本文以Java语言为例,讲解在服务端通过Java代码完成签名,并且设置上传回调,然后通过表单直传数据到OSS。
前提条件
应用服务器对应的域名可通过公网访问。
确保应用服务器已安装
Java 1.6
以上版本(执行命令java -version
进行查看)。确保PC端浏览器支持JavaScript。
步骤1:配置应用服务器
下载应用服务器源码(Java版本)。
本示例中以
Ubuntu 16.04
为例,将下载的文件解压到/home/aliyun/aliyun-oss-appserver-java目录下。进入该目录,打开源码文件CallbackServer.java,然后结合实际情况修改源码文件。源码文件修改示例如下:
// 从环境变量中获取访问凭证。运行本代码示例之前,请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。 EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。 String endpoint = "oss-cn-hangzhou.aliyuncs.com"; // 填写Bucket名称,例如examplebucket。 String bucket = "examplebucket"; // 填写Host地址,格式为https://bucketname.endpoint。 String host = "https://examplebucket.oss-cn-hangzhou.aliyuncs.com"; // 设置上传回调URL,即回调服务器地址,用于处理应用服务器与OSS之间的通信。OSS会在文件上传完成后,把文件上传信息通过此回调URL发送给应用服务器。 String callbackUrl = "https://192.168.0.0:8888"; // 设置上传到OSS文件的前缀,可置空此项。置空后,文件将上传至Bucket的根目录下。 String dir = "exampledir/";
步骤2:配置客户端
下载客户端源码。
将文件解压,本例中以解压到
D:\aliyun\aliyun-oss-appserver-js
目录为例。进入该目录,打开
upload.js
文件,找到下面的代码语句:// serverUrl是用户获取签名和Policy等信息的应用服务器的URL,请对应替换以下IP地址和Port端口信息。 serverUrl = 'http://192.0.2.0:8888'
将
severUrl
改成应用服务器的地址,客户端可以通过它获取签名直传Policy等信息。如本例中可修改为serverUrl = 'https://192.168.0.0:8888'
。
步骤3:修改CORS
客户端进行表单直传到OSS时,会从浏览器向OSS发送带有Origin
的请求消息。OSS对带有Origin
头的请求消息会进行跨域规则(CORS)的验证。因此需要为Bucket设置跨域规则以支持Post方法。
步骤4:体验上传回调
启动应用服务器。
在/home/aliyun/aliyun-oss-appserver-java目录下,执行mvn package命令编译打包,然后执行java -jar target/appservermaven-1.0.0.jar 1234命令启动应用服务器。
说明请将IP和端口改成您配置的应用服务器的IP和端口。
您也可以在PC端使用Eclipse/IntelliJ IDEA等IDE工具导出jar包,然后将jar包拷贝到应用服务器,再执行jar包启动应用服务器。
启动客户端。
在PC端的客户端源码目录中,打开index.html文件。
重要index.html文件不保证兼容IE 10以下版本浏览器,若使用IE 10以下版本浏览器出现问题时,您需要自行调试。
单击选择文件,选择指定类型的文件,单击开始上传。
上传成功后,显示回调服务器返回的内容。
应用服务器核心代码解析
应用服务器源码包含了签名直传服务以及上传回调服务,完整示例代码如下:
package com.aliyun.oss.appservermaven;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URI;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;
import java.sql.Date;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import com.aliyun.oss.OSSClient;
import com.aliyun.oss.common.utils.BinaryUtil;
import com.aliyun.oss.model.MatchMode;
import com.aliyun.oss.model.PolicyConditions;
import com.aliyun.oss.common.auth.*;
//import org.junit.Assert;
import net.sf.json.JSONObject;
@SuppressWarnings("deprecation")
@WebServlet(asyncSupported = true)
public class CallbackServer extends HttpServlet {
private static final long serialVersionUID = 5522372203700422672L;
/**
* Get请求
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 从环境变量中获取访问凭证。运行本代码示例之前,请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。
String endpoint = "oss-cn-hangzhou.aliyuncs.com";
// 填写Bucket名称,例如examplebucket。
String bucket = "examplebucket";
// 填写Host地址,格式为https://bucketname.endpoint。
String host = "https://examplebucket.oss-cn-hangzhou.aliyuncs.com";
// 设置上传回调URL,即回调服务器地址,用于处理应用服务器与OSS之间的通信。OSS会在文件上传完成后,把文件上传信息通过此回调URL发送给应用服务器。
String callbackUrl = "https://192.168.0.0:8888";
// 设置上传到OSS文件的前缀,可置空此项。置空后,文件将上传至Bucket的根目录下。
String dir = "exampledir/";
// 创建ossClient实例。
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
long expireTime = 30;
long expireEndTime = System.currentTimeMillis() + expireTime * 1000;
Date expiration = new Date(expireEndTime);
PolicyConditions policyConds = new PolicyConditions();
policyConds.addConditionItem(PolicyConditions.COND_CONTENT_LENGTH_RANGE, 0, 1048576000);
policyConds.addConditionItem(MatchMode.StartWith, PolicyConditions.COND_KEY, dir);
String postPolicy = ossClient.generatePostPolicy(expiration, policyConds);
byte[] binaryData = postPolicy.getBytes("utf-8");
String encodedPolicy = BinaryUtil.toBase64String(binaryData);
String postSignature = ossClient.calculatePostSignature(postPolicy);
Map<String, String> respMap = new LinkedHashMap<String, String>();
respMap.put("accessid", accessId);
respMap.put("policy", encodedPolicy);
respMap.put("signature", postSignature);
respMap.put("dir", dir);
respMap.put("host", host);
respMap.put("expire", String.valueOf(expireEndTime / 1000));
// respMap.put("expire", formatISO8601Date(expiration));
JSONObject jasonCallback = new JSONObject();
jasonCallback.put("callbackUrl", callbackUrl);
jasonCallback.put("callbackBody",
"filename=${object}&size=${size}&mimeType=${mimeType}&height=${imageInfo.height}&width=${imageInfo.width}");
jasonCallback.put("callbackBodyType", "application/x-www-form-urlencoded");
String base64CallbackBody = BinaryUtil.toBase64String(jasonCallback.toString().getBytes());
respMap.put("callback", base64CallbackBody);
JSONObject ja1 = JSONObject.fromObject(respMap);
// System.out.println(ja1.toString());
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "GET, POST");
response(request, response, ja1.toString());
} catch (Exception e) {
// Assert.fail(e.getMessage());
