/**
* Returns {@code true} if and only if the connection can remain open and thus 'kept alive'. This
* methods respects the value of the {@code "Connection"} header first and then the return value
* of {@link HttpVersion#isKeepAliveDefault()}.
*/
public static boolean isKeepAlive(HttpMessage message) {
String connection = message.headers().get(Names.CONNECTION);
if (connection != null && equalsIgnoreCase(Values.CLOSE, connection)) {
return false;
}
if (message.getProtocolVersion().isKeepAliveDefault()) {
return !equalsIgnoreCase(Values.CLOSE, connection);
} else {
return equalsIgnoreCase(Values.KEEP_ALIVE, connection);
}
}
/**
* Sets the value of the {@code "Connection"} header depending on the protocol version of the
* specified message. This getMethod sets or removes the {@code "Connection"} header depending on
* what the default keep alive mode of the message's protocol version is, as specified by {@link
* HttpVersion#isKeepAliveDefault()}.
*
* <ul>
* <li>If the connection is kept alive by default:
* <ul>
* <li>set to {@code "close"} if {@code keepAlive} is {@code false}.
* <li>remove otherwise.
* </ul>
* <li>If the connection is closed by default:
* <ul>
* <li>set to {@code "keep-alive"} if {@code keepAlive} is {@code true}.
* <li>remove otherwise.
* </ul>
* </ul>
*/
public static void setKeepAlive(HttpMessage message, boolean keepAlive) {
HttpHeaders h = message.headers();
if (message.getProtocolVersion().isKeepAliveDefault()) {
if (keepAlive) {
h.remove(Names.CONNECTION);
} else {
h.set(Names.CONNECTION, Values.CLOSE);
}
} else {
if (keepAlive) {
h.set(Names.CONNECTION, Values.KEEP_ALIVE);
} else {
h.remove(Names.CONNECTION);
}
}
}
/**
* Returns {@code true} if and only if the specified message contains the {@code "Expect:
* 100-continue"} header.
*/
public static boolean is100ContinueExpected(HttpMessage message) {
// Expect: 100-continue is for requests only.
if (!(message instanceof HttpRequest)) {
return false;
}
// It works only on HTTP/1.1 or later.
if (message.getProtocolVersion().compareTo(HttpVersion.HTTP_1_1) < 0) {
return false;
}
// In most cases, there will be one or zero 'Expect' header.
String value = message.headers().get(Names.EXPECT);
if (value == null) {
return false;
}
if (equalsIgnoreCase(Values.CONTINUE, value)) {
return true;
}
// Multiple 'Expect' headers. Search through them.
return message.headers().contains(Names.EXPECT, Values.CONTINUE, true);
}
public static boolean isKeepAlive(HttpMessage message) {
return HttpHeaders.isKeepAlive(message)
&& message.getProtocolVersion().equals(HttpVersion.HTTP_1_1);
}
