Method write_head

lib_acl_cpp/src/http/http_client.cpp:335–415

}

bool http_client::write_head(const http_header& header)
{
	if (head_sent_) {
		return true;
	}
	head_sent_ = true;

	// �ȱ����Ƿ�Ϊ�鴫���״̬
	chunked_transfer_ = header.chunked_transfer();

	// �����Ӧ����ʱ������ gzip ���䷽ʽ������Ҫ�ȳ�ʼ�� zlib ������
	if (header.is_transfer_gzip()) {
		delete zstream_;
		zstream_ = NEW zlib_stream;
		if (zstream_->zip_begin(zlib_default, -zlib_wbits_15,
			zlib_mlevel_9)) {
			// ��ʼ�� crc32 У���
			gzip_crc32_ = zstream_->crc32_update(0, Z_NULL, 0);
		} else {
			logger_error("zip_begin error!");
			delete zstream_;
			zstream_ = NULL;

			// �����ʼ�� zip ʧ�ܣ���ǿ��ת���ɷ� zip ģʽ
			const_cast<http_header*>
				(&header)->set_transfer_gzip(false);
		}

		// ��ʼ����ѹ�������ܳ���
		gzip_total_in_ = 0;
	}

	// ���� HTTP ����/��Ӧͷ
	string buf;
	if (header.is_request()) {
		header.build_request(buf);
	} else {
		header.build_response(buf);
	}

	ostream& out = get_ostream();

	// ��д HTTP ͷ
	if (out.write(buf.c_str(), buf.length(), true,
		header.get_content_length() > 0) < 0) {

		disconnected_ = true;
		return false;
	} else if (zstream_ == NULL) {
		return true;
	}

	// ����Dz��� gzip ����ѹ����ʽ������Ҫ����� gzip ͷ

	/**
	 * RFC 1952 Section 2.3 defines the gzip header:
	 * +---+---+---+---+---+---+---+---+---+---+
	 * |ID1|ID2|CM |FLG|     MTIME     |XFL|OS |