Question

我正在尝试使用angular.js抓取一个网页。我的理解是R中唯一的选择是使用RSelenium首先加载页面，然后解析内容。但是，我发现rvest比RSelenium更直观地解析内容，因此我希望尽可能少地使用RSelenium，然后尽快切换到rvest。

到目前为止，我已经意识到我可能至少需要使用RSelenium来连接并使用htmlTreeParse下载html代码。假设这是我输出的一部分：

structure(list(name = "div", attributes = structure(c("im_dialog_date", 
"dialogMessage.dateText"), .Names = c("class", "ng-bind")), children = structure(list(
    text = structure(list(name = "text", attributes = NULL, children = NULL, 
        namespace = NULL, namespaceDefinitions = NULL, value = "6:52 PM"), .Names = c("name", 
    "attributes", "children", "namespace", "namespaceDefinitions", 
    "value"), class = c("XMLTextNode", "XMLNode", "RXMLAbstractNode", 
    "XMLAbstractNode", "oldClass"))), .Names = "text"), namespace = NULL, 
    namespaceDefinitions = NULL), .Names = c("name", "attributes", 
"children", "namespace", "namespaceDefinitions"), class = c("XMLNode", 
"RXMLAbstractNode", "XMLAbstractNode", "oldClass"))

如何将其传递给rvest::read_html()？

Answer 1

如果您查看商品的类别，则它是XMLNode，这是XML包定义的类。在其中，它定义了toString（但不是as.character，奇怪地）的方法，允许您将节点转换为普通字符串，而该字符串又可以由xml2::read_html读入：

library(rvest)
#> Loading required package: xml2

node <- structure(list(name = "div", attributes = structure(c("im_dialog_date", 
"dialogMessage.dateText"), .Names = c("class", "ng-bind")), children = structure(list(
    text = structure(list(name = "text", attributes = NULL, children = NULL, 
        namespace = NULL, namespaceDefinitions = NULL, value = "6:52 PM"), .Names = c("name", 
    "attributes", "children", "namespace", "namespaceDefinitions", 
    "value"), class = c("XMLTextNode", "XMLNode", "RXMLAbstractNode", 
    "XMLAbstractNode", "oldClass"))), .Names = "text"), namespace = NULL, 
    namespaceDefinitions = NULL), .Names = c("name", "attributes", 
"children", "namespace", "namespaceDefinitions"), class = c("XMLNode", 
"RXMLAbstractNode", "XMLAbstractNode", "oldClass"))

node %>% XML::toString.XMLNode() %>% read_html()
#> {xml_document}
#> <html>
#> [1] <body><div class="im_dialog_date" ng-bind="dialogMessage.dateText">6 ...

也就是说，我通常只使用RSelenium::remoteDriver的{{1}}方法来获取所有HTML，然后使用rvest轻松解析。

如何使用rRE使用RSelenium访问页面？

1 个答案: