重构共用参数的添加和签名算法

src/main/kotlin/com/hiczp/bilibili/api/BilibiliClient.kt

@@ -6,6 +6,7 @@ import com.hiczp.bilibili.api.member.MemberAPI
 import com.hiczp.bilibili.api.message.MessageAPI
 import com.hiczp.bilibili.api.passport.PassportAPI
 import com.hiczp.bilibili.api.passport.model.LoginResponse
+import com.hiczp.bilibili.api.retrofit.Param
 import com.hiczp.bilibili.api.retrofit.ParamType
 import com.hiczp.bilibili.api.retrofit.exception.BilibiliApiException
 import com.hiczp.bilibili.api.retrofit.interceptor.CommonHeaderInterceptor
@@ -75,8 +76,8 @@ class BilibiliClient(
 
     @Suppress("SpellCheckingInspection")
     private val defaultCommonParamArray = arrayOf(
-            "access_key" to { token },
-            "appkey" to { billingClientProperties.appKey },
+            Param.ACCESS_KEY to { token },
+            Param.APP_KEY to { billingClientProperties.appKey },
             "build" to { billingClientProperties.build },
             "channel" to { billingClientProperties.channel },
             "mobi_app" to { billingClientProperties.platform },
@@ -85,7 +86,7 @@ class BilibiliClient(
     )
 
     private val defaultCommonQueryParamInterceptor = CommonParamInterceptor(ParamType.QUERY, *defaultCommonParamArray)
-    private val defaultQuerySignInterceptor = SortAndSignInterceptor(ParamType.QUERY, billingClientProperties.appSecret)
+    private val defaultSortAndSignInterceptor = SortAndSignInterceptor(billingClientProperties.appSecret)
 
     /**
      * 用户鉴权相关的接口
@@ -95,14 +96,14 @@ class BilibiliClient(
         createAPI<PassportAPI>(BaseUrl.passport,
                 defaultCommonHeaderInterceptor,
                 CommonParamInterceptor(ParamType.FORM_URL_ENCODED,
-                        "appkey" to { billingClientProperties.appKey },
+                        Param.APP_KEY to { billingClientProperties.appKey },
                         "build" to { billingClientProperties.build },
                         "channel" to { billingClientProperties.channel },
                         "mobi_app" to { billingClientProperties.platform },
                         "platform" to { billingClientProperties.platform },
                         "ts" to { Instant.now().epochSecond.toString() }
                 ),
-                SortAndSignInterceptor(ParamType.FORM_URL_ENCODED, billingClientProperties.appSecret)
+                defaultSortAndSignInterceptor
         )
     }
 
@@ -117,7 +118,7 @@ class BilibiliClient(
                         "actionKey" to { "appkey" },
                         "has_up" to { "1" }
                 ),
-                defaultQuerySignInterceptor
+                defaultSortAndSignInterceptor
         )
     }
 
@@ -129,7 +130,7 @@ class BilibiliClient(
         createAPI<AppAPI>(BaseUrl.app,
                 defaultCommonHeaderInterceptor,
                 defaultCommonQueryParamInterceptor,
-                defaultQuerySignInterceptor
+                defaultSortAndSignInterceptor
         )
     }
 
@@ -147,7 +148,7 @@ class BilibiliClient(
                         "Device-ID" to { billingClientProperties.hardwareId }
                 ),
                 defaultCommonQueryParamInterceptor,
-                defaultQuerySignInterceptor
+                defaultSortAndSignInterceptor
         )
     }
 
@@ -166,7 +167,7 @@ class BilibiliClient(
                         "uid" to { userId?.toString() },
                         "version" to { billingClientProperties.version }
                 ),
-                defaultQuerySignInterceptor
+                defaultSortAndSignInterceptor
         )
     }
 
@@ -177,7 +178,7 @@ class BilibiliClient(
         createAPI<MemberAPI>(BaseUrl.member,
                 defaultCommonHeaderInterceptor,
                 defaultCommonQueryParamInterceptor,
-                defaultQuerySignInterceptor
+                defaultSortAndSignInterceptor
         )
     }
 

src/main/kotlin/com/hiczp/bilibili/api/retrofit/HttpConstant.kt

@@ -1,5 +1,7 @@
 package com.hiczp.bilibili.api.retrofit
 
+//该文件用于防止拼写错误
+
 object Method {
     const val GET = "GET"
     const val POST = "POST"
@@ -13,3 +15,10 @@ object ContentType {
     const val JSON = "application/json"
     const val FORM_URLENCODED = "application/x-www-form-urlencoded; charset=utf-8"
 }
+
+object Param {
+    const val ACCESS_KEY = "access_key"
+    @Suppress("SpellCheckingInspection")
+    const val APP_KEY = "appkey"
+    const val SIGN = "sign"
+}

src/main/kotlin/com/hiczp/bilibili/api/retrofit/RetrofitExtension.kt

@@ -26,6 +26,13 @@ fun FormBody.sortedRaw(): String {
     return nameAndValue.sorted().joinToString(separator = "&")
 }
 
