Integration Guide - Node (Express) SDK

Express middleware to automatically capture incoming REST API requests/responses and send to Moesif for error analysis.

Source Code on GitHub

Package on NPMJS

How to install

npm install --save moesif-express

How to use

The following shows how import the controllers and use:

1. Import the module:

// Import Modules
var express = require('express');
var app = express();

var moesifExpress = require('moesif-express');

// Set the options, the only required field is applicationId.
var options = {

  applicationId: 'Your Moesif application_id',

  identifyUser: function (req, res) {
    if (req.user) {
      return req.user.id;
    }
    return undefined;
  },

  getSessionToken: function (req, res) {
    return req.headers['Authorization'];
  }
};

// Load the Moesif middleware
app.use(moesifExpress(options));

2. Enter Moesif Application Id.

You can find your Application Id from Moesif Dashboard -> Top Right Menu -> App Setup

Not using Express?

If you’re not using the express framework, you can still use this library. The library does not depend on express, so you can still call the middleware from a basic HTTP server.

var moesifExpress = require('moesif-express');
const http = require('http');

var options = {
  applicationId: 'Your Application Id'
};

var server = http.createServer(function (req, res) {
  moesifExpress(options)(req, res, function () {
    // Callback
  });

  req.on('end', function () {

    res.write(JSON.stringify({
      message: "hello world!",
      id: 2
    }));
    res.end();
  });
});

server.listen(8080);

Configuration options

identifyUser

Type: (Request, Response) => String identifyUser is a function that takes express req and res as arguments and returns a userId. This helps us attribute requests to unique users. Even though Moesif can automatically retrieve the userId without this, this is highly recommended to ensure accurate attribution.

options.identifyUser = function (req, res) {
  // your code here, must return a string
  return req.user.id
}

getSessionToken

Type: (Request, Response) => String getSessionToken a function that takes express req and res arguments and returns a session token (i.e. such as an API key).

options.getSessionToken = function (req, res) {
  // your code here, must return a string.
  return req.headers['Authorization'];
}

getTags

Type: (Request, Response) => String getTags is a function that takes a express req and res arguments and returns a comma-separated string containing a list of tags. See Moesif documentation for full list of tags.

options.getTags = function (req, res) {
  // your code here. must return a comma-separated string.
  if (req.path.startsWith('/users') && req.method == 'GET'){
    return 'user'
  }
  return 'random_tag_1, random_tag2'
}

getApiVersion

Type: (Request, Response) => String getApiVersion is a function that takes a express req and res arguments and returns a string to tag requests with a specific version of your API.

options.getApiVersion = function (req, res) {
  // your code here. must return a string.
  return '1.0.5'
}

skip

Type: (Request, Response) => Boolean skip is a function that takes a express req and res arguments and returns true if the event should be skipped (i.e. not logged)
The default is shown below and skips requests to the root path “/”.

options.skip = function (req, res) {
  // your code here. must return a boolean.
  if (req.path === '/') {
    // Skip probes to home page.
    return true;
  }
  return false
}

maskContent

Type: MoesifEventModel => MoesifEventModel maskContent is a function that takes the final Moesif event model (rather than the Express req/res objects) as an argument before being sent to Moesif. With maskContent, you can make modifications to headers or body such as removing certain header or body fields.

javascript options.maskContent = function(event) { // remove any field that you don't want to be sent to Moesif. return event; }

EventModel format:

{
  "request": {
    "time": "2016-09-09T04:45:42.914",
    "uri": "https://api.acmeinc.com/items/83738/reviews/",
    "verb": "POST",
    "api_version": "1.1.0",
    "ip_address": "61.48.220.123",
    "headers": {
      "Host": "api.acmeinc.com",
      "Accept": "*/*",
      "Connection": "Keep-Alive",
      "Content-Type": "application/json",
      "Content-Length": "126",
      "Accept-Encoding": "gzip"
    },
    "body": {
      "items": [
        {
          "direction_type": 1,
          "item_id": "fwdsfrf",
          "liked": false
        },
        {
          "direction_type": 2,
          "item_id": "d43d3f",
          "liked": true
        }
      ]
    }
  },
  "response": {
    "time": "2016-09-09T04:45:42.914",
    "status": 500,
    "headers": {
      "Vary": "Accept-Encoding",
      "Pragma": "no-cache",
      "Expires": "-1",
      "Content-Type": "application/json; charset=utf-8",
      "Cache-Control": "no-cache"
    },
    "body": {
      "Error": "InvalidArgumentException",
      "Message": "Missing field location"
    }
  },
  "user_id": "mndug437f43",
  "session_token":"end_user_session_token",
  "tags": "tag1, tag2"
}

For more documentation regarding what fields and meaning, see below or the Moesif Node API Documentation.

Fields Required Description
request.time Required Timestamp for the request in ISO 8601 format
request.uri Required Full uri such as https://api.com/?query=string including host, query string, etc
request.verb Required HTTP method used, i.e. GET, POST
request.api_version Optional API Version you want to tag this request with
request.ip_address Optional IP address of the end user
request.headers Required Headers of the request
request.body Optional Body of the request in JSON format
     
response.time Required Timestamp for the response in ISO 8601 format
response.status Required HTTP status code such as 200 or 500
request.ip_address Optional IP address of the responding server
response.headers Required Headers of the response
response.body Required Body of the response in JSON format

callback

Type: error => null callback is for internal errors. For example, if there is has been an error sending events to moesif or network issue, you can use this to see if there is any issues with integration.

updateUser method

A method is attached to the moesif middleware object to update the users profile or metadata.


var moesifMiddleware = moesifExpress(options);
var user = {
  userId: 'your user id',  // required.
  metadata: {
    email: 'user@email.com',
    name: 'George'
  }
}

moesifMiddleware.updateUser(user, callback);

The metadata field can be any custom data you want to set on the user. The userId field is required.

Example

An example can be found here.

Other integrations

To view more more documentation on integration options, please visit the Integration Options Documentation.

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