mongo-express-middleware

Express middleware that will give you CRUD APIs on top of any MongoDB collection

Usage

const { MongoClient } = require("mongodb");
const express = require('express');
const app = express();

const MongoExpressMiddleware = require('@jerrymannel/mongo-express-middleware');

const uri = "mongodb://localhost:27017";

const client = new MongoClient(uri);
const database = client.db('test');
const testCollection = database.collection('users');

const crud = new MongoExpressMiddleware(testCollection, null);

console.log(new Date());

app.use(express.json());

app.get('/', crud.find);
app.get('/:id', crud.findById);
app.get('/utils/count', crud.count);
app.post('/', crud.create);
app.put('/:id', crud.update);
app.delete('/', crud.deleteMany);
app.delete('/:id', crud.deleteById);
app.post('/utils/aggregate', crud.aggregate);


app.listen(3000, () => {
	console.log('Example app listening on port 3000!');
});

• mongo-express-middleware
• Usage
• Install
• Documentation
  • find(req, res)
    • Response
    • How page param works
  • findById(req, res)
    • Response
    • Why isObjectId ?
  • count(req, res)
    • Response
  • create(req, res)
    • Response
  • update(req, res)
    • Response
  • deleteMany(req, res)
  • deleteById(req, res)
  • aggregate(req, res)

Install

npm i @jerrymannel/mongo-express-middleware

Documentation

find(req, res)

Query a collection with a given filter, which is send as URL params. This simulates the Mongodb find operation.

Query	Type	Description	e.g.
filter	Object	Apply a filter for retrieving data. Accepts any valid MongoDB filter expression.	{"buying_price": {"$ne": 100}}
select	Object	Select the attributes you want to retrieve. If select is not set, then the whole document is retrieved. Accepts any valid MOngoDB projection expression	{"amount":1, "units":1, "name":1}
sort	Object	Sorts the data. Accepts MongoDB sort syntax	{"name":-1}
limit	Number	The maximum number of documents to return. If unspecified, then defaults to 10
page	Number	Page based on the limit specified.

Response

Returns an array of JSONs or an empty array

Filter and select expressions are similar to MongoDB Query and Projection Operators .

How page param works

Page param for find(req, res) works together with filter, limit, and total document count.

Let's assume that the total number of documents in the collection is 10 and your filter condition doesn't change between API calls, then

• Setting limit=5 and page=1 fetched the first 5 documents.
• Setting limit=5 and page=2 fetched the next 5 documents. etc

findById(req, res)

Query the collection and find the document with the _id that matches req.params.id

Query	Type	Default	Description
isObjectId	Boolean	false	If isObjectId is set then we find the document where _id is of type ObjectId

Response

Returns a single JSON.

Why isObjectId ?

You can create two documents in MongoDB with the same _id where one is of type string and the other of type ObjectId.

When you create a document using the create(req, res), you can set the _id of the document. If the isObjectId param is not set for create then the user-specified _id is set as type string.

Hence, I have made provision under findById(req, res) to query documents where _id can be of either type.

count(req, res)

Count the number of documents under the collection that matches the specified filter param. If filter is not set then this returns the total number of documents.

Query	Type	Description	e.g.
filter	Object	Apply a filter for retrieving data. Accepts any valid MongoDB filter expression.	{"buying_price": {"$ne": 100}}

Response

Returns a non negative interger value.

create(req, res)

Input - Single JSON or an Array of JSONs

Creates a single or multiple documents when an array of JSONs are passed.

Query	Type	Default	Description
isObjectId	Boolean	false	If isObjectId is set then we parse the _id of the document, if present, as type ObjectId

Response

If a single JSON is given as input then, the response is a JSON document with only the _id of the document that was created.

If an array of JSONs are given as input then,

• HTTP 200 OK if all the documents where inserted successfully.
• HTTP 207 if someof the documents got inserted.

Response will be a JSON that gives you the insertedCount and the insertedIds. The documents in the insertedIds will either have the _id or the error at the same index as the input array. e.g.

{
  "insertedCount": 3,
  "insertedIds": [
    {
      "_id": "63deca5b04463760d5bb7bed"
    },
    {
      "_id": "63deca5b04463760d5bb7bee"
    },
    {
      "_id": "63deca5b04463760d5bb7bef"
    }
  ]
}

update(req, res)

Update/replace/upserts a document with the _id that matches req.params.id

Query	Type	Default	Description
isObjectId	Boolean	false	If isObjectId is set then we find the document where _id is of type ObjectId
isReplace	Boolean	false	Replace the existing document in the collection with the document in the payload
upsert	Boolean	false	Update the document is present, else create a new document. Read more about upsert here.

Response

JSON that has the _id of the document that was updated/replaced/upserted.

deleteMany(req, res)

Deletes multiple documents that matches the filter query.

Accepts filter as a query param. Refer filter documentation under find

deleteById(req, res)

Deletes a single document with the _id that matches req.params.id.

Accepts isObjectId as a query param. Refer isObjectId documentation under findById

aggregate(req, res)

Input - MongoDB aggregation pipeline

Returns the result of running the MongoDB aggregation pipeline.