Retrofit2.0 公共参数(固定参数)

2021年6月30日 1点热度 0条评论 来源: 一叶飘舟

请先阅读:
Retrofit 动态参数(非固定参数、非必须参数)(Get、Post请求)

在实际项目中,对于有需要统一进行公共参数添加的网络请求,可以使用下面的代码来实现:

RestAdapter restAdapter = new RestAdapter.Builder()
                .setEndpoint(ctx).setRequestInterceptor(new RequestInterceptor() {
                    @Override
                    public void intercept(RequestFacade request) {
                        request.addQueryParam("publicParams", "1");
                    }
                }).setConverter(new BaseConverter())
                .build();

在RestAdapter的实例化对象的时候,为其指定一个RequestInterceptor接口的实现类即可,在该类中,可以对请求体的相关参数进行设置,如addHeader、addQueryParam等。

不过遗憾的是Retrofit2.0已经没有了该类,该怎么做呢?通过Interceptor实现。

Interceptor是拦截器, 在发送之前, 添加一些参数, 或者获取一些信息。

/** * 封装公共参数(Key和密码) * <p> */
public class CommonInterceptor implements Interceptor { 
    private final String mApiKey;
    private final String mApiSecret;

    public CommonInterceptor(String apiKey, String apiSecret) {
        mApiKey = apiKey;
        mApiSecret = apiSecret;
    }

    @Override public Response intercept(Interceptor.Chain chain) throws IOException {
        String marvelHash = ApiUtils.generateMarvelHash(mApiKey, mApiSecret);
        Request oldRequest = chain.request();

        // 添加新的参数
        HttpUrl.Builder authorizedUrlBuilder = oldRequest.url()
                .newBuilder()
                .scheme(oldRequest.url().scheme())
                .host(oldRequest.url().host())
                .addQueryParameter(MarvelService.PARAM_API_KEY, mApiKey)
                .addQueryParameter(MarvelService.PARAM_TIMESTAMP, ApiUtils.getUnixTimeStamp())
                .addQueryParameter(MarvelService.PARAM_HASH, marvelHash);

        // 新的请求
        Request newRequest = oldRequest.newBuilder()
                .method(oldRequest.method(), oldRequest.body())
                .url(authorizedUrlBuilder.build())
                .build();

        return chain.proceed(newRequest);
    }
}

Okhttp3使用了装饰者模式, 使用Builder添加Interceptor。


CommonInterceptor commonInterceptor = new CommonInterceptor(
                "key", "Secret");

OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(commonInterceptor)
                .build();

// 适配器
Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("url")             
        .addConverterFactory(GsonConverterFactory.create()
        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .client(client)
        .build();

有时候你找到了一条线,就能顺着线找到更多。

BasicParamsInterceptor - 为 OkHttp 请求添加公共参数

背景

在 Android Http API 请求开发中经常遇到这样的需求:每一次请求带上一个或者多个固定不变的参数,例如:

  • 设备唯一标识:device_id = 7a4391e28f309c21
  • 业务唯一标识:uid = 2231001
  • 平台类型:platform = android
  • 客户端版本号:version_code = 6

这些参数是每一次发生请求都需要的,我们姑且称他们为公共参数(或者基础参数)。公共参数一般以 header line、url query 或者 post body(较少) 这些形式插入请求。

实现

如果使用 OkHttp 作为 http request client, 这件事情就变得简单多了。OkHttp 提供了强大的拦截器组件 (Interceptor):

Interceptors are a powerful mechanism that can monitor, rewrite, and retry calls.

也就是说,OkHttp 的拦截器功能之一就是对将要发出的请求进行拦截、改造然后再发出。这正是我们想要的。BasicParamsInterceptor 实现了 okhttp3.Interceptor 接口。

实现 public Response intercept(Chain chain) throws IOException 方法。使用 Builder 模式,暴露以下接口:

addParam(String key, String value)

post 请求,且 body type 为 x-www-form-urlencoded 时,键值对公共参数插入到 body 参数中,其他情况插入到 url query 参数中。

addParamsMap(Map paramsMap)

同上,不过这里用键值对 Map 作为参数批量插入。

addHeaderParam(String key, String value)

