Appolo Context

nodejs async hooks context storage can be used to create context per request

Attention! This package is using the new experimental async hooks API.

Installation:

npm install appolo-context --save

Usage

import {namespace} from "appolo-context";

let context = namespace.create("someName");
context.initialize();

class A {
 run(){
    let context = namespace.get("someName")

    context.set("id","someId")

    return Promise.resolve();
 }
}

class B {
 run(){
    let context = namespace.get("someName")

    let id = context.get("id");

    return Promise.resolve(id);
 }
}

context.scope(async()=>{
    await new A().run();
    let id  = await new B().run();

    console.log(id) // someId
})

Express Usage

import {context} from "appolo-context";
import * as express from "express";

context.initialize();

let app = express();
app.use((req,res,next)=>{
    context.scope(()=>{
        context.set("id",uuid.v1());
        next();
    })
})

app.use(async (req,res,next())=>{
    let reuslt  = await doSomethingAsync();
    res.send(reuslt)
})

Now you can retrieve the context in any file or function.

import {context} from "appolo-context";

async function doSomethingAsync(){

    return context.get("id");
}

Namespace

create(name:string|Symbol):Context

Create new context by given name

import {namespace} from "appolo-context";

let context = namespace.create("someName");
context.initialize();

get(name:string|Symbol):Context

get context by given name

import {namespace} from "appolo-context";

let context = namespace.get("someName");
context.get("someValue")

delete(name:string|Symbol)

delete context by given name and destroy it

import {namespace} from "appolo-context";

let context = namespace.delete("someName");

get context():Context

get the default context

import {namespace} from "appolo-context";

let context = namespace.context;

context.initialize()

Context

initialize()

initialize the async hooks must be called before any get or set methods this will create the async hooks and enable them.

Context

scope(fn:Function)

create new context scope and triggers the given function

import {context} from "appolo-context";
import * as express from "express";

context.initialize();

let app = express();
app.use((req,res,next)=>{
    context.scope(()=>{
        context.set("id",uuid.v1());
        next();
    })
})

get(key:any):any

get context value by key

set(key:any,value:any)

set context value by key

enable()

enable the async hooks

destroy()

destroy the context and clean all resources.

License

MIT