/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.impl.io;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.HttpMessage;
import org.apache.http.MessageConstraintException;
import org.apache.http.ParseException;
import org.apache.http.ProtocolException;
import org.apache.http.annotation.NotThreadSafe;
import org.apache.http.config.MessageConstraints;
import org.apache.http.io.HttpMessageParser;
import org.apache.http.io.SessionInputBuffer;
import org.apache.http.message.BasicLineParser;
import org.apache.http.message.LineParser;
import org.apache.http.params.HttpParamConfig;
import org.apache.http.params.HttpParams;
import org.apache.http.util.Args;
import org.apache.http.util.CharArrayBuffer;
/**
* Abstract base class for HTTP message parsers that obtain input from
* an instance of {@link SessionInputBuffer}.
*
* @since 4.0
*/
@SuppressWarnings("deprecation")
@NotThreadSafe
public abstract class AbstractMessageParser<T extends HttpMessage> implements HttpMessageParser<T> {
private static final int HEAD_LINE = 0;
private static final int HEADERS = 1;
private final SessionInputBuffer sessionBuffer;
private final MessageConstraints messageConstraints;
private final List<CharArrayBuffer> headerLines;
protected final LineParser lineParser;
private int state;
private T message;
/**
* Creates an instance of AbstractMessageParser.
*
* @param buffer the session input buffer.
* @param parser the line parser.
* @param params HTTP parameters.
*
* @deprecated (4.3) use {@link AbstractMessageParser#AbstractMessageParser(SessionInputBuffer,
* LineParser, MessageConstraints)}
*/
@Deprecated
public AbstractMessageParser(
final SessionInputBuffer buffer,
final LineParser parser,
final HttpParams params) {
super();
Args.notNull(buffer, "Session input buffer");
Args.notNull(params, "HTTP parameters");
this.sessionBuffer = buffer;
this.messageConstraints = HttpParamConfig.getMessageConstraints(params);
this.lineParser = (parser != null) ? parser : BasicLineParser.INSTANCE;
this.headerLines = new ArrayList<CharArrayBuffer>();
this.state = HEAD_LINE;
}
/**
* Creates new instance of AbstractMessageParser.
*
* @param buffer the session input buffer.
* @param lineParser the line parser. If {@code null} {@link BasicLineParser#INSTANCE}
* will be used.
* @param constraints the message constraints. If {@code null}
* {@link MessageConstraints#DEFAULT} will be used.
*
* @since 4.3
*/
public AbstractMessageParser(
final SessionInputBuffer buffer,
final LineParser lineParser,
final MessageConstraints constraints) {
super();
this.sessionBuffer = Args.notNull(buffer, "Session input buffer");
this.lineParser = lineParser != null ? lineParser : BasicLineParser.INSTANCE;
this.messageConstraints = constraints != null ? constraints : MessageConstraints.DEFAULT;
this.headerLines = new ArrayList<CharArrayBuffer>();
this.state = HEAD_LINE;
}
/**
* Parses HTTP headers from the data receiver stream according to the generic
* format as given in Section 3.1 of RFC 822, RFC-2616 Section 4 and 19.3.
*
* @param inbuffer Session input buffer
* @param maxHeaderCount maximum number of headers allowed. If the number
* of headers received from the data stream exceeds maxCount value, an
* IOException will be thrown. Setting this parameter to a negative value
* or zero will disable the check.
* @param maxLineLen maximum number of characters for a header line,
* including the continuation lines. Setting this parameter to a negative
* value or zero will disable the check.
* @return array of HTTP headers
* @param parser line parser to use. Can be {@code null}, in which case
* the default implementation of this interface will be used.
*
* @throws IOException in case of an I/O error
* @throws HttpException in case of HTTP protocol violation
*/
public static Header[] parseHeaders(
final SessionInputBuffer inbuffer,
final int maxHeaderCount,
final int maxLineLen,
final LineParser parser) throws HttpException, IOException {
final List<CharArrayBuffer> headerLines = new ArrayList<CharArrayBuffer>();
return parseHeaders(inbuffer, maxHeaderCount, maxLineLen,
parser != null ? parser : BasicLineParser.INSTANCE,
headerLines);
}
/**
* Parses HTTP headers from the data receiver stream according to the generic
* format as given in Section 3.1 of RFC 822, RFC-2616 Section 4 and 19.3.
