*** No longer developed -- see https://github.com/drivenet/gridfs_server/ ***

This is an Apache 2.2+ module that supports serving files from MongoDB GridFS.

See http://www.mongodb.org/ and http://docs.mongodb.org/manual/core/gridfs/ for more information.

See LICENSE file for licensing details.

Availability:
This code is available free of charge from https://bitbucket.org/onyxmaster/mod_gridfs/ (be sure to grab the "release" tag of the latest branch).
Old driver that is written in C and used MongoDB C driver is still available in the "c-driver" branch.

Building (see next section for Ubuntu fast-forward instructions):
Make sure you have g++, SConstruct and boost libraries (filesystem, system, thread) installed
Install Apache 2.2+ and APXS (choose worker MPM)
Grab the module from https://bitbucket.org/onyxmaster/mod_gridfs/, remember the absolute path to the directory (referenced as /path/to/mod_gridfs later on)
Grab MongoDB C++ driver from http://dl.mongodb.org/dl/cxx-driver (2.1+ required, 2.6+ not yet supported, don't use *-latest and unreleased versions), unpack it and go to its directory
Fix the driver build environment (build static library with PIC to allow module to be built as a shared library):
	echo 'env.Append(CCFLAGS="-fPIC")' >> SConstruct
Apply the GridFS patch (might need fixing for different driver versions):
	patch -d src/mongo/client < /path/to/mod_gridfs/patches/gridfs
Build the driver:
	scons
Build+install the module with make

Ubuntu pre-build instructions:
sudo apt-get -y install wget g++ scons apache2 apache2-threaded-dev libboost-filesystem-dev libboost-system-dev libboost-thread-dev

Ubuntu build instructions (MongoDB C++ driver v2.4):
wget http://downloads.mongodb.org/cxx-driver/mongodb-linux-x86_64-v2.4-latest.tgz
tar xzf mongodb-linux-x86_64-v2.4-latest.tgz
rm mongodb-linux-x86_64-v2.4-latest.tgz
mv mongo-cxx-driver-v2.4 mongo-cxx-driver
echo 'env.Append(CCFLAGS="-fPIC")' >> mongo-cxx-driver/SConstruct
patch -d mongo-cxx-driver/src/mongo/client < patches/gridfs
scons -C mongo-cxx-driver
make -C gridfs

Ubuntu pre-installation instructions:
sudo apt-get -y install apache2 libstdc++6 libboost-filesystem[version] libboost-system[version] libboost-thread[version] && sudo apt-get -y install make apache2-threaded-dev

Ubuntu installation instructions (copy mod_gridfs directory to a target machine first):
cd mod_gridfs
sudo make -C gridfs install

Ubuntu post-installation instructions (cleanup, not required but recommended for production machines):
sudo apt-get -y purge make apache2-threaded-dev && sudo apt-get -y --purge autoremove

Configuration:
GridFSConnection -- sets connection string ("host[:port]" for single hosts, "replicaSetName/host[:port],[host[:port], ...]" for replica sets)
GridFSDatabase <database> -- sets database name
GridFSCollectionPrefix <collection prefix> -- optional, sets collection prefix (default is "fs")
GridFSFilenameField <filename field> -- optional, sets filename field (default is "filename")
GridFSFilenameFieldType <filename field type> -- optional, sets filename field type (default is "string", also available: "objectid")
GridFSCacheMaxAge <max age> -- optional, sets cache max age in seconds (default is 1 week, maximum is 10 years), set to 0 to disable expiration caching (see Notes below)
GridFSConnectTimeout <timeout> -- optional, sets MongoDB connection timeout in seconds (default is 5 seconds)
GridFSReadPrefMode <mode> -- optional, sets MongoDB read preference mode (MongoDB v2.2+, http://docs.mongodb.org/manual/core/read-preference/#read-preference-modes)
GridFSReadPrefTags <tagSets>* -- optional, sets MongoDB read preference tag sets (MongoDB v2.2+, see http://docs.mongodb.org/manual/core/read-preference/#tag-sets), requires GridFSReadPrefMode to be properly set
GridFSUsername <username> -- optional, sets MongoDB authentication user name
GridFSPassword <password> -- optional, sets MongoDB authentication password

* Multiple tag sets are supported, for example:
GridFSReadPrefTags "{dc:'east', use:'production'}, {dc:'east', use:'reporting'}, {dc:'east'}"

Configuration example:
GridFSConnection rsTest/db1,db2
GridFSDatabase my_database
GridFSReadPrefMode nearest
GridFSReadPrefTags {group:'b1'}

Implementation notes:
This module was developed to serve static content that is cached on frontend reverse proxies, hence by default it sets the following headers:
	Cache-Control: public, max-age=<max_age>
	Expires: <Date+max_age>
	Last-Modified: <uploadDate>
	Etag: <md5> (if MD5 is available for file)
You can disable "Cache-Control" and "Expires" headers by setting GridFSCacheMaxAge to 0.

Content-type, if not specified in GridFS file "contentType" field, is automatically determined using mod_mime (or any other type checker module that works without accessing file contents).
Also, it supports HEAD requests, conditional queries (If-Modified-Since and/or If-None-Match with proper 304 Not Modified response).
It doesn't support range queries (not going to be implemented soon).

Known problems:
If you're using gcc version less than 4.5, Apache parent process would crash when reloading modules (on a restart after module list is updated).
This is a known problem with gcc and libstdc++. Unfortunately, the only workaround is to upgrade your compiler and standard C++ library.

Credits:
Written by Aristarkh Zagorodnikov
Initial context (location) awareness suggestion and implementation by Stafford Brunk (https://bitbucket.org/wingrunr21)
Authentication support implementation by Radoslav Hampartsumyan (https://bitbucket.org/rado_h)
Custom filename field by ggrundik (https://bitbucket.org/ggrundik)
Custom filename field type by Dmitry Yantsen (https://bitbucket.org/dyantsen)