SSDB network protocol development

SSDB’s network protocol is super simple!

Message

Packet := Block+ '\n'Block  := Size '\n' Data '\n'Size   := literal_integer
Data   := size_bytes_of_data

Request

Request := Cmd BlocksCmd     := Block

Request commands include: get, set, del, ...

##Response

Response := Status BlockStatus   := Block

Response status codes include:

ok, not_found, error, fail, client_error

Example

Use telnet or nc command to connect to the SSDB server, then enter the following code (end with the last blank line):

3get3key

You will see something like Response like this:

2
ok
3
val

High-performance SSDB protocol parser

#include <stdlib.h>#include <string.h>int len = buffer->size();char ptr = buffer->data();while(len > 0){    char data = (char *)memchr(ptr, '\n', len);    if(data == NULL){        break;
    }
    data += 1;    int num = data - ptr;    if(num == 1 || (num == 2 && ptr[0] == '\r')){        // Packet received.        return OK;
    }    // Size received    int size = (int)strtol(ptr, NULL, 10);

    len -= num + size;
    ptr += num + size;    if(len >= 1 && ptr[0] = '\n'){
        len -= 1;
        ptr += 1;
    }else if(len >= 2 && ptr[0] == '\r' && ptr[1] == '\n'){
        len -= 2;
        ptr += 2;
    }else{        break;
    }    // Data received}

Suggestions for SDK developers: Data can contain any characters, including \r, \n, \0. .., so youdon’tthink that these characters will not appear in Data.