package com.firefly.codec.http2.hpack;
import com.firefly.codec.http2.hpack.HpackContext.Entry;
import com.firefly.codec.http2.hpack.HpackContext.StaticEntry;
import com.firefly.codec.http2.model.*;
import com.firefly.utils.lang.TypeUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.nio.ByteBuffer;
import java.util.EnumSet;
public class HpackEncoder {
private static final Logger log = LoggerFactory.getLogger("firefly-system");
private final static HttpField[] __status = new HttpField[599];
final static EnumSet<HttpHeader> __DO_NOT_HUFFMAN =
EnumSet.of(
HttpHeader.AUTHORIZATION,
HttpHeader.CONTENT_MD5,
HttpHeader.PROXY_AUTHENTICATE,
HttpHeader.PROXY_AUTHORIZATION);
final static EnumSet<HttpHeader> __DO_NOT_INDEX =
EnumSet.of(
// HttpHeader.C_PATH, // TODO more data needed
// HttpHeader.DATE, // TODO more data needed
HttpHeader.AUTHORIZATION,
HttpHeader.CONTENT_MD5,
HttpHeader.CONTENT_RANGE,
HttpHeader.ETAG,
HttpHeader.IF_MODIFIED_SINCE,
HttpHeader.IF_UNMODIFIED_SINCE,
HttpHeader.IF_NONE_MATCH,
HttpHeader.IF_RANGE,
HttpHeader.IF_MATCH,
HttpHeader.LOCATION,
HttpHeader.RANGE,
HttpHeader.RETRY_AFTER,
// HttpHeader.EXPIRES,
HttpHeader.LAST_MODIFIED,
HttpHeader.SET_COOKIE,
HttpHeader.SET_COOKIE2);
final static EnumSet<HttpHeader> __NEVER_INDEX =
EnumSet.of(
HttpHeader.AUTHORIZATION,
HttpHeader.SET_COOKIE,
HttpHeader.SET_COOKIE2);
static {
for (HttpStatus.Code code : HttpStatus.Code.values())
__status[code.getCode()] = new PreEncodedHttpField(HttpHeader.C_STATUS, Integer.toString(code.getCode()));
}
private final HpackContext _context;
private final boolean _debug;
private int _remoteMaxDynamicTableSize;
private int _localMaxDynamicTableSize;
private int _maxHeaderListSize;
private int _headerListSize;
public HpackEncoder() {
this(4096, 4096, -1);
}
public HpackEncoder(int localMaxDynamicTableSize) {
this(localMaxDynamicTableSize, 4096, -1);
}
public HpackEncoder(int localMaxDynamicTableSize, int remoteMaxDynamicTableSize) {
this(localMaxDynamicTableSize, remoteMaxDynamicTableSize, -1);
}
public HpackEncoder(int localMaxDynamicTableSize, int remoteMaxDynamicTableSize, int maxHeaderListSize) {
_context = new HpackContext(remoteMaxDynamicTableSize);
_remoteMaxDynamicTableSize = remoteMaxDynamicTableSize;
_localMaxDynamicTableSize = localMaxDynamicTableSize;
_maxHeaderListSize = maxHeaderListSize;
_debug = log.isDebugEnabled();
}
public int getMaxHeaderListSize() {
return _maxHeaderListSize;
}
public void setMaxHeaderListSize(int maxHeaderListSize) {
_maxHeaderListSize = maxHeaderListSize;
}
public HpackContext getHpackContext() {
return _context;
}
public void setRemoteMaxDynamicTableSize(int remoteMaxDynamicTableSize) {
_remoteMaxDynamicTableSize = remoteMaxDynamicTableSize;
}
public void setLocalMaxDynamicTableSize(int localMaxDynamicTableSize) {
_localMaxDynamicTableSize = localMaxDynamicTableSize;
}
public void encode(ByteBuffer buffer, MetaData metadata) {
if (log.isDebugEnabled())
log.debug(String.format("CtxTbl[%x] encoding", _context.hashCode()));
_headerListSize = 0;
int pos = buffer.position();
// Check the dynamic table sizes!
