RequestExpectContinue.java 文件源码

@Override
public void process(final HttpRequest request, final HttpContext context)
        throws HttpException, IOException {
    Args.notNull(request, "HTTP request");

    if (!request.containsHeader(HTTP.EXPECT_DIRECTIVE)) {
        if (request instanceof HttpEntityEnclosingRequest) {
            final ProtocolVersion ver = request.getRequestLine().getProtocolVersion();
            final HttpEntity entity = ((HttpEntityEnclosingRequest)request).getEntity();
            // Do not send the expect header if request body is known to be empty
            if (entity != null
                    && entity.getContentLength() != 0 && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
                final HttpClientContext clientContext = HttpClientContext.adapt(context);
                final RequestConfig config = clientContext.getRequestConfig();
                if (config.isExpectContinueEnabled()) {
                    request.addHeader(HTTP.EXPECT_DIRECTIVE, HTTP.EXPECT_CONTINUE);
                }
            }
        }
    }
}