最近半年来,我一直在从事开发公司的自助手机回收机项目。该项目有点类似于 IoT 项目,通过 Android 系统来操作回收机中的各种传感器,以此来控制回收机中的各种硬件。这涉及到各种通信协议,例如串口的通信,还有 TCP、http 协议等。
在我们的回收机中,Android 上使用的 http 服务来自一个第三方的库,从监控上看最近该库报错有一点多。
我们回收机本身提供的 TCP、WebSocket 服务均由 Netty 开发,而 http 服务它运行在TCP之上,因此也可以使用 Netty 来提供 http 服务,从而可以减少第三方库的依赖。
正是基于上面的开发背景,我最近抽空开发了一个 AndroidServer
github 地址: github.com/fengzhizi71…
它的特性包括:
一个完整的 http 服务一定需要 Request、Response
/** * * @FileName: * com.safframework.server.core.http.Request * @author: Tony Shen * @date: 2020-03-21 12:31 * @version: V1.0 <描述当前版本功能> */ interface Request { fun method(): HttpMethod fun url(): String fun headers(): MutableMap<String, String> fun header(name: String): String? fun cookies(): Set<HttpCookie> fun params(): MutableMap<String, String> fun param(name: String): String? fun content(): String } 复制代码
/** * * @FileName: * com.safframework.server.core.http.Response * @author: Tony Shen * @date: 2020-03-21 13:09 * @version: V1.0 <描述当前版本功能> */ interface Response { fun setStatus(status: HttpResponseStatus): Response fun setBodyJson(any: Any): Response fun setBodyHtml(html: String): Response fun setBodyData(contentType: String, data: ByteArray): Response fun setBodyText(text: String): Response fun addHeader(key: CharSequence, value: CharSequence): Response fun addHeader(key: AsciiString, value: AsciiString): Response fun addCookie(cookie: HttpCookie): Response } 复制代码
在 AndroidServer 中他们的实现者分别是:HttpRequest、HttpResponse。
其中, HttpRequest 包含了 Netty 的 FullHttpRequest,HttpResponse 包含了 Netty 的 Channel、DefaultFullHttpResponse。
FullHttpRequest 包含了 HttpRequest 和 FullHttpMessage,是一个 HTTP 请求的完全体。
通过 FullHttpRequest 可以从中提取 http 请求方法、请求头、请求体的具体信息,包括 cookie、parameter 等等。
Channel 是 Netty 网络操作抽象类,包括网络的读、写、发起连接、链路关闭等,它是 Netty 网络通信的主体。
Channel代表了一个 Socket 链接。
通过 DefaultFullHttpResponse 来构造完整的 HttpResponse。
fun buildFullH1Response(): FullHttpResponse { var status = this.status val response = DefaultFullHttpResponse(HttpVersion.HTTP_1_1, status?:HttpResponseStatus.OK, buildBodyData()) response.headers().set(HttpHeaderNames.SERVER, SERVER_VALUE) headers.forEach { (key, value) -> response.headers().set(key, value) } response.headers().set(HttpHeaderNames.CONTENT_LENGTH, buildBodyData().readableBytes()) return response } 复制代码
因此,最终通过如下的配置完成简单的 http 服务:
pipeline .addLast("http-codec", HttpServerCodec()) .addLast("aggregator", HttpObjectAggregator(builder.maxContentLength)) .addLast("request-handler", H1BrokerHandler(routeRegistry)) 复制代码
class H1BrokerHandler(private val routeRegistry: RouteTable): ChannelInboundHandlerAdapter() { @Throws(Exception::class) override fun channelRead(ctx: ChannelHandlerContext, msg: Any) { if (msg is FullHttpRequest) { val request = HttpRequest(msg) val response = routeRegistry.getHandler(request)?.let { val impl = it.invoke(request, HttpResponse(ctx.channel())) as HttpResponse impl.buildFullH1Response() } ctx.channel().writeAndFlush(response).addListener(ChannelFutureListener.CLOSE) } else { LogManager.w("H1BrokerHandler","unknown message type ${msg}") } ctx.fireChannelRead(msg) } } 复制代码
在 H1BrokerHandler 中,request 请求通过查找路由表来找到对应的 RequestHandler。
typealias RequestHandler = (Request, Response) -> Response 复制代码
路由表中定义了多个字典树
/** * * @FileName: * com.safframework.server.core.router.RouteTable * @author: Tony Shen * @date: 2020-03-21 21:28 * @version: V1.0 <描述当前版本功能> */ object RouteTable { private val getTrie: PathTrie<RequestHandler> = PathTrie() private val postTrie: PathTrie<RequestHandler> = PathTrie() private val putTrie: PathTrie<RequestHandler> = PathTrie() private val deleteTrie: PathTrie<RequestHandler> = PathTrie() private val headTrie: PathTrie<RequestHandler> = PathTrie() private val traceTrie: PathTrie<RequestHandler> = PathTrie() private val connectTrie: PathTrie<RequestHandler> = PathTrie() private val optionsTrie: PathTrie<RequestHandler> = PathTrie() private val patchTrie: PathTrie<RequestHandler> = PathTrie() private var errorController: RequestHandler?