问题
I have been trying to scrape my local government's Power BI dashboard using R but it seems like it might be impossible. I've read from the Microsoft site that it is not possible to scrable Power BI dashboards but I am going through several forums showing that it is possible, however I am going through a loop
I am trying to scrape the Zip Code tab data from this dashboard:
https://app.powerbigov.us/view?r=eyJrIjoiZDFmN2ViMGEtNzQzMC00ZDU3LTkwZjUtOWU1N2RiZmJlOTYyIiwidCI6IjNiMTg1MTYzLTZjYTMtNDA2NS04NDAwLWNhNzJiM2Y3OWU2ZCJ9&pageName=ReportSectionb438b98829599a9276e2&pageName=ReportSectionb438b98829599a9276e2
I've tried several "techniques" from the given code below
scc_webpage <- xml2::read_html("https://app.powerbigov.us/view?r=eyJrIjoiZDFmN2ViMGEtNzQzMC00ZDU3LTkwZjUtOWU1N2RiZmJlOTYyIiwidCI6IjNiMTg1MTYzLTZjYTMtNDA2NS04NDAwLWNhNzJiM2Y3OWU2ZCJ9&pageName=ReportSectionb438b98829599a9276e2&pageName=ReportSectionb438b98829599a9276e2")
# Attempt using xpath
scc_webpage %>%
rvest::html_nodes(xpath = '//*[@id="pvExplorationHost"]/div/div/exploration/div/explore-canvas-modern/div/div[2]/div/div[2]/div[2]/visual-container-repeat/visual-container-group/transform/div/div[2]/visual-container-modern[1]/transform/div/div[3]/div/visual-modern/div/div/div[2]/div[1]/div[4]/div/div/div[1]/div[1]') %>%
rvest::html_text()
# Attempt using div.<class>
scc_webpage %>%
rvest::html_nodes("div.pivotTableCellWrap cell-interactive tablixAlignRight ") %>%
rvest::html_text()
# Attempt using xpathSapply
query = '//*[@id="pvExplorationHost"]/div/div/exploration/div/explore-canvas-modern/div/div[2]/div/div[2]/div[2]/visual-container-repeat/visual-container-group/transform/div/div[2]/visual-container-modern[1]/transform/div/div[3]/div/visual-modern/div/div/div[2]/div[1]/div[4]/div/div/div[1]/div[1]'
XML::xpathSApply(xml, query, xmlValue)
scc_webpage %>%
html_nodes("ui-view")
But I always either get an output saying character(0) when using xpath and getting the div class and id, or even {xml_nodeset (0)} when trying to go through html_nodes. The weird thing is that it wouldn't show the whole html of the tableau data when I do:
scc_webpage %>%
html_nodes("div")
And this would be the output, leaving the chunk that I needed blank:
{xml_nodeset (2)}
[1] <div id="pbi-loading"><svg version="1.1" class="pulsing-svg-item" xmlns="http://www.w3.org/2000/svg" xmlns:xlink ...
[2] <div id="pbiAppPlaceHolder">\r\n <ui-view></ui-view><root></root>\n</div>
I guess the issue may be because the numbers are within a series of nested div attributes??
The main data I am trying to get are the numbers from the table showing the Zip code, confirmed cases, % total cases, deaths, % total deaths.
If this is possible to do in R or possibly in Python using Selenium, any help with this would be greatly appreciated!!
回答1:
The problem is that the site you want to analyze relies on JavaScript to run and fetch the content for you. In such a case, httr::GET is of no help to you.
However, since manual work is also not an option, we have Selenium.
The following does what you're looking for:
library(dplyr)
library(purrr)
library(readr)
library(wdman)
library(RSelenium)
library(xml2)
library(selectr)
# using wdman to start a selenium server
selServ <- selenium(
port = 4444L,
version = 'latest',
chromever = '84.0.4147.30', # set this to a chrome version that's available on your machine
)
# using RSelenium to start a chrome on the selenium server
remDr <- remoteDriver(
remoteServerAddr = 'localhost',
port = 4444L,
browserName = 'chrome'
)
# open a new Tag on Chrome
remDr$open()
# navigate to the site you wish to analyze
report_url <- "https://app.powerbigov.us/view?r=eyJrIjoiZDFmN2ViMGEtNzQzMC00ZDU3LTkwZjUtOWU1N2RiZmJlOTYyIiwidCI6IjNiMTg1MTYzLTZjYTMtNDA2NS04NDAwLWNhNzJiM2Y3OWU2ZCJ9&pageName=ReportSectionb438b98829599a9276e2&pageName=ReportSectionb438b98829599a9276e2"
remDr$navigate(report_url)
# find and click the button leading to the Zip Code data
zipCodeBtn <- remDr$findElement('.//button[descendant::span[text()="Zip Code"]]', using="xpath")
zipCodeBtn$clickElement()
# fetch the site source in XML
zipcode_data_table <- read_html(remDr$getPageSource()[[1]]) %>%
querySelector("div.pivotTable")
Now we have the page source read into R, probably what you had in mind when you started your scraping task.
From here on it's smooth sailing and merely about converting that xml to a useable table:
col_headers <- zipcode_data_table %>%
querySelectorAll("div.columnHeaders div.pivotTableCellWrap") %>%
map_chr(xml_text)
rownames <- zipcode_data_table %>%
querySelectorAll("div.rowHeaders div.pivotTableCellWrap") %>%
map_chr(xml_text)
zipcode_data <- zipcode_data_table %>%
querySelectorAll("div.bodyCells div.pivotTableCellWrap") %>%
map(xml_parent) %>%
unique() %>%
map(~ .x %>% querySelectorAll("div.pivotTableCellWrap") %>% map_chr(xml_text)) %>%
setNames(col_headers) %>%
bind_cols()
# tadaa
df_final <- tibble(zipcode = rownames, zipcode_data) %>%
type_convert(trim_ws = T, na = c(""))
The resulting df looks like this:
> df_final
# A tibble: 15 x 5
zipcode `Confirmed Cases ` `% of Total Cases ` `Deaths ` `% of Total Deaths `
<chr> <dbl> <chr> <dbl> <chr>
1 63301 1549 17.53% 40 28.99%
2 63366 1364 15.44% 38 27.54%
3 63303 1160 13.13% 21 15.22%
4 63385 1091 12.35% 12 8.70%
5 63304 1046 11.84% 3 2.17%
6 63368 896 10.14% 12 8.70%
7 63367 882 9.98% 9 6.52%
8 534 6.04% 1 0.72%
9 63348 105 1.19% 0 0.00%
10 63341 84 0.95% 1 0.72%
11 63332 64 0.72% 0 0.00%
12 63373 25 0.28% 1 0.72%
13 63386 17 0.19% 0 0.00%
14 63357 13 0.15% 0 0.00%
15 63376 5 0.06% 0 0.00%
来源：https://stackoverflow.com/questions/64286279/scrape-websites-power-bi-dashboard-using-r