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HttpComponents HttpClient - Cache
/*
* ====================================================================
* 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
* .
*
*/
package org.apache.http.impl.client.cache;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.http.Header;
import org.apache.http.client.utils.DateUtils;
/** This class provides for parsing and understanding Warning headers. As
* the Warning header can be multi-valued, but the values can contain
* separators like commas inside quoted strings, we cannot use the regular
* {@link Header#getElements()} call to access the values.
*/
class WarningValue {
private int offs;
private int init_offs;
private final String src;
private int warnCode;
private String warnAgent;
private String warnText;
private Date warnDate;
WarningValue(final String s) {
this(s, 0);
}
WarningValue(final String s, final int offs) {
this.offs = this.init_offs = offs;
this.src = s;
consumeWarnValue();
}
/** Returns an array of the parseable warning values contained
* in the given header value, which is assumed to be a
* Warning header. Improperly formatted warning values will be
* skipped, in keeping with the philosophy of "ignore what you
* cannot understand."
* @param h Warning {@link Header} to parse
* @return array of WarnValue
objects
*/
public static WarningValue[] getWarningValues(final Header h) {
final List out = new ArrayList();
final String src = h.getValue();
int offs = 0;
while(offs < src.length()) {
try {
final WarningValue wv = new WarningValue(src, offs);
out.add(wv);
offs = wv.offs;
} catch (final IllegalArgumentException e) {
final int nextComma = src.indexOf(',', offs);
if (nextComma == -1) {
break;
}
offs = nextComma + 1;
}
}
final WarningValue[] wvs = {};
return out.toArray(wvs);
}
/*
* LWS = [CRLF] 1*( SP | HT )
* CRLF = CR LF
*/
protected void consumeLinearWhitespace() {
while(offs < src.length()) {
switch(src.charAt(offs)) {
case '\r':
if (offs+2 >= src.length()
|| src.charAt(offs+1) != '\n'
|| (src.charAt(offs+2) != ' '
&& src.charAt(offs+2) != '\t')) {
return;
}
offs += 2;
break;
case ' ':
case '\t':
break;
default:
return;
}
offs++;
}
}
/*
* CHAR =
*/
private boolean isChar(final char c) {
final int i = c;
return (i >= 0 && i <= 127);
}
/*
* CTL =
*/
private boolean isControl(final char c) {
final int i = c;
return (i == 127 || (i >=0 && i <= 31));
}
/*
* separators = "(" | ")" | "<" | ">" | "@"
* | "," | ";" | ":" | "\" | <">
* | "/" | "[" | "]" | "?" | "="
* | "{" | "}" | SP | HT
*/
private boolean isSeparator(final char c) {
return (c == '(' || c == ')' || c == '<' || c == '>'
|| c == '@' || c == ',' || c == ';' || c == ':'
|| c == '\\' || c == '\"' || c == '/'
|| c == '[' || c == ']' || c == '?' || c == '='
|| c == '{' || c == '}' || c == ' ' || c == '\t');
}
/*
* token = 1*
*/
protected void consumeToken() {
if (!isTokenChar(src.charAt(offs))) {
parseError();
}
while(offs < src.length()) {
if (!isTokenChar(src.charAt(offs))) {
break;
}
offs++;
}
}
private boolean isTokenChar(final char c) {
return (isChar(c) && !isControl(c) && !isSeparator(c));
}
private static final String TOPLABEL = "\\p{Alpha}([\\p{Alnum}-]*\\p{Alnum})?";
private static final String DOMAINLABEL = "\\p{Alnum}([\\p{Alnum}-]*\\p{Alnum})?";
private static final String HOSTNAME = "(" + DOMAINLABEL + "\\.)*" + TOPLABEL + "\\.?";
private static final String IPV4ADDRESS = "\\d+\\.\\d+\\.\\d+\\.\\d+";
private static final String HOST = "(" + HOSTNAME + ")|(" + IPV4ADDRESS + ")";
private static final String PORT = "\\d*";
private static final String HOSTPORT = "(" + HOST + ")(\\:" + PORT + ")?";
private static final Pattern HOSTPORT_PATTERN = Pattern.compile(HOSTPORT);
protected void consumeHostPort() {
final Matcher m = HOSTPORT_PATTERN.matcher(src.substring(offs));
if (!m.find()) {
parseError();
}
if (m.start() != 0) {
parseError();
}
offs += m.end();
}
/*
* warn-agent = ( host [ ":" port ] ) | pseudonym
* pseudonym = token
*/
protected void consumeWarnAgent() {
final int curr_offs = offs;
try {
consumeHostPort();
warnAgent = src.substring(curr_offs, offs);
consumeCharacter(' ');
return;
} catch (final IllegalArgumentException e) {
offs = curr_offs;
}
consumeToken();
warnAgent = src.substring(curr_offs, offs);
consumeCharacter(' ');
}
/*
* quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
* qdtext = >
*/
protected void consumeQuotedString() {