=null fun registHandler(method: HttpMethod, url: String, handler: RequestHandler) { getTable(method).insert(url, handler) } private fun getTable(method: HttpMethod): PathTrie<RequestHandler> = when (method) { HttpMethod.GET -> getTrie HttpMethod.POST -> postTrie HttpMethod.PUT -> putTrie HttpMethod.DELETE -> deleteTrie HttpMethod.HEAD -> headTrie HttpMethod.TRACE -> traceTrie HttpMethod.CONNECT -> connectTrie HttpMethod.OPTIONS -> optionsTrie HttpMethod.PATCH -> patchTrie } /** * 支持自定义错误的 */ fun errorController(errorController: RequestHandler) { this.errorController = errorController } fun getHandler(request: Request): RequestHandler = getTable(request.method()).fetch(request.url(),request.params()) ?: errorController ?: NotFound() fun isNotEmpty():Boolean = !isEmpty() fun isEmpty():Boolean = getTrie.getRoot().getChildren().isEmpty() && postTrie.getRoot().getChildren().isEmpty() && putTrie.getRoot().getChildren().isEmpty() && deleteTrie.getRoot().getChildren().isEmpty() && headTrie.getRoot().getChildren().isEmpty() && traceTrie.getRoot().getChildren().isEmpty() && connectTrie.getRoot().getChildren().isEmpty() && optionsTrie.getRoot().getChildren().isEmpty() && patchTrie.getRoot().getChildren().isEmpty() } 复制代码
在计算机科学中, trie ,又称 前缀树 或 字典树 ,是一种有序树,用于保存关联数组,其中的键通常是字符串。与二叉查找树不同,键不是直接保存在节点中,而是由节点在树中的位置决定。一个节点的所有子孙都有相同的前缀,也就是这个节点对应的字符串,而根节点对应空字符串。一般情况下,不是所有的节点都有对应的值,只有叶子节点和部分内部节点所对应的键才有相关的值。
字典树的核心思想是空间换时间,它在搜索字符串时是非常地高效,特别适用于构建文本搜索和词频统计等应用。
在 AndroidServer 中,使用字典树来存储 http 服务的路径和对应的 RequestHandler。正是因为其查找的速度快于正则表达式。
可以参考之前的文章 Kotlin + Netty 在 Android 上实现 Socket 的服务端
通过使用 Service 来提供一个 http 服务,它的 http 服务本身支持 rest 风格、支持跨域、cookies 等。
class HttpService : Service() { private lateinit var androidServer: AndroidServer override fun onCreate() { super.onCreate() startServer() } // 启动 Http 服务端 private fun startServer() { androidServer = AndroidServer.Builder().converter(GsonConverter()).build() androidServer .get("/hello") { _, response: Response -> response.setBodyText("hello world") } .get("/sayHi/{name}") { request,response: Response -> val name = request.param("name") response.setBodyText("hi $name!") } .post("/uploadLog") { request,response: Response -> val requestBody = request.content() response.setBodyText(requestBody) } .start() } override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int { return super.onStartCommand(intent, flags, startId) } override fun onDestroy() { androidServer.close() super.onDestroy() } override fun onBind(intent: Intent): IBinder? { return null } } 复制代码
测试:
curl -v 127.0.0.1:8080/hello * Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8080 (#0) > GET /hello HTTP/1.1 > Host: 127.0.0.1:8080 > User-Agent: curl/7.50.1-DEV > Accept: */* > < HTTP/1.1 200 OK < server: monica < content-type: text/plain < content-length: 11 < * Connection #0 to host 127.0.0.1 left intact hello world 复制代码
curl -v -d 测试 127.0.0.1:8080/uploadLog * Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8080 (#0) > POST /uploadLog HTTP/1.1 > Host: 127.0.0.1:8080 > User-Agent: curl/7.50.1-DEV > Accept: */* > Content-Length: 6 > Content-Type: application/x-www-form-urlencoded > * upload completely sent off: 6 out of 6 bytes < HTTP/1.1 200 OK < server: monica < content-type: text/plain < content-length: 6 < * Connection #0 to host 127.0.0.1 left intact 测试 复制代码
Socket 服务,AndroidServer 支持同一个端口同时提供 TCP/WebSocket 服务
class SocketService : Service() { private lateinit var androidServer: AndroidServer override fun onCreate() { super.onCreate() startServer() } // 启动 Socket 服务端 private fun startServer() { androidServer = AndroidServer.Builder().converter(GsonConverter()).port(8888).logProxy(LogProxy).build() androidServer .socket("/ws", object: SocketListener<String> { override fun onMessageResponseServer(msg: String, ChannelId: String) { LogManager.d("SocketService","msg = $msg") } override fun onChannelConnect(channel: Channel) { val insocket = channel.remoteAddress() as InetSocketAddress val clientIP = insocket.address.hostAddress LogManager.d("SocketService","connect client: $clientIP") } override fun onChannelDisConnect(channel: Channel) { val ip = channel.remoteAddress().toString() LogManager.d("SocketService","disconnect client: $ip") } }) .start() } override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int { return super.onStartCommand(intent, flags, startId) } override fun onDestroy() { androidServer.close() super.onDestroy() } override fun onBind(intent: Intent): IBinder? { return null } } 复制代码
Socket 服务可以使用 : github.com/fengzhizi71… 进行测试