调用示例 - 视频点播

调用视频点播服务接口，是向视频点播服务端发送HTTP请求（可通过HTTP或HTTPS通道发送），并获取响应结果的过程。视频点播服务端接收到用户请求后，对请求进行身份验证和参数验证，验证成功后，根据请求的指定参数提交或完成相应操作，并把处理结果以HTTP响应的形式返回给调用者。

以下Java示例代码演示了如何添加公共参数和私有参数、如何用请求参数构造规范化请求字符串、如何构造StringToSign字符串，以及如何获得OpenAPI地址，最终以Get方式发送Http请求，获取相应的响应结果。如果您需要使用以下示例，请替换示例中的必选参数及私有参数。

添加jar包依赖

注意使用httpclient get请求。

  <dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.1</version>
  </dependency>

JAVA代码

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import sun.misc.BASE64Encoder;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.security.SignatureException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.logging.Logger;

/**
 * 视频点播OpenAPI调用示例
 * 以GetVideoPlayAuth接口为例，其他接口请替换相应接口名称及私有参数
 */
public class Main {
	//账号AccessKey信息请填写(必选)
	private static String access_key_id = "";
	//账号AccessKey信息请填写(必选)
	private static String access_key_secret = "";
	//STS临时授权方式访问时该参数为必选，使用主账号AccessKey和RAM子账号AccessKey不需要填写
	private static String security_token = "";
	//VOD API 的服务接入地址为：vod.{ApiRegion}.aliyuncs.com，{ApiRegion}请替换成对应API接入区域的标识
	private final static String VOD_DOMAIN = "http://vod.cn-shanghai.aliyuncs.com";
						
	//以下参数不需要修改
	private final static String ISO8601_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ss'Z'";
	private final static String HTTP_METHOD = "GET";
	private final static String HMAC_SHA1_ALGORITHM = "HmacSHA1";
	private final static String UTF_8 = "utf-8";
	private final static Logger LOG = Logger.getLogger(Main.class.getName());

public static void main(String[] args) throws Exception {
    //生成私有参数，不同API需要修改
    Map<String, String> privateParams = generatePrivateParamters();
    //生成公共参数，不需要修改
    Map<String, String> publicParams = generatePublicParamters();
    //生成OpenAPI地址，不需要修改
    String URL = generateOpenAPIURL(publicParams, privateParams);
    //发送HTTP GET 请求
    httpGet(URL);
}
  /**
    * 生成视频点播OpenAPI私有参数
    * 不同API需要修改此方法中的参数
    * @return
   */
private static Map<String, String> generatePrivateParamters() {
    // 接口私有参数列表, 不同API请替换相应参数
    Map<String, String> privateParams = new HashMap<>();
    // 视频ID
    privateParams.put("VideoId","5aed81b74ba84920be578cdfe004af4b");
    // API名称
    privateParams.put("Action", "GetVideoPlayAuth");
    return privateParams;
}
  /**
   * 生成视频点播OpenAPI公共参数
   * 不需要修改
   * @return
   */
private static Map<String, String> generatePublicParamters() {
    Map<String, String> publicParams = new HashMap<>();
    publicParams.put("Format", "JSON");
    publicParams.put("Version", "2017-03-21");
    publicParams.put("AccessKeyId", access_key_id);
    publicParams.put("SignatureMethod", "HMAC-SHA1");
    publicParams.put("Timestamp", generateTimestamp());
    publicParams.put("SignatureVersion", "1.0");
    publicParams.put("SignatureNonce", generateRandom());
    if (security_token != null && security_token.length() > 0) {
    	publicParams.put("SecurityToken", security_token);
    }
	return publicParams;
}

 /**
   * 生成OpenAPI地址
   * @param privateParams
   * @return
   * @throws Exception
   */
private static String generateOpenAPIURL(Map<String, String> publicParams, Map<String, String> privateParams) {
	return generateURL(VOD_DOMAIN, HTTP_METHOD, publicParams, privateParams);
}
/**
  * @param domain        请求地址
  * @param httpMethod    HTTP请求方式GET，POST等
  * @param publicParams  公共参数
  * @param privateParams 接口的私有参数
  * @return 最后的url
 */
private static String generateURL(String domain, String httpMethod, Map<String, String> publicParams, Map<String, String> privateParams) {
	List<String> allEncodeParams = getAllParams(publicParams, privateParams);
	String cqsString = getCQS(allEncodeParams);
	out("CanonicalizedQueryString = " + cqsString);
	String stringToSign = httpMethod + "&" + percentEncode("/") + "&" + percentEncode(cqsString);
	out("StringtoSign = " + stringToSign);
	String signature = hmacSHA1Signature(access_key_secret, stringToSign);
	out("Signature = " + signature);
	return domain + "?" + cqsString + "&" + percentEncode("Signature") + "=" + percentEncode(signature);
}