+fun FormBody.containsEncodedName(name: String): Boolean {
+    repeat(size()) {
+        if (encodedName(it) == name) return true
+    }
+    return false
+}
+
 fun FormBody.Builder.addAllEncoded(formBody: FormBody): FormBody.Builder {
     with(formBody) {
         repeat(size()) {

src/main/kotlin/com/hiczp/bilibili/api/retrofit/interceptor/CommonParamInterceptor.kt

@@ -1,6 +1,5 @@
 package com.hiczp.bilibili.api.retrofit.interceptor
 
-import com.hiczp.bilibili.api.retrofit.Method
 import com.hiczp.bilibili.api.retrofit.ParamType
 import com.hiczp.bilibili.api.retrofit.addAllEncoded
 import com.hiczp.bilibili.api.retrofit.forEachNonNull
@@ -22,46 +21,49 @@ class CommonParamInterceptor(
         private vararg val additionParams: Pair<String, () -> String?>
 ) : Interceptor {
     override fun intercept(chain: Interceptor.Chain): Response {
-        val request = chain.request()
+        var request = chain.request()
+        val body = request.body()
 
-        //如果欲添加的参数类型为 Query 则直接添加
-        if (paramType == ParamType.QUERY) {
-            val httpUrl = request.url().newBuilder().apply {
-                additionParams.forEachNonNull { name, value ->
-                    addQueryParameter(name, value)
-                }
-            }.build()
-            return chain.proceed(
-                    request.newBuilder().url(httpUrl).build()
-            )
-        }
+        request = when {
+            //如果欲添加参数的位置为 Query 则直接添加, paramType 为 FORM_URL_ENCODED 则继续下面的判断
+            paramType == ParamType.QUERY -> {
+                val httpUrl = request.url().newBuilder().apply {
+                    additionParams.forEachNonNull { name, value ->
+                        addQueryParameter(name, value)
+                    }
+                }.build()
+                request.newBuilder().url(httpUrl).build()
+            }
 
-        //如果请求方式为 POST(只要方式为 POST, body 就一定不为 null)
-        if (request.method() == Method.POST) {
-            val body = request.body()!!
-            val newFormBody = {
-                FormBody.Builder().apply {
+            //BODY 不存在或者是空的
+            body == null || body.contentLength() == 0L -> {
+                val formBody = FormBody.Builder().apply {
                     additionParams.forEachNonNull { name, value ->
                         add(name, value)
                     }
-                }
+                }.build()
+                request.newBuilder().method(request.method(), formBody).build()
             }
-            if (body.contentType() == null) {   //如果 body 为空
-                return chain.proceed(
-                        request.newBuilder().post(newFormBody().build()).build()
-                )
-            } else if (body is FormBody) {  //如果 body 为 FormBody
-                return chain.proceed(
-                        request.newBuilder().post(newFormBody().addAllEncoded(body).build()).build()
-                )
+
+            //只要 BODY 为 FormBody, 那么里面一定有内容
+            body is FormBody -> {
+                val formBody = FormBody.Builder().apply {
+                    addAllEncoded(body)
+                    additionParams.forEachNonNull { name, value ->
+                        add(name, value)
+                    }
+                }.build()
+                request.newBuilder().method(request.method(), formBody).build()
+            }
+
+            else -> {
+                logger.error {
+                    "Cannot add params to request: ${request.method()} ${request.url()} ${body.javaClass.simpleName}"
+                }
+                request
             }
         }
 
-        //其他情况, 例如请求方式为 GET 或 Body 为 Json
-        logger.error {
-            "Impossible add FormUrlEncoded params to ${request.body()?.javaClass?.simpleName ?: "<NullBody>"}. " +
-                    "Request: ${request.method()} ${request.url()}"
-        }
         return chain.proceed(request)
     }
 }

src/main/kotlin/com/hiczp/bilibili/api/retrofit/interceptor/SortAndSignInterceptor.kt

@@ -1,7 +1,7 @@
 package com.hiczp.bilibili.api.retrofit.interceptor
 
-import com.hiczp.bilibili.api.retrofit.Method
-import com.hiczp.bilibili.api.retrofit.ParamType
+import com.hiczp.bilibili.api.retrofit.Param
+import com.hiczp.bilibili.api.retrofit.containsEncodedName
 import com.hiczp.bilibili.api.retrofit.sortedRaw
 import mu.KotlinLogging
 import okhttp3.FormBody
@@ -13,60 +13,73 @@ private val logger = KotlinLogging.logger {}
 
