feat(proxy): M1a 本地 HTTP 服务 + Sub2API 透传

- 引入 Ktor 3.0.3（server-core / cio / content-negotiation / kotlinx-json）
- Sub2ApiChatProxy：把 /v1/chat/completions 与 /v1/models 透传到用户配置的 Sub2API 实例
- KtorLocalProxyServer：绑定 127.0.0.1:8787，提供 /health、/v1/models、/v1/chat/completions
- NetworkModule 提供 Hilt 注入

app/build.gradle.kts

@@ -214,6 +214,12 @@ dependencies {
     implementation(libs.kotlinx.serialization.json)
     implementation(libs.retrofit.kotlinx.serialization.converter)
 
+    // Ktor 本地反代 HTTP 服务
+    implementation(libs.ktor.server.core)
+    implementation(libs.ktor.server.cio)
+    implementation(libs.ktor.server.content.negotiation)
+    implementation(libs.ktor.serialization.kotlinx.json)
+
     // DataStore
     implementation(libs.androidx.datastore.preferences)
 

app/src/main/java/com/rainy/token/data/proxy/KtorLocalProxyServer.kt

@@ -0,0 +1,109 @@
+package com.rainy.token.data.proxy
+
+import io.ktor.http.ContentType
+import io.ktor.http.HttpStatusCode
+import io.ktor.serialization.kotlinx.json.json
+import io.ktor.server.application.Application
+import io.ktor.server.application.install
+import io.ktor.server.cio.CIO
+import io.ktor.server.engine.EmbeddedServer
+import io.ktor.server.engine.embeddedServer
+import io.ktor.server.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.server.request.receiveText
+import io.ktor.server.response.respond
+import io.ktor.server.response.respondBytes
+import io.ktor.server.routing.get
+import io.ktor.server.routing.post
+import io.ktor.server.routing.routing
+import javax.inject.Inject
+import javax.inject.Singleton
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * 基于 Ktor CIO 的本地 HTTP 反代服务。
+ *
+ * M1a 能力：
+ * - GET /health
+ * - GET /v1/models    → Sub2API 透传
+ * - POST /v1/chat/completions → Sub2API 透传
+ *
+ * 只绑定 127.0.0.1，默认端口 8787。
+ */
+@Singleton
+class KtorLocalProxyServer @Inject constructor(
+    private val sub2ApiChatProxy: Sub2ApiChatProxy,
+) : LocalProxyServer {
+
+    private val _isRunning = MutableStateFlow(false)
+    override val isRunning: StateFlow<Boolean> = _isRunning.asStateFlow()
+
+    private var server: EmbeddedServer<*, *>? = null
+
+    override fun start(config: ProxyServerConfig): Result<Unit> = try {
+        if (_isRunning.value) return Result.success(Unit)
+        val engine = embeddedServer(CIO, host = "127.0.0.1", port = config.port) {
+            proxyModule(config, sub2ApiChatProxy)
+        }
+        engine.start(wait = false)
+        server = engine
+        _isRunning.value = true
+        Result.success(Unit)
+    } catch (e: Throwable) {
+        Result.failure(e)
+    }
+
+    override fun stop() {
+        runCatching { server?.stop(gracePeriodMillis = 500, timeoutMillis = 2000) }
+        server = null
+        _isRunning.value = false
+    }
+
+    private fun Application.proxyModule(
+        config: ProxyServerConfig,
+        sub2Api: Sub2ApiChatProxy,
+    ) {
+        install(ContentNegotiation) {
+            json()
+        }
+        routing {
+            get("/health") {
+                call.respond(mapOf("status" to "ok"))
+            }
+            get("/v1/models") {
+                val result = sub2Api.forwardModels()
+                if (result == null) {
+                    call.respondBytes(
+                        errorBody("Sub2API 未配置或未登录，请在设置中填写 API Key"),
+                        ContentType.Application.Json,
+                        HttpStatusCode.BadRequest
+                    )
+                } else {
+                    call.respondBytes(result.body, contentTypeOf(result.contentType), HttpStatusCode(result.status, ""))
+                }
+            }
+            post("/v1/chat/completions") {
+                val body = call.receiveText()
+                val result = sub2Api.forwardChat(body)
+                if (result == null) {
+                    call.respondBytes(
+                        errorBody("Sub2API 未配置或未登录，请在设置中填写 API Key"),
+                        ContentType.Application.Json,
+                        HttpStatusCode.BadRequest
+                    )
+                } else {
+                    call.respondBytes(result.body, contentTypeOf(result.contentType), HttpStatusCode(result.status, ""))
+                }
+            }
+        }
+    }
+
+    private fun errorBody(message: String): ByteArray {
+        val safe = message.replace("\"", "'")
+        return "{\"error\":{\"message\":\"$safe\",\"type\":\"invalid_request_error\"}}".toByteArray()
+    }
+
+    private fun contentTypeOf(raw: String): ContentType =
+        runCatching { ContentType.parse(raw) }.getOrDefault(ContentType.Application.Json)
+}

