Develop C Apps

• YEDIS

Prerequisites

The tutorial assumes that you have:

• installed YugabyteDB, created a universe and are able to interact with it using the Redis shell. Ifnot please follow these steps in the Quick Start guide.
• have C++11.

Installing the Redis C++ driver

We use the cpp_redis driver. To install the library do the following:

• Clone the cpp_redis repository

$ git clone https://github.com/Cylix/cpp_redis.git

• Get the networking module (tacopie)

$ cd cpp_redis
$ git submodule init && git submodule update

• Create a build directory and move into it

$ mkdir build && cd build

• Generate the Makefile using CMake

$ cmake .. -DCMAKE_BUILD_TYPE=Release

• Build and install the library

$ make
$ make install

Writing a hello world Redis application

Create a file ybredis_hello_world.cpp and copy the contents below:

#include <cpp_redis/cpp_redis>
#include<iostream>
#include<vector>
#include<string>
#include<utility>
using namespace std;
int main() {
  cpp_redis::client client;
  client.connect("127.0.0.1", 6379, [](const std::string& host, std::size_t port, cpp_redis::client::connect_state status) {
    if (status == cpp_redis::client::connect_state::dropped) {
      std::cout << "client disconnected from " << host << ":" << port << std::endl;
    }
  });
  string userid = "1";
  vector<pair<string, string>> userProfile;
  userProfile.push_back(make_pair("name", "John"));
  userProfile.push_back(make_pair("age", "35"));
  userProfile.push_back(make_pair("language", "Redis"));
  // Insert the data
  client.hmset(userid, userProfile, [](cpp_redis::reply& reply) {
      cout<< "HMSET returned " << reply << ": id=1, name=John, age=35, language=Redis" << endl;
  });
  // Query the data
  client.hgetall(userid, [](cpp_redis::reply& reply) {
    std::vector<cpp_redis::reply> retVal;
    if (reply.is_array()) {
      retVal = reply.as_array();
    }
    cout << "Query result:" <<endl;
    for (int i = 0; i < retVal.size(); i=i+2) {
      cout << retVal[i] << "=" <<retVal[i+1] << endl;
    }
  });
  // synchronous commit, no timeout
  client.sync_commit();
  return 0;
}

Running the application

To compile the file, run the following command.

$ g++ -ltacopie -lcpp_redis -std=c++11 -o ybredis_hello_world ybredis_hello_world.cpp

To run the application, run the following command.

$ ./ybredis_hello_world

You should see the following output.

HMSET returned OK: id=1, name=John, age=35, language=Redis
Query result:
age=35
language=Redis
name=John