 /**
  * 排序参数并添加签名
+ * 必须保证在进入此拦截器前, 公共参数已被添加
+ * 此拦截器将自动识别 appKey 在 Query 还是在 FormBody 并添加 sign 到相应位置
+ *
+ * @param appSecret 密钥
  */
-class SortAndSignInterceptor(private val paramType: ParamType, private val appSecret: String) : Interceptor {
+class SortAndSignInterceptor(private val appSecret: String) : Interceptor {
     override fun intercept(chain: Interceptor.Chain): Response {
-        val request = chain.request()
-
-        //如果欲签名的参数类型为 Query
-        if (paramType == ParamType.QUERY) {
-            //如果代码是正确的, 那么传到这里的 Query 参数一定包含了公共参数
-            val sortedEncodedQuery = request.url().encodedQuery()!!
-                    .split('&')
-                    .sorted()
-                    .joinToString(separator = "&")
-            val sign = calculateSign(sortedEncodedQuery, appSecret)
-            return chain.proceed(
-                    request.newBuilder()
-                            .url(request.url().newBuilder()
-                                    .encodedQuery("$sortedEncodedQuery&sign=$sign")
-                                    .build()
-                            )
-                            .build()
-            )
-        }
-
+        var request = chain.request()
+        val url = request.url()
         val body = request.body()
-        if (request.method() == Method.POST && body is FormBody) {
-            val sortedRaw = body.sortedRaw()
-            val sign = calculateSign(sortedRaw, appSecret)
-            val newFormBody = FormBody.Builder().apply {
-                sortedRaw.split('&').forEach {
-                    val (name, value) = it.split('=')
-                    addEncoded(name, value)
-                }
-                addEncoded("sign", sign)
-            }.build()
-            return chain.proceed(request.newBuilder().post(newFormBody).build())
+
+        request = when {
+            //判断 appKey 是否在 Query 里
+            url.queryParameter(Param.APP_KEY) != null -> {
+                val sortedEncodedQuery = url.encodedQuery()!!
+                        .split('&')
+                        .sorted()
+                        .joinToString(separator = "&")
+                val sign = calculateSign(sortedEncodedQuery, appSecret)
+                request.newBuilder()
+                        .url(url.newBuilder()
+                                .encodedQuery("$sortedEncodedQuery&${Param.SIGN}=$sign")
+                                .build()
+                        ).build()
+            }
+
+            //在 FormBody 里
+            body is FormBody && body.containsEncodedName(Param.APP_KEY) -> {
+                val sortedRaw = body.sortedRaw()
+                val sign = calculateSign(sortedRaw, appSecret)
+                val formBody = FormBody.Builder().apply {
+                    sortedRaw.split('&').forEach {
+                        val (name, value) = it.split('=')
+                        addEncoded(name, value)
+                    }
+                    addEncoded(Param.SIGN, sign)
+                }.build()
+                request.newBuilder()
+                        .method(request.method(), formBody)
+                        .build()
+            }
+
+            //不存在 accessKey
+            else -> {
+                logger.error { "Fail to sign request because no ${Param.APP_KEY} found in request" }
+                request
+            }
         }
 
-        //其他情况, 例如请求方式为 GET 或 Body 为 Json
-        logger.error {
-            "Impossible add sign to ${request.body()?.javaClass?.simpleName ?: "<NullBody>"}. " +
-                    "Request: ${request.method()} ${request.url()}"
-        }
         return chain.proceed(request)
     }
 
     companion object {
+        private val md5Instance = MessageDigest.getInstance("MD5")
         /**
          * 签名算法为 "$排序后的参数字符串$appSecret".md5()
          */
         private fun calculateSign(string: String, appSecret: String) =
-                MessageDigest.getInstance("MD5")
-                        .digest((string + appSecret).toByteArray())
-                        .joinToString(separator = "") {
-                            "%02x".format(it)
-                        }
+                StringBuilder(32).apply {
+                    //优化过的 md5 字符串生成算法
+                    md5Instance.digest((string + appSecret).toByteArray()).forEach {
+                        val value = it.toInt() and 0xFF
+                        val high = value / 16
+                        val low = value - high * 16
+                        append(if (high <= 9) '0' + high else 'a' - 10 + high)
+                        append(if (low <= 9) '0' + low else 'a' - 10 + low)
+                    }
+                }.toString()
     }
 }