System.out.println(e.getMessage());
}
}
/**
* 获取public key
*
* @param url
* @return
*/
@SuppressWarnings({ "finally" })
public String executeGet(String url) {
BufferedReader in = null;
String content = null;
try {
// 定义HttpClient。
@SuppressWarnings("resource")
DefaultHttpClient client = new DefaultHttpClient();
// 实例化HTTP方法。
HttpGet request = new HttpGet();
request.setURI(new URI(url));
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
content = sb.toString();
} catch (Exception e) {
} finally {
if (in != null) {
try {
in.close();// 关闭BufferedReader。
} catch (Exception e) {
e.printStackTrace();
}
}
return content;
}
}
/**
* 获取Post消息体
*
* @param is
* @param contentLen
* @return
*/
public String GetPostBody(InputStream is, int contentLen) {
if (contentLen > 0) {
int readLen = 0;
int readLengthThisTime = 0;
byte[] message = new byte[contentLen];
try {
while (readLen != contentLen) {
readLengthThisTime = is.read(message, readLen, contentLen - readLen);
if (readLengthThisTime == -1) {// Should not happen.
break;
}
readLen += readLengthThisTime;
}
return new String(message);
} catch (IOException e) {
}
}
return "";
}
/**
* 验证上传回调的Request
*
* @param request
* @param ossCallbackBody
* @return
* @throws NumberFormatException
* @throws IOException
*/
protected boolean VerifyOSSCallbackRequest(HttpServletRequest request, String ossCallbackBody)
throws NumberFormatException, IOException {
boolean ret = false;
String autorizationInput = new String(request.getHeader("Authorization"));
String pubKeyInput = request.getHeader("x-oss-pub-key-url");
byte[] authorization = BinaryUtil.fromBase64String(autorizationInput);
byte[] pubKey = BinaryUtil.fromBase64String(pubKeyInput);
String pubKeyAddr = new String(pubKey);
if (!pubKeyAddr.startsWith("http://gosspublic.alicdn.com/")
&& !pubKeyAddr.startsWith("https://gosspublic.alicdn.com/")) {
System.out.println("pub key addr must be oss addrss");
return false;
}
String retString = executeGet(pubKeyAddr);
retString = retString.replace("-----BEGIN PUBLIC KEY-----", "");
retString = retString.replace("-----END PUBLIC KEY-----", "");
String queryString = request.getQueryString();
String uri = request.getRequestURI();
String decodeUri = java.net.URLDecoder.decode(uri, "UTF-8");
String authStr = decodeUri;
if (queryString != null && !queryString.equals("")) {
authStr += "?" + queryString;
}
authStr += "\n" + ossCallbackBody;
ret = doCheck(authStr, authorization, retString);
return ret;
}
/**
* Post请求
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String ossCallbackBody = GetPostBody(request.getInputStream(),
Integer.parseInt(request.getHeader("content-length")));
boolean ret = VerifyOSSCallbackRequest(request, ossCallbackBody);
System.out.println("verify result : " + ret);
// System.out.println("OSS Callback Body:" + ossCallbackBody);
if (ret) {
response(request, response, "{\"Status\":\"OK\"}", HttpServletResponse.SC_OK);
} else {
response(request, response, "{\"Status\":\"verify not ok\"}", HttpServletResponse.SC_BAD_REQUEST);
}
}
/**
* 验证RSA
*
* @param content
* @param sign
* @param publicKey
* @return
*/
public static boolean doCheck(String content, byte[] sign, String publicKey) {
try {
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
byte[] encodedKey = BinaryUtil.fromBase64String(publicKey);
PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
java.security.Signature signature = java.security.Signature.getInstance("MD5withRSA");
signature.initVerify(pubKey);
signature.update(content.getBytes());
boolean bverify = signature.verify(sign);
return bverify;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
/**
* 服务器响应结果
*
* @param request
* @param response
* @param results
* @param status
* @throws IOException
*/
private void response(HttpServletRequest request, HttpServletResponse response, String results, int status)
throws IOException {
String callbackFunName = request.getParameter("callback");
response.addHeader("Content-Length", String.valueOf(results.length()));
if (callbackFunName == null || callbackFunName.equalsIgnoreCase(""))
response.getWriter().println(results);
else
response.getWriter().println(callbackFunName + "( " + results + " )");
response.setStatus(status);
response.flushBuffer();
}
/**
* 服务器响应结果
*/
private void response(HttpServletRequest request, HttpServletResponse response, String results) throws IOException {
String callbackFunName = request.getParameter("callback");
if (callbackFunName == null || callbackFunName.equalsIgnoreCase(""))
response.getWriter().println(results);
else
response.getWriter().println(callbackFunName + "( " + results + " )");
response.setStatus(HttpServletResponse.SC_OK);
response.flushBuffer();
}
}
关于上传回调的API接口说明,请参见Callback。