Context Deadline exceeded and WebSocket Url timeout issue
Ajay Sharma
I want to create pdf from a page and I am using chromedp to capture inner html from url, it takes 3-4 seconds to capture html from url
Now I used this functionality in cron for sending pdf to the customer
We have 25000 merchants and every merchant have many customers. Let suppose if 1 merchant has 100 customer and he wants to send email notification with attachment(pdf) and then we have total 2500000 customers.
example- In cron we process 1 merchant at a time and sent 100 emails with pdf to the customer. Now we capture inner html in loops and it takes 5-6 seconds to send email notification with pdf to the customer.
So there is any way we can reduce time for capturing inner html from url using chromedp
and sometimes it gives error of "context deadline exceeded" and "websocket url timeout reached"
I am thinking to use channels for email sending with the attachment but I am already using Worker pool with buffered channel for running my cron.
There is a sample of a code-
```
func CaptureHtml()(template.HTML, error){
ctx, cancel := chromedp.NewContext(context.Background())
defer cancel()
url := "url_from_where_you want to capture html"
var dataHTML string
err := chromedp.Run(ctx, chromedp.Navigate(url), RunWithTimeOut(&ctx, 30, chromedp.Tasks{
chromedp.WaitVisible("#root", chromedp.ByQuery)}))
if err != nil {
log.Fatal(err)
}
fmt.Println("Page loaded successfully")
// Sleep for a brief period to ensure the data rendering is complete (adjust timing as needed)
time.Sleep(2 * time.Second)
// Capture the HTML content of the element containing the rendered API data
if err := chromedp.Run(ctx,
chromedp.OuterHTML("#root", &dataHTML, chromedp.NodeVisible),
); err != nil {
log.Fatal(err)
}
CreatePdfInBytes(ctx, dataHTML)
return template.HTML(htmlContent), err
}
func CreatePdfInBytes(ctx context.Context, html string){
var wg sync.WaitGroup
var pdfBuf []byte
navigate := chromedp.Navigate("about:blank")
eventLoader := chromedp.ActionFunc(func(ctx context.Context) error {
loaderctx, cancel := context.WithCancel(ctx)
chromedp.ListenTarget(loaderctx, func(event interface{}) {
if _, ok := event.(*page.EventLoadEventFired); ok {
wg.Done()
cancel()
}
})
return nil
})
setDocContent := chromedp.ActionFunc(func(ctx context.Context) error {
frameTree, err := page.GetFrameTree().Do(ctx)
if err != nil {
return err
}
return page.SetDocumentContent(http://frameTree.Frame.ID, html).Do(ctx)
})
loaderWg := chromedp.ActionFunc(func(ctx context.Context) error {
wg.Wait()
return nil
})
genPdf := chromedp.ActionFunc(func(ctx context.Context) error {
buf, _, err := page.PrintToPDF().WithMarginTop(0.3).WithMarginBottom(0.3).WithPrintBackground(true).Do(ctx)
if err != nil {
return err
}
pdfBuf = buf
return nil
})
wg.Add(1)
err := chromedp.Run(ctx, navigate, eventLoader, setDocContent, loaderWg, genPdf)
if err != nil {
fmt.Println(err)
}
file, err := os.Create("abc.pdf")
if err != nil {
panic(err)
}
defer file.Close()
// Write the PDF data to the file
_, err = file.Write(pdfBuf)
if err != nil {
panic(err)
}
return
}
```