[netty5: HttpObjectEncoder HttpObjectDecoder]-源码解析

在阅读该篇文章之前，推荐先阅读以下内容：

  1. [netty5: HttpObject]-源码解析
  2. [netty5: MessageToMessageCodec & MessageToMessageEncoder & MessageToMessageDecoder]-源码分析
  3. [netty5: ByteToMessageCodec & MessageToByteEncoder & ByteToMessageDecoder]-源码分析

HttpObjectEncoder

HttpObjectEncoder 类用于编码 HTTP 消息对象（如请求和响应），并根据不同的消息类型（如普通内容、分块内容或无内容）来处理编码过程。它支持对 HTTP 头、初始行、内容和尾部进行编码，并根据消息类型和内容长度动态调整内存分配，以提高编码效率。此外，还提供了一个方法来处理分块传输编码的内容，并在消息为空时输出合适的空缓冲区。

public abstract class HttpObjectEncoder<H extends HttpMessage> extends MessageToMessageEncoder<Object> {static final short CRLF_SHORT = (CR << 8) | LF;private static final int ZERO_CRLF_MEDIUM = ('0' << 16) | CRLF_SHORT;// \r\nprivate static final byte[] CRLF = {CR, LF};// 0\r\nprivate static final byte[] ZERO_CRLF_CRLF = { '0', CR, LF, CR, LF };// 新的头部数据权重	0.2private static final float HEADERS_WEIGHT_NEW = 1 / 5f;// 历史头部数据权重 0.8private static final float HEADERS_WEIGHT_HISTORICAL = 1 - HEADERS_WEIGHT_NEW;// 新的尾部数据权重	0.2private static final float TRAILERS_WEIGHT_NEW = HEADERS_WEIGHT_NEW;// 历史尾部数据权重 0.8private static final float TRAILERS_WEIGHT_HISTORICAL = HEADERS_WEIGHT_HISTORICAL;// 初始假设的头部大小private float headersEncodedSizeAccumulator = 256;// 初始假设的尾部大小private float trailersEncodedSizeAccumulator = 256;private static final int ST_INIT = 0;private static final int ST_CONTENT_NON_CHUNK = 1;private static final int ST_CONTENT_CHUNK = 2;private static final int ST_CONTENT_ALWAYS_EMPTY = 3;private Supplier<Buffer> crlfBufferSupplier;private Supplier<Buffer> zeroCrlfCrlfBufferSupplier;@SuppressWarnings("RedundantFieldInitialization")private int state = ST_INIT;@Overrideprotected void encodeAndClose(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception {Buffer buf = null;if (msg instanceof HttpMessage) {if (state != ST_INIT) {throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg) + ", state: " + state);}@SuppressWarnings({ "unchecked", "CastConflictsWithInstanceof" })H m = (H) msg;buf = ctx.bufferAllocator().allocate((int) headersEncodedSizeAccumulator);encodeInitialLine(buf, m);state = isContentAlwaysEmpty(m) ? ST_CONTENT_ALWAYS_EMPTY :HttpUtil.isTransferEncodingChunked(m) ? ST_CONTENT_CHUNK : ST_CONTENT_NON_CHUNK;sanitizeHeadersBeforeEncode(m, state == ST_CONTENT_ALWAYS_EMPTY);encodeHeaders(m.headers(), buf);buf.writeShort(CRLF_SHORT);headersEncodedSizeAccumulator = HEADERS_WEIGHT_NEW * padSizeForAccumulation(buf.readableBytes()) +HEADERS_WEIGHT_HISTORICAL * headersEncodedSizeAccumulator;}//  跳过空的消息，优化数据流的处理if (msg instanceof Buffer && ((Buffer) msg).readableBytes() == 0) {out.add(msg);return;}if (msg instanceof HttpContent || msg instanceof Buffer || msg instanceof FileRegion) {switch (state) {case ST_INIT:// 如果当前状态是 ST_INIT，但消息类型是 HttpContent 或 Buffer 或 FileRegion，则抛出 IllegalStateException，说明这个消息类型在 ST_INIT 状态下是不允许出现的。// 在抛出异常之前，释放消息 msg 占用的资源Resource.dispose(msg);throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg) + ", state: " + state);case ST_CONTENT_NON_CHUNK:// 处理非分块内容：对于 ST_CONTENT_NON_CHUNK 状态，首先获取内容的长度 contentLength(msg)final long contentLength = contentLength(msg);if (contentLength > 0) {// 如果内容长度大于零且 buf 缓冲区有足够的可写空间，则将内容合并到 buf 中（提高性能，避免频繁分配新的缓冲区）if (buf != null && buf.writableBytes() >= contentLength && msg instanceof HttpContent) {buf.writeBytes(((HttpContent<?>) msg).payload());Resource.dispose(msg);out.add(buf);} else {if (buf != null) {out.add(buf);}out.add(encode(msg));}// 如果 msg 是 LastHttpContent（即最后一部分 HTTP 内容），则将 state 重置为 ST_INIT，表示处理完成if (msg instanceof LastHttpContent) {state = ST_INIT;}break;} else {// do not break, let's fall-through}// fall-through!case ST_CONTENT_ALWAYS_EMPTY:Resource.dispose(msg);if (buf != null) {out.add(buf);} else {out.add(ctx.bufferAllocator().allocate(0));}break;case ST_CONTENT_CHUNK:// 先将现有的缓冲区 buf 添加到 out 中if (buf != null) {// We allocated a buffer so add it now.out.add(buf);}// 处理分块传输编码（chunked transfer encoding）内容encodeChunkedContent(ctx, msg, contentLength(msg), out);break;default:throw new Error();}if (msg instanceof LastHttpContent) {state = ST_INIT;}} else if (buf != null) {out.add(buf);}}// 将传入的 HttpHeaders 对象中的所有头部字段逐个编码，并将编码后的字节数据写入 buf 中protected void encodeHeaders(HttpHeaders headers, Buffer buf) {for (Entry<CharSequence, CharSequence> header : headers) {HttpHeadersEncoder.encoderHeader(header.getKey(), header.getValue(), buf);}}// 负责将数据分块并添加到 out 列表中。具体处理流程包括：// 1. 编码分块大小并将其添加到输出缓冲区。// 2. 处理 LastHttpContent，如果有尾部头部（trailers），则处理并编码它们。// 3. 处理内容长度为 0 的情况，不进行分块传输，直接将消息添加到输出列表。private void encodeChunkedContent(ChannelHandlerContext ctx, Object msg, long contentLength, List<Object> out) {if (contentLength > 0) {String lengthHex = Long.toHexString(contentLength);Buffer buf = ctx.bufferAllocator().allocate(lengthHex.length() + 2);buf.writeCharSequence(lengthHex, StandardCharsets.US_ASCII);buf.writeShort(CRLF_SHORT);out.add(buf);out.add(encode(msg));out.add(crlfBuffer(ctx.bufferAllocator()));}if (msg instanceof LastHttpContent) {HttpHeaders headers = ((LastHttpContent<?>) msg).trailingHeaders();if (headers.isEmpty()) {out.add(zeroCrlfCrlfBuffer(ctx.bufferAllocator()));} else {Buffer buf = ctx.bufferAllocator().allocate((int) trailersEncodedSizeAccumulator);buf.writeMedium(ZERO_CRLF_MEDIUM);encodeHeaders(headers, buf);buf.writeShort(CRLF_SHORT);trailersEncodedSizeAccumulator = TRAILERS_WEIGHT_NEW * padSizeForAccumulation(buf.readableBytes()) +TRAILERS_WEIGHT_HISTORICAL * trailersEncodedSizeAccumulator;out.add(buf);}if (contentLength == 0) {// EmptyLastHttpContent or LastHttpContent with empty payload((LastHttpContent<?>) msg).close();}} else if (contentLength == 0) {out.add(encode(msg));}}// 在编码消息之前清理其头部，默认实现为空操作（noop），但可以根据需要进行扩展。protected void sanitizeHeadersBeforeEncode(@SuppressWarnings("unused") H msg, boolean isAlwaysEmpty) {// noop}// 判断某些特殊消息（如 `HEAD` 或 `CONNECT` 请求）是否始终没有消息体，以便跳过内容处理。protected boolean isContentAlwaysEmpty(@SuppressWarnings("unused") H msg) {return false;}// 判断是否接受传出的消息。// 检查消息是否为 HttpObject、Buffer 或 FileRegion 类型，只有这些类型的消息才会被接受并继续处理@Overridepublic boolean acceptOutboundMessage(Object msg) throws Exception {return msg instanceof HttpObject || msg instanceof Buffer || msg instanceof FileRegion;}private static Object encode(Object msg) {if (msg instanceof Buffer) {return msg;}if (msg instanceof HttpContent) {return ((HttpContent<?>) msg).payload();}if (msg instanceof FileRegion) {return msg;}Resource.dispose(msg);throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg));}private static long contentLength(Object msg) {if (msg instanceof HttpContent) {return ((HttpContent<?>) msg).payload().readableBytes();}if (msg instanceof Buffer) {return ((Buffer) msg).readableBytes();}if (msg instanceof FileRegion) {return ((FileRegion) msg).count();}Resource.dispose(msg);throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg));}// 为缓冲区增加一些额外的空间。其目的是避免内存过度分配和防止在需要时发生缓冲区扩展或复制private static int padSizeForAccumulation(int readableBytes) {return (readableBytes << 2) / 3;}// GET /index.html HTTP/1.1// HTTP/1.1 200 OKprotected abstract void encodeInitialLine(Buffer buf, H message) throws Exception;// \r\nprotected Buffer crlfBuffer(BufferAllocator allocator) {if (crlfBufferSupplier == null) {crlfBufferSupplier = allocator.constBufferSupplier(CRLF);}return crlfBufferSupplier.get();}// 0\r\n\r\nprotected Buffer zeroCrlfCrlfBuffer(BufferAllocator allocator) {if (zeroCrlfCrlfBufferSupplier == null) {zeroCrlfCrlfBufferSupplier = allocator.constBufferSupplier(ZERO_CRLF_CRLF);}return zeroCrlfCrlfBufferSupplier.get();}
}

