddlRegioes` = "0",
                 `ctl00$conteudo$ddlMunicipios` = municipio,
                 `ctl00$conteudo$ddlDelegacias` = "0")

  httr::POST(url, body = params, encode = "form") %>%
    xml2::read_html() %>%
    rvest::html_table(dec = ",") %>%
    dplyr::first() %>%
    dplyr::mutate(municipio = municipio, ano = ano)
}
#'Index para parear dados
#'
#'@param x e um vetor qualquer, precisamos do tamanho dele
#'
#'@param vec e o vetor de indexacao (1:645 municipios) que sera replicado
#' \code{x} vezes
#'
#'@return uma \code{list} com dois vetores igual a \code{vec}.
#'
#'@export
insert_munic_idx <- function(x, vec = seq(645)) {

  lista <- vector("list", length(x))

  vec <- vec
  for (idx in 1:length(x)) lista[[idx]] <- vec

  return(lista)

}