if (src.charAt(offs) != '\"') {
parseError();
}
offs++;
boolean foundEnd = false;
while(offs < src.length() && !foundEnd) {
final char c = src.charAt(offs);
if (offs + 1 < src.length() && c == '\\'
&& isChar(src.charAt(offs+1))) {
offs += 2; // consume quoted-pair
} else if (c == '\"') {
foundEnd = true;
offs++;
} else if (c != '\"' && !isControl(c)) {
offs++;
} else {
parseError();
}
}
if (!foundEnd) {
parseError();
}
}
/*
* warn-text = quoted-string
*/
protected void consumeWarnText() {
final int curr = offs;
consumeQuotedString();
warnText = src.substring(curr, offs);
}
private static final String MONTH = "Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec";
private static final String WEEKDAY = "Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday";
private static final String WKDAY = "Mon|Tue|Wed|Thu|Fri|Sat|Sun";
private static final String TIME = "\\d{2}:\\d{2}:\\d{2}";
private static final String DATE3 = "(" + MONTH + ") ( |\\d)\\d";
private static final String DATE2 = "\\d{2}-(" + MONTH + ")-\\d{2}";
private static final String DATE1 = "\\d{2} (" + MONTH + ") \\d{4}";
private static final String ASCTIME_DATE = "(" + WKDAY + ") (" + DATE3 + ") (" + TIME + ") \\d{4}";
private static final String RFC850_DATE = "(" + WEEKDAY + "), (" + DATE2 + ") (" + TIME + ") GMT";
private static final String RFC1123_DATE = "(" + WKDAY + "), (" + DATE1 + ") (" + TIME + ") GMT";
private static final String HTTP_DATE = "(" + RFC1123_DATE + ")|(" + RFC850_DATE + ")|(" + ASCTIME_DATE + ")";
private static final String WARN_DATE = "\"(" + HTTP_DATE + ")\"";
private static final Pattern WARN_DATE_PATTERN = Pattern.compile(WARN_DATE);
/*
* warn-date = <"> HTTP-date <">
*/
protected void consumeWarnDate() {
final int curr = offs;
final Matcher m = WARN_DATE_PATTERN.matcher(src.substring(offs));
if (!m.lookingAt()) {
parseError();
}
offs += m.end();
warnDate = DateUtils.parseDate(src.substring(curr+1,offs-1));
}
/*
* warning-value = warn-code SP warn-agent SP warn-text [SP warn-date]
*/
protected void consumeWarnValue() {
consumeLinearWhitespace();
consumeWarnCode();
consumeWarnAgent();
consumeWarnText();
if (offs + 1 < src.length() && src.charAt(offs) == ' ' && src.charAt(offs+1) == '\"') {
consumeCharacter(' ');
consumeWarnDate();
}
consumeLinearWhitespace();
if (offs != src.length()) {
consumeCharacter(',');
}
}
protected void consumeCharacter(final char c) {
if (offs + 1 > src.length()
|| c != src.charAt(offs)) {
parseError();
}
offs++;
}
/*
* warn-code = 3DIGIT
*/
protected void consumeWarnCode() {
if (offs + 4 > src.length()
|| !Character.isDigit(src.charAt(offs))
|| !Character.isDigit(src.charAt(offs + 1))
|| !Character.isDigit(src.charAt(offs + 2))
|| src.charAt(offs + 3) != ' ') {
parseError();
}
warnCode = Integer.parseInt(src.substring(offs,offs+3));
offs += 4;
}
private void parseError() {
final String s = src.substring(init_offs);
throw new IllegalArgumentException("Bad warn code \"" + s + "\"");
}
/** Returns the 3-digit code associated with this warning.
* @return int
*/
public int getWarnCode() { return warnCode; }
/** Returns the "warn-agent" string associated with this warning,
* which is either the name or pseudonym of the server that added
* this particular Warning header.
* @return {@link String}
*/
public String getWarnAgent() { return warnAgent; }
/** Returns the human-readable warning text for this warning. Note
* that the original quoted-string is returned here, including
* escaping for any contained characters. In other words, if the
* header was:
*
* Warning: 110 fred "Response is stale"
*
* then this method will return "\"Response is stale\""
* (surrounding quotes included).
* @return {@link String}
*/
public String getWarnText() { return warnText; }
/** Returns the date and time when this warning was added, or
* null
if a warning date was not supplied in the
* header.
* @return {@link Date}
*/
public Date getWarnDate() { return warnDate; }
/** Formats a WarningValue
as a {@link String}
* suitable for including in a header. For example, you can:
*
* WarningValue wv = ...;
* HttpResponse resp = ...;
* resp.addHeader("Warning", wv.toString());
*
* @return {@link String}
*/
@Override
public String toString() {
if (warnDate != null) {
return String.format("%d %s %s \"%s\"", warnCode,
warnAgent, warnText, DateUtils.formatDate(warnDate));
} else {
return String.format("%d %s %s", warnCode, warnAgent, warnText);
}
}
}