HttpRequestEncoder

HttpRequestEncoder 类用于将 HTTP 请求消息（HttpRequest）编码为符合 HTTP 协议规范的字节数据。它的主要任务是将请求的初始行（包括请求方法、URI 和协议版本）正确地编码到 Buffer 中，并处理 URI 中可能存在的一些细节（如缺失的斜杠或查询参数）。

/*** Encodes an {@link HttpRequest} or an {@link HttpContent} into a {@link Buffer}.*/
public class HttpRequestEncoder extends HttpObjectEncoder<HttpRequest> {private static final char SLASH = '/';private static final char QUESTION_MARK = '?';private static final short SLASH_AND_SPACE_SHORT = SLASH << 8 | SP;private static final int SPACE_SLASH_AND_SPACE_MEDIUM = SP << 16 | SLASH_AND_SPACE_SHORT;@Overridepublic boolean acceptOutboundMessage(Object msg) throws Exception {return super.acceptOutboundMessage(msg) && !(msg instanceof HttpResponse);}// GET /index.html HTTP/1.1@Overrideprotected void encodeInitialLine(Buffer buf, HttpRequest request) throws Exception {buf.writeCharSequence(request.method().asciiName(), StandardCharsets.US_ASCII);String uri = request.uri();if (uri.isEmpty()) {// Add " / " as absolute path if uri is not present.// See https://tools.ietf.org/html/rfc2616#section-5.1.2buf.writeMedium(SPACE_SLASH_AND_SPACE_MEDIUM);} else {CharSequence uriCharSequence = uri;boolean needSlash = false;int start = uri.indexOf("://");if (start != -1 && uri.charAt(0) != SLASH) {start += 3;// Correctly handle query params.// See https://github.com/netty/netty/issues/2732int index = uri.indexOf(QUESTION_MARK, start);if (index == -1) {if (uri.lastIndexOf(SLASH) < start) {needSlash = true;}} else {if (uri.lastIndexOf(SLASH, index) < start) {uriCharSequence = new StringBuilder(uri).insert(index, SLASH);}}}buf.writeByte(SP).writeCharSequence(uriCharSequence, StandardCharsets.UTF_8);if (needSlash) {// write "/ " after uribuf.writeShort(SLASH_AND_SPACE_SHORT);} else {buf.writeByte(SP);}}request.protocolVersion().encode(buf);buf.writeShort(CRLF_SHORT);}
}