app/src/main/java/com/rainy/token/data/proxy/Sub2ApiChatProxy.kt

@@ -0,0 +1,103 @@
+package com.rainy.token.data.proxy
+
+import com.rainy.token.data.repository.CredentialRepository
+import com.rainy.token.domain.model.Credential
+import com.rainy.token.domain.service.ServiceType
+import javax.inject.Inject
+import javax.inject.Singleton
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import okhttp3.MediaType.Companion.toMediaType
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.RequestBody.Companion.toRequestBody
+
+/**
+ * Sub2API Chat 透传代理。
+ *
+ * Sub2API 实例本身暴露 OpenAI 兼容接口，因此这里不做协议转换：
+ * 取出用户保存的 Sub2ApiCredential（优先 sk- API Key，其次面板 authToken），
+ * 把客户端请求原样转发到 {base}/v1/chat/completions，
+ * 并把上游响应（含 SSE 流式内容）原样返回给本地客户端。
+ *
+ * M1a 阶段：先做整包透传（流式也先缓冲），后续由 StreamNormalizer 升级为逐块转发。
+ */
+@Singleton
+class Sub2ApiChatProxy @Inject constructor(
+    private val okHttpClient: OkHttpClient,
+    private val credentialRepository: CredentialRepository,
+) {
+
+    /** 转发 POST /v1/chat/completions。 */
+    suspend fun forwardChat(requestBody: String, accountId: String? = null): ProxyUpstreamResponse? {
+        val base = resolveBase(accountId) ?: return null
+        return forward(base = base, path = "/v1/chat/completions", requestBody = requestBody, accountId = accountId)
+    }
+
+    /** 转发 GET /v1/models。 */
+    suspend fun forwardModels(accountId: String? = null): ProxyUpstreamResponse? {
+        val base = resolveBase(accountId) ?: return null
+        return forward(base = base, path = "/v1/models", requestBody = null, accountId = accountId)
+    }
+
+    private suspend fun resolveBase(accountId: String?): String? {
+        val credential = credentialRepository.get(ServiceType.SUB2API, accountId) ?: return null
+        if (credential !is Credential.Sub2ApiCredential) return null
+        if (resolveAuth(credential) == null) return null
+        return normalizeBase(credential.baseUrl)
+    }
+
+    private suspend fun forward(
+        base: String,
+        path: String,
+        requestBody: String?,
+        accountId: String?,
+    ): ProxyUpstreamResponse? = withContext(Dispatchers.IO) {
+        val credential = credentialRepository.get(ServiceType.SUB2API, accountId)
+            ?: return@withContext null
+        if (credential !is Credential.Sub2ApiCredential) return@withContext null
+        val auth = resolveAuth(credential) ?: return@withContext null
+
+        val builder = Request.Builder()
+            .url(base + path)
+            .addHeader("Authorization", auth)
+        val body = requestBody?.takeIf { it.isNotBlank() }
+        if (body != null) {
+            builder
+                .addHeader("Content-Type", "application/json")
+                .post(body.toRequestBody("application/json".toMediaType()))
+        }
+
+        val response = try {
+            okHttpClient.newCall(builder.build()).execute()
+        } catch (_: Throwable) {
+            return@withContext null
+        }
+        val bytes = try { response.body?.bytes() ?: ByteArray(0) } catch (_: Throwable) { ByteArray(0) }
+        val contentType = response.header("Content-Type") ?: "application/json"
+        val status = response.code
+        response.close()
+        ProxyUpstreamResponse(status, contentType, bytes)
+    }
+
+    private fun resolveAuth(credential: Credential.Sub2ApiCredential): String? {
+        credential.apiKey?.trim()?.takeIf { it.isNotBlank() }?.let { return "Bearer $it" }
+        credential.authToken?.trim()?.takeIf { it.isNotBlank() }?.let { return "Bearer $it" }
+        return null
+    }
+
+    private fun normalizeBase(raw: String): String? {
+        var s = raw.trim()
+        while (s.endsWith("/")) s = s.dropLast(1)
+        return s.takeIf { it.isNotBlank() }
+    }
+}
+
+/**
+ * 上游 HTTP 响应（透传用）。
+ */
+data class ProxyUpstreamResponse(
+    val status: Int,
+    val contentType: String,
+    val body: ByteArray,
+)

