相关疑难解决方法(0)

我试图使用rvest来蜘蛛网页,该网页需要在表单上登录电子邮件/密码.

rm(list=ls())
library(rvest)

### Trying to sign into a form using email/password 

url       <-"http://www.perfectgame.org/"   ## page to spider
pgsession <-html_session(url)               ## create session
pgform    <-html_form(pgsession)[[1]]       ## pull form from session

set_values(pgform, `ctl00$Header2$HeaderTop1$tbUsername` = "myemail@gmail.com") 
set_values(pgform, `ctl00$Header2$HeaderTop1$tbPassword` = "mypassword")

submit_form(pgsession,pgform,submit=`ctl00$Header2$HeaderTop1$Button1`)

这给我以下错误信息:

Error in submit_request(form, submit) : 

找不到对象'ctl00 $ Header2 $ HeaderTop1 $ Button1'

如果我在没有指定submit参数的情况下提交表单,我会得到:

Submitting with 'ctl00$Header2$HeaderTop1$Button1'
Error in function (type, msg, asError = TRUE)  : <url> malformed

我也尝试将参数直接传递给httr,如本问题所述:如何在R中发布一个简单的HTML表单？,但"submit"参数不接受提交按钮,使用向后引号(``),引号或没有任何引号:

library(httr)

url <- "http://www.perfectgame.org/Rankings/Players/Default.aspx?gyear=2015&num=500"

fd <- list(
    submit = `ctl00$Header2$HeaderTop1$Button1`, …