Mongo Golang Search

Mongo Golang Search provides a query language to a MongoDB database.
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Mongo Golang Search (mgs)

Content index

• What is this?
• Getting Started
  • Installation
• Usage
• Supported features
  • Filtering
  • Pagination
  • Sorting
  • Projection
  • Advanced queries
• Available options
  • Customize limit value
  • Specify casting per param keys
• Contributing
• License

What is this?

Mongo Golang Search provides a simple query language to perform advanced searches for your collections in MongoDB.

You could also use Mongo Golang Search to searching, sorting, pagination and combining logical operators.

Getting Started

Installation

The recommended way to get started using the Mongo Golang Search is by using Go modules to install the dependency in your project. This can be done either by importing packages from github.com/ajclopez/mgs and having the build step install the dependency or by explicitly running

go get github.com/ajclopez/mgs

Usage

To get started with mgs, import the mgs package and implement the Primitives ObjectID function which is used to convert strings to ObjectID.

type Primitives struct{}

func (primitives *Primitives) ObjectID(oidStr string) (interface{}, error) {
	return ObjectID() // invoke ObjectID from MongoDB Driver
}

Then create an instance of QueryHandler:

queryHandler := mgs.NewQueryHandler(&Primitives{})

Finally use a mgs.MongoGoSearch function:

queryHandler.MongoGoSearch(query string, opts *FindOptions)

Arguments

query: query string part of the requested API URL.

opts: object for advanced configuration See below [optional].

Using mgs.MongoGoSearch function with mongo-go-driver library to filter, sort, limit and skip in MongoDB:

import (
    "context"

    "github.com/ajclopez/mgs"
    "go.mongodb.org/mongo-driver/bson/primitive"
    "go.mongodb.org/mongo-driver/mongo/options"
)

type Primitives struct{}

func (primitives *Primitives) ObjectID(oidStr string) (interface{}, error) {
	return primitive.ObjectIDFromHex(oidStr)
}

queryHandler := mgs.NewQueryHandler(&Primitives{})

opts := mgs.FindOption()
result, err := queryHandler.MongoGoSearch(query, opts)

...

findOpts := options.Find()
findOpts.SetLimit(result.Limit)
findOpts.SetSkip(result.Skip)
findOpts.SetSort(result.Sort)
findOpts.SetProjection(result.Projection)

cur, err := collection.Find(context.TODO(), result.Filter, findOpts)

...

Using optional configurations:

import (
    "context"

    "github.com/ajclopez/mgs"
    "go.mongodb.org/mongo-driver/bson/primitive"
    "go.mongodb.org/mongo-driver/mongo/options"
)

type Primitives struct{}

func (primitives *Primitives) ObjectID(oidStr string) (interface{}, error) {
	return primitive.ObjectIDFromHex(oidStr)
}

queryHandler := mgs.NewQueryHandler(&Primitives{})

opts := mgs.FindOption()
opts.SetCaster(map[string]mgs.CastType{
	"mobile": mgs.STRING,
})
opts.SetMaxLimit(1000)
opts.SetDefaultLimit(10)
result, err := queryHandler.MongoGoSearch(query, opts)

...

findOpts := options.Find()
findOpts.SetLimit(result.Limit)
findOpts.SetSkip(result.Skip)
findOpts.SetSort(result.Sort)
findOpts.SetProjection(result.Projection)

cur, err := collection.Find(context.TODO(), result.Filter, findOpts)

...

Example

A request of the form:

'employees?status=sent&date>2020-01-06T14:00:00.000Z&author.firstname=Jhon&skip=50&limit=100&sort=-date&fields=id,date';

Is translated to:

Query{
    Filter: map[string]interface{}{
        "author.firstname":     "John",
        "date":                 map[string]interface{}{"$gt": "2020-01-06T14:00:00.000Z"},
        "status":               "SENT",
    },
    Sort:  map[string]int{
        "date": 1,
        "id": 1
    },
    Limit: 100,
    Skip:  50,
}

Supported features

Filtering

Operator	URI	Example
$eq	key=val	type=public
$ne	key!=val	status!=SENT
$gt	key>val	price>5
$gte	key>=val	price>=9
$lt	key<val	date<2020-01-01T14:00:00.000Z
$lte	key<=val	priority<=-5
$in	key=val1,val2	status=QUEUED,DEQUEUED
$nin	key!=val1,val2	status!=QUEUED,DEQUEUED
$exists	key	email
$exists	!key	!email
$regex	key=/value/<opts>	email=/@gmail\.com$/
$regex	key!=/value/<opts>	phone!=/^58/

Pagination

Useful to limit the number of records returned.

• Operator keys are skip and limit.
• Use limit operator to limit the number of records returned.
• Use skip operator to skip the specified number of records.

skip=20&limit=10

Sorting

Useful to sort returned records.

• Operator key is sort.
• It accepts a comma-separated list of fields.
• Use - prefixes to sort in descending order.
• Use + prefixes to sort in ascedending order.

sort=id,-date

Projection

Useful to limit fields to return in each records.

• Operator key is fields.
• It accepts a comma-separated list of fields.

fields=firstname,lastname,phone,email

Note:

• The _id field (returned by default).

Advanced queries

For more advanced usage (and, or logic operations), pass query filter as string with the logical operations, for example:

filter=(country=Mexico OR country=Spain) and gender=female

What operations are possible?

• Filtering operations.
• The AND/and operator.
• The OR/or operator.
• Parenthesis can be used for grouping.

Available options

You can use advanced options:

opts := mgs.FindOption()
opts.SetCaster(map[string]mgs.CastType{
	"mobile": mgs.STRING,
})
opts.SetMaxLimit(100)
opts.SetDefaultLimit(10)

• FindOption creates a new FindOptions instance.
• SetCaster object to specify custom casters, key is the caster name, and value is a type (BOOLEAN, NUMBER, PATTERN, DATE, STRING).
• SetDefaultLimit which contains custom value to return records.
• SetMaxLimit which contains custom value to return a maximum of records.

Customize limit value

You can specify your own maximum or default limit value.

• defaultLimit: custom value to return records.
• maxLimit: custom value to return a maximum of records.

opts := mgs.FindOption()
opts.SetMaxLimit(1000)
opts.SetDefaultLimit(10)

result, err := mgs.MongoGoSearch("city=Madrid&skip=10&limit=1000", opts)

Specify casting per param keys

You can specify how query parameter values are casted by passing an object.

• casters: object which map keys to casters.

opts := mgs.FindOption()
opts.SetCaster(map[string]mgs.CastType{
	"key1": mgs.STRING,
    "key2": mgs.NUMBER,
    "key3": mgs.STRING,
    "key4": mgs.BOOLEAN
})

result, err := mgs.MongoGoSearch("key1=VALUE&key2=10&key3=20&key4=true", opts)

Contributing

Should you like to provide any feedback, please open up an Issue, I appreciate feedback and comments. Any contributions you make are greatly appreciated.

1. Fork the Project
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing-feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This software is released under the MIT license. See LICENSE for more information.