在 header 中插入键值对参数。

addHeaderParamsMap(Map headerParamsMap)

在 header 中插入键值对 Map 集合,批量插入。

addHeaderLine(String headerLine)

在 header 中插入 headerLine 字符串,字符串需要符合 -1 != headerLine.indexOf(“:”) 的规则,即可以解析成键值对。

addHeaderLinesList(List headerLinesList)

同上,headerLineList: List 为参数,批量插入 headerLine。

addQueryParam(String key, String value)

插入键值对参数到 url query 中。

addQueryParamsMap(Map queryParamsMap)

插入键值对参数 map 到 url query 中,批量插入。

示例

使用 Buider 模式创建 Interceptor 对象,然后调用 OkHttp 的 addInterceptor(Interceptor i) 方法将 interceptor 对象添加至 client 中:

BasicParamsInterceptor basicParamsInterceptor =
        new OkPublicParamsInterceptor.Builder()
                .addHeaderParam("device_id", DeviceUtils.getDeviceId())
                .addParam("uid", UserModel.getInstance().getUid())
                .addQueryParam("api_version", "1.1")
                .build();
OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(basicParamsInterceptor)
        .build();

TODO

  • 自动时间戳公共参数的支持
  • 动态参数的支持(例如登录后插入服务器返回的 uid)
    源码

源码与引用:https://github.com/jkyeo/okhttp-basicparamsinterceptor

basicparamsinterceptor应用

配置基本提交参数

我们可以建一个拦截器,这里我举例加些简单的系统参数,如下:

 class HttpBaseParamsLoggingInterceptor implements Interceptor{

        @Override
        public Response intercept(Chain chain) throws IOException {
            Request request = chain.request();
            Request.Builder requestBuilder = request.newBuilder();
            RequestBody formBody = new FormBody.Builder()
            .add("userId", "10000")
            .add("sessionToken", "E34343RDFDRGRT43RFERGFRE")
            .add("q_version", "1.1")
            .add("device_id", "android-344365")
            .add("device_os", "android")
            .add("device_osversion","6.0")
            .add("req_timestamp", System.currentTimeMillis() + "")
            .add("app_name","forums")
            .add("sign", "md5")
            .build();
            String postBodyString = Utils.bodyToString(request.body());
            postBodyString += ((postBodyString.length() > 0) ? "&" : "") +  Utils.bodyToString(formBody);
            request = requestBuilder
                    .post(RequestBody.create(MediaType.parse("application/x-www-form-urlencoded;charset=UTF-8"),
                            postBodyString))
                    .build();
            return chain.proceed(request);
        }
    }

上面Utils类是使用的okio.Buffer里面的工具类。通过RequestBody构建要上传的一些基本公共的参数,然后通过”&”符号在http 的body里面其他要提交参数拼接。然后再通过requestBuilder重新创建request对象,然后再通过chain.proceed(request)返回Response 。

接下来在创建OkHttpClient对象的时候修改为如下代码:

mOkHttpClient = new OkHttpClient.Builder()
     .addInterceptor(interceptor)
     .addInterceptor(new HttpBaseParamsLoggingInterceptor())
     .build();

这样就添加好了一些基本的公共参数。

下面我们借助BasicParamsInterceptor实现,代码如下:

public class BasicParamsInterceptor implements Interceptor { 

    Map<String, String> queryParamsMap = new HashMap<>();
    Map<String, String> paramsMap = new HashMap<>();
    Map<String, String> headerParamsMap = new HashMap<>();
    List<String> headerLinesList = new ArrayList<>();

    private BasicParamsInterceptor() {

    }

    @Override
    public Response intercept(Chain chain) throws IOException {

        Request request = chain.request();
        Request.Builder requestBuilder = request.newBuilder();

        // process header params inject
        Headers.Builder headerBuilder = request.headers().newBuilder();
        if (headerParamsMap.size() > 0) {
            Iterator iterator = headerParamsMap.entrySet().iterator();
            while (iterator.hasNext()) {
                Map.Entry entry = (Map.Entry) iterator.next();
                headerBuilder.add((String) entry.getKey(), (String) entry.getValue());
            }
        }

        if (headerLinesList.size() > 0) {
            for (String line: headerLinesList) {
                headerBuilder.add(line);
            }
        }

        requestBuilder.headers(headerBuilder.build());
        // process header params end




