如何执行网络抓取以获取 Google Play 中应用程序的所有评论？

Question

我假装能够获得用户在 Google Play 上留下的关于这些应用的所有评论。我有这个代码，他们在那里指出 Web scraping in R through Google playstore 。但问题是您只能获得前 40 条评论。有没有可能拿到app的所有cmet？

```

#Loading the rvest package
library(rvest)
library(magrittr) # for the '%>%' pipe symbols
library(RSelenium) # to get the loaded html of 

#Specifying the url for desired website to be scraped
url <- 'https://play.google.com/store/apps/details? 
id=com.phonegap.rxpal&hl=en_IN&showAllReviews=true'

# starting local RSelenium (this is the only way to start RSelenium that 
is working for me atm)
selCommand <- wdman::selenium(jvmargs = c("- 
Dwebdriver.chrome.verboseLogging=true"), retcommand = TRUE)
shell(selCommand, wait = FALSE, minimized = TRUE)
remDr <- remoteDriver(port = 4567L, browserName = "firefox")
remDr$open()

# go to website
remDr$navigate(url)

# get page source and save it as an html object with rvest
html_obj <- remDr$getPageSource(header = TRUE)[[1]] %>% read_html()

# 1) name field (assuming that with 'name' you refer to the name of the 
reviewer)
names <- html_obj %>% html_nodes(".kx8XBd .X43Kjb") %>% html_text()

# 2) How much star they got 
stars <- html_obj %>% html_nodes(".kx8XBd .nt2C1d [role='img']") %>% 
html_attr("aria-label")

# 3) review they wrote
reviews <- html_obj %>% html_nodes(".UD7Dzf") %>% html_text()

# create the df with all the info
review_data <- data.frame(names = names, stars = stars, reviews = reviews, 
stringsAsFactors = F)

```

Answer 1

您可以从 GooglePlay 的网上商店获取所有评论。

如果您滚动查看评论，您可以看到 XHR 请求被发送到：

https://play.google.com/_/PlayStoreUi/data/batchexecute

使用表单数据：

f.req: [[["rYsCDe","[[\"com.playrix.homescapes\",7]]",null,"55"]]]
at: AK6RGVZ3iNlrXreguWd7VvQCzkyn:1572317616250

和参数：

rpcids=rYsCDe
f.sid=-3951426241423402754
bl=boq_playuiserver_20191023.08_p0
hl=en
authuser=0
soc-app=121
soc-platform=1
soc-device=1
_reqid=839222
rt=c

玩弄了不同的参数，发现很多是可选的，请求可以简化为：

表单数据：

f.req: [[["UsvDTd","[null,null,[2, $sort,[$review_size,null,$page_token]],[$package_name,7]]",null,"generic"]]]

参数：

hl=$review_language

响应是神秘的，但它本质上是带有键的 JSON 数据，类似于 protobuf，我为响应编写了一个解析器，将其转换为常规的 dict 对象。

https://gist.github.com/xlrtx/af655f05700eb76bb29aec876493ed90