app/src/main/java/com/rainy/token/di/NetworkModule.kt

@@ -20,6 +20,9 @@ import com.rainy.token.data.repository.OllamaRepository
 import com.rainy.token.data.repository.Sub2ApiRepository
 import com.rainy.token.data.repository.TraeRepository
 import com.rainy.token.data.repository.UpdateRepository
+import com.rainy.token.data.proxy.KtorLocalProxyServer
+import com.rainy.token.data.proxy.LocalProxyServer
+import com.rainy.token.data.proxy.Sub2ApiChatProxy
 import com.rainy.token.data.repository.WorkBuddyRepository
 import dagger.Module
 import dagger.Provides
@@ -223,6 +226,21 @@ object NetworkModule {
         balanceCache: BalanceCache
     ): Sub2ApiRepository = Sub2ApiRepository(okHttpClient, credentialRepository, balanceCache)
 
+    // ---- 本地反代网关 ----
+
+    @Provides
+    @Singleton
+    fun provideSub2ApiChatProxy(
+        okHttpClient: OkHttpClient,
+        credentialRepository: CredentialRepository
+    ): Sub2ApiChatProxy = Sub2ApiChatProxy(okHttpClient, credentialRepository)
+
+    @Provides
+    @Singleton
+    fun provideLocalProxyServer(
+        sub2ApiChatProxy: Sub2ApiChatProxy
+    ): LocalProxyServer = KtorLocalProxyServer(sub2ApiChatProxy)
+
     /** 余额缓存 DataStore（计划 7.1） */
     @Provides
     @Singleton

gradle/libs.versions.toml

@@ -15,6 +15,9 @@ navigationCompose = "2.9.8"
 
 # Network (Retrofit 2.11.0 配 OkHttp 4.12.0 — 稳定组合，避开 Retrofit 3.x + OkHttp 5.x 的前沿兼容性问题)
 retrofit = "2.11.0"
+
+# Ktor (本地反代 HTTP 服务)
+ktor = "3.0.3"
 okhttp = "4.12.0"
 kotlinxSerializationJson = "1.7.3"
 retrofitKotlinxSerializationConverter = "1.0.0"
@@ -67,6 +70,10 @@ androidx-navigation-compose = { group = "androidx.navigation", name = "navigatio
 retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
 okhttp = { group = "com.squareup.okhttp3", name = "okhttp", version.ref = "okhttp" }
 okhttp-logging-interceptor = { group = "com.squareup.okhttp3", name = "logging-interceptor", version.ref = "okhttp" }
+ktor-server-core = { group = "io.ktor", name = "ktor-server-core", version.ref = "ktor" }
+ktor-server-cio = { group = "io.ktor", name = "ktor-server-cio", version.ref = "ktor" }
+ktor-server-content-negotiation = { group = "io.ktor", name = "ktor-server-content-negotiation", version.ref = "ktor" }
+ktor-serialization-kotlinx-json = { group = "io.ktor", name = "ktor-serialization-kotlinx-json", version.ref = "ktor" }
 kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinxSerializationJson" }
 retrofit-kotlinx-serialization-converter = { group = "com.jakewharton.retrofit", name = "retrofit2-kotlinx-serialization-converter", version.ref = "retrofitKotlinxSerializationConverter" }