I am trying to scrape the following page with R:
http://monitoramento.sema.mt.gov.br/simlam/ListarTituloImovelRural.aspx?modeloTitulo=117
using the code "17942" as the trial input in "Número do CAR" as I know that works (see pic below).
As far as I can tell aspx are webforms using ajax requests to return data using a mix of javascript and html (apologies if I have this wrong).
From other stack overflows I have seen that others have used Selenium (e.g. Scrape "aspx" page with R), however from inspecting the page it seems to be obtaining data through a POST request.
I have tried getting the data using:
search1 <- "http://monitoramento.sema.mt.gov.br/simlam/ListarTituloImovelRural.aspx?modeloTitulo=117"
rawdata <- POST(search1,encode="form",add_headers(`txtNumeroTitulo` = 17821
,`hdnCodigoPagina` = "869E318BBE656CB74E76744CD3026"
), progress())
d_content <- content(rawdata,"text") %>%
read_html() %>%
html_text()
Just as a really basic attempt to get something out I could look through, but the data I am hoping to get (see picture) is not there. I wonder if the issue is that the POST request on the site has request headers as well as headers within the form data, which my request is not getting right.
Any help greatly appreciated!
Related
I'm trying to webscrape in R from webpages such as these. But the html is only 50 lines so I'm assuming the numbers are hidden in a javascript file or on their server. I'm not sure how to find the numbers I want (e.g., the enrollment number under student population).
When I try to use rvest, as in
num <- school_webpage %>%
html_elements(".number no-mrg-btm") %>%
html_text()
I get an error that says "could not find function "html_elements"" even though I've installed and loaded rvest.
What's my best strategy for getting those various numbers and why am I getting that error message? Thnx.
That data is coming from an API request you can find in the browser network tab. It returns json. Make a request direct to that page (as you don't have a browser to do this based off landing page):
library(jsonlite)
data <- jsonlite::read_json('https://api.caschooldashboard.org/LEAs/01611766000590/6/true')
print(data$enrollment)
There are 2 parts of my questions as I explored 2 methods in this exercise, however I succeed in none. Greatly appreciated if someone can help me out.
[PART 1:]
I am attempting to scrape data from a webpage on Singapore Stock Exchange https://www2.sgx.com/derivatives/negotiated-large-trade containing data stored in a table. I have some basic knowledge of scraping data using (rvest). However, using Inspector on chrome, the html hierarchy is much complex then I expected. I'm able to see that the data I want is hidden under < div class= "table-container" >,and here's what I've tied:
library(rvest)
library(httr)
library(XML)
SGXurl <- "https://www2.sgx.com/derivatives/negotiated-large-trade"
SGXdata <- read_html(SGXurl, stringsASfactors = FALSE)
html_nodes(SGXdata,".table-container")
However, nothing has been picked up by the code and I'm doubt if I'm using these code correctly.
[PART 2:]
As I realize that there's a small "download" button on the page which can download exactly the data file i want in .csv format. So i was thinking to write some code to mimic the download button and I found this question Using R to "click" a download file button on a webpage, but i'm unable to get it to work with some modifications to that code.
There's a few filtera on the webpage, mostly I will be interested downloading data for a particular business day while leave other filters blank, so i've try writing the following function:
library(httr)
library(rvest)
library(purrr)
library(dplyr)
crawlSGXdata = function(date){
POST("https://www2.sgx.com/derivatives/negotiated-large-trade",
body = NULL
encode = "form",
write_disk("SGXdata.csv")) -> resfile
res = read.csv(resfile)
return(res)
}
I was intended to put the function input "date" into the “body” argument, however i was unable to figure out how to do that, so I started off with "body = NULL" by assuming it doesn't do any filtering. However, the result is still unsatisfactory. The file download is basically empty with the following error:
Request Rejected
The requested URL was rejected. Please consult with your administrator.
Your support ID is: 16783946804070790400
The content is loaded dynamically from an API call returning json. You can find this in the network tab via dev tools.
The following returns that content. I find the total number of pages of results and loop combining the dataframe returned from each call into one final dataframe containing all results.
library(jsonlite)
url <- 'https://api.sgx.com/negotiatedlargetrades/v1.0?order=asc&orderby=contractcode&category=futures&businessdatestart=20190708&businessdateend=20190708&pagestart=0&pageSize=250'
r <- jsonlite::fromJSON(url)
num_pages <- r$meta$totalPages
df <- r$data
url2 <- 'https://api.sgx.com/negotiatedlargetrades/v1.0?order=asc&orderby=contractcode&category=futures&businessdatestart=20190708&businessdateend=20190708&pagestart=placeholder&pageSize=250'
if(num_pages > 1){
for(i in seq(1, num_pages)){
newUrl <- gsub("placeholder", i , url2)
newdf <- jsonlite::fromJSON(newUrl)$data
df <- rbind(df, newdf)
}
}
I am looking to scrape the main table from this website. I have managed to get the table into R and working, but the one problem is the website defaults to PS4, while I wanted the data for Xbox (this is changed in the top-right dropdown menu).
Ideally there would be a way to pass a parameter in the URL that will define the platform in this way, but I haven't been able to find anything about that.
Looking around it seems that PhantomJS would be the best way to go but I have no experience using Javascript and I'm not sure how you would implement performing an action on the page, then scraping the resulting table.
