检查http状态码时循环报错

Question

我有一个网站列表，我的目标是检查每个网站的状态代码。我有以下内容，其中 urls 是网站列表。

for (i in seq_along(urls)) {
  r <- GET(test[i])
  s <- status_code(r)
}

当我运行 for 循环时，我得到消息： Error in curl::curl_fetch_memory(url, handle = handle) : schannel: SNI or certificate check failed: SEC_E_WRONG_PRINCIPAL (0x80090322) - The target principal name is incorrect.

我正在考虑用 tryCatch 处理这个问题，但我不确定语法或是否将整个 for 循环放在 tryCatch.

中

Answer 1

你 for 循环实际上工作正常。

# install.packages('httr')
library(httr)

urls <- c('
          'https://whosebug.com/')

s <- numeric(length(urls))
for (i in seq_along(urls)) {
  
  # if URLs are listed
  if(inherits(urls, 'list')) {
    r <- GET(urls[[i]])
  }
  # if URLs are concatenated
  if(inherits(urls, 'character')) {
    r <- GET(urls[i])
  }
  
  s[i] <- status_code(r)
}

#> s
#[1] 200 200

（在OP评论后编辑）如果您想 try 某个 GET 是否工作，如果不工作，则忽略错误并继续循环，您可以使用以下结构。

s <- numeric(length(urls))
for (i in seq_along(urls)) {

  # if URLs are listed
  if(inherits(urls, 'list')) {
    r <- try(GET(urls[[i]]))
    if(inherits(r, "try-error")) next
  }

  # if URLs are concatenated
  if(inherits(urls, 'character')) {
    r <- try(GET(urls[i]))
    if(inherits(r, "try-error")) next
  }
  
  s[i] <- status_code(r)
}

#> s
#[1] 200 200

检查http状态码时循环报错

Loop through error when checking http status code

error-handling

for-loop

r

http-status-codes

dataframe