mw.js

mw.js

const grpc = require('grpc'),
    resolve = require('path').resolve

const tyk = grpc.load({
    file: 'coprocess_object.proto',
    root: resolve(__dirname, 'tyk-protobuf/proto')
  }).coprocess

const listenAddr = '127.0.0.1:5555',
      authHeader = 'Authorization'
      validToken = '71f6ac3385ce284152a64208521c592b'

// The dispatch function is called for every hook:
const dispatch = (call, callback) => {
    var obj = call.request
    // We dispatch the request based on the hook name, we pass obj.request which is the coprocess.Object:
    switch (obj.hook_name) {
        case 'MyPreMiddleware':
            preMiddleware(obj, callback)
            break
        case 'MyAuthMiddleware':
            authMiddleware(obj, callback)
            break
        default:
            callback(null, obj)
            break
    }
}

const preMiddleware = (obj, callback) => {
    console.log("preMiddleware called")
    var req = obj.request

    // req is the coprocess.MiniRequestObject, we inject a header using the "set_headers" field:
    req.set_headers = {
        'mycustomheader': 'mycustomvalue'
    }

    // Use this callback to finish the operation, sending back the modified object:
    callback(null, obj)
}

const authMiddleware = (obj, callback) => {
    console.log("authMiddleware caled")
    var req = obj.request

    // We take the value from the "Authorization" header:
    var token = req.headers[authHeader]

    // The token should be attached to the object metadata, this is used internally for key management:
    obj.metadata = {
        token: token
    }

    // If the request token doesn't match the  "validToken" constant we return the call:
    if (token != validToken) {
        callback(null, obj)
        return
    }

    // At this point the token is valid and a session state object is initialized and attached to the coprocess.Object:
    var session = new tyk.SessionState()
    session.id_extractor_deadline = Date.now() + 100000000000
    obj.session = session
    callback(null, obj)
}

main = function() {
    server = new grpc.Server()
    server.addService(tyk.Dispatcher.service, {
        dispatch: dispatch
    })
    server.bind(listenAddr, grpc.ServerCredentials.createInsecure())
    server.start()
}

main()