如何消除R代码中字符串多余字符以实现Teams通知正常发送

问题描述 #

我写了一段R代码，用于遍历表格内容并向Teams发送通知，但代码因字符串格式错误抛出异常。

原代码如下：

# Loop through each message and send Teams notification
for (i in seq_along(messages)) {
  message <- messages[[i]]
  payload <- list(text = message)
  json_payload <- gsub("\"", "\\\"", jsonlite::toJSON(payload))  # escape double quotes with a single backslash
  command <- sprintf('curl -H "Content-Type: application/json" -d "%s" %s', json_payload, teams_webhook_url)  # use single quotes for the command string and double quotes for the header value
  system(command, intern = TRUE)  # use intern = TRUE to capture the output of the system command
  print(command)
}

打印出的command内容不符合要求：

[1] "curl -H "Content-Type: application/json" -d "{"text":["Subnet 10.0.0.0 has a higher than usual round trip time:  0.07 ms"]}" https://my.webhook.office.com/webhookb2/webhook"

正确的格式应该是：

curl -H "Content-Type: application/json" -d "{\"text\": \"Subnet 100.95.13.0 has a higher than usual round trip time:  0.25 ms\"}" https://my.webhook.office.com/webhookb2/webhook"

需要消除的多余字符：

• 开头的引号
• Content-Type:前的反斜杠
• json后的反斜杠
• {"text":前的反斜杠
• 包裹文本的方括号[]
• ms"}后的反斜杠

尝试过的无效方案 #

我试了多种调整方式，但都没能修正字符串格式：

json_payload <- gsub("\"", "\\\\\\\"", jsonlite::toJSON(payload))


for (i in seq_along(messages)) {
  message <- messages[[i]]
  payload <- list(text = message)
  json_payload <- gsub("\"", "\\\\\"", jsonlite::toJSON(payload))  # escape double quotes with three backslashes
  command <- sprintf("curl -H 'Content-Type: application/json' -d '%s' %s", json_payload, teams_webhook_url)
  output <- system(command, intern = TRUE)
  output <- gsub("^\"", "", output) # remove the first "
  cat(output, "\n")
}


for (i in seq_along(messages)) {
  message <- messages[[i]]
  payload <- list(text = message)
  json_payload <- jsonlite::toJSON(payload, auto_unbox = TRUE, escape_unicode = FALSE)
  command <- sprintf('curl -H "Content-Type: application/json" -d \'%s\' %s', json_payload, teams_webhook_url)
  system(command, intern = TRUE)
}

for (i in seq_along(messages)) {
  message <- messages[[i]]
  payload <- list(text = message)
  json_payload <- gsub('"', '\\\\\"', jsonlite::toJSON(payload))
  command <- sprintf("curl -H \"Content-Type: application/json\" -d '%s' %s", json_payload, teams_webhook_url)
  command <- gsub("\\[|\\]", "", command)
  command <- gsub("\\\\", "", command)
  system(command, intern = TRUE)
}

可行解决方案 #

方案1：修复curl命令的转义逻辑 #

问题根源在于jsonlite::toJSON默认会把单个字符串包装成数组（产生方括号），同时shell环境下的双引号转义逻辑错误。调整代码如下：

for (i in seq_along(messages)) {
  message <- messages[[i]]
  # 用auto_unbox=TRUE取消数组包装，直接输出标量值
  payload <- list(text = message)
  json_payload <- jsonlite::toJSON(payload, auto_unbox = TRUE)
  
  # 对JSON中的双引号做shell适配的转义
  escaped_json <- gsub('"', '\\"', json_payload)
  
  # 构建正确的curl命令，外层用单引号避免嵌套冲突
  command <- sprintf('curl -H "Content-Type: application/json" -d "%s" "%s"', escaped_json, teams_webhook_url)
  
  # 执行命令
  system(command, intern = TRUE)
  print(command)
}

方案2：使用httr包直接发送请求（更推荐） #

避免调用系统curl带来的转义问题，直接用R的httr包发送POST请求，自动处理JSON格式和请求头：

library(httr)

for (i in seq_along(messages)) {
  message <- messages[[i]]
  payload <- list(text = message)
  
  # 发送POST请求，自动编码JSON并设置请求头
  response <- POST(
    url = teams_webhook_url,
    body = payload,
    encode = "json",
    add_headers("Content-Type" = "application/json")
  )
  
  # 可选：打印响应状态码，确认请求是否成功
  print(status_code(response))
}

内容的提问来源于stack exchange，提问作者Alienvolm