node-red-node-mongodb ===================== A Node-RED node to save data in a MongoDB database. **Note** : This is the same node as was in the core of Node-RED. As of v0.10.8 you will need to install it from here if still required. Pre-requisite ------------- To run this you need a local MongoDB server running. For details see the MongoDB site. Install ------- Run the following command in your Node-RED user directory - typically `~/.node-red` ``` npm install node-red-node-mongodb ``` Note that this package requires a MongoDB client package at least version 3.6.1 - if you have an older (version 2) client, you may need to remove that before installing this ``` npm remove mongodb npm install node-red-node-mongodb ``` Usage ----- Nodes to save and retrieve data in a MongoDB instance - the database server can be local (mongodb//:localhost:27017), remote (mongodb://hostname.network:27017), replica-set or cluster (mongodb://hostnameA.network:27017,hostnameB.network:27017), and DNS seedlist cluster (mongodb+srv://clustername.network). Reference [MongoDB docs](https://docs.mongodb.com/manual/reference/connection-string/) to see which connection method (host or clustered) to use for your MongoDB instance. ### Input Calls a MongoDB collection method based on the selected operator. *Find* queries a collection using the `msg.payload` as the query statement as per the *.find()* function. Optionally, you may also (via a function) set - a `msg.projection` object to constrain the returned fields, - a `msg.sort` object, - a `msg.limit` number, - a `msg.skip` number. *Count* returns a count of the number of documents in a collection or matching a query using the `msg.payload` as the query statement. *Aggregate* provides access to the aggregation pipeline using the `msg.payload` as the pipeline array. You can either set the collection method in the node config or on `msg.collection`. Setting it in the node will override `msg.collection`. See the *MongoDB collection methods docs* for examples. The result is returned in `msg.payload`. ### Output A simple MongoDB output node. Can save, insert, update and remove objects from a chosen collection. MongoDB only accepts objects. Save and insert can either store `msg` or `msg.payload`. If msg.payload is selected it should contain an object. If not it will be wrapped in an object with a name of payload. *Save* will update an existing object or insert a new object if one does not already exist. *Insert* will insert a new object. *Update* will modify an existing object or objects. The query to select objects to update uses `msg.query` and the update to the element uses `msg.payload`. Update can add an object if it does not exist or update multiple objects. *Remove* will remove objects that match the query passed in on `msg.payload`. A blank query will delete *all of the objects* in the collection. You can either set the collection method in the node config or on `msg.collection`. Setting it in the node will override `msg.collection`. By default MongoDB creates an `msg._id` property as the primary key - so repeated injections of the same `msg` will result in many database entries. If this is NOT the desired behaviour - ie. you want repeated entries to overwrite, then you must set the `msg._id` property to be a constant by the use of a previous function node. This must be done at the correct level. If only writing msg.payload then payload must contain the \_id property. If writing the whole msg object then it must contain an \_id property. This could be a unique constant or you could create one based on some other msg property. Currently we do not limit or cap the collection size at all...