阿里云OSS 第三方授权上传+上传回调流程

在阿里云OSS使用过程中，一般都是服务器端配置账号密钥 发起上传请求至客户端。不过现在项目一般都是 B/S或者 C/S结构，有时候我们需要从客户端或者浏览器端上传文件，那么先需要将文件从客户端上传至服务器端，然后再从服务器端上传至OSS。在这个过程中，一份数据需要在网络上传输两次，对服务器的带宽压力比较大。不过如果直接从客户端上传，那么也要OSS账号密钥的安全性。

      今天我们介绍如何授权第三方直接上传文件到OSS而不通过服务器端转发，减轻服务器端的压力，以及保证OSS的账号安全。目前授权上传有两种实现方式：URL签名和临时访问凭证。我们采用的是URL签名的方式。

pom 文件添加 

    com.aliyun.oss
    aliyun-sdk-oss
    2.7.0


    org.apache.httpcomponents
    httpclient
    4.5.3

生成授权Url签名以及上传文件

   public static void upload() throws Exception {
        String endpoint = "http://oss-cn-hangzhou.aliyuncs.com";
        String accessKeyId = "xxx";
        String accessKeySecret = "xxx";
        String bucketName = "xxx-center-cloud";
        String objectName = "23/234234783/48/357918432.reg";


        OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);

        // 生成签名URL。
        GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.PUT);
        // 设置过期时间。
        Date expiration = new Date(System.currentTimeMillis() + 1000 * 60 * 2);
        request.setExpiration(expiration);
        // 设置Content-Type。
        request.setContentType("application/octet-stream;charset=utf-8");
        // 生成签名URL（HTTP PUT请求）。
        URL signedUrl = ossClient.generatePresignedUrl(request);


        //使用httpClient模拟客户端 通过http put请求将文件上传上去
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPut httppost = new HttpPut(signedUrl.toURI());
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(200000).setSocketTimeout(200000).build();
        httppost.setHeader("Content-type", "application/octet-stream;charset=utf-8");
        httppost.setConfig(requestConfig);

        //文件放进http请求的 body里
        HttpEntity reqEntity = new FileEntity(new File("C:\\xxx\\vvvv.txt"));
        httppost.setEntity(reqEntity);

        CloseableHttpResponse response = httpclient.execute(httppost);

        HttpEntity resEntity = response.getEntity();
        if (resEntity != null) {
            String responseEntityStr = EntityUtils.toString(response.getEntity());
            System.out.println(responseEntityStr);
            System.out.println("Response content length: " + resEntity.getContentLength());
        }
        EntityUtils.consume(resEntity);
        response.close();
        httpclient.close();
    }

 生成授权Url签名+oss上传回调

public static void uploadAndCallback() throws Exception {
        String endpoint = "http://oss-cn-hangzhou.aliyuncs.com";
        String accessKeyId = "xxx";
        String accessKeySecret = "xxx";
        String bucketName = "xxx-center-cloud";
        String objectName = "23/234234783/48/357918432.reg";

        //上传回调参数
        Map callbackMap = new HashMap(){
    {
            //回调URL
            put("callbackUrl", "http://33gaac.natappfree.cc/appCenter/swyCallback.action");
            put( "callbackHost", "33gaac.natappfree.cc");
            // 设置发起回调时请求body的值, mimeType size这两个参数oss自动填充，其他为自定义参数。
            put("callbackBody", "{'mimeType':${mimeType},'size':${size},'filekey':${x:filekey},'path':${x:path}}");
            // 设置发起回调请求的Content-Type。
            put("callbackBodyType", "application/json");
        }};

        //设置发起回调请求的自定义参数，由Key和Value组成，Key必须以x:开始, 与callbackBody中使用到的key相对应
        Map callbackVarMap = new HashMap(){
    {
            put("x:filekey", "23/234234783/48/");
            put("x:path", "357918432.reg");
        }};
        //上传回调的内容与参数需要进行base64编码
        String callbackBase64 = Base64.getEncoder().encodeToString(JSON.toJSONString(callbackMap).getBytes());
        String callbackVarBase64X = Base64.getEncoder().encodeToString(JSON.toJSONString(callbackVarMap).getBytes());


        OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);
        // 生成签名URL。
        GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.PUT);
        // 设置过期时间。
        Date expiration = new Date(System.currentTimeMillis() + 1000 * 60 * 2);
        request.setExpiration(expiration);
        // 设置Content-Type。
        request.setContentType("application/octet-stream;charset=utf-8");
        //将上传回调参数放入header参加签名计算
        Map hmap = Maps.newHashMap();
         hmap.put("x-oss-callback", callbackBase64);
        hmap.put("x-oss-callback-var", callbackVarBase64X);
        request.setHeaders(hmap);
        // 添加用户自定义元信息。
        //request.addUserMetadata("author", "aliy");
        // 生成签名URL（HTTP PUT请求）。
        URL signedUrl = ossClient.generatePresignedUrl(request);
        System.out.println("---------" + signedUrl);

        //使用httpClient模拟客户端 通过http put请求将文件上传上去
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPut httppost = new HttpPut(signedUrl.toURI());
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(200000).setSocketTimeout(200000).build();
        httppost.setHeader("Content-type", "application/octet-stream;charset=utf-8");
        //上传回调参数
        httppost.setHeader("x-oss-callback", callbackBase64);
        httppost.setHeader("x-oss-callback-var", callbackVarBase64X);
        httppost.setConfig(requestConfig);

        //文件放进http请求的 body里
        HttpEntity reqEntity = new FileEntity(new File("C:\\xxx\\vvvv.txt"));
        httppost.setEntity(reqEntity);

        System.out.println("executing request " + httppost.getRequestLine());
        CloseableHttpResponse response = httpclient.execute(httppost);
        System.out.println(response.getStatusLine());
        HttpEntity resEntity = response.getEntity();
        if (resEntity != null) {
            String responseEntityStr = EntityUtils.toString(response.getEntity());
            System.out.println(responseEntityStr);
            System.out.println("Response content length: " + resEntity.getContentLength());
        }
        EntityUtils.consume(resEntity);
        response.close();
        httpclient.close();
    }