I would like to scrape the title and authors of journal articles from all staff-members' official web-pages. e.g.
https://eps.leeds.ac.uk/civil-engineering/staff/581/samuel-adu-amankwah
The specific part in question that I'm trying to access is this:
I'm following this guide: https://www.datacamp.com/community/tutorials/r-web-scraping-rvest but it refers to HTML tags which this site doesn't have. Can any point me in the right direction please?
CodePudding user response：
The page loads these citations dynamically using an XHR call that returns a json object. In this case, we can replicate the query and parse the json ourselves to get the publication list:
library(httr)
library(rvest)
library(jsonlite)
url <- paste0("https://eps.leeds.ac.uk/site/custom_scripts/symplectic_ajax.php?",
"uniqueid=00970757",
"&tries=0",
"&hash=f6a214dc99686895d6bf3de25507356f",
"&citationStyle=1")
GET(url) %>%
content("text") %>%
fromJSON() %>%
`[[`("publications") %>%
`[[`("journal_article") %>%
lapply(function(x) paste(x$authors, x$title, x$journal, sep = " ; ")) %>%
unlist() %>%
as.character()
#> [1] "Adu-Amankwah S, Zajac M, Skocek J, Nemecek J, Haha MB, Black L ; Combined influence of carbonation and leaching on freeze-thaw resistance of limestone ternary cement concrete ; Construction and Building Materials"
#> [2] "Wang H, Hou P, Li Q, Adu-Amankwah S, Chen H, Xie N, Zhao P, Huang Y, Wang S, Cheng X ; Synergistic effects of supplementary cementitious materials in limestone and calcined clay-replaced slag cement ; Construction and Building Materials"
#> [3] "Shamaki M, Adu-Amankwah S, Black L ; Reuse of UK alum water treatment sludge in cement-based materials ; Construction and Building Materials"
#> [4] "Adu-Amankwah S, Bernal Lopez S, Black L ; Influence of component fineness on hydration and strength development in ternary slag-limestone cements ; RILEM Technical Letters"
#> [5] "Adu-Amankwah S, Zajac M, Skocek J, Ben Haha M, Black L ; Relationship between cement composition and the freeze-thaw resistance of concretes ; Advances in Cement Research"
#> [6] "Zajac M, Skocek J, Adu-Amankwah S, Black L, Ben Haha M ; Impact of microstructure on the performance of composite cements: Why higher total porosity can result in higher strength ; Cement and Concrete Composites"
#> [7] "Adu-Amankwah S, Black L, Skocek J, Ben Haha M, Zajac M ; Effect of sulfate additions on hydration and performance of ternary slag-limestone composite cements ; Construction and Building Materials"
#> [8] "Adu-Amankwah S, Zajac M, Stabler C, Lothenbach B, Black L ; Influence of limestone on the hydration of ternary slag cement ; Cement and Concrete Research"
#> [9] "Adu-Amankwah S, Khatib JM, Searle DE, Black L ; Effect of synthesis parameters on the performance of alkali-activated non-conformant EN 450 pulverised fuel ash ; Construction and Building Materials"
Update
It is possible to get the json url from the html of the faculty member's homepage with a bit of text parsing:
get_json_url <- function(url)
{
carveout <- function(string, start, end)
{
string %>% strsplit(start) %>% `[[`(1) %>% `[`(2) %>%
strsplit(end) %>% `[[`(1) %>% `[`(1)
}
params <- GET(url) %>%
content("text") %>%
carveout("var dataGetQuery = ", ";")
id <- carveout(params, "uniqueid: '", "'")
tries <- carveout(params, "tries: ", ",")
hash <- carveout(params, "hash: '", "'")
citationStyle <- carveout(params, "citationStyle: ", "\n")
paste0("https://eps.leeds.ac.uk/site/custom_scripts/symplectic_ajax.php?",
"uniqueid=", id,
"&tries=", tries,
"&hash=", hash,
"&citationStyle=", citationStyle)
}
Which allows:
url <- "https://eps.leeds.ac.uk/civil-engineering/staff/581/samuel-adu-amankwah"
get_json_request(url)
#> [1] "https://eps.leeds.ac.uk/site/custom_scripts/symplectic_ajax.php?uniqueid=00970757&tries=0&hash=f7266eb42b24715cfdf2851f24b229c6&citationStyle=1"
And, if you want to be able to just lapply a vector of homepage urls to get the final publication list:
publications_from_homepage <- function(url)
{
get_json_request(url) %>%
GET() %>%
content("text") %>%
fromJSON() %>%
`[[`("publications") %>%
`[[`("journal_article") %>%
lapply(function(x) paste(x$authors, x$title, x$journal, sep = " ; ")) %>%
unlist() %>%
as.character()
}
So you have:
publications_from_homepage(url)
#> [1] "Adu-Amankwah S, Zajac M, Skocek J, Nemecek J, Haha MB, Black L ; Combined influence of carbonation and leaching on freeze-thaw resistance of limestone ternary cement concrete ; Construction and Building Materials"
#> [2] "Wang H, Hou P, Li Q, Adu-Amankwah S, Chen H, Xie N, Zhao P, Huang Y, Wang S, Cheng X ; Synergistic effects of supplementary cementitious materials in limestone and calcined clay-replaced slag cement ; Construction and Building Materials"
#> [3] "Shamaki M, Adu-Amankwah S, Black L ; Reuse of UK alum water treatment sludge in cement-based materials ; Construction and Building Materials"
#> [4] "Adu-Amankwah S, Bernal Lopez S, Black L ; Influence of component fineness on hydration and strength development in ternary slag-limestone cements ; RILEM Technical Letters"
#> [5] "Adu-Amankwah S, Zajac M, Skocek J, Ben Haha M, Black L ; Relationship between cement composition and the freeze-thaw resistance of concretes ; Advances in Cement Research"
#> [6] "Zajac M, Skocek J, Adu-Amankwah S, Black L, Ben Haha M ; Impact of microstructure on the performance of composite cements: Why higher total porosity can result in higher strength ; Cement and Concrete Composites"
#> [7] "Adu-Amankwah S, Black L, Skocek J, Ben Haha M, Zajac M ; Effect of sulfate additions on hydration and performance of ternary slag-limestone composite cements ; Construction and Building Materials"
#> [8] "Adu-Amankwah S, Zajac M, Stabler C, Lothenbach B, Black L ; Influence of limestone on the hydration of ternary slag cement ; Cement and Concrete Research"
#> [9] "Adu-Amankwah S, Khatib JM, Searle DE, Black L ; Effect of synthesis parameters on the performance of alkali-activated non-conformant EN 450 pulverised fuel ash ; Construction and Building Materials"
Created on 2021-11-04 by the 