*
* @param inbuffer Session input buffer
* @param maxHeaderCount maximum number of headers allowed. If the number
* of headers received from the data stream exceeds maxCount value, an
* IOException will be thrown. Setting this parameter to a negative value
* or zero will disable the check.
* @param maxLineLen maximum number of characters for a header line,
* including the continuation lines. Setting this parameter to a negative
* value or zero will disable the check.
* @param parser line parser to use.
* @param headerLines List of header lines. This list will be used to store
* intermediate results. This makes it possible to resume parsing of
* headers in case of a {@link java.io.InterruptedIOException}.
*
* @return array of HTTP headers
*
* @throws IOException in case of an I/O error
* @throws HttpException in case of HTTP protocol violation
*
* @since 4.1
*/
public static Header[] parseHeaders(
final SessionInputBuffer inbuffer,
final int maxHeaderCount,
final int maxLineLen,
final LineParser parser,
final List<CharArrayBuffer> headerLines) throws HttpException, IOException {
Args.notNull(inbuffer, "Session input buffer");
Args.notNull(parser, "Line parser");
Args.notNull(headerLines, "Header line list");
CharArrayBuffer current = null;
CharArrayBuffer previous = null;
for (;;) {
if (current == null) {
current = new CharArrayBuffer(64);
} else {
current.clear();
}
final int l = inbuffer.readLine(current);
if (l == -1 || current.length() < 1) {
break;
}
// Parse the header name and value
// Check for folded headers first
// Detect LWS-char see HTTP/1.0 or HTTP/1.1 Section 2.2
// discussion on folded headers
if ((current.charAt(0) == ' ' || current.charAt(0) == '\t') && previous != null) {
// we have continuation folded header
// so append value
int i = 0;
while (i < current.length()) {
final char ch = current.charAt(i);
if (ch != ' ' && ch != '\t') {
break;
}
i++;
}
if (maxLineLen > 0
&& previous.length() + 1 + current.length() - i > maxLineLen) {
throw new MessageConstraintException("Maximum line length limit exceeded");
}
previous.append(' ');
previous.append(current, i, current.length() - i);
} else {
headerLines.add(current);
previous = current;
current = null;
}
if (maxHeaderCount > 0 && headerLines.size() >= maxHeaderCount) {
throw new MessageConstraintException("Maximum header count exceeded");
}
}
final Header[] headers = new Header[headerLines.size()];
for (int i = 0; i < headerLines.size(); i++) {
final CharArrayBuffer buffer = headerLines.get(i);
try {
headers[i] = parser.parseHeader(buffer);
} catch (final ParseException ex) {
throw new ProtocolException(ex.getMessage());
}
}
return headers;
}
/**
* Subclasses must override this method to generate an instance of
* {@link HttpMessage} based on the initial input from the session buffer.
* <p>
* Usually this method is expected to read just the very first line or
* the very first valid from the data stream and based on the input generate
* an appropriate instance of {@link HttpMessage}.
*
* @param sessionBuffer the session input buffer.
* @return HTTP message based on the input from the session buffer.
* @throws IOException in case of an I/O error.
* @throws HttpException in case of HTTP protocol violation.
* @throws ParseException in case of a parse error.
*/
protected abstract T parseHead(SessionInputBuffer sessionBuffer)
throws IOException, HttpException, ParseException;
@Override
public T parse() throws IOException, HttpException {
final int st = this.state;
switch (st) {
case HEAD_LINE:
try {
this.message = parseHead(this.sessionBuffer);
} catch (final ParseException px) {
throw new ProtocolException(px.getMessage(), px);
}
this.state = HEADERS;
//$FALL-THROUGH$
case HEADERS:
final Header[] headers = AbstractMessageParser.parseHeaders(
this.sessionBuffer,
this.messageConstraints.getMaxHeaderCount(),
this.messageConstraints.getMaxLineLength(),
this.lineParser,
this.headerLines);
this.message.setHeaders(headers);
final T result = this.message;
this.message = null;
this.headerLines.clear();
this.state = HEAD_LINE;
return result;
default:
throw new IllegalStateException("Inconsistent parser state");
}
}
}