Learn from the technical principles of Apache HTTPCORE

Learn from the technical principles of Apache httpcore Apache HTTPCORE is a Java -based open source framework that is used to build high -performance, scalable HTTP protocol processors.It is one of the core components of the Apache HTTPCOMPONENTS project, providing developers with the underlying function and API of handling the HTTP protocol.Understanding the technical principle of Apache HTTPCORE can help developers better understand and use the framework, and achieve customized HTTP protocol processing logic. 1 Overview The technical principles of Apache HTTPCORE mainly include three aspects: request processing, response processing, and connection management.The request processing includes the process of analyzing HTTP requests, interpretation of the request header, and processing request body.The response treatment includes the process of generating HTTP response, setting response header, and sending response.The connection management is responsible for the establishment, reuse and closing of the HTTP connection. 2. Request processing When HTTPCORE received the HTTP request, it first needed to analyze the request.The HTTP request can use the httprequestparser class, which can analyze the HTTP request message into an HTTPRequest object.The HTTPRequest object contains information such as request methods, URI, request head, and request body. Developers can obtain and modify the request -related data through this object. The following is a simple sample code that shows how to use HTTPREQUESTPARSER to resolve the HTTP request: import org.apache.hc.core5.http.HttpRequest; import org.apache.hc.core5.http.io.entity.EntityUtils; import org.apache.hc.core5.http.message.BasicHttpRequest; import org.apache.hc.core5.http.message.BasicHttpResponse; import org.apache.hc.core5.http.protocol.* public class RequestParsingExample { public static void main(String[] args) throws Exception { String requestString = "GET /index.html HTTP/1.1\r Host: localhost\r \r "; SessionInputBufferImpl inputBuffer = new SessionInputBufferImpl(4096); inputBuffer.fill(new ByteArrayInputStream(requestString.getBytes(StandardCharsets.US_ASCII))); DefaultHttpRequestParser reqParser = new DefaultHttpRequestParser(inputBuffer, BasicLineParser.INSTANCE, DefaultHttpRequestFactory.INSTANCE, HttpCoreContext.create()); HttpRequest request = reqParser.parse(); System.out.println(request.getMethod()); System.out.println(request.getRequestUri()); System.out.println(EntityUtils.toString(request.getEntity())); } } 3. Response treatment After processing the HTTP request, HTTPCORE needs to generate an HTTP response based on business logic.The HTTP response can use the HTTPRESPONSE class, which contains information such as response status code, response head, and response body.Developers can set HTTP response related information through this class, and use the HTTPRESPONSEWRITER class to send the response to the client. The following is a simple example code that shows how to generate HTTP response and send it back to the client: import org.apache.hc.core5.http.*; import org.apache.hc.core5.http.message.BasicHttpResponse; import org.apache.hc.core5.http.protocol.HttpCoreContext; import org.apache.hc.core5.http.protocol.BasicHttpContext; import org.apache.hc.core5.http.protocol.BasicHttpProcessor; import org.apache.hc.core5.http.protocol.ResponseConnControl; public class ResponseGenerationExample { public static void main(String[] args) throws Exception { BasicHttpResponse response = new BasicHttpResponse(HttpStatus.SC_OK); response.setHeader("Content-Type", "text/html"); response.setEntity(EntityBuilder.create().setText("Hello, World!").build()); SessionOutputBufferImpl outputBuffer = new SessionOutputBufferImpl(4096); DefaultHttpResponseWriter responseWriter = new DefaultHttpResponseWriter(outputBuffer); HttpCoreContext context = HttpCoreContext.create(); BasicHttpProcessor httpProcessor = new BasicHttpProcessor(); httpProcessor.addInterceptor(new ResponseConnControl()); context.setProtocolProcessor(httpProcessor); context.setHttpContext(new BasicHttpContext()); responseWriter.write(response, context); byte[] responseBytes = outputBuffer.toByteArray(); // Send responseBytes back to the client } } 4. Connection management HTTPCORE also includes the function of connecting management, which is mainly responsible for the establishment, reuse and closing of HTTP connection.The connection management can be configured through the ConnectionReuseSestrategy interface. By default, HTTPCORE will enable a connection reuse strategy based on the HTTP/1.1 protocol.Developers can also customize the connection reuse strategy to meet specific needs. The following is a simple example code, which shows how to use the connection management function of HTTPCORE: import org.apache.hc.core5.http.HttpHost; import org.apache.hc.core5.http.protocol.HttpCoreContext; import org.apache.hc.core5.http.protocol.DefaultConnectionReuseStrategy; import org.apache.hc.core5.http.protocol.HttpProcessorBuilder; import org.apache.hc.core5.http.protocol.HttpRequestExecutor; import org.apache.hc.core5.http.protocol.HttpRequestExecutorBuilder; import org.apache.hc.core5.io.CloseMode; import org.apache.hc.core5.pool.ConnPoolControl; public class ConnectionManagementExample { public static void main(String[] args) throws Exception { HttpProcessorBuilder<HttpProcessorBuilder> builder = HttpProcessorBuilder.create(); builder.setRequestExecutor(HttpRequestExecutorBuilder.create().build()); HttpCoreContext context = HttpCoreContext.create(); context.setProtocolProcessor(builder.build()); context.setConnectionReuseStrategy(DefaultConnectionReuseStrategy.INSTANCE); ConnPoolControl<HttpHost> connPoolControl = null; // Get a reference to the connection pool control object CloseMode closeMode = connPoolControl.closeIdle(Duration.ofSeconds(30)); if (closeMode == CloseMode.GRACEFUL) { // Gracefully close idle connections // ... } } } By understanding the technical principles of Apache HTTPCORE, developers can better use the underlying function and API of the framework to achieve customized HTTP protocol processing logic.Through detailed understanding of request processing, response processing, and connection management, developers can use Apache HTTPCORE more flexibly to develop high -performance HTTP applications.