private static List<String> getAllParams(Map<String, String> publicParams, Map<String, String> privateParams) {
  List<String> encodeParams = new ArrayList<String>();
	if (publicParams != null) {
    	for (String key : publicParams.keySet()) {
      		String value = publicParams.get(key);
            //将参数和值都urlEncode一下。
            String encodeKey = percentEncode(key);
            String encodeVal = percentEncode(value);
            encodeParams.add(encodeKey + "=" + encodeVal);
        }
    }
    if (privateParams != null) {
        for (String key : privateParams.keySet()) {
            String value = privateParams.get(key);
            //将参数和值都urlEncode一下。
            String encodeKey = percentEncode(key);
            String encodeVal = percentEncode(value);
            encodeParams.add(encodeKey + "=" + encodeVal);
        }
    }
    return encodeParams;
}
/**
* 参数urlEncode
*
* @param value
* @return
*/
private static String percentEncode(String value) {
	try {
		String urlEncodeOrignStr = URLEncoder.encode(value, "UTF-8");
		String plusReplaced = urlEncodeOrignStr.replace("+", "%20");
		String starReplaced = plusReplaced.replace("*", "%2A");
		String waveReplaced = starReplaced.replace("%7E", "~");
		return waveReplaced;
	} catch (UnsupportedEncodingException e) {
		e.printStackTrace();
	}
	return value;
}

/**
* 获取CQS 的字符串
*
* @param allParams
* @return
*/
private static String getCQS(List<String> allParams) {
	ParamsComparator paramsComparator = new ParamsComparator();
	Collections.sort(allParams, paramsComparator);
	String cqString = "";
	for (int i = 0; i < allParams.size(); i++) {
		cqString += allParams.get(i);
		if (i != allParams.size() - 1) {
			cqString += "&";
        }
	}
	return cqString;
}

private static class ParamsComparator implements Comparator<String> {
	@Override
	public int compare(String lhs, String rhs) {
		return lhs.compareTo(rhs);
	}
}

private static String hmacSHA1Signature(String accessKeySecret, String stringtoSign) {
	try {
		String key = accessKeySecret + "&";
		try {
			SecretKeySpec signKey = new SecretKeySpec(key.getBytes(), HMAC_SHA1_ALGORITHM);
			Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
			mac.init(signKey);
			byte[] rawHmac = mac.doFinal(stringtoSign.getBytes());
			//按照Base64 编码规则把上面的 HMAC 值编码成字符串，即得到签名值（Signature）
			return new String(new BASE64Encoder().encode(rawHmac));
            } catch (Exception e) {
			throw new SignatureException("Failed to generate HMAC : " + e.getMessage());
        }
    } catch (SignatureException e) {
		e.printStackTrace();
    }
	return "";
}

/**
* 生成随机数
*
* @return
*/
private static String generateRandom() {
	String signatureNonce = UUID.randomUUID().toString();
	return signatureNonce;
}

/**
* 生成当前UTC时间戳
*
* @return
*/
public static String generateTimestamp() {
	Date date = new Date(System.currentTimeMillis());
	SimpleDateFormat df = new SimpleDateFormat(ISO8601_DATE_FORMAT);
	df.setTimeZone(new SimpleTimeZone(0, "GMT"));
	return df.format(date);
}

private static String httpGet(String url) throws Exception {
    CloseableHttpClient httpClient = null;
    try {
        httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet();
        httpGet.setURI(new URI(url));
        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(3000)
                .setSocketTimeout(3000)
                .build();
        httpGet.setConfig(requestConfig);
        HttpResponse result = httpClient.execute(httpGet);

        String str;
        try {
            /**读取服务器返回过来的json字符串数据**/
            str = EntityUtils.toString(result.getEntity());
            EntityUtils.consume(result.getEntity());
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        }
        out(str);
        // 这里可以解析视频云点播服务端的响应结果
        return str;
    } catch (URISyntaxException e) {
        e.printStackTrace();
        throw e;
    } catch (ClientProtocolException e) {
        e.printStackTrace();
        throw e;
    } catch (IOException e) {
        e.printStackTrace();
        throw e;
    } finally {
        try {
            if (httpClient != null)
                httpClient.close();
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        }
    }
}

private static void out(String newLine) {
    System.out.println(newLine);
    LOG.info(newLine);
}
}

最终得到URL：

http://vod.cn-shanghai.aliyuncs.com?Signature=UI%2FwKfuvTtphzCKHwPhP0ErtLnc%3D&SignatureVersion=1.0&Action=GetVideoPlayAuth&Format=JSON&VideoId=68a4d2629a339db3207963ac073a88cd&SignatureNonce=578a50c1-280d-4a34-bffc-e06aa6b2df76&Version=2017-03-21&AccessKeyId=testId&SignatureMethod=HMAC-SHA1&Timestamp=2017-03-29T12%3A09%3A11Z

通过HTTP请求的方式向上述URL地址发送HTTP请求，得到响应结果，此处以JSON格式为例：

{
 "RequestId": "25818875-5F78-4A13-BEF6-D7393642CA58",
 "VideoMeta": {
     "VideoId": "93ab850b4f6f44eab54b6e91d24d81d4",
     "Title": "阿里云VOD",
     "Duration": 135.6,
     "CoverURL": "https://image.example.com/sample.jpg",
     "Status": "Normal"
  },
  "PlayAuth": "sstyYuew678999ew90000000xtt7TYUh"
}