HttpResponseEncoder

HttpResponseEncoder 类用于将 HTTP 响应消息（HttpResponse）编码为符合 HTTP 协议规范的字节数据。它的主要任务是将响应的状态行（包括状态码、状态描述和协议版本）编码到 Buffer 中，并根据响应的状态（如 204 No Content 或 304 Not Modified）决定是否移除 Content-Length 和 Transfer-Encoding 等头部信息，以确保响应符合 HTTP 规范。

/*** Encodes an {@link HttpResponse} or an {@link HttpContent} into a {@link Buffer}.*/
public class HttpResponseEncoder extends HttpObjectEncoder<HttpResponse> {@Overridepublic boolean acceptOutboundMessage(Object msg) throws Exception {return super.acceptOutboundMessage(msg) && !(msg instanceof HttpRequest);}// HTTP/1.1 200 OK@Overrideprotected void encodeInitialLine(Buffer buf, HttpResponse response) throws Exception {response.protocolVersion().encode(buf);buf.writeByte(SP);response.status().encode(buf);buf.writeShort(CRLF_SHORT);}// 在响应头编码前，对响应头进行清理，去除不必要的 Content-Length 和 Transfer-Encoding 头，// 特别是对于无内容的响应（如 204 No Content、304 Not Modified）或 205 Reset Content 响应。@Overrideprotected void sanitizeHeadersBeforeEncode(HttpResponse msg, boolean isAlwaysEmpty) {if (isAlwaysEmpty) {HttpResponseStatus status = msg.status();if (status.codeClass() == HttpStatusClass.INFORMATIONAL ||status.code() == HttpResponseStatus.NO_CONTENT.code()) {msg.headers().remove(HttpHeaderNames.CONTENT_LENGTH);msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);} else if (status.code() == HttpResponseStatus.RESET_CONTENT.code()) {msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);msg.headers().set(HttpHeaderNames.CONTENT_LENGTH, HttpHeaderValues.ZERO);}}}// 根据响应的状态码判断该响应是否包含内容。// 如果是信息性状态、204 No Content、304 Not Modified 或 205 Reset Content 等，返回 true 表示响应没有内容；// 其他情况则返回 false，表示响应包含内容@Overrideprotected boolean isContentAlwaysEmpty(HttpResponse msg) {HttpResponseStatus status = msg.status();if (status.codeClass() == HttpStatusClass.INFORMATIONAL) {if (status.code() == HttpResponseStatus.SWITCHING_PROTOCOLS.code()) {return msg.headers().contains(HttpHeaderNames.SEC_WEBSOCKET_VERSION);}return true;}return status.code() == HttpResponseStatus.NO_CONTENT.code() ||status.code() == HttpResponseStatus.NOT_MODIFIED.code() ||status.code() == HttpResponseStatus.RESET_CONTENT.code();}
}

