在本教程中,我们将介绍如何实现 Web 呈现器的异步方法。您只需要将 HTML 内容发送到 SubmitPDFFromHTMLTask 或 SubmitImageFromHTMLTask API 方法即可接收任务标识符作为响应。还有SubmitPDFFromUrlTask和SubmitImageFromUrlTask方法,用于从公共Web Uri呈现PDF或图像。

收到任务标识符后,您需要通过调用 GetRenderingTaskStatus 方法来检查任务状态。只要任务状态等于“Waiting”,您需要在几秒钟延迟后调用相同的方法。一旦你从GetRenderingTaskStatus方法收到“Completed”,你可以调用DownloadResult方法来下载最终文件。您可以使用下面的 Go Lang 实现。

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package main

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"
	"time"
)

func createReqBody(htmlContent string, uri string, pageLabel string, useCompression string, messageLabel string, browserHeight string, browserWidth string) (string, io.Reader, error) {
	buf := new(bytes.Buffer)
	bw := multipart.NewWriter(buf)

	htmlContentField, _ := bw.CreateFormField("htmlContent")
	htmlContentField.Write([]byte(htmlContent))

	uriField, _ := bw.CreateFormField("uri")
	uriField.Write([]byte(uri))

	useCompressionField, _ := bw.CreateFormField("useCompression")
	useCompressionField.Write([]byte(useCompression))

	pageLabelField, _ := bw.CreateFormField("pageLabel")
	pageLabelField.Write([]byte(pageLabel))

	messageLabelField, _ := bw.CreateFormField("messageLabel")
	messageLabelField.Write([]byte(messageLabel))

	browserHeightField, _ := bw.CreateFormField("browserHeight")
	browserHeightField.Write([]byte(browserHeight))

	browserWidthField, _ := bw.CreateFormField("browserWidth")
	browserWidthField.Write([]byte(browserWidth))

	bw.Close()
	return bw.FormDataContentType(), buf, nil
}

func submitPdfRenderTask(htmlContent string, uri string, rapidApiKey string) (string, error) {
	contType, reader, err := createReqBody(htmlContent, uri, "Home Page", "false",
		"Initial Capture", "768", "1024")
	if err != nil {
		return "", err
	}

	req, err := http.NewRequest("POST", "https://web-renderer.p.rapidapi.com/SubmitPDFFromHTMLTask", reader)
	req.Header.Add("Content-Type", contType)
	req.Header.Add("X-RapidAPI-Key", rapidApiKey)

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil || resp.StatusCode != 200 {
		fmt.Println("Cannot upload request to render error:", err)
		return "", err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	return string(b), nil
}

func getRenderingTaskStatus(taskId string, rapidApiKey string) (string, error) {
	url := fmt.Sprintf("https://web-renderer.p.rapidapi.com/GetRenderingTaskStatus?taskId=%s", taskId)
	req, err := http.NewRequest("GET", url, nil)
	req.Header.Add("X-RapidAPI-Key", rapidApiKey)

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil || resp.StatusCode != 200 {
		fmt.Println("Cannot check rendering status of task with error:", err)
		return "", err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	return string(b), nil
}

func downloadResult(taskId string, rapidApiKey string) ([]byte, error) {
	url := fmt.Sprintf("https://web-renderer.p.rapidapi.com/DownloadResult?taskId=%s", taskId)
	req, err := http.NewRequest("GET", url, nil)
	req.Header.Add("X-RapidAPI-Key", rapidApiKey)

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil || resp.StatusCode != 200 {
		fmt.Println("Cannot download rendered file with error:", err)
		return nil, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	return b, nil
}

func main() {
	htmlContent := "<!DOCTYPE html><html lang=\"en\"><head><meta charset=\"UTF-8\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\"></head><body><h1>Hello World!</h1></body></html>"
	uriOfHtmlContent := "https://www.google.com?hl=en"
	rapidApiKey := "<YOUR RAPIDAPI KEY HERE>"
	taskId, err := submitPdfRenderTask(htmlContent, uriOfHtmlContent, rapidApiKey)
	if err != nil {
		panic(err)
	}
	retryCount := 0
	for retryCount < 100 {
		retryCount++
		time.Sleep(5 * time.Second)
		status, err := getRenderingTaskStatus(taskId, rapidApiKey)
		if err != nil {
			panic(err)
		}
		if status == "Completed" {
			fileBytes, err := downloadResult(taskId, rapidApiKey)
			if err != nil {
				panic(err)
			}
			err = os.WriteFile("html_from_html.pdf", fileBytes, 0644)
			if err != nil {
				panic(err)
			}
			break
		} else if status == "Waiting" {
			continue
		} else if status == "Failed" {
			panic(errors.New("Cannot render html"))
		} else {
			panic(errors.New("Cannot render html"))
		}
	}
}