int maxDynamicTableSize = Math.min(_remoteMaxDynamicTableSize, _localMaxDynamicTableSize);
if (maxDynamicTableSize != _context.getMaxDynamicTableSize())
encodeMaxDynamicTableSize(buffer, maxDynamicTableSize);
// Add Request/response meta fields
if (metadata.isRequest()) {
MetaData.Request request = (MetaData.Request) metadata;
// TODO optimise these to avoid HttpField creation
String scheme = request.getURI().getScheme();
encode(buffer, new HttpField(HttpHeader.C_SCHEME, scheme == null ? HttpScheme.HTTP.asString() : scheme));
encode(buffer, new HttpField(HttpHeader.C_METHOD, request.getMethod()));
encode(buffer, new HttpField(HttpHeader.C_AUTHORITY, request.getURI().getAuthority()));
encode(buffer, new HttpField(HttpHeader.C_PATH, request.getURI().getPathQuery()));
} else if (metadata.isResponse()) {
MetaData.Response response = (MetaData.Response) metadata;
int code = response.getStatus();
HttpField status = code < __status.length ? __status[code] : null;
if (status == null)
status = new HttpField.IntValueHttpField(HttpHeader.C_STATUS, code);
encode(buffer, status);
}
// Add all the other fields
for (HttpField field : metadata)
encode(buffer, field);
// Check size
if (_maxHeaderListSize > 0 && _headerListSize > _maxHeaderListSize) {
log.warn("Header list size too large {} > {} for {}", _headerListSize, _maxHeaderListSize);
if (log.isDebugEnabled())
log.debug("metadata={}", metadata);
}
if (log.isDebugEnabled())
log.debug(String.format("CtxTbl[%x] encoded %d octets", _context.hashCode(), buffer.position() - pos));
}
public void encodeMaxDynamicTableSize(ByteBuffer buffer, int maxDynamicTableSize) {
if (maxDynamicTableSize > _remoteMaxDynamicTableSize)
throw new IllegalArgumentException();
buffer.put((byte) 0x20);
NBitInteger.encode(buffer, 5, maxDynamicTableSize);
_context.resize(maxDynamicTableSize);
}
public void encode(ByteBuffer buffer, HttpField field) {
if (field.getValue() == null)
field = new HttpField(field.getHeader(), field.getName(), "");
int field_size = field.getName().length() + field.getValue().length();
_headerListSize += field_size + 32;
final int p = _debug ? buffer.position() : -1;
String encoding = null;
// Is there an entry for the field?
Entry entry = _context.get(field);
if (entry != null) {
// Known field entry, so encode it as indexed
if (entry.isStatic()) {
buffer.put(((StaticEntry) entry).getEncodedField());
if (_debug)
encoding = "IdxFieldS1";
} else {
int index = _context.index(entry);
buffer.put((byte) 0x80);
NBitInteger.encode(buffer, 7, index);
if (_debug)
encoding = "IdxField" + (entry.isStatic() ? "S" : "") + (1 + NBitInteger.octectsNeeded(7, index));
}
} else {
// Unknown field entry, so we will have to send literally.
final boolean indexed;
// But do we know it's name?
HttpHeader header = field.getHeader();
// Select encoding strategy
if (header == null) {
// Select encoding strategy for unknown header names
Entry name = _context.get(field.getName());
if (field instanceof PreEncodedHttpField) {
int i = buffer.position();
((PreEncodedHttpField) field).putTo(buffer, HttpVersion.HTTP_2);
byte b = buffer.get(i);
indexed = b < 0 || b >= 0x40;
if (_debug)
encoding = indexed ? "PreEncodedIdx" : "PreEncoded";
}
// has the custom header name been seen before?
else if (name == null) {
// unknown name and value, so let's index this just in case it is
// the first time we have seen a custom name or a custom field.
// unless the name is changing, this is worthwhile
indexed = true;
encodeName(buffer, (byte) 0x40, 6, field.getName(), null);
encodeValue(buffer, true, field.getValue());
if (_debug)
encoding = "LitHuffNHuffVIdx";
} else {
// known custom name, but unknown value.