HttpObjectDecoder

public abstract class HttpObjectDecoder extends ByteToMessageDecoder {public static final int DEFAULT_MAX_INITIAL_LINE_LENGTH = 4096;public static final int DEFAULT_MAX_HEADER_SIZE = 8192;public static final boolean DEFAULT_CHUNKED_SUPPORTED = true;public static final boolean DEFAULT_VALIDATE_HEADERS = true;public static final int DEFAULT_INITIAL_BUFFER_SIZE = 128;public static final boolean DEFAULT_ALLOW_DUPLICATE_CONTENT_LENGTHS = false;private final boolean chunkedSupported;protected final HttpHeadersFactory headersFactory;protected final HttpHeadersFactory trailersFactory;private final boolean allowDuplicateContentLengths;private final Buffer parserScratchBuffer;private final HeaderParser headerParser;private final LineParser lineParser;private HttpMessage message;private long chunkSize;private long contentLength = Long.MIN_VALUE;private boolean chunked;private boolean isSwitchingToNonHttp1Protocol;private final AtomicBoolean resetRequested = new AtomicBoolean();// These will be updated by splitHeader(...)private AsciiString name;private String value;private LastHttpContent<?> trailer;private State currentState = State.SKIP_CONTROL_CHARS;protected HttpObjectDecoder() {this(new HttpDecoderConfig());}protected HttpObjectDecoder(HttpDecoderConfig config) {headersFactory = config.getHeadersFactory();trailersFactory = config.getTrailersFactory();parserScratchBuffer = MemoryManager.unpooledHeap(config.getInitialBufferSize());lineParser = new LineParser(parserScratchBuffer, config.getMaxInitialLineLength());headerParser = new HeaderParser(parserScratchBuffer, config.getMaxHeaderSize());chunkedSupported = config.isChunkedSupported();allowDuplicateContentLengths = config.isAllowDuplicateContentLengths();}@Overrideprotected void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {try (parserScratchBuffer) {super.handlerRemoved0(ctx);}}@Overrideprotected void decode(ChannelHandlerContext ctx, Buffer buffer) throws Exception {if (resetRequested.get()) {resetNow();}switch (currentState) {case SKIP_CONTROL_CHARS:// Fall-throughcase READ_INITIAL: try {// 跳过前面错误的ASCII码小于32的内容，解析第一行内容Buffer line = lineParser.parse(buffer);if (line == null) {return;}// 用于将初始行拆分成多个部分（如 HTTP 方法、URL 和协议版本）final String[] initialLine = splitInitialLine(line);assert initialLine.length == 3 : "initialLine::length must be 3";// 根据解析出的初始行创建消息对象message = createMessage(initialLine);currentState = State.READ_HEADER;// fall-through} catch (Exception e) {ctx.fireChannelRead(invalidMessage(ctx, message, buffer, e));return;}case READ_HEADER: try {// 解析 HTTP 头部信息，根据头部中的字段（如 Content-Length, Transfer-Encoding）决定解码后续的内容// 如果没有消息体（Content-Length == 0 或 -1 且是请求消息），则直接跳到下一步。// 如果是分块传输编码，跳转到 READ_CHUNK_SIZE。// 否则，继续读取固定长度或可变长度的消息体。State nextState = readHeaders(buffer);if (nextState == null) {return;}currentState = nextState;switch (nextState) {case SKIP_CONTROL_CHARS:addCurrentMessage(ctx);ctx.fireChannelRead(new EmptyLastHttpContent(ctx.bufferAllocator()));resetNow();return;case READ_CHUNK_SIZE:if (!chunkedSupported) {throw new IllegalArgumentException("Chunked messages not supported");}// Chunked encoding - generate HttpMessage first.  HttpChunks will follow.addCurrentMessage(ctx);return;default:if (contentLength == 0 || contentLength == -1 && isDecodingRequest()) {ctx.fireChannelRead(message);ctx.fireChannelRead(new EmptyLastHttpContent(ctx.bufferAllocator()));resetNow();return;}assert nextState == State.READ_FIXED_LENGTH_CONTENT ||nextState == State.READ_VARIABLE_LENGTH_CONTENT;addCurrentMessage(ctx);if (nextState == State.READ_FIXED_LENGTH_CONTENT) {chunkSize = contentLength;}return;}} catch (Exception e) {ctx.fireChannelRead(invalidMessage(ctx, message, buffer, e));return;}case READ_VARIABLE_LENGTH_CONTENT: {// 继续读取消息体，直到连接关闭。一般用于请求/响应没有明确的 Content-Length 或使用了 Transfer-Encoding: chunked。int toRead = buffer.readableBytes();if (toRead > 0) {Buffer content = buffer.split();ctx.fireChannelRead(new DefaultHttpContent(content));}return;}case READ_FIXED_LENGTH_CONTENT: {// 读取固定长度的消息体。如果读取到的字节数与剩余的 chunkSize 相等，则解码完成，跳转到下一个阶段。int toRead = buffer.readableBytes();if (toRead == 0) {return;}if (toRead > chunkSize) {toRead = (int) chunkSize;}Buffer content = buffer.readSplit(toRead);chunkSize -= toRead;if (chunkSize == 0) {// Read all content.ctx.fireChannelRead(new DefaultLastHttpContent(content, trailersFactory));resetNow();} else {ctx.fireChannelRead(new DefaultHttpContent(content));}return;}// 解析分块传输编码的块大小。每个块有自己的大小，解析出大小后进入 READ_CHUNKED_CONTENT 状态case READ_CHUNK_SIZE: try {Buffer line = lineParser.parse(buffer);if (line == null) {return;}assert line.countComponents() == 1: "line should have exactly one component";try (var componentIterator = line.forEachComponent()) {var component = componentIterator.first();int chunkSize = getChunkSize(component.readableArray(),component.readableArrayOffset() + line.readerOffset(),line.readableBytes());this.chunkSize = chunkSize;if (chunkSize == 0) {currentState = State.READ_CHUNK_FOOTER;return;}currentState = State.READ_CHUNKED_CONTENT;}// fall-through} catch (Exception e) {ctx.fireChannelRead(invalidChunk(ctx.bufferAllocator(), buffer, e));return;}// 读取分块内容，根据解析出的块大小读取数据。如果读取完成，跳到 READ_CHUNK_DELIMITER 状态。case READ_CHUNKED_CONTENT: {assert chunkSize <= Integer.MAX_VALUE;int toRead = (int) chunkSize;toRead = Math.min(toRead, buffer.readableBytes());if (toRead == 0) {return;}HttpContent<?> chunk = new DefaultHttpContent(buffer.readSplit(toRead));chunkSize -= toRead;ctx.fireChannelRead(chunk);if (chunkSize != 0) {return;}currentState = State.READ_CHUNK_DELIMITER;// fall-through}// 处理分块传输编码中的块分隔符（即 CRLF）。根据是否有剩余数据，决定是否继续读取下一个数据块。case READ_CHUNK_DELIMITER: {// include LF in the bytes to skipint bytesToSkip = buffer.bytesBefore(HttpConstants.LF) + 1;if (bytesToSkip > 0) {currentState = State.READ_CHUNK_SIZE;buffer.skipReadableBytes(bytesToSkip);} else {buffer.skipReadableBytes(buffer.readableBytes());}return;}// 解析分块传输编码的尾部，通常是 HTTP 头部中的 Trailer 信息。解析完成后重置状态。case READ_CHUNK_FOOTER: try {LastHttpContent<?> trailer = readTrailingHeaders(ctx.bufferAllocator(), buffer);if (trailer == null) {return;}ctx.fireChannelRead(trailer);resetNow();return;} catch (Exception e) {ctx.fireChannelRead(invalidChunk(ctx.bufferAllocator(), buffer, e));return;}// 处理错误的消息。如果解码过程中发生异常，会进入该状态并丢弃数据。case BAD_MESSAGE: {// Keep discarding until disconnection.buffer.skipReadableBytes(buffer.readableBytes());break;}// 处理协议升级。在这种情况下，解码器会将剩余的数据交给新的协议解码器继续处理。case UPGRADED: {int readableBytes = buffer.readableBytes();if (readableBytes > 0) {ctx.fireChannelRead(buffer.split());}break;}default:break;}}// ...
}

