动态改变Retrofit的 base url和 path
1. 需求与前提
base url
默认base url: https://cloud.devwiki.net
测试版 url : https://dev.devwiki.net
私有云版本url: https://private.devwiki.net
rest 版本
/rest/v1/
/rest/v2/
/rest/v3/
需求点
- 大部分接口使用 cloud host, 部分接口使用 private host
- 大部分接口使用 rest/v3 版本, 部分接口使用 v2, v1版本.
- 每个host 都有可能存在 rest v1, v2, v3的接口
2. 实现思路
okhttp 可以添加拦截器, 可在发起访问前进行拦截, 通常我们会在 拦截器中统一添加 header, 比如:
class HeaderInterceptor implements Interceptor {
private static final String ENCODING_GZIP = "gzip";
private static final String CONTENT_TYPE_JSON = "application/json;charset=UTF-8";
private static final String HEADER_CONTENT_TYPE = "Content-Type";
private static final String HEADER_ACCEPT_TYPE = "application/json";
private static final String HEADER_CONTENT_ENCODING = "Content-Encoding";
private final static String CHARSET = "UTF-8";
@Override
public Response intercept(Chain chain) throws IOException {
Request originRequest = chain.request();
Request.Builder newBuilder = originRequest.newBuilder();
newBuilder.addHeader("Accept", HEADER_ACCEPT_TYPE);
newBuilder.addHeader("Accept-Charset", CHARSET);
newBuilder.addHeader("Accept-Encoding", ENCODING_GZIP);
newBuilder.addHeader("Accept-Language", Locale.getDefault().toString().replace("_", "-"));
newBuilder.addHeader(HEADER_CONTENT_TYPE, CONTENT_TYPE_JSON);
return chain.proceed(newBuilder.build());
}
}
同理我们也可以在所有请求中添加统一的uuid 或者 key 进行防劫持或者认证. 比如:
Request originRequest = chain.request();
if (paramsMap != null) {
HttpUrl originUrl = originRequest.url();
HttpUrl.Builder newBuilder = originUrl.newBuilder();
for (String key : paramsMap.keySet()) {
newBuilder.addEncodedQueryParameter(key, paramsMap.get(key));
}
HttpUrl newUrl = newBuilder.build();
Request newRequest = originRequest.newBuilder().url(newUrl).build();
return chain.proceed(newRequest);
}
return chain.proceed(originRequest);
那么, 同样我们可以再拦截器中进行host 和 path的替换, 那么怎么替换呢?
3. 实现过程
3.1 定义host 类型和 rest 版本
host类型:
interface HostName {
String CLOUD = "CLOUD";
String PRIVATE = "PRIVATE";
String DEV = "DEV";
}
interface HostValue {
String CLOUD = "https://www.baidu.com";
String PRIVATE = "https://private.bidu.com";
String DEV = "https://dev.baidu.com";
}
rest 版本:
interface RestVersionCode {
String EMPTY = "EMPTY";
String V1 = "V1";
String V2 = "V2";
String PRIVATE = "PRIVATE";
}
/**
* path 前缀值
*/
interface RestVersionValue {
String EMPTY = "";
String V1 = "rest/v1";
String V2 = "rest/v2";
String PRIVATE = "rest/private";
}
设置一个默认的 host 和 rest 版本, 然后在需要更改host和rest 版本的请求接口处添header, 根据header设置来变更.
interface BaiduApiService {
@GET("s")
Observable<Response<Object>> search(@Query("wd")String wd);
@GET("s")
@Headers({UrlConstants.Header.REST_VERSION_V1})
Observable<Response<Object>> searchChangePath(@Query("wd")String wd);
@GET("s")
@Headers({UrlConstants.Header.HOST_DEV})
Observable<Response<Object>> searchChangeHost(@Query("wd")String wd);
@Headers({UrlConstants.Header.HOST_PRIVATE, UrlConstants.Header.REST_VERSION_PRIVATE})
@GET("s")
Observable<Response<Object>> searchChangeHostPath(@Query("wd")String wd);
}
header 的可选值:
interface Header {
String SPLIT_COLON = ":";
String HOST = "HostName";
String HOST_CLOUD = HOST + SPLIT_COLON + HostName.CLOUD;
String HOST_PRIVATE = HOST + SPLIT_COLON + HostName.PRIVATE;
String HOST_DEV = HOST + SPLIT_COLON + HostName.DEV;
String REST_VERSION = "RestVersion";
String REST_VERSION_V1 = REST_VERSION + SPLIT_COLON + RestVersionCode.V1;
String REST_VERSION_V2 = REST_VERSION + SPLIT_COLON + RestVersionCode.V2;
String REST_VERSION_PRIVATE = REST_VERSION + SPLIT_COLON + RestVersionCode.PRIVATE;
String REST_VERSION_EMPTY = REST_VERSION + SPLIT_COLON + RestVersionCode.EMPTY;
}
然后是解析:
class RequestInterceptor implements Interceptor {
@Override
public Response intercept(Chain chain) throws IOException {
Request originRequest = chain.request();
HttpUrl originUrl = originRequest.url();
HttpUrl.Builder newBuilder;
String hostType = originRequest.header(UrlConstants.Header.HOST);
System.out.println("hostType:" + hostType);
if (hostType != null && hostType.length() > 0) {
String hostValue = UrlManager.getInstance().getHost(hostType);
HttpUrl temp = HttpUrl.parse(hostValue);
if (temp == null) {
