Skip to content

ralgervstyphoeus

MIT 3 1 153
1.2 thousand (month) Dec 22 2019 2.2.4(3 years ago)
4,057 15 142 MIT
1.4.1(4 months ago) Oct 06 2009 946.7 thousand (month)

ralger is a small web scraping framework for R based on rvest and xml2.

It's goal to simplify basic web scraping and it provides a convenient and easy to use API.

It offers functions for retrieving pages, parsing HTML using CSS selectors, automatic table parsing and auto link, title, image and paragraph extraction.

Typhoeus is a Ruby library that allows you to make parallel HTTP requests, which can greatly speed up the process of making multiple requests to different servers. It is built on top of the C library libcurl, which is known for its high performance and reliability.

One of the main features of Typhoeus is its ability to make parallel requests. This means that it can send multiple requests at the same time, and wait for all of them to finish before returning the results. This can greatly reduce the time it takes to make multiple requests, as it eliminates the need to wait for each request to complete before sending the next one.

In addition to its parallelism feature, Typhoeus also provides a convenient and easy-to-use Ruby interface for making HTTP requests. It supports all of the common HTTP methods (GET, POST, PUT, DELETE, etc.) and allows you to set various request options, such as headers, timeouts, and authentication. It also supports streaming responses, which allows you to process large responses piece by piece, rather than loading the entire response into memory at once.

Typhoeus is also supports HTTP/2 protocol which provides faster load times and reduced network usage. It also supports streaming which is an essential feature for large data transfer.

Typhoeus is well-documented, actively maintained, and has a large and active community of users. It is widely used in the Ruby ecosystem and is a popular choice for building high-performance web scraping and data-gathering applications.

Note that Typhoeus can also be used as an adapter in popular alternative package Faraday.

Highlights


http2asyncuses-curl

Example Use


library("ralger")

url <- "http://www.shanghairanking.com/rankings/arwu/2021"

# retrieve HTML and select elements using CSS selectors:
best_uni <- scrap(link = url, node = "a span", clean = TRUE)
head(best_uni, 5)
#>  [1] "Harvard University"
#>  [2] "Stanford University"
#>  [3] "University of Cambridge"
#>  [4] "Massachusetts Institute of Technology (MIT)"
#>  [5] "University of California, Berkeley"

# ralger can also parse HTML attributes
attributes <- attribute_scrap(
  link = "https://ropensci.org/",
  node = "a", # the a tag
  attr = "class" # getting the class attribute
)

head(attributes, 10) # NA values are a tags without a class attribute
#>  [1] "navbar-brand logo" "nav-link"          NA
#>  [4] NA                  NA                  "nav-link"
#>  [7] NA                  "nav-link"          NA
#> [10] NA
#

# ralger can automatically scrape tables:
data <- table_scrap(link ="https://www.boxofficemojo.com/chart/top_lifetime_gross/?area=XWW")

head(data)
#> # A tibble: 6 × 4
#>    Rank Title                                      `Lifetime Gross`  Year
#>   <int> <chr>                                      <chr>            <int>
#> 1     1 Avatar                                     $2,847,397,339    2009
#> 2     2 Avengers: Endgame                          $2,797,501,328    2019
#> 3     3 Titanic                                    $2,201,647,264    1997
#> 4     4 Star Wars: Episode VII - The Force Awakens $2,069,521,700    2015
#> 5     5 Avengers: Infinity War                     $2,048,359,754    2018
#> 6     6 Spider-Man: No Way Home                    $1,901,216,740    2021
# GET request
Typhoeus.get("www.example.com")
# POST request
Typhoeus.post("www.example.com/posts", body: { title: "test post", content: "this is my test"})

# make parallel requests:
# hydra is a request queue manager
hydra = Typhoeus::Hydra.hydra
# create request object
first_request = Typhoeus::Request.new("http://example.com/posts/1")
# add complete callbacks
first_request.on_complete do |response|
  # callbacks can queue new requests
  third_url = response.body
  third_request = Typhoeus::Request.new(third_url)
  hydra.queue third_request
end
second_request = Typhoeus::Request.new("http://example.com/posts/2")
# queue requests:
hydra.queue first_request
hydra.queue second_request

hydra.run # this is a blocking call that returns once all requests are complete

Alternatives / Similar