State

State 枚举定义了 HTTP 消息解码过程中各个阶段的状态。每个状态代表了解码器在解析 HTTP 消息时的不同步骤。

StateDescription
SKIP_CONTROL_CHARS跳过控制字符（如回车、换行符等）。
READ_INITIAL读取初始行（如请求行或响应行）。
READ_HEADER读取头部信息。
READ_VARIABLE_LENGTH_CONTENT读取可变长度的消息体。
READ_FIXED_LENGTH_CONTENT读取固定长度的消息体。
READ_CHUNK_SIZE读取分块传输编码中的块大小。
READ_CHUNKED_CONTENT读取分块传输编码中的数据内容。
READ_CHUNK_DELIMITER读取分块传输编码中的块分隔符（CRLF）。
READ_CHUNK_FOOTER读取分块传输编码的尾部（如结尾的 CRLF）。
BAD_MESSAGE解析过程中发生错误，无法继续解码。
UPGRADED协议已升级，用于处理协议升级。

这些状态帮助控制解码器在不同解析阶段的行为，确保按正确的顺序和格式解析 HTTP 消息。

private enum State {SKIP_CONTROL_CHARS,READ_INITIAL,READ_HEADER,READ_VARIABLE_LENGTH_CONTENT,READ_FIXED_LENGTH_CONTENT,READ_CHUNK_SIZE,READ_CHUNKED_CONTENT,READ_CHUNK_DELIMITER,READ_CHUNK_FOOTER,BAD_MESSAGE,UPGRADED
}

HeaderParser

HeaderParser 类用于解析 HTTP 请求或响应头部的内容。它接收一个缓冲区 Buffer，逐步解析其中的数据，并将解析结果存储在 seq 中。它会根据最大长度 maxLength 限制头部的解析大小，如果超过限制则抛出异常。该类还处理 CRLF（回车换行符）分隔符，确保解析到有效的头部数据，并且能够在头部数据解析完毕时更新缓冲区的读取位置。

private static class HeaderParser {protected final Buffer seq;protected final int maxLength;int size;HeaderParser(Buffer seq, int maxLength) {this.seq = seq;this.maxLength = maxLength;}public Buffer parse(Buffer buffer) {final int readableBytes = buffer.readableBytes();final int readerIndex = buffer.readerOffset();final int maxBodySize = maxLength - size;assert maxBodySize >= 0;// adding 2 to account for both CR (if present) and LF// don't remove 2L: it's key to cover maxLength = Integer.MAX_VALUEfinal long maxBodySizeWithCRLF = maxBodySize + 2L;final int toProcess = (int) Math.min(maxBodySizeWithCRLF, readableBytes);final int toIndexExclusive = readerIndex + toProcess;assert toIndexExclusive >= readerIndex;int toLf = buffer.bytesBefore(HttpConstants.LF);final int indexOfLf = readerIndex + toLf;if (toLf == -1) {if (readableBytes > maxBodySize) {// TODO: Respond with Bad Request and discard the traffic//    or close the connection.//       No need to notify the upstream handlers - just log.//       If decoding a response, just throw an exception.throw newException(maxLength);}return null;}final int endOfSeqIncluded;if (indexOfLf > readerIndex && buffer.getByte(indexOfLf - 1) == HttpConstants.CR) {// Drop CR if we had a CRLF pairendOfSeqIncluded = indexOfLf - 1;} else {endOfSeqIncluded = indexOfLf;}final int newSize = endOfSeqIncluded - readerIndex;if (newSize == 0) {seq.resetOffsets();buffer.readerOffset(indexOfLf + 1);return seq;}int size = this.size + newSize;if (size > maxLength) {throw newException(maxLength);}this.size = size;seq.resetOffsets();seq.ensureWritable(newSize, newSize, false);buffer.copyInto(readerIndex, seq, 0, newSize);seq.writerOffset(newSize);buffer.readerOffset(indexOfLf + 1);return seq;}public void reset() {size = 0;}protected TooLongFrameException newException(int maxLength) {return new TooLongHttpHeaderException("HTTP header is larger than " + maxLength + " bytes.");}
}

LineParser

LineParser 类继承自 HeaderParser，用于解析 HTTP 请求或响应的单行（如请求行、状态行或头部行）。它首先跳过控制字符（如回车、换行等），然后调用父类 HeaderParser 解析有效的 HTTP 行。类中的 skipControlChars 方法负责跳过这些不需要的字符，并在必要时抛出异常。如果超出了最大长度 maxLength，会抛出 TooLongHttpLineException 异常。

private final class LineParser extends HeaderParser {LineParser(Buffer seq, int maxLength) {super(seq, maxLength);}@Overridepublic Buffer parse(Buffer buffer) {// Suppress a warning because HeaderParser.reset() is supposed to be calledreset();final int readableBytes = buffer.readableBytes();if (readableBytes == 0) {return null;}final int readerIndex = buffer.readerOffset();if (currentState == State.SKIP_CONTROL_CHARS && skipControlChars(buffer, readableBytes, readerIndex)) {return null;}return super.parse(buffer);}private boolean skipControlChars(Buffer buffer, int readableBytes, int readerIndex) {assert currentState == State.SKIP_CONTROL_CHARS;final int maxToSkip = Math.min(maxLength, readableBytes);final int firstNonControlIndex = buffer.openCursor(readerIndex, maxToSkip).process(SKIP_CONTROL_CHARS_BYTES);if (firstNonControlIndex == -1) {buffer.skipReadableBytes(maxToSkip);if (readableBytes > maxLength) {throw newException(maxLength);}return true;}// from now on we don't care about control charsbuffer.readerOffset(readerIndex + firstNonControlIndex);currentState = State.READ_INITIAL;return false;}@Overrideprotected TooLongFrameException newException(int maxLength) {return new TooLongHttpLineException("An HTTP line is larger than " + maxLength + " bytes.");}
}

