koa-bridge

A simple repeater for Koa for forwarding requests, from client, to another service (or api) with the same request method and headers, queries, body from the client, and response the data, from another server, to client.

Installation

$ npm i @lvchengbin/koa-bridge --save

Examples

bridge

const Koa = require( 'koa' );
const request = require( 'request' );
const router = require( '@lvchengbin/koa-router' );
const bridge = require( '@lvchengbin/koa-bridge' );

const app = new Koa();

router.any( '*', '/bridge', async ctx => {
    return bridge( ctx, {
        dest : 'http://127.0.0.1:3000/dest'
    } )
} );

router.any( '*', '/dest', async ctx => {
    ctx.set( 'x-bridge-response', 'yes' );
    ctx.cookies.set( 'n', '1' );
    ctx.body = 'the dest service';
} );


app.listen( 3000 );

request( {
    method : 'POST',
    uri : 'http://127.0.0.1:3000/bridge?==1&y=2'
    headers : {
        cookie : 'name=value; n=v',
        'x-bridge-request' : 'yes'
    },
    body : {
        name : 'bridge'
    },
    json : true
} );

In the code above, the request method send a POST request to http://127.0.0.1:3000/bridge?==1&y=2 with some headers and its body as the content-type is 'application/json'. The bridge will send the request with taking all properties along to http://127.0.0.1:3000/dest, and respond with all data, includes headers, body, from the dest service.

For POST request, bridge support forwarding json, urlencoded and plain, request with other type will be taken as application/json.

You can specify a field in request body or params as the dest url, default by __ouri__, for example:

router.any( '*', '/bridge', async ctx => {
    return bridge( ctx, {
        ouri : '__ouri__'
    } )
} );

request( {
    method : 'GET',
    uri : 'http://127.0.0.1:3000/bridge?==1&y=2&__ouri__=http%3A%2F%2F127.0.0.1%3A3000%2Fdest'
} );

You can add some properties before bridge send the request to the dest api:

• headers | Object or Function

  The headers you want to add to the request, if the value is a Function, headers will be replaced by the returned value of the function.

• cookies | Object or Function

  Cookies that you want to add to the request, if the value is a Function, all cookies will be replaced by the returned value of the function.

• body | Object or Function

  The data that you want to add to request body if the request can handle a body ( such as POST and PUT ). If the value is a Function, the return value of the function will overwrite the original body.

• params | Object or Function

  Params that you want to add for the request.

router.any( '*', '/bridge', async ctx => {
    return bridge( ctx, {
        headers : {
            'x-custom-header' : 'value'
        },
        cookies : {
            name : 'value'
        },
        body : {
            name : 'value'
        },
        params : {
            name : 'value'
        }
    } );
} );

bridge.request & bridge.response

bridge.request and bridge.response will support more flexibility.

router.any( '*', '/bridge', async ctx => {
    const response = await bridge.request( ctx, {
        ouri : '__ouri__'
    } );

    ctx.set( 'x-custom-header', 'xxx' );
    return bridge.response( ctx, response );
} );