模拟点击 R 中的下载按钮

Question

如何在 R 会话中模拟点击以下网站中的下载按钮并下载 TSV table？

https://comptox.epa.gov/dashboard/chemical_lists

我知道以前有Rselenium and PhantomJS, which are both somehow not up to date anymore and there's apparently V8。但是，我真的无法使用后者。

Answer 1

此站点从 GraphQL API 调用获取数据：

POST https://comptox.epa.gov/dashboard/graphql

当您单击下载按钮时，它会将相同的数据发送到另一个 api 以格式化数据并下载 tsv。

您可以从 API 获取数据并首先将其格式化为 tsv 文件：

library(httr)

query <- "{
    lists { 
        label 
        abbreviation 
        short_description 
        chemical_count 
        updated_at
    }
}"

r <- POST("https://comptox.epa.gov/dashboard/graphql", 
    content_type("application/json"),
    body = list(
        query = query
    ), encode = "json")

data <- content(r, "parsed")

#add link column
for(i in seq_along(data$data$lists)){
  data$data$lists[[i]]$acronym <- paste("https://comptox.epa.gov/dashboard/chemical_lists", data$data$lists[[i]]$abbreviation, sep="/")
}

#convert to dataframe
df <- do.call(rbind.data.frame, data$data$lists)

write.table(df, file = "chemical.tsv", row.names=FALSE, sep="\t", quote = FALSE)

文件输出：

模拟点击 R 中的下载按钮

Imitate click on download button from R

html

javascript

v8

r

web-scraping