Simple C++-server to store byte arrays by key, uses leveldb as a backend
It is written using C++ on the top of boost::asio::io_service. Also contains Java client implementation.
On Ubuntu you can install requirements with apt install g++ libsnappy-dev libleveldb-dev librocksdb-dev libboost-all-dev
Riorita uses a very simple binary request-response protocol. It supports keep-alive out-of-the-box, a client should connect to the server via TCP and send requests. The client receives a response after each request.
The server closes a connection on any error, a client can reopen a connection.
Protocol uses LITTLE_ENDIAN byte order.
There three types of requests:
| Type | Byte value | Description | Parameters | Return value |
|---|---|---|---|---|
PING |
1 | Just ping a server to be sure that it is alive | No parameters | verdict is always 1 |
HAS |
2 | Checks that server has value by given key | String key | verdict is 1 if has and 0 if has no |
GET |
3 | Returns value by given key | String key | verdict is 1 if the server contains value by key or 0 in opposite case |
PUT |
4 | Puts value by given key, overwrites existing data | String key, byte[] value | verdict is always 1 |
DELETE |
5 | Deletes data by given key | String key | verdict is always 1 |
Each request has a form:
<total-request-size:4><magic-byte:1><protocol-version:1><request-type-byte-value:1><request-id:8> + <key-length:4><key-data:key-length>
where :x stands for the length of a field in bytes. Operator + stands for simple concatenation and used just to break long line.
Also if type is PUT the request is appended with:
<value-length:4><value-data:value-length>
For PING request the key should be empty (key-length=0).
Each response returns at least one boolean field: success, where success equals to 1 if and only if the request has been processed without unexpected errors. If success=1 then a response contains verdict (equals to 0 or 1), it stands for the result of operation.
Each response has a form:
<total-response-size:4><magic-byte:1><protocol-version:1><request-id:8><success:1>
If success=1 the response is appended with:
<verdict:1>
If request type was GET and verdict=1 then the response is appended with:
<value-length:4><value-data:value-length>