Headless Chrme Automation with

class: center, middle, inverse, title-slide

# Headless Chr<svg style="height:20pt;fill:#83929b;" viewBox="0 0 496 512"><path d="M131.5 217.5L55.1 100.1c47.6-59.2 119-91.8 192-92.1 42.3-.3 85.5 10.5 124.8 33.2 43.4 25.2 76.4 61.4 97.4 103L264 133.4c-58.1-3.4-113.4 29.3-132.5 84.1zm32.9 38.5c0 46.2 37.4 83.6 83.6 83.6s83.6-37.4 83.6-83.6-37.4-83.6-83.6-83.6-83.6 37.3-83.6 83.6zm314.9-89.2L339.6 174c37.9 44.3 38.5 108.2 6.6 157.2L234.1 503.6c46.5 2.5 94.4-7.7 137.8-32.9 107.4-62 150.9-192 107.4-303.9zM133.7 303.6L40.4 120.1C14.9 159.1 0 205.9 0 256c0 124 90.8 226.7 209.5 244.9l63.7-124.8c-57.6 10.8-113.2-20.8-139.5-72.5z"/></svg>me<br>Automation with <svg style="height:32pt;fill:#83929b;" viewBox="0 0 581 512"><path d="M581 226.6C581 119.1 450.9 32 290.5 32S0 119.1 0 226.6C0 322.4 103.3 402 239.4 418.1V480h99.1v-61.5c24.3-2.7 47.6-7.4 69.4-13.9L448 480h112l-67.4-113.7c54.5-35.4 88.4-84.9 88.4-139.7zm-466.8 14.5c0-73.5 98.9-133 220.8-133s211.9 40.7 211.9 133c0 50.1-26.5 85-70.3 106.4-2.4-1.6-4.7-2.9-6.4-3.7-10.2-5.2-27.8-10.5-27.8-10.5s86.6-6.4 86.6-92.7-90.6-87.9-90.6-87.9h-199V361c-74.1-21.5-125.2-67.1-125.2-119.9zm225.1 38.3v-55.6c57.8 0 87.8-6.8 87.8 27.3 0 36.5-38.2 28.3-87.8 28.3zm-.9 72.5H365c10.8 0 18.9 11.7 24 19.2-16.1 1.9-33 2.8-50.6 2.9v-22.1z"/></svg>
## About the crrri package
### Romain Lesur & Christophe Dervieux
### useR! 2019 - 2019/07/12</br>Toulouse - France

---

.row[
.column[
.left[### A web browser is like a shadow puppet theater]
![:scale 100%](https://upload.wikimedia.org/wikipedia/commons/4/4d/Tholpava_koothu_shadow_puppet_Ramayana_show_%281%29.jpg)

]
.column[
### </br></br>
![:scale 100%](https://upload.wikimedia.org/wikipedia/commons/9/9b/Ratchaburi_Shadow_Puppet_Museum_%28Wat_Khanon%29_3.jpg)
.right[### With behind the scene the puppet master]
]
]

???

From : https://commons.wikimedia.org/wiki/File:Ratchaburi_Shadow_Puppet_Museum_(Wat_Khanon)_3.jpg
Mr.Niwat Tantayanusorn, Ph.D. [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

---

# Using a headless browser

.center[
.big[Be the stage director...]

.big[... and fully decide what should be done...]

.big[... *but in the dark !* 🙈]

.big[**No visual interface** to see the result of your actions]
]
.pull-left[
![:scale 90%](img/chromium.png)
]
.pull-right[
![:scale 90%](img/in-the-dark.png)
]
---

## Chrome Headless mode and the Devtools protocol

**Full control of Chrome** using Node.js modules like  
`puppeteer`, `chrome-remote-interface`

.center[.small[https://chromedevtools.github.io/devtools-protocol/]]

Interact with the protocol using json messages exchange through **websockets**.

.center[![:scale 65%](img/devtools-protocol.png)]

---

# You may already know other R related work

- [RSelenium](http://ropensci.github.io/RSelenium/) (@ropensci) client for Selenium WebDriver, requires a **`Selenium` server (Java)**.

