DCHK Client Version 0.5.7 - Documentation |
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Structure to hold a IRIS/LWZ payload request descriptor. More...
#include <dchk.h>
The IRISLWZ_HEADER has as size of 6 Bytes and is used as payload request and answer descriptor in the communication with the DCHK-Server. In a request all fields are used, in an answer only header and transactionId.
Data Fields | |
unsigned char | authority_length |
the length of the authority field in the payload descriptor | |
unsigned char | header |
Payload Header. | |
unsigned short | max_response_length |
Total length of response packet. | |
unsigned short | transactionId |
A 16 bit value identifying the transaction. A 16 bit value identifying the transaction. This value will be returned in the payload response descriptor (Section 3.1.2) and can be used by clients to match requests with responses. Clients SHOULD NOT use sequential values. Clients MUST NOT set all the bits in this value to 1 (i.e. use a value of 0xFFFF). |
The bits of the payload header are ordered according to RFC 1166, where bit 0 is the most significant and bit 7 is the least significant. Each bit in the one octet payload header has the following meaning:
Bits | Mask | Description |
---|---|---|
0+1 | 64+128 | version number ('V' field) - If 0 (both bits are zero), the protocol is the version defined in this document. Otherwise, the rest of the bits in the header and the payload may be interpreted as another version. |
2 | 32 | request/response flag ('RR' flag) - If 0, this packet is a request (Section 3.1.1) packet. If 1, this packet is a response (Section 3.1.2) packet. |
3 | 16 | payload deflated ('PD' flag) - If 1, the payload is compressed using the DEFLATE algorithm (RFC 1951). |
4 | 8 | deflate supported ('DS' flag) - If 1, the sender of this packet supports compression using the DEFLATE algorithm (RFC 1951). When this bit is 0 in a request, the payload of the response MUST NOT be compressed with DEFLATE. If it is set, it does not necessarily mean the server will compress all answers. The server will only use compression, when an uncompressed answer will not fit in the answer packet. |
5 | 4 | reserved - This MUST be 0. |
6+7 | 1+2 | The value of these bits indicate payload types (See Payload Types) |
The total length of the UDP packet (i.e. UDP header length + payload descriptor length + XML payload length) that should not be exceeded when responding to this request. If the server cannot provide a response that is equal to or less than this value, then it MUST respond with size information.
The value must be stored in network byte order (use htons).
The value must be stored in network byte order (use htons).