Store Remark42 comments, images and avatars on MongoDB.
Tested with Remark42 v1.10.1.

Warning The fix for the following issues on Remark42 are required for Remark42 MongoDB Server to work:

• Type cast panic when using RPC
• Key() method invoked with wrong siteID

Until version v1.10.2 is released it's mandatory to build Remark42 from its master branch.

Initialize the server with remark42-mongodb.js init:

A configuration file remark42-mongodb.json is created:

{
    "port": 9000,
    "hostname": "localhost",
    "database": "mongodb://localhost:27017/remark42-mongodb",
    "avatars": "remark_avatars",
    "bodyLimit": "8mb",
    "dynamicPosts": true,
    "logDir": "logs",
    "logMaxSize": "8m",
    "logMaxFiles": 30
}

The following options are available:

• port: the TCP port on which the Remark42 MongoDB Server listens for client connections;
• hostname: the hostname where to listen for client connections;
• database: the MongoDB connection URI;
• avatars: Remark42 can be configured to store avatars in a GridFS bucket. This optional setting is the name of the GridFS bucket; once configured, remark42-mongodb periodically cleans up unused avatars;
• bodyLimit: maximum size of request bodies, should be calibrated accordingly to the maximum image size accepted by Remark42 (IMAGE_MAX_SIZE);
• dynamicPosts: if true, any post referenced by comments is created if not existing; if false, comments referencing a non-existing post are rejected: in that case, available sites/posts must be initialized either by hand or by using sites create and posts create commands;
• logDir: logs folder path;
• logMaxSize: the maximum size for each log file (e.g. 32k, 8m, 2g).
• logMaxFiles (optional): maximum number of days the logs are kept; if omitted, logs are kept indefinitely;

All options can be overridden via REMARK42_MONGODB_XXX environment variables, for example REMARK42_MONGODB_DATABASE or REMARK42_MONGODB_LOG_MAX_SIZE.

Start the server with remark42-mongodb.js serve.

Three log files are created:

• access-YYYY-MM-DD.log: collecting information about served requests;
• error-YYYY-MM-DD.log: collecting errors;
• main-YYYY-MM-DD.log: collecting general information;

Log files are rotated daily and are limited both in size (logMaxSize) and number (logMaxFiles).

Service health can be checked by sending a GET /health request, that will respond with 200 OK or 503 Service Unavailable depending on the state of the server and database connection.

New sites can be created with remark42-mongodb.js sites create [name]:

Sites must be created regardless of whether dynamicPosts is set to true or false.
The encryption key and email are described on Remark42 documentation, respectively SECRET and ADMIN_SHARED_EMAIL. \ Note that Remark42 MongoDB Server handles different values for each site (i.e. they are not "shared").

Current sites can be listed with remark42-mongodb.js sites list:

New posts can be created with remark42-mongodb.js posts create [site] [url]:

This is useful for initializing the database when dynamicPosts is set to false.
The posts on a specific site can be listed with remark42-mongodb.js posts list [site]:

Set the following environment variables in Remark42 to enable integration with Remark42 MongoDB Server (adjust values according to your configuration):

STORE_TYPE=rpc
STORE_RPC_API=http://localhost:9000

ADMIN_TYPE=rpc
ADMIN_RPC_API=http://localhost:9000

IMAGE_TYPE=rpc
IMAGE_RPC_API=http://localhost:9000

Remark42 can also store avatars in a GridFS bucket with the following configuration:

AVATAR_TYPE=uri
AVATAR_URI=mongodb://localhost:27017/remark42-mongodb?ava_db=remark42-mongodb&ava_coll=remark_avatars

Warning At the moment mongodb+srv URIs (used by MongoDB Atlas) are not handled correctly (open issue).

Remark42 MongoDB Server can periodically clean up unused avatars by configuring avatars to remark_avatars.

More information on how to configure Remark42 available at Remark42 documentation.