windows和Linux下mongocxx编译及使用说明

• 基于mongo-c-driver-1.13.0和mongo-cxx-driver-r3.4.0，地址分别为：mongo-cxx-driver 和 mongo-c-driver
• windows使用visual studio 2017编译release库，依赖boost1.66
• Linux使用系统自带的gcc和boost版本库，在ubuntu16.04编译成功

• mongo-c-driver-1.13.0

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local .. 

make
sudo make install

• mongo-cxx-driver-r3.4.0

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local ..

sudo make
sudo make install

需要注明的是需要sudo make ，目的是自动安装依赖库EP_mnmlstc_core

• mongo-c-driver-1.13.0

cmake.exe -G "Visual Studio 15 Win64"  "-DCMAKE_INSTALL_PREFIX=D:mongomongocdriver" ..

• mongo-cxx-driver-r3.4.0

cmake -G "Visual Studio 15 Win64" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=D:mongomongocxx -DCMAKE_PREFIX_PATH=D:mongomongocdriver -DLIBBSON_DIR=D:mongomongocdriver -DLIBMONGOC_DIR=D:mongomongocdriver -DBOOST_ROOT=D:developboost_1_66_0 -DBOOST_LIBRARYDIR=D:developboost_1_66_0lib64-msvc-14.1  ..

cmake.exe -G "Visual Studio 15"  "-DCMAKE_INSTALL_PREFIX=D:mongomongocdriver" ..

• mongo-cxx-driver-r3.4.0

cmake -G "Visual Studio 15" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=D:mongomongocxx -DCMAKE_PREFIX_PATH=D:mongomongocdriver -DLIBBSON_DIR=D:mongomongocdriver -DLIBMONGOC_DIR=D:mongomongocdriver -DBOOST_ROOT=D:developboost_1_66_0 -DBOOST_LIBRARYDIR=D:developboost_1_66_0lib64-msvc-14.1  ..

由于mongocxx使用了C++17的一些特性，如std::optional 和 std::string_view，而windows下visual studio 2017默认没有开启C++17，因此需要手动开启C++17支持。

• 开启方式

  visual studio 2017

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或者在CMake中添加

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /std:c++17")

linux平台CMake添加

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std:c++17")

• mongocxx::client vs mongocxx::pool区别

参考：http://mongocxx.org/mongocxx-v3/connection-pools/

A standalone mongocxx::client uses a single-threaded algorithm to monitor the state of the cluster it’s connected to. When connected to a replica set, the thread “stops the world” every 60 seconds to check the status of the cluster. A mongocxx::pool, on the other hand, uses a separate background thread for each server in the cluster, each of which checks the status of the server it monitors every 10 seconds. Because of the performance advantages of monitoring the cluster in the background rather than “stopping the world”, it’s highly recommended to use a mongocxx::pool rather than a set of standalone clients if your application has access to multiple threads, even if your application only uses one thread.

• 一个简单的实例

#include 
#include 
#include 
#include 
#include 

int main(int, char**) {
    auto mongouri = "mongodb://192.168.10.83:27017";
    mongocxx::instance inst{};
    mongocxx::client conn{ mongocxx::uri{mongouri} };
    bsoncxx::builder::stream::document document{};

    auto collection = conn["testdb"]["testcollection"];
    document << "hello" << "world";

    collection.insert_one(document.view());
    auto cursor = collection.find({});

    for (auto&& doc : cursor) {
        std::cout << bsoncxx::to_json(doc) << std::endl;
    }
    return 0;
}

• 使用连接池

#include 
#include 
#include 
#include 
#include 
#include 


int main(int, char**) {

    mongocxx::instance inst{};
    mongocxx::uri mongouri{ "mongodb://192.168.10.83:27017" };
    mongocxx::pool pool{mongouri};
    auto client = pool.acquire();
    auto collection = (*client)["testdb"]["testcollection"];
    bsoncxx::builder::stream::document document{};
    document << "hello" << "world";

    collection.insert_one(document.view());
    auto cursor = collection.find({});

    for (auto&& doc : cursor) {
        std::cout << bsoncxx::to_json(doc) << std::endl;
    }

    return 0;
}

MongoDB CXX Driver examples