SSO介绍
什么是SSO
百科：SSO英文全称Single Sign On，单点登录。SSO是在多个应用系统中，用户只需要登录一次就可以访问所有相互信任的应用系统。它包括可以将这次主要的登录映射到其他应用中用于同一个用户的登录的机制。它是目前比较流行的企业业务整合的解决方案之一。
简单来说，SSO出现的目的在于解决同一产品体系中，多应用共享用户session的需求。SSO通过将用户登录信息映射到浏览器cookie中，解决其它应用免登获取用户session的问题。
为什么需要SSO
开放平台业务本身不需要SSO，但是如果平台的普通用户也可以在申请后成为一个应用开发者，那么就需要将平台加入到公司的整体账号体系中去，另外，对于企业级场景来说，一般都会有SSO系统，充当统一的账号校验入口。
CAS协议中概念介绍
SSO单点登录只是一个方案，而目前市面上最流行的单端登录系统是由耶鲁大学开发的CAS系统，而由其实现的CAS协议，也成为目前SSO协议中的既定协议，下文中的单点登录协议及结构，均为CAS中的体现结构
CAS协议中有以下几个概念：
1.CAS Client：需要集成单点登录的应用，称为单点登录客户端
2.CAS Server：单点登录服务器，用户登录鉴权、凭证下发及校验等操作
3.TGT：ticker granting ticket，用户凭证票据，用以标记用户凭证，用户在单点登录系统中登录一次后，再其有效期内，TGT即代表用户凭证，用户在其它client中无需再进行二次登录操作，即可共享单点登录系统中的已登录用户信息
4.ST：service ticket，服务票据，服务可以理解为客户端应用的一个业务模块，体现为客户端回调url，CAS用以进行服务权限校验，即CAS可以对接入的客户端进行管控
5.TGC：ticket granting cookie，存储用户票据的cookie，即用户登录凭证最终映射的cookies
CAS核心协议介绍
1.用户在浏览器中访问应用 2.应用发现需要索要用户信息，跳转至SSO服务器 3.SSO服务器向用户展示登录界面，用户进行登录操作，SSO服务器进行用户校验后，映射出TGC 4.SSO服务器向回调应用服务url，返回ST 5.应用去SSO服务器校验ST权限及合法性 6.SSO服务器校验成功后，返回用户信息
CAS基本流程介绍
以下为基本的CAS协议流程，图一为初次登录时的流程，图二为已进行过一次登录后的流程
以上是oauth的单点登录的流程,下面我们来看下应该如何配置单点登录:
继承了WebSecurityConfigurerAdapter的类上加@EnableOAuth2Sso注解来表示支持单点登录:
@Configuration
@EnableOAuth2Sso
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {}另外还需要在应用中添加如下的两个类:
SsoApprovalEndpoint:
package urity.demo.sso;
import org.apache.catalina.util.ParameterMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.SessionAttributes;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import java.util.Map;
@RestController
@SessionAttributes("authorizationRequest")
public class SsoApprovalEndpoint {
@RequestMapping("/oauth/confirm_access")
public ModelAndView getAccessConfirmation(Map model, HttpServletRequest request) throws Exception {
String template = createTemplate(model, request);
if (request.getAttribute("_csrf") != null) {
model.put("_csrf", request.getAttribute("_csrf"));
}
return new ModelAndView(new SsoSpelView(template), model);
}
protected String createTemplate(Map model, HttpServletRequest request) {
//解决从登录跳转到授权 和 应用之间跳转授权 form表单内action值相同 导致无法完成授权的问题
if((request.getParameterMap()) instanceof ParameterMap){
this.DENIAL="";
this.TEMPLATE="认证授权
"
+ "你确定授权应用 '【${authorizationRequest.clientId}】' 登录并访问你的信息?
"
+ ""
+ "%denial%";
}else{
this.DENIAL="";
this.TEMPLATE="认证授权
"
+ "你确定授权应用 '【${authorizationRequest.clientId}】' 登录并访问你的信息?
"
+ ""
+ "%denial%";
}
String template = TEMPLATE;
if (model.containsKey("scopes") || request.getAttribute("scopes") != null) {
template = template.replace("%scopes%", createScopes(model, request)).replace("%denial%", "");
}
else {
template = template.replace("%scopes%", "").replace("%denial%", DENIAL);
}
if (model.containsKey("_csrf") || request.getAttribute("_csrf") != null) {
template = template.replace("%csrf%", CSRF);
}
else {
template = template.replace("%csrf%", "");
}
return template;
}
private CharSequence createScopes(Map model, HttpServletRequest request) {
StringBuilder builder = new StringBuilder("");
@SuppressWarnings("unchecked")
Map scopes = (Map) (model.containsKey("scopes") ? model.get("scopes") : request
.getAttribute("scopes"));
for (String scope : scopes.keySet()) {
String approved = "true".equals(scopes.get(scope)) ? " checked" : "";
String denied = !"true".equals(scopes.get(scope)) ? " checked" : "";
String value = SCOPE.replace("%scope%", scope).replace("%key%", scope).replace("%approved%", approved)
.replace("%denied%", denied);
builder.append(value);
}
builder.append("
");
return builder.toString();
}
private static String CSRF = "";
private String DENIAL = "";
// private static String TEMPLATE = "";
private String TEMPLATE = "认证授权
"
+ "你确定授权应用 '【${authorizationRequest.clientId}】' 登录并访问你的信息?
