I recently added support for subscriptions via WebSockets to my React+Redux+ApolloGraphQL application. Since doing that I cannot run my unit tests anymore.
The problem I come up with is:
Unable to find native implementation, or alternative implementation for WebSocket!
It seems there is not an available implementation for WebSockets on the node environment where I run my tests.
There are a couple of proposed solutions in this bug report that involve using the 'ws' library for node but I cannot make them work. Either I cannot load the library properly, or I can but then the application doesn't work.
I was thinking of a way to load the library depending on the environment I'm on but:
I don't know how to do that
I don't know if it's the right approach.
Any suggestions?
How are you running your tests? In my case, I'm using Jest, so I've put inside setupTests file (which is executed before running all of your tests) this code:
import WebSocket from 'ws';
Object.assign(global, {
WebSocket,
});
This is necessary because for tests which aren't running in browser, there's no native Web Socket implementation.
Related
I am working on an Automation project which has some xmlrpc calls integrated with it, as my setup is based on client server model.
I want to get an end to end code coverage details for the complete project while running automation tests.
I am wondering if there is any way through which we can determined code coverage over xmlrpc calls ? I have tried working with coverage.py but it works fine for local code only. Seems it can not go beyond rpc.
Is it possible to write C++ code to interface with a server, but to be executed on client side, but on the browser instead of native?
Like, for example, imagine using open source classes so that you produce a file.
But because you don't want all this work to be done on the server, you run it on the browser.
So that the client gives a file or two or more as inputs, then the code runs on his machine, the final result is produced, then this file is uploaded to database on the server.
please see google native client project. http://code.google.com/p/nativeclient/
This is strange question.
You can prepare binaries that do task that you want done on client side and make server send proper binary to client when asked for it. Client then runs this binary and returns results to server.
It is possible if you know configurations of client machines (binaries must work on them). Also it have to be some security layer implemented - you don't want to allow every binary run on client (imagine man-in-the-middle attack when some malicious code is run on client).
I think your request contradicts with the idea behind server-side programming. The main purpose in using server-side programs is to make use of infrastructural components like database, network, etc. in a controlled manner. (The most typical usage of server-side applications are web sites with server side coding like JSP and ASP.)
Since servers are machines that are to be kept secure, a remote application should not be permitted to make changes or access filesystem freely. If you want to do changes on a server like doing database operations or reading/writing files, you should use applications that run on the server or provide interfaces like web services or web sites to remote client applications.
So there are a couple solutions when if you want to do work on the browser, then have the results posted in a server database.
First of all, you must set up your server ready for database work. I have done this using the MEAN stack, set up a MongoDB and interfaced it with the Mongoose API.
Now, for the meat of the question, there are many examples of browsers doing intensive work. The majority of these applications thought is not C++, but it is Javascript.
If you really want to focus on C++ (like i did in the past, in the time i asked this question, wanting to make something big for college), then you could do one of the following:
*Use Google Native Client (NaCl). This is a sandbox for running compiled C and C++ code in the browser efficiently and securely, independent of the user’s operating system.
*Maybe you should want to check out Emscripten, which is a framwork for translating C and C++ code to jaascript. This way, you can have your C or C++ binaries that worked, and have them translated to Javascript, in order to have them work in the browser too.
I have a couple of Android and iOS native mobile application that I wrote which connect directly to an XMPP server that I host. They push and pull realtime data through XMPP. I also use some of the XMPP XEP extensions. For other operations, I have a django application running on the same server which all the mobile applications consume through an HTTP REST interface. I use Celery and Redis for the django side to do some operations asynchronously (like doing heavy batched writes to my db).
This all works fine and dandy. Yay.
But now I want to write a web front-end to all of this, so I started researching my options and well - there are so many ways to skin the cat that I wanted to check with the SO community first.
The idea to have a js library that gives me a unified API for socket communications (i.e try different implementations of web sockets or fall back to flash) appeals to me hence why I mention Socket IO. The idea of having to run a nodejs server, well, not so much (one