MongoDB-Cpp

A replacement for the mongo-cxx-driver that focuses on memory safety, speed, and ease of use. It uses the FastBSON library (https://github.com/Lumate/FastBSON-Cpp) to handle decoding and encoding BSON.

Prerequisites

This database driver requires the ZMQ libraries (and associated dependencies) and FastBSON. Build system requirements are CMake and a modern C++ compiler that is C++11 compliant.

Build Instructions

This software uses CMake as it's build system; as such out of source builds are preferred.

You should create a build directory in the source directory and cd to it.

To prepare for release (from the build directory) : cmake .. && make mongocpp

To run code coverage: cmake .. -DCMAKE_BUILD_TYPE=Debug && make mongo_coverage

To generate Cobertura xml output for code coverage: cmake .. -DCMAKE_BUILD_TYPE=Debug && make mongo_cobertura

Progress

This is an evolving work in progress; it implements the MongoDB wire protocol, and over time will evolve in both ease of use and power. The checklist at http://docs.mongodb.org/meta-driver/latest/legacy/mongodb-driver-requirements/ is used as a base.

What works?

• CRUD Operations (Create, remove, update, destroy)
• Database commands (through the runCommand function)
• BSON (de/en)coding
• Cursor support
• closing exhausted cursors

What's left?

• Authentication (not on any priority list)
• Simplified wrappers around common commands
• Graceful error handling (getting last error works, using it...)
• hint(), explain(), count(), $where (se second todo)
• profiling
• replica sets/slave OK, etc
• automatic reconnection (unsure what/how this means)

Getting Started

All database functions take additional parameters. See the function documentation for more information. In all examples, initialization lists of intitialization lists are bson::Documents

Creating a connection and connecting

mongo::MongoClient c;
c.connect("localhost"); //port is an optional string
// or
mongo::MongoClient c2("localhost", "27017"); //Again, port is optional

Finding elements in the DB

Finding a single element

const std::string FINDCOLL = "database.collection"
bson::Document d = c.findOne(FINDCOLL); // Find any single
bson::Document d = c.findOne(FINDCOLL, {{"a", 5}}); // Find one element matches {"a": 5}, second param is a bson::Document
bson::Document d = c.findOne(FINDCOLL, {{"a", 5}}, {{"a", 1}}); // Same as above, but only include the "a" field in the doc
bson::Document d = c.findOne(FINDCOLL, {{"a", 5}}, {{"a", 0}}); // Same as above, omit the "a" field (projections)

Finding all elements that matches

mongo::Cursor curr = c.find(FINDCOLL);
while (curr.more())
{
  bson::Document d =  curr.next();
}

Finding all elements takes the same parameters as findOne. See the function documentation for more details on the parameters

Inserting elements

const std::string INSCOLL = "database.collection";
c.insert(INSCOLL, {{"a", thing}});

Batch inserting is currently not supported (future work)

Removing elements

const std::string REMCOLL = "database.collection";
c.remove(REMCOLL, {{"a", thing}}); //remove a single element in the database that matches
c.remove(REMCOLL, {{"a", thing}}, true); //same as above
c.remove(REMCOLL, {{"a", thing}}, false); //Remove all elements that match

Updating elements

const std::string UPDCOLL = "database.collection";
c.update(UPDCOLL, {{"a", oldthing}}, {{"a", thing}});

Running database commands

const std::string DBNAME = "database";
bson::Document d = c.runCommand(DBNAME, {{"getLastError", 1}}); //Second parameter is formatted command

Commonly used commands will be wrapped in helper functions as progress continues