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decapitated

Headless 'Chrome' Orchestration

Description

The 'Chrome' browser https://www.google.com/chrome/ has a headless mode which can be instrumented programmatically. Tools are provided to perform headless 'Chrome' instrumentation on the command-line and will eventually provide support for the 'DevTools' instrumentation 'API' or the forthcoming 'phantomjs'-like higher-level 'API' being promised by the development team.

IMPORTANT

macOS High Sierra and Headless Chrome dinna work so good together.

This pkg will eventually do much under the covers to find the location of the Chrome binary on all operating systems. For now, you'll need to set an envrionment variable HEADLESS_CHROME to one of these two values:

Windows(32bit): C:/Program Files/Google/Chrome/Application/chrome.exe
Windows(64bit): C:/Program Files (x86)/Google/Chrome/Application/chrome.exe
macOS: /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome
Linux: /usr/bin/google-chrome

A guess is made (but not verified yet) if HEADLESS_CHROME is non-existent.

Use ~/.Renviron to store this value for the time being.

The following functions are implemented:

chrome_dump_pdf: "Print" to PDF
chrome_read_html: Read a URL via headless Chrome and return the renderd ' ' 'innerHTML' DOM elements
chrome_shot: Capture a screenshot
chrome_version: Get Chrome version
get_chrome_env: get an envrionment variable 'HEADLESS_CHROME'
set_chrome_env: set an envrionment variable 'HEADLESS_CHROME'

Installation

devtools::install_github("hrbrmstr/decapitated")

Usage

library(decapitated)

# current verison
packageVersion("decapitated")

## [1] '0.2.0'

chrome_version()

chrome_read_html("http://httpbin.org/")

## {xml_document}
## <html>
## [1] <body id="manpage"></body>

chrome_dump_pdf("http://httpbin.org/")
## [0502/094321.911089:INFO:headless_shell.cc(436)] Written to file output.pdf.

chrome_shot("http://httpbin.org/")

## [0502/094257.370837:INFO:headless_shell.cc(436)] Written to file screenshot.png.
##   format width height colorspace filesize
## 1    PNG  1600   1200       sRGB   238967