// This is probably a custom field with changing value, so don't index.
indexed = false;
encodeName(buffer, (byte) 0x00, 4, field.getName(), null);
encodeValue(buffer, true, field.getValue());
if (_debug)
encoding = "LitHuffNHuffV!Idx";
}
} else {
// Select encoding strategy for known header names
Entry name = _context.get(header);
if (field instanceof PreEncodedHttpField) {
// Preencoded field
int i = buffer.position();
((PreEncodedHttpField) field).putTo(buffer, HttpVersion.HTTP_2);
byte b = buffer.get(i);
indexed = b < 0 || b >= 0x40;
if (_debug)
encoding = indexed ? "PreEncodedIdx" : "PreEncoded";
} else if (__DO_NOT_INDEX.contains(header)) {
// Non indexed field
indexed = false;
boolean never_index = __NEVER_INDEX.contains(header);
boolean huffman = !__DO_NOT_HUFFMAN.contains(header);
encodeName(buffer, never_index ? (byte) 0x10 : (byte) 0x00, 4, header.asString(), name);
encodeValue(buffer, huffman, field.getValue());
if (_debug)
encoding = "Lit" +
((name == null) ? "HuffN" : ("IdxN" + (name.isStatic() ? "S" : "") + (1 + NBitInteger.octectsNeeded(4, _context.index(name))))) +
(huffman ? "HuffV" : "LitV") +
(indexed ? "Idx" : (never_index ? "!!Idx" : "!Idx"));
} else if (field_size >= _context.getMaxDynamicTableSize() || header == HttpHeader.CONTENT_LENGTH && field.getValue().length() > 2) {
// Non indexed if field too large or a content length for 3 digits or more
indexed = false;
encodeName(buffer, (byte) 0x00, 4, header.asString(), name);
encodeValue(buffer, true, field.getValue());
if (_debug)
encoding = "LitIdxNS" + (1 + NBitInteger.octectsNeeded(4, _context.index(name))) + "HuffV!Idx";
} else {
// indexed
indexed = true;
boolean huffman = !__DO_NOT_HUFFMAN.contains(header);
encodeName(buffer, (byte) 0x40, 6, header.asString(), name);
encodeValue(buffer, huffman, field.getValue());
if (_debug)
encoding = ((name == null) ? "LitHuffN" : ("LitIdxN" + (name.isStatic() ? "S" : "") + (1 + NBitInteger.octectsNeeded(6, _context.index(name))))) +
(huffman ? "HuffVIdx" : "LitVIdx");
}
}
// If we want the field referenced, then we add it to our
// table and reference set.
if (indexed)
if (_context.add(field) == null)
throw new IllegalStateException();
}
if (_debug) {
int e = buffer.position();
if (log.isDebugEnabled())
log.debug("encode {}:'{}' to '{}'", encoding, field, TypeUtils.toHexString(buffer.array(), buffer.arrayOffset() + p, e - p));
}
}
private void encodeName(ByteBuffer buffer, byte mask, int bits, String name, Entry entry) {
buffer.put(mask);
if (entry == null) {
// leave name index bits as 0
// Encode the name always with lowercase huffman
buffer.put((byte) 0x80);
NBitInteger.encode(buffer, 7, Huffman.octetsNeededLC(name));
Huffman.encodeLC(buffer, name);
} else {
NBitInteger.encode(buffer, bits, _context.index(entry));
}
}
static void encodeValue(ByteBuffer buffer, boolean huffman, String value) {
if (huffman) {
// huffman literal value
buffer.put((byte) 0x80);
NBitInteger.encode(buffer, 7, Huffman.octetsNeeded(value));
Huffman.encode(buffer, value);
} else {
// add literal assuming iso_8859_1
buffer.put((byte) 0x00);
NBitInteger.encode(buffer, 7, value.length());
for (int i = 0; i < value.length(); i++) {
char c = value.charAt(i);
if (c < ' ' || c > 127)
throw new IllegalArgumentException();
buffer.put((byte) c);
}
}
}
}