"
+ ""
+ "%denial%";
private static String SCOPE = "%scope%: Approve Deny ";
}
SsoSpelView:
package urity.demo.sso;
import org.springframework.context.expression.MapAccessor;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.security.oauth2.common.util.RandomValueStringGenerator;
import org.springframework.util.PropertyPlaceholderHelper;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;
public class SsoSpelView implements View {
private final String template;
private final String prefix;
private final SpelExpressionParser parser = new SpelExpressionParser();
private final StandardEvaluationContext context = new StandardEvaluationContext();
private PropertyPlaceholderHelper.PlaceholderResolver resolver;
public SsoSpelView(String template) {
this.template = template;
this.prefix = new RandomValueStringGenerator().generate() + "{";
this.context.addPropertyAccessor(new MapAccessor());
this.resolver = new PropertyPlaceholderHelper.PlaceholderResolver() {
public String resolvePlaceholder(String name) {
Expression expression = parser.parseExpression(name);
Object value = expression.getValue(context);
return value == null ? null : value.toString();
}
};
}
public String getContentType() {
return "text/html";
}
public void render(Map model, HttpServletRequest request, HttpServletResponse response)
throws Exception {
Map map = new HashMap(model);
String path = ServletUriComponentsBuilder.fromContextPath(request).build()
.getPath();
map.put("path", (Object) path==null ? "" : path);
context.setRootObject(map);
String maskedTemplate = template.replace("${", prefix);
PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(prefix, "}");
String result = helper.replacePlaceholders(maskedTemplate, resolver);
result = result.replace(prefix, "${");
response.setContentType(getContentType());
response.getWriter().append(result);
}
}
分析:SsoApprovalEndpoint这个类的来源于WhitelabelApprovalEndpoint这个类,主要用于单点登录是否授权进入用的,默认会有有个白色的授权页面出现让客户选择是否授权登录,看下源码:
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
package org.springframework.security.oauth2.provider.endpoint;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.SessionAttributes;
import org.springframework.web.servlet.ModelAndView;
@FrameworkEndpoint
@SessionAttributes({"authorizationRequest"})
public class WhitelabelApprovalEndpoint {
private static String CSRF = "";
private static String DENIAL = "";
private static String TEMPLATE = "OAuth Approval
Do you authorize '${authorizationRequest.clientId}' to access your protected resources?
%denial%";
private static String SCOPE = "%scope%: Approve Deny ";
public WhitelabelApprovalEndpoint() {
}
@RequestMapping({"/oauth/confirm_access"})
public ModelAndView getAccessConfirmation(Map model, HttpServletRequest request) throws Exception {
String template = this.createTemplate(model, request);
if (request.getAttribute("_csrf") != null) {
model.put("_csrf", request.getAttribute("_csrf"));
}
return new ModelAndView(new SpelView(template), model);
}
protected String createTemplate(Map model, HttpServletRequest request) {
String template = TEMPLATE;
if (!model.containsKey("scopes") && request.getAttribute("scopes") == null) {
template = template.replace("%scopes%", "").replace("%denial%", DENIAL);
} else {
template = template.replace("%scopes%", this.createScopes(model, request)).replace("%denial%", "");
}
if (!model.containsKey("_csrf") && request.getAttribute("_csrf") == null) {
template = template.replace("%csrf%", "");
} else {
template = template.replace("%csrf%", CSRF);
}
return template;
}
private CharSequence createScopes(Map model, HttpServletRequest request) {
StringBuilder builder = new StringBuilder("");
Map scopes = (Map)((Map)(model.containsKey("scopes") ? model.get("scopes") : request.getAttribute("scopes")));
Iterator var5 = scopes.keySet().iterator();
while(var5.hasNext()) {
String scope = (String)var5.next();
String approved = "true".equals(scopes.get(scope)) ? " checked" : "";
String denied = !"true".equals(scopes.get(scope)) ? " checked" : "";
String value = SCOPE.replace("%scope%", scope).replace("%key%", scope).replace("%approved%", approved).replace("%denied%", denied);
builder.append(value);
}
builder.append("
");
return builder.toString();
}
} TEMPLATE这里面的网页代码字符串就是相关的授权页面,显示是否授权或者拒绝授权的页面,当我们选择授权后我们会跳转到另一个服务器的页面.
如果我们不想让它显示出来授权页面(因为这样会影响用户体验),我们可以在原始的文档中写
private static String TEMPLATE = "
";
我们用