This is currently all I have in terms of my main code scraping the data:
library(rvest)
url1 <- "https://www.futbin.com/19/players?page="
pge <- 1
tbl <- paste0(url1, pge) %>%
read_html() %>%
html_nodes(xpath='//*[#id="repTb"]') %>%
html_table()
Thanks in advance for any help.
I'm trying to harvest data using rvest (also tried using XML and selectr) but I am having difficulties with the following problem:
In my browser's web inspector the html looks like
<span data-widget="turboBinary_tradologic1_rate" class="widgetPlaceholder widgetRate rate-down">1226.45</span>
(Note: rate-downand 1226.45 are updated periodically.) I want to harvest the 1226.45 but when I run my code (below) it says there is no information stored there. Does this have something to do with
the fact that its a widget? Any suggestions on how to proceed would be appreciated.
library(rvest);library(selectr);library(XML)
zoom.turbo.url <- "https://www.zoomtrader.com/trade-now?game=turbo"
zoom.turbo <- read_html(zoom.turbo.url)
# Navigate to node
zoom.turbo <- zoom.turbo %>% html_nodes("span") %>% `[[`(90)
# No value
as.character(zoom.turbo)
html_text(zoom.turbo)
# Using XML and Selectr
doc <- htmlParse(zoom.turbo, asText = TRUE)
xmlValue(querySelector(doc, 'span'))
For websites that are difficult to scrape, for example where the content is dynamic, you can use RSelenium. With this package and a browser docker, you are able to navigate websites with R commands.
I have used this method to scrape a website that had a dynamic login script, that I could not get to work with other methods.
I'm stuck on this one after much searching....
I started with scraping the contents of a table from:
http://www.skatepress.com/skates-top-10000/artworks/
Which is easy:
data <- data.frame()
for (i in 1:100){
print(paste("page", i, "of 100"))
url <- paste("http://www.skatepress.com/skates-top-10000/artworks/", i, "/", sep = "")
temp <- readHTMLTable(stringsAsFactors = FALSE, url, which = 1, encoding = "UTF-8")
data <- rbind(data, temp)
} # end of scraping loop
However, I need to additionally scrape the detail that is contained in a pop-up box when you click on each name (and on the artwork title) in the list on the site.
I can't for the life of me figure out how to pass the breadcrumb (or artist-id or painting-id) through in order to make this happen. Since straight up using rvest to access the contents of the nodes doesn't work, I've tried the following:
I tried passing the painting id through in the url like this:
url <- ("http://www.skatepress.com/skates-top-10000/artworks/?painting_id=576")
site <- html(url)
But it still gives an empty result when scraping:
node1 <- "bread-crumb > ul > li.activebc"
site %>% html_nodes(node1) %>% html_text(trim = TRUE)
character(0)
I'm (clearly) not a scraping expert so any and all assistance would be greatly appreciated! I need a way to capture this additional information for each of the 10,000 items on the list...hence why I'm not interested in doing this manually!
Hoping this is an easy one and I'm just overlooking something simple.
This will be a more efficient base scraper and you can get progress bars for free with the pbapply package:
library(xml2)
library(httr)
library(rvest)
library(dplyr)
library(pbapply)
library(jsonlite)
base_url <- "http://www.skatepress.com/skates-top-10000/artworks/%d/"
n <- 100
bind_rows(pblapply(1:n, function(i) {
mutate(html_table(html_nodes(read_html(sprintf(base_url, i)), "table"))[[1]],
`Sale Date`=as.Date(`Sale Date`, format="%m.%d.%Y"),
`Premium Price USD`=as.numeric(gsub(",", "", `Premium Price USD`)))
})) -> skatepress
I added trivial date & numeric conversions.
I belive your main issue is that the site requires a login to get the additional data. You should give that (i.e. logging in) a shot using httr and grab the wordpress_logged_inXXXXXXX… cookie from that endeavour. I just grabbed it from inspecting the session with Developer Tools in Chrome and that will also work for you (but it's worth the time to learn how to do it via httr).
You'll need to scrape two additional <a … tags from each table row. The one for "artist" looks like:
Pablo Picasso
You can scrape the contents with:
POST("http://www.skatepress.com/wp-content/themes/skatepress/scripts/query_artist.php",
set_cookies(wordpress_logged_in_XXX="userid%XXXXXreallylongvalueXXXXX…"),
encode="form",
body=list(id="pab_pica_1881"),
verbose()) -> artist_response
fromJSON(content(artist_response, as="text"))
(The return value is too large to post here)
The one for "artwork" looks like:
Les femmes d′Alger (Version ′O′)
and you can get that in similar fashion:
POST("http://www.skatepress.com/wp-content/themes/skatepress/scripts/query_artwork.php",
set_cookies(wordpress_logged_in_XXX="userid%XXXXXreallylongvalueXXXXX…"),
encode="form",
body=list(id=576),
verbose()) -> artwork_response
fromJSON(content(artwork_response, as="text"))
That's not huge but I won't clutter the response with it.
NOTE that you can also use rvest's html_session to do the login (which will get you cookies for free) and then continue to use that session in the scraping (vs read_html) which will mean you don't have to do the httr GET/PUT.
You'll have to figure out how you want to incorporate that data into the data frame or associate it with it via various id's in the data frame (or some other strategy).
You can see it call those two php scripts via Developer Tools and it also shows the data it passes in. I'm also really shocked that site doesn't have any anti-scraping clauses in their ToS but they don't.