HttpRequestDecoder

HttpRequestDecoder 类用于解码 HTTP 请求消息（HttpRequest）并将其转换为 HttpMessage 对象。它继承自 HttpObjectDecoder，并通过解析请求行（包括请求方法、URI 和协议版本）以及请求头（如 Host、Content-Type、Content-Length）来完成解码过程。该类支持不同的 HTTP 方法（如 GET 和 POST）和协议版本（如 HTTP/1.0 和 HTTP/1.1）。它还能够根据特定的头部标识符对请求头进行拆分，以便正确识别请求中的各个字段。通过 HttpDecoderConfig，它允许自定义解码器的配置，如最大初始行长度和最大头部大小。

public class HttpRequestDecoder extends HttpObjectDecoder {private static final AsciiString Accept = AsciiString.cached("Accept");private static final AsciiString Host = AsciiString.cached("Host");private static final AsciiString Connection = AsciiString.cached("Connection");private static final AsciiString ContentType = AsciiString.cached("Content-Type");private static final AsciiString ContentLength = AsciiString.cached("Content-Length");private static final int GET_AS_INT = (int) charsToLong("GET");private static final int POST_AS_INT = (int) charsToLong("POST");private static final long HTTP_1_1_AS_LONG = charsToLong("HTTP/1.1");private static final long HTTP_1_0_AS_LONG = charsToLong("HTTP/1.0");;private static final int HOST_AS_INT = (int) charsToLong("Host");;private static final long CONNECTION_AS_LONG_0 = charsToLong("Connecti");private static final short CONNECTION_AS_SHORT_1 = (short) charsToLong("on");private static final long CONTENT_AS_LONG = charsToLong("Content-");;private static final int TYPE_AS_INT = (int) charsToLong("Type");private static final long LENGTH_AS_LONG = charsToLong("Length");private static final long ACCEPT_AS_LONG = charsToLong("Accept");private static long charsToLong(String cs) {long result = cs.charAt(0);int shift = 0;for (int i = 1; i < cs.length(); i++) {result |= (long) cs.charAt(i) << (shift += 8);}return result;}public HttpRequestDecoder() {}public HttpRequestDecoder(int maxInitialLineLength, int maxHeaderSize) {super(new HttpDecoderConfig().setMaxInitialLineLength(maxInitialLineLength).setMaxHeaderSize(maxHeaderSize));}public HttpRequestDecoder(HttpDecoderConfig config) {super(config);}// [GET, /index.html, HTTP/1.1]@Overrideprotected HttpMessage createMessage(String[] initialLine) throws Exception {return new DefaultHttpRequest(// Do strict version checkingHttpVersion.valueOf(initialLine[2], true),HttpMethod.valueOf(initialLine[0]), initialLine[1], headersFactory);}// 解析 HTTP 请求中的头部字段名（Header Name）@Overrideprotected AsciiString splitHeaderName(final byte[] sb, final int start, final int length) {// 获取头部字段的第一个字符final byte firstChar = sb[start];// 如果第一个字符是 'H'，检查是否是 "Host" 头部字段if (firstChar == 'H') {if (length == 4 && isHost(sb, start)) {return Host;}} // 如果第一个字符是 'A'，检查是否是 "Accept" 头部字段else if (firstChar == 'A') {if (length == 6 && isAccept(sb, start)) {return Accept;}} // 如果第一个字符是 'C'，检查是否是 "Connection"、"Content-Type" 或 "Content-Length" 头部字段else if (firstChar == 'C') {if (length == 10) {if (isConnection(sb, start)) {return Connection;}} else if (length == 12) {if (isContentType(sb, start)) {return ContentType;}} else if (length == 14) {if (isContentLength(sb, start)) {return ContentLength;}}}// 如果没有匹配的情况，调用父类方法来处理return super.splitHeaderName(sb, start, length);}// 解析 HTTP 请求的初始行，并识别出 HTTP 方法@Overrideprotected String splitFirstWordInitialLine(final byte[] sb, final int start, final int length) {if (length == 3) {if (isGetMethod(sb, start)) {return HttpMethod.GET.name();}} else if (length == 4) {if (isPostMethod(sb, start)) {return HttpMethod.POST.name();}}return super.splitFirstWordInitialLine(sb, start, length);}// 解析 HTTP 请求的初始行，并识别出 HTTP 版本@Overrideprotected String splitThirdWordInitialLine(final byte[] sb, final int start, final int length) {if (length == 8) {final long maybeHttp1_x = sb[start] |sb[start + 1] << 8 |sb[start + 2] << 16 |sb[start + 3] << 24 |(long) sb[start + 4] << 32 |(long) sb[start + 5] << 40 |(long) sb[start + 6] << 48 |(long) sb[start + 7] << 56;if (maybeHttp1_x == HTTP_1_1_AS_LONG) {return HttpVersion.HTTP_1_1_STRING;} else if (maybeHttp1_x == HTTP_1_0_AS_LONG) {return HttpVersion.HTTP_1_0_STRING;}}return super.splitThirdWordInitialLine(sb, start, length);}@Overrideprotected HttpMessage createInvalidMessage(ChannelHandlerContext ctx) {return new DefaultFullHttpRequest(HttpVersion.HTTP_1_0, HttpMethod.GET, "/bad-request",ctx.bufferAllocator().allocate(0), headersFactory, trailersFactory);}// 指示当前正在解析的是一个 HTTP 请求而不是响应@Overrideprotected boolean isDecodingRequest() {return true;}// 判断消息类型来优化内容解析，对于 `DefaultHttpRequest` 返回 `false` 表示请求可能包含内容，而其他类型的消息则交由父类处理。@Overrideprotected boolean isContentAlwaysEmpty(final HttpMessage msg) {if (msg.getClass() == DefaultHttpRequest.class) {return false;}return super.isContentAlwaysEmpty(msg);}
}

