/**
* Returns {@code true} if and only if the specified message contains the {@code "Expect:
* 100-continue"} header.
*/
public static boolean is100ContinueExpected(HttpHeader message) {
// Expect: 100-continue is for requests only.
if (!(message instanceof HttpRequestHeader)) {
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.getHeader(Names.EXPECT);
if (value == null) {
return false;
}
if (Values.CONTINUE.equalsIgnoreCase(value)) {
return true;
}
// Multiple 'Expect' headers. Search through them.
for (String v : message.getHeaders(Names.EXPECT)) {
if (Values.CONTINUE.equalsIgnoreCase(v)) {
return true;
}
}
return false;
}
/**
* Returns the header value with the specified header name. If there are more than one header
* value for the specified header name, the first value is returned.
*
* @return the header value or the {@code defaultValue} if there is no such header
*/
public static String getHeader(HttpHeader message, String name, String defaultValue) {
String value = message.getHeader(name);
if (value == null) {
return defaultValue;
}
return value;
}
/**
* 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(HttpHeader message) {
String connection = message.getHeader(Names.CONNECTION);
if (Values.CLOSE.equalsIgnoreCase(connection)) {
return false;
}
if (message.getProtocolVersion().isKeepAliveDefault()) {
return !Values.CLOSE.equalsIgnoreCase(connection);
} else {
return Values.KEEP_ALIVE.equalsIgnoreCase(connection);
}
}
/**
* Returns the length of the content. Please note that this value is not retrieved from {@link
* HttpContent#getContent()} but from the {@code "Content-Length"} header, and thus they are
* independent from each other.
*
* @return the content length or {@code defaultValue} if this message does not have the {@code
* "Content-Length"} header or its value is not a number
*/
public static long getContentLength(HttpHeader message, long defaultValue) {
String contentLength = message.getHeader(Names.CONTENT_LENGTH);
if (contentLength != null) {
try {
return Long.parseLong(contentLength);
} catch (NumberFormatException e) {
return defaultValue;
}
}
// We know the content length if it's a Web Socket message even if
// Content-Length header is missing.
long webSocketContentLength = getWebSocketContentLength(message);
if (webSocketContentLength >= 0) {
return webSocketContentLength;
}
// Otherwise we don't.
return defaultValue;
}
/** Returns the value of the {@code "Host"} header. */
public static String getHost(HttpHeader message) {
return message.getHeader(Names.HOST);
}
/**
* Returns the header value with the specified header name. If there are more than one header
* value for the specified header name, the first value is returned.
*
* @return the header value or {@code null} if there is no such header
*/
public static String getHeader(HttpHeader message, String name) {
return message.getHeader(name);
}