throw new IllegalArgumentException(hostType + "对应的host地址不合法:" + hostValue);
}
newBuilder = temp.newBuilder();
} else {
newBuilder = new HttpUrl.Builder()
.scheme(originUrl.scheme())
.host(originUrl.host())
.port(originUrl.port());
}
String restVersion = originRequest.header(UrlConstants.Header.REST_VERSION);
System.out.println("restVersion:" + restVersion);
if (restVersion == null) {
restVersion = UrlConstants.RestVersionCode.V2;
}
String restValue = UrlManager.getInstance().getRest(restVersion);
if (restValue.contains("/")) {
String[] paths = restValue.split("/");
for (String path : paths) {
newBuilder.addEncodedPathSegment(path);
}
} else {
newBuilder.addEncodedPathSegment(restValue);
}
for (int i = 0; i < originUrl.pathSegments().size(); i++) {
newBuilder.addEncodedPathSegment(originUrl.encodedPathSegments().get(i));
}
newBuilder.encodedPassword(originUrl.encodedPassword())
.encodedUsername(originUrl.encodedUsername())
.encodedQuery(originUrl.encodedQuery())
.encodedFragment(originUrl.encodedFragment());
HttpUrl newUrl = newBuilder.build();
System.out.println("newUrl:" + newUrl.toString());
Request newRequest = originRequest.newBuilder().url(newUrl).build();
return chain.proceed(newRequest);
}
}
为了能动态设置host, 我们需要一个map来存储host 类型和值.
private Map<String, String> hostMap;
private Map<String, String> restMap;
private UrlManager() {
hostMap = new HashMap<>(16);
for (UrlConstants.Host host : UrlConstants.Host.values()) {
hostMap.put(host.getName(), host.getValue());
}
restMap = new HashMap<>();
for (UrlConstants.Rest rest : UrlConstants.Rest.values()) {
restMap.put(rest.getVersion(), rest.getValue());
}
}
//更新host 的值
public void setHost(String name, String value) {
if (hostMap.containsKey(name)) {
HttpUrl httpUrl = HttpUrl.parse(value);
if (httpUrl == null) {
throw new IllegalArgumentException("要存入的Host " + name + "对应的value:"
+ value + "不合法!");
}
hostMap.put(name, value);
} else {
throw new NoSuchElementException("没有找到已经定义的Host名称:" + name + ",请先在" +
"net.devwiki.manager.UrlConstants.Host中定义!");
}
}
//根据host 获取值
public String getHost(String name) {
if (!hostMap.containsKey(name)) {
throw new NoSuchElementException("没有找到已经定义的Host名称:" + name + ",请先在" +
"net.devwiki.manager.UrlConstants.Host中定义!");
}
return hostMap.get(name);
}
这样就可以动态替换host 和 rest版本了.
4.测试运行
测试代码:
private static void testRequest() {
BaiduRest rest = new BaiduRest();
testDefault(rest);
testChangeHost(rest);
testChangePath(rest);
testChangeHostPath(rest);
}
测试运行结果:
ostType:null
restVersion:null
newUrl:https://www.baidu.com/rest/v2/s?wd=123
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://www.baidu.com/rest/v2/s?wd=123 http/1.1
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://www.baidu.com/rest/v2/s?wd=123 (83ms, 154-byte body)
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf http/1.1
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf (46ms, unknown-length body)
hostType:DEV
restVersion:null
newUrl:https://dev.baidu.com/rest/v2/s?wd=123
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://dev.baidu.com/rest/v2/s?wd=123 http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://dev.baidu.com/rest/v2/s?wd=123 (154ms, 154-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://developer.baidu.com/error.html http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 301 Moved Permanently http://developer.baidu.com/error.html (18ms, 73-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://developer.baidu.com/error.html http/1.1
hostType:null
restVersion:V1
newUrl:https://www.baidu.com/rest/v1/s?wd=123
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK https://developer.baidu.com/error.html (157ms, unknown-length body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://www.baidu.com/rest/v1/s?wd=123 http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://www.baidu.com/rest/v1/s?wd=123 (46ms, 154-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf (54ms, unknown-length body)
hostType:PRIVATE
restVersion:PRIVATE
newUrl:https://private.bidu.com/rest/private/s?wd=123
结果按照设置进行了host 和 rest 的变更.
5. 项目代码
项目代码地址: Dev-Wiki/OkHttpDemo
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