HttpResponseDecoder

HttpResponseDecoder 类用于解析 HTTP 响应消息的初始行（版本、状态码和状态描述）和头部，生成对应的 HttpResponse 对象，并在解析失败时返回一个无效的响应。

public class HttpResponseDecoder extends HttpObjectDecoder {private static final HttpResponseStatus UNKNOWN_STATUS = new HttpResponseStatus(999, "Unknown");public HttpResponseDecoder() {}public HttpResponseDecoder(int maxInitialLineLength, int maxHeaderSize) {super(new HttpDecoderConfig().setMaxInitialLineLength(maxInitialLineLength).setMaxHeaderSize(maxHeaderSize));}public HttpResponseDecoder(HttpDecoderConfig config) {super(config);}@Overrideprotected HttpMessage createMessage(String[] initialLine) {return new DefaultHttpResponse(// Do strict version checkingHttpVersion.valueOf(initialLine[0], true),HttpResponseStatus.valueOf(Integer.parseInt(initialLine[1]), initialLine[2]), headersFactory);}@Overrideprotected HttpMessage createInvalidMessage(ChannelHandlerContext ctx) {return new DefaultFullHttpResponse(HttpVersion.HTTP_1_0, UNKNOWN_STATUS, ctx.bufferAllocator().allocate(0),headersFactory, trailersFactory);}@Overrideprotected boolean isDecodingRequest() {return false;}
}

本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。
如若转载，请注明出处：http://www.pswp.cn/bicheng/87956.shtml
繁体地址，请注明出处：http://hk.pswp.cn/bicheng/87956.shtml

如若内容造成侵权/违法违规/事实不符，请联系多彩编程网进行投诉反馈email:809451989@qq.com，一经查实，立即删除！

相关文章

uniapp的navigator跳转功能

uniapp的navigator跳转功能

接下来&#xff0c;我将围绕一个常见的电商小程序来构建一系列连贯的使用场景。在这个过程中&#xff0c;我们将把 <navigator> 组件的所有关键属性和方法都串联起来&#xff0c;并详细解释它们在每个环节所扮演的角色和作用。 核心场景&#xff1a;构建一个电商小程序的…
阅读更多...
v-for的用法及案例

v-for的用法及案例

目录 一.v-for的用法 1.举例1 2.举例2 二.购物车案例 1.代码 2.存在的问题&#xff1a;复选框错位 3.解决方案&#xff1a; 赋值给key属性一个唯一的值 一.v-for的用法 1.举例1 <template><view><view v-for"(item,index) in 10" :key"…
阅读更多...
BigQuery对象引用（ObjectRef）全面指南：一站式整合结构化与非结构化多模态数据分析

BigQuery对象引用（ObjectRef）全面指南：一站式整合结构化与非结构化多模态数据分析

引言 企业需要同时管理有组织表格中的结构化数据&#xff0c;以及日益增长的非结构化数据&#xff08;如图片、音频和文档&#xff09;。传统上&#xff0c;联合分析这些多样化数据类型非常复杂&#xff0c;通常需要使用不同的工具。非结构化媒体通常需要导出到专门的服务进行…
阅读更多...
【开源品鉴】FRP源码阅读

【开源品鉴】FRP源码阅读

frp 是一款高性能的反向代理应用&#xff0c;专注于内网穿透&#xff0c;支持多种协议和 P2P 通信功能&#xff0c;目前在 GitHub 上已有 80k 的 star。本文将深入探讨其源码&#xff0c;揭示其背后的实现原理。1. 前言 frp 是一款高性能的反向代理应用&#xff0c;专注于内网…
阅读更多...
day048-系统负载高排查流程与前后端分离项目

day048-系统负载高排查流程与前后端分离项目

文章目录 0. 老男孩思想1. 系统负载高排查流程1.1 进程/线程相关命令1.1.1 jps1.1.2 jstack1.1.3 jmap1.1.4 top -Hp pid 1.2 排查流程图 2. 前后端分离项目2.1 项目说明2.2 负载均衡2.3 数据库配置2.3.1 安装数据库服务2.3.2 配置数据库环境 2.4 后端配置2.5 四层负载均衡配置…
阅读更多...
Spring Boot 牵手EasyExcel：解锁高效数据处理姿势

Spring Boot 牵手EasyExcel：解锁高效数据处理姿势

引言 在日常的 Java 开发中&#xff0c;处理 Excel 文件是一个极为常见的需求。无论是数据的导入导出&#xff0c;还是报表的生成&#xff0c;Excel 都扮演着重要的角色。例如&#xff0c;在企业的财务管理系统中&#xff0c;需要将每月的财务数据导出为 Excel 报表&#xff0…
阅读更多...
【ARM AMBA AXI 入门 21 -- AXI partial 访问和 narrow 访问的区别】

【ARM AMBA AXI 入门 21 -- AXI partial 访问和 narrow 访问的区别】

文章目录 Overview一、定义区别二、AXI 信号层面对比三、举例说明示例一：Partial Access示例二：Narrow Access四、硬件/系统处理角度五、AXI 总线接口信号举例对比Partial Write 事务：Narrow Write 事务（32-bit Master on 64-bit Bus）：六、总结对比表七，软件判断判断 Pa…
阅读更多...
使用Ideal创建一个spring boot的helloWorld项目

使用Ideal创建一个spring boot的helloWorld项目

说明&#xff1a;本篇将介绍如何使用Ideal2024.2.1去创建一个spring boot的helloWorld项目&#xff0c;本篇将包含创建的详细步骤以及spring boot项目的目录结构说明&#xff0c;创建过程中的选项说明等。详细步骤如下&#xff1a;第一步&#xff1a;点击文件——新建——项目&…
阅读更多...
国内Ubuntu访问不了github等外网

