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。一旦您从GetRenderingTaskStatus方法收到“Completed”,您就可以调用DownloadResult方法来下载最终文件。在本教程中,我们使用了 Apache HTTP 客户端库。您可以在 pom.xml 文件中添加下面的依赖项。

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<dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpclient</artifactId>
     <version>4.5.13</version>
</dependency>

<dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpmime</artifactId>
     <version>4.5.13</version>
</dependency>

<dependency>
     <groupId>commons-io</groupId>
     <artifactId>commons-io</artifactId>
     <version>2.11.0</version>
</dependency>

您可以使用下面的 Java 实现。

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import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;

public class WebRenderer {
    private static String submitPDFFromHTMLTask(CloseableHttpClient httpClient, String htmlContent, String uri, String rapidApiKey) throws IOException {
        HttpPost submitPDFFromHTMLTaskPost = new HttpPost("https://web-renderer.p.rapidapi.com/SubmitPDFFromHTMLTask");
        submitPDFFromHTMLTaskPost.addHeader("X-RapidAPI-Key", rapidApiKey);

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        builder.addTextBody("uri", uri, ContentType.TEXT_PLAIN);
        builder.addTextBody("useCompression", "false", ContentType.TEXT_PLAIN);
        builder.addTextBody("pageLabel", "Home Page", ContentType.TEXT_PLAIN);
        builder.addTextBody("messageLabel", "Initial Capture", ContentType.TEXT_PLAIN);
        builder.addTextBody("browserHeight", "768", ContentType.TEXT_PLAIN);
        builder.addTextBody("browserWidth", "1024", ContentType.TEXT_PLAIN);
        builder.addTextBody("htmlContent", htmlContent, ContentType.TEXT_PLAIN);

        HttpEntity requestEntity = builder.build();
        submitPDFFromHTMLTaskPost.setEntity(requestEntity);
        HttpResponse response = httpClient.execute(submitPDFFromHTMLTaskPost);
        if (response.getStatusLine().getStatusCode() != 200) {
            throw  new IOException("Cannot post rendering task");
        }

        HttpEntity responseEntity = response.getEntity();
        return EntityUtils.toString(responseEntity, "UTF-8");
    }

    private static String getRenderingTaskStatus(CloseableHttpClient httpClient, String taskId, String rapidApiKey) throws IOException {
        HttpGet getConversionTaskStatus = new HttpGet("https://web-renderer.p.rapidapi.com/GetRenderingTaskStatus?taskId=" + taskId);
        getConversionTaskStatus.addHeader("X-RapidAPI-Key", rapidApiKey);

        HttpResponse response = httpClient.execute(getConversionTaskStatus);
        if (response.getStatusLine().getStatusCode() != 200) {
            throw  new IOException("Cannot get rendering task status");
        }

        HttpEntity responseEntity = response.getEntity();
        return EntityUtils.toString(responseEntity, "UTF-8");
    }

    private static byte[] downloadResult(CloseableHttpClient httpClient, String taskId, String rapidApiKey) throws IOException {
        HttpGet downloadResult = new HttpGet("https://web-renderer.p.rapidapi.com/DownloadResult?taskId=" + taskId);
        downloadResult.addHeader("X-RapidAPI-Key", rapidApiKey);

        HttpResponse response = httpClient.execute(downloadResult);
        if (response.getStatusLine().getStatusCode() != 200) {
            throw  new IOException("Cannot get rendered file");
        }

        HttpEntity responseEntity = response.getEntity();
        return EntityUtils.toByteArray(responseEntity);
    }

    public static void main(String[] args) throws Exception {
        String rapidApiKey = "<YOUR RAPID API KEY HERE>";
        String 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>";
        String uriOfHtmlContent = "https://www.google.com?hl=en";

        CloseableHttpClient httpClient = HttpClients.createDefault();
        String taskId = submitPDFFromHTMLTask(httpClient, htmlContent, uriOfHtmlContent, rapidApiKey);
        int retryCount = 0;
        while (retryCount < 100)
        {
            retryCount++;
            Thread.sleep(5000);
            String status = getRenderingTaskStatus(httpClient, taskId, rapidApiKey);
            if (status.equals("Completed"))
            {
                byte[] fileBytes = downloadResult(httpClient, taskId, rapidApiKey);
                File outputFile =new File("html_from_html.pdf");
                Files.write(outputFile.toPath(), fileBytes);
                break;
            }
            else if (status.equals("Waiting"))
            {
                continue;
            }
            else if (status.equals("Failed"))
            {
                throw new Exception("Cannot rendered file");
            }
            else
            {
                throw new Exception("Invalid status");
            }
        }
    }
}