middleware

Documentation

Overview

Package middleware provides middleware for the res package:

https://github.com/jirenius/go-res

Middleware can be used for adding handler functions to a res.Handler, to perform tasks such as:

* storing, loading and updating persisted data * synchronize changes between multiple service instances * add additional logging * provide helpers for complex live queries

Currently, only the BadgerDB middleware is created, to demonstrate database persistance.

Usage

Add middleware to a resource:

s.Handle("user.$id",
	middlware.BadgerDB{DB: db},
)

Index

• type BadgerDB
  • func (o BadgerDB) SetOption(hs *res.Handler)
  • func (o BadgerDB) WithDB(db *badger.DB) BadgerDB
  • func (o BadgerDB) WithDefault(i interface{}) BadgerDB
  • func (o BadgerDB) WithType(v interface{}) BadgerDB

Examples

• BadgerDB
• BadgerDB.WithDefault
• BadgerDB.WithType

Types

type BadgerDB

type BadgerDB struct {
	// BadgerDB database
	DB *badger.DB
	// Default resource value if not found in database. Will return res.ErrNotFound if not set.
	Default interface{}
	// Type used to marshal into when calling r.Value() or r.RequireValue().
	Type interface{}
}

BadgerDB provides persistance to BadgerDB for the res Handlers.

It will set the GetResource and Apply* handlers to load, store, and update the resources in the database, using the resource ID as key value.

Example

package main

import (
	"github.com/dgraph-io/badger"
	res "github.com/jirenius/go-res"
	"github.com/jirenius/go-res/middleware"
)

func main() {
	db := &badger.DB{} // Dummy. Use badger.Open

	s := res.NewService("directory")
	s.Handle("user.$id",
		res.Model,
		middleware.BadgerDB{DB: db},
		/* ... */
	)
}

func (BadgerDB) SetOption

func (o BadgerDB) SetOption(hs *res.Handler)

SetOption is to implement the res.Option interface

func (BadgerDB) WithDB

func (o BadgerDB) WithDB(db *badger.DB) BadgerDB

WithDB returns a new BadgerDB value with the DB set to db.

func (BadgerDB) WithDefault

func (o BadgerDB) WithDefault(i interface{}) BadgerDB

WithDefault returns a new BadgerDB value with the Default resource value set to i.

Example

package main

import (
	"github.com/dgraph-io/badger"
	res "github.com/jirenius/go-res"
	"github.com/jirenius/go-res/middleware"
)

func main() {
	db := &badger.DB{} // Dummy. Use badger.Open

	s := res.NewService("directory")
	badgerDB := middleware.BadgerDB{DB: db}
	s.Handle("users",
		res.Collection,
		// Default to an empty slice of references
		badgerDB.WithType([]res.Ref{}).WithDefault([]res.Ref{}),
		/* ... */
	)
}

func (BadgerDB) WithType

func (o BadgerDB) WithType(v interface{}) BadgerDB

WithType returns a new BadgerDB value with the Type value set to v.

Example

package main

import (
	"github.com/dgraph-io/badger"
	res "github.com/jirenius/go-res"
	"github.com/jirenius/go-res/middleware"
)

func main() {
	db := &badger.DB{} // Dummy. Use badger.Open

	type User struct {
		ID   int    `json:"id"`
		Name string `json:"name"`
	}

	s := res.NewService("directory")
	badgerDB := middleware.BadgerDB{DB: db}
	s.Handle("user.$id",
		res.Model,
		badgerDB.WithType(User{}),
		res.Set(func(r res.CallRequest) {
			_ = r.RequireValue().(User)
			/* ... */
			r.OK(nil)
		}),
	)
}