        // process queryParams inject whatever it's GET or POST
        if (queryParamsMap.size() > 0) {
            injectParamsIntoUrl(request, requestBuilder, queryParamsMap);
        }
        // process header params end




        // process post body inject
        if (request.method().equals("POST") && request.body().contentType().subtype().equals("x-www-form-urlencoded")) {
            FormBody.Builder formBodyBuilder = new FormBody.Builder();
            if (paramsMap.size() > 0) {
                Iterator iterator = paramsMap.entrySet().iterator();
                while (iterator.hasNext()) {
                    Map.Entry entry = (Map.Entry) iterator.next();
                    formBodyBuilder.add((String) entry.getKey(), (String) entry.getValue());
                }
            }
            RequestBody formBody = formBodyBuilder.build();
            String postBodyString = bodyToString(request.body());
            postBodyString += ((postBodyString.length() > 0) ? "&" : "") +  bodyToString(formBody);
            requestBuilder.post(RequestBody.create(MediaType.parse("application/x-www-form-urlencoded;charset=UTF-8"), postBodyString));
        } else {    // can't inject into body, then inject into url
            injectParamsIntoUrl(request, requestBuilder, paramsMap);
        }

        request = requestBuilder.build();
        return chain.proceed(request);
    }

    // func to inject params into url
    private void injectParamsIntoUrl(Request request, Request.Builder requestBuilder, Map<String, String> paramsMap) {
        HttpUrl.Builder httpUrlBuilder = request.url().newBuilder();
        if (paramsMap.size() > 0) {
            Iterator iterator = paramsMap.entrySet().iterator();
            while (iterator.hasNext()) {
                Map.Entry entry = (Map.Entry) iterator.next();
                httpUrlBuilder.addQueryParameter((String) entry.getKey(), (String) entry.getValue());
            }
        }

        requestBuilder.url(httpUrlBuilder.build());
    }

    private static String bodyToString(final RequestBody request){
        try {
            final RequestBody copy = request;
            final Buffer buffer = new Buffer();
            if(copy != null)
                copy.writeTo(buffer);
            else
                return "";
            return buffer.readUtf8();
        }
        catch (final IOException e) {
            return "did not work";
        }
    }

    public static class Builder { 

        BasicParamsInterceptor interceptor;

        public Builder() {
            interceptor = new BasicParamsInterceptor();
        }

        public Builder addParam(String key, String value) {
            interceptor.paramsMap.put(key, value);
            return this;
        }

        public Builder addParamsMap(Map<String, String> paramsMap) {
            interceptor.paramsMap.putAll(paramsMap);
            return this;
        }

        public Builder addHeaderParam(String key, String value) {
            interceptor.headerParamsMap.put(key, value);
            return this;
        }

        public Builder addHeaderParamsMap(Map<String, String> headerParamsMap) {
            interceptor.headerParamsMap.putAll(headerParamsMap);
            return this;
        }

        public Builder addHeaderLine(String headerLine) {
            int index = headerLine.indexOf(":");
            if (index == -1) {
                throw new IllegalArgumentException("Unexpected header: " + headerLine);
            }
            interceptor.headerLinesList.add(headerLine);
            return this;
        }

        public Builder addHeaderLinesList(List<String> headerLinesList) {
            for (String headerLine: headerLinesList) {
                int index = headerLine.indexOf(":");
                if (index == -1) {
                    throw new IllegalArgumentException("Unexpected header: " + headerLine);
                }
                interceptor.headerLinesList.add(headerLine);
            }
            return this;
        }

        public Builder addQueryParam(String key, String value) {
            interceptor.queryParamsMap.put(key, value);
            return this;
        }

        public Builder addQueryParamsMap(Map<String, String> queryParamsMap) {
            interceptor.queryParamsMap.putAll(queryParamsMap);
            return this;
        }

        public BasicParamsInterceptor build() {
            return interceptor;
        }

    }
}

只要像上面一样配置就行了。

    原文作者:一叶飘舟
    原文地址: https://blog.csdn.net/jdsjlzx/article/details/52063950
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