- [webshot](http://wch.github.io/webshot/) (@wch), [webdriver](https://github.com/rstudio/webdriver) (@rstudio) relies on the abandoned **`PhantomJS`** library.

- [htmlunit](https://gitlab.com/hrbrmstr/htmlunit) (@hrbrmstr) uses the **`HtmlUnit` Java library**.

- [splashr](https://gitlab.com/hrbrmstr/splashr) (@hrbrmstr) works with the **`Splash` JavaScript Rendering Service**

- [decapitated](https://gitlab.com/hrbrmstr/decapitated) (@hrbrmstr) uses **headless Chrome command-line** instructions or the **Node.js gepetto module** (built-on top of the puppeteer Node.js module)

- [chradle](https://github.com/MilesMcBain/chradle) (@MilesMcBain), first tests for driving Chromium/Chrome from R using a websocket connection. An inspiration for `crrri`

---

# What is different with the crrri package ?

.big[<svg style="height:32pt;fill:#6c71c4;" viewBox="0 0 496 512"><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"/></svg>   https://github.com/RLesur/crrri/]

.big[Have the full control of <svg style="height:18pt;fill:#6c71c4;" viewBox="0 0 496 512"><path d="M131.5 217.5L55.1 100.1c47.6-59.2 119-91.8 192-92.1 42.3-.3 85.5 10.5 124.8 33.2 43.4 25.2 76.4 61.4 97.4 103L264 133.4c-58.1-3.4-113.4 29.3-132.5 84.1zm32.9 38.5c0 46.2 37.4 83.6 83.6 83.6s83.6-37.4 83.6-83.6-37.4-83.6-83.6-83.6-83.6 37.3-83.6 83.6zm314.9-89.2L339.6 174c37.9 44.3 38.5 108.2 6.6 157.2L234.1 503.6c46.5 2.5 94.4-7.7 137.8-32.9 107.4-62 150.9-192 107.4-303.9zM133.7 303.6L40.4 120.1C14.9 159.1 0 205.9 0 256c0 124 90.8 226.7 209.5 244.9l63.7-124.8c-57.6 10.8-113.2-20.8-139.5-72.5z"/></svg> from <svg style="height:20pt;fill:#6c71c4;" viewBox="0 0 581 512"><path d="M581 226.6C581 119.1 450.9 32 290.5 32S0 119.1 0 226.6C0 322.4 103.3 402 239.4 418.1V480h99.1v-61.5c24.3-2.7 47.6-7.4 69.4-13.9L448 480h112l-67.4-113.7c54.5-35.4 88.4-84.9 88.4-139.7zm-466.8 14.5c0-73.5 98.9-133 220.8-133s211.9 40.7 211.9 133c0 50.1-26.5 85-70.3 106.4-2.4-1.6-4.7-2.9-6.4-3.7-10.2-5.2-27.8-10.5-27.8-10.5s86.6-6.4 86.6-92.7-90.6-87.9-90.6-87.9h-199V361c-74.1-21.5-125.2-67.1-125.2-119.9zm225.1 38.3v-55.6c57.8 0 87.8-6.8 87.8 27.3 0 36.5-38.2 28.3-87.8 28.3zm-.9 72.5H365c10.8 0 18.9 11.7 24 19.2-16.1 1.9-33 2.8-50.6 2.9v-22.1z"/></svg> **without Java, NodeJS or any server**]

.big[Low-level API inspired by the [chrome-remote-interface](https://github.com/cyrus-and/chrome-remote-interface) JS module **gives access to 500+ functions to control Chrome**]

.big[Dedicated to advanced uses / R packages developers]

.big[Also compatible with Opera, EdgeHtml and Safari]

Only on github for now: `remotes::install_github("rlesur/crrri")`

---

# What is different with the crrri package ?

.big[Low-level API inspired by the [chrome-remote-interface](https://github.com/cyrus-and/chrome-remote-interface) JS module **gives access to 500+ functions to control Chrome**]

.big[Dedicated to advanced uses / R packages developers]

.big[Also compatible with Opera, EdgeHtml and Safari]

Only on github for now: `remotes::install_github("rlesur/crrri")`

---
# How to interact from R with Chrome ?

