自动摘要
正在生成中……
In this post we will look at leveraging Chrome’s debug protocol to load up a webpage and take a screenshot. This is all made possible from a package called chromedp which allows us to control a Chrome instance through our Go code. You will also need Chrome installed or to be using something akin to the chrome/headless-shell docker image.
We’ve split the process in code up into:
- Start Chrome
- Run tasks: like loading the webpage and taking a screenshot
- Saving the screenshot to file
package main
import (
"context"
"io/ioutil"
"log"
"github.com/chromedp/cdproto/page"
"github.com/chromedp/chromedp"
)
func main() {
// Start Chrome
// Remove the 2nd param if you don't need debug information logged
ctx, cancel := chromedp.NewContext(context.Background(), chromedp.WithDebugf(log.Printf))
defer cancel()
url := "https://golangcode.com/"
filename := "golangcode.png"
// Run Tasks
// List of actions to run in sequence (which also fills our image buffer)
var imageBuf []byte
if err := chromedp.Run(ctx, ScreenshotTasks(url, &imageBuf)); err != nil {
log.Fatal(err)
}
// Write our image to file
if err := ioutil.WriteFile(filename, imageBuf, 0644); err != nil {
log.Fatal(err)
}
}
func ScreenshotTasks(url string, imageBuf *[]byte) chromedp.Tasks {
return chromedp.Tasks{
chromedp.Navigate(url),
chromedp.ActionFunc(func(ctx context.Context) (err error) {
*imageBuf, err = page.CaptureScreenshot().WithQuality(90).Do(ctx)
return err
}),
}
}
As an added bonus, if you wanted to save the page as a pdf instead of an image, you can replace the CaptureScreenshot line with following:
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*imageBuf, _, err = page.PrintToPDF().WithPrintBackground(false).Do(ctx)
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