pressly / screenshot-nodejs Goto Github PK

	resp, body, err := c.Do(req)

	if err != nil {
		return nil, err
	}

	if resp.StatusCode != 200 {
		return nil, errors.New("Couldn't take png screenshot")
	}
	reader := bytes.NewReader(body)

You can pass resp.Body (which is io.Reader itself) down to the callers right away.

resp, err := c.Do(req)

// return nil, error

// return resp.Body, nil

I noticed we're using node:8-slim as a base image. That's fine, and will work great.

But I wonder, if we could potentially switch to

• Alpine-based image (ie. 9.2-alpine)
• Node 9.2 (or do we have to stick with Node 8 because of Puppeteer?)

In golang, we usually put the client pkg into the top-level directory (unless the project is too big and has multiple clients, of course). Imho you can get rid of the lib/ subdirectory :)

If you wanted to implement CLI (a terminal program that downloads screenshots from a remote server), it'd live in /cmd/screenshot/main.go.

When the client pkg is in the top-level directory, the imports are as easy as

import (
     "github.com/pressly/screenshot"
)

func main() {
   screenshot, _ := screenshot.New(...)

   // ... 
}

Uuups
https://github.com/pressly/screenshot/blob/master/screenshot

Can we remove the file from the history and force-push the master branch?

Error -
(node:1) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Failed to launch chrome!
/app/node_modules/puppeteer/.local-chromium/linux-515411/chrome-linux/chrome: error while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory

Things are still working outside of docker.

Even the example puppeteer code on puppeteer's github doesn't seem to work, so it seems like a puppeteer / chromium issue. Can't figure out if it's just on my computer or if it's legit right now.

GET localhost:{port}/png?url=https://www.google.com&window=500x500&crop=75x80&x=350&y=190

1. Do we assume that the URL is url_encoded?
2. Or is localhost:{port}/png?window=500x500&crop=75x80&x=350&y=190&url=https://www.google.com?some=third&party=arguments gonna work?
3. Can we document this in the README and let the url argument to be the last one in all the examples?

https://github.com/pressly/screenshot/blob/master/cmd/screenshot/main.go#L15-L39

• Always check the error, never ignore it (Golang is very explicit about errors)
• Replace var window [2]int https://github.com/pressly/screenshot/blob/master/cmd/screenshot/main.go#L16-L18 with WindowWidth int and WindowHeight int on the ScreenshotOptions{} struct
• Can we rename ScreenshotOptions to Page or Options?
• PdfOptions - I'm fine with a single argument to PDF() as long as the PdfOptions embed the above ScreenshotOptions{}
• well need to use io.ReadCloser, so the consumer can close the Body

This would allow us to get rid of the Node.js server wrapper. And we could write the whole service in Go only, effectively reimplement the Puppetteer.

Pros:

• HTTP throttling would be super easy
• Managing Headless processes would be much easier too, ie we could spin up a pool of Headless "workers" in the server, and throttle incoming requests to each available worker.
• Zero overhead
• HTTP/2 for free, potentially generate a GRPC client for many languages

Chrome DevTools Protocol

• https://github.com/raff/godet
• https://github.com/knq/chromedp

I'll look into feasibility of this option.

example github, amazon, many more

somehow setting headers on puppeteer breaks things - https://github.com/pressly/screenshot/blob/master/server/src/browser.ts#L37

will need to find a better way to forward headers

Create a Golang HTTP client for accessing the screenshot endpoints.

screenshot, err := screenshot.New("https://screenshot-api.example.com:8787")

/*io.Reader, error*/
pngBytesReader, err := screenshot.PNG(ctx, websiteUrl, screenshot.Page{/*Headers, Window, Crop, X, Y, WaitUntil */})

jpegBytesReader, err := screenshot.JPEG(ctx, websiteUrl, screenshot.Page{/*Headers, Window, Crop, X, Y, WaitUntil */}, 80 /*JPEG quality .. 0-100*/)

pdfBytesReader, err := screenshot.PDF(ctx, websiteUrl, screenshot.Page{/*Headers, Window, Crop, X, Y*/}, screenshot.PDFOptions{/*Format etc. */}) // see https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#pagepdfoptions

@MarcelRusu do you prefer a separate repository for client(s) and server?