国内Ubuntu访问不了github等外网

各位小伙伴们&#xff0c;大家好呀。 大家是不是经常遇到访问不了外网的情况呀。 在Ubuntu中可以这样做。 访问这个网站网站测速-Ping检测-Trace查询-Dig查询-路由跟踪查询-tools.ipip.net&#xff0c; 对于github.com&#xff0c;在这个网站输入github.com&#xff0c;会返…
阅读更多...
PDF转换工具，即开即用

PDF转换工具，即开即用

在办公室里&#xff0c;这句话被反复验证。每天面对成堆的Word和Excel文件&#xff0c;将它们转换成PDF格式是常有的事。可之前用过的工具&#xff0c;不是一次只能转一个&#xff0c;就是操作繁琐得让人头疼。记得有次赶项目&#xff0c;需要把二十多个文档转成PDF&#xff0c…
阅读更多...
2. 你可以说一下 http 版本的发展过程吗

2. 你可以说一下 http 版本的发展过程吗

你可以说一下 http 版本的发展过程吗 总结&#xff1a;0.9&#xff1a;只能发送 get&#xff0c;无状态。1.0&#xff1a;新增 post&#xff0c;请求头&#xff0c;状态码&#xff0c;cookie。1.1&#xff1a;新增 put/delete/options/patch&#xff0c;keep-alive&#xff0c…
阅读更多...
04-Linux驱动模块的自动加载

04-Linux驱动模块的自动加载

概述 上一节&#xff0c;我们讲述了Linux驱动开发的基本的模块代码编写和手动执行模块加载的操作&#xff0c; 这一节&#xff0c;我们讲述嵌入式设备上使用Sysvint引导方式下如何开机自动加载模块的步骤。感兴趣的同学看下使用systemd引导方式的开启自动加载模块的步骤 操作…
阅读更多...
【牛客算法】游游的整数切割

【牛客算法】游游的整数切割

文章目录 一、题目介绍1.1 题目链接1.2 题目描述1.3 输入描述1.4 输出描述1.5 示例二、解题思路2.1 核心算法设计2.2 性能优化关键2.3 算法流程图三、解法实现3.1 解法一：基础遍历法3.1.1 初级版本分析3.2 解法二：奇偶预统计法（推荐）3.2.1 优化版本分析四、总结与拓展4.1 关…
阅读更多...
笔记本电脑忽亮忽暗问题

笔记本电脑忽亮忽暗问题

关于笔记本电脑忽亮忽暗的问题这个问题困扰了我大半年&#xff0c;最后忽然找到解决方法了---主要的话有三种可能性1.关闭显示器自动调亮的功能2.关闭节能模式自动调亮功能3.调整显卡的功率&#xff0c;关闭自动调亮功能一开始一直都是尝试的第一种方法&#xff0c;没解决。。。…
阅读更多...
Qt的顶部工具栏在多个界面使用

Qt的顶部工具栏在多个界面使用

Qt的工具栏在多个界面使用1、前言2、创建一个工具栏类2.1 新建一个工具栏类3、提升工具栏类3.1登录界面添加工具栏3.2 创建工具栏对象4、总结1、前言 今天遇到了个问题&#xff0c;顶部的工具栏&#xff0c;像软键盘&#xff0c;时间显示和退出按钮那些&#xff0c;想在多个界…
阅读更多...
C#和SQL Server连接常用通讯方式

C#和SQL Server连接常用通讯方式

C#和SQL Server连接通讯 在 C# 中与 SQL Server 建立数据库连接&#xff0c;主要通过 ADO.NET 技术实现。以下是几种常见的连接方式及相关实践&#xff1a; ADO.NET 全面指南&#xff1a;C# 数据库访问核心技术 ADO.NET 是 .NET Framework 中用于数据访问的核心组件&#xf…
阅读更多...
安卓10.0系统修改定制化____实现自动开启 USB 调试​的步骤解析 列举常用的几种修改方法

安卓10.0系统修改定制化____实现自动开启 USB 调试​的步骤解析 列举常用的几种修改方法

对于安卓开发者、测试人员，甚至是喜欢折腾手机的数码爱好者来说，USB 调试是一个非常重要的功能。它能让手机与电脑相连，实现应用安装、系统调试、数据传输等操作。但每次连接手机都要手动去设置里开启 USB 调试，实在麻烦。其实，通过修改安卓 10.0 的 ROM，就能让手机自动开…
阅读更多...
Redisson详细教程 - 从入门到精通

Redisson详细教程 - 从入门到精通

目录 1. 什么是Redisson 2. 为什么要用Redisson 3. 环境准备和配置 4. 基础使用方法 5. 分布式数据结构 6. 分布式锁详解 7. 分布式服务 8. 实际应用场景 9. 最佳实践 10. 常见问题解答 总结 1. 什么是Redisson 简单理解 想象一下，Redis就像一个超级强大的"内…
阅读更多...
动态规划VS记忆化搜索（2)

动态规划VS记忆化搜索（2)

luoguP1434滑雪 题目描述 Michael 喜欢滑雪。这并不奇怪&#xff0c;因为滑雪的确很刺激。可是为了获得速度&#xff0c;滑的区域必须向下倾斜&#xff0c;而且当你滑到坡底&#xff0c;你不得不再次走上坡或者等待升降机来载你。Michael 想知道在一个区域中最长的滑坡。区域由…
阅读更多...
如何将服务守护进程化

如何将服务守护进程化

进程组 什么是进程组 之前我们提到了进程的概念&#xff0c; 其实每一个进程除了有一个进程 ID(PID)之外 还属于一个进程组。进程组是一个或者多个进程的集合&#xff0c; 一个进程组可以包含多个进程。 每一个进程组也有一个唯一的进程组 ID(PGID)&#xff0c; 并且这个 PGID …
阅读更多...
最新文章

Copyright @ 2022~2023