Headless Chrome can be controlled using the
**Chrome DevTools Protocol (CDP)**

1. Launch Chrome in headless mode

2. Connect R to Chrome through websockets

3. Build an **asynchronous** function that
    - sends CDP commands to Chrome
    - listens to CDP events from Chrome

4. Execute this async flow with R

</br>
.center[The goal of {crrri} is to **ease these steps**.]
.footnote[Requirement: You need to install chrome or [chromium](https://chromium.woolyss.com/#notes)]
---

# Play with it from RStudio IDE 1.2

```r
library(crrri)
# launch headless Chrome
chrome <- Chrome$new()
# Inspect Headless chrome inside Rstudio viewer
client <- chrome$connect(callback = ~.x$inspect())
```

.center[![:scale 83%](img/inspect.png)]

---

## First step : Go to a page

Use a domain and its commands or event listeners

```r
# extract a domain from the protocol to work with
Page <- client$Page
# Send the 'Page.navigate' command from the protocol
Page$navigate(url = "http://user2019.r-project.org/")
```

.center[![:scale 83%](img/goto-page.png)]

---
# One example: Web Scraping

.left-column[
#### Using `promises` package to build aynchronous function to perform with chrome

#### An API close to Javascript
]

.right-column[

```r
# Build an aynchronous flow - the puppet
library(crrri)
dump_DOM <- function(client) {
  Page <- client$Page
  Runtime <- client$Runtime
  Page$enable() %...>% {
    Page$navigate(
      url = 'http://user2019.r-project.org/talk_schedule/'
    )} %...>% {
      Page$loadEventFired()
    } %>% wait(3) %...>% {
*      Runtime$evaluate(
        expression = 'document.documentElement.outerHTML'
      )
    } %...>% {
      writeLines(.$result$value, "users2019-talks.html")
    }
}
# and execute it using chrome - be the puppet master
*perform_with_chrome(dump_DOM)
```
]
---
# One example: Web Scraping

.left-column[
#### Using `promises` package to build aynchronous function to perform with chrome

#### An API close to Javascript
]

.right-column[

# What is also possible ?

.pull-left[
### Print PDF

```r
print_pdf <- function(client) {
  Page <- client$Page
  Page$enable() %...>% {
    Page$navigate(
     url = "https://r-project.org/"
    )
    # await the load event
    Page$loadEventFired()
  } %...>% {
*    Page$printToPDF() 
  } %...>% # await PDF reception
    write_base64("r_project.pdf")
}
# To modify depending on the page 
# content (JS libraries…)
perform_with_chrome(print_pdf)
```
]

.pull-right[
### Screenshot and Device emulation
```r
Emulation$setDeviceMetricsOverride(
  width = 375, height = 667,
  mobile = TRUE, 
  deviceScaleFactor = 2
)
```
### Screencast

* `Page$screencastFrame`
* `Page$startScreencast`
* `Page$stopScreencast`

.center[[Exemple on YouTube](https://youtu.be/VFAhPAdzTFY)]
]
---
class: middle, center

# Questions ?

.center[
See also [uRos2019 talk by R.Lesur](https://speakerdeck.com/rlesur/headless-chrome-automation-with-r-the-crrri-package)

</br>
**We welcome feebacks, issues and ideas !**
</br>
Tell us how you would use `crrri`

]

.center[
https://rlesur.github.io/crrri/
</br>
]

.row[
.column[
.row[
.column[
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</br>@cderv
]
.column[
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</br>@chrisderv
]
]]
.column[
.row[
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</br>@RLesur
]
.column[
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</br>@RLesur
]
]
]
]

---
class: middle, center

# Questions ?

.center[
See also [uRos2019 talk by R.Lesur](https://speakerdeck.com/rlesur/headless-chrome-automation-with-r-the-crrri-package)

</br>
**We welcome feebacks, issues and ideas !**
</br>
Tell us how you would use `crrri`

]

.center[
https://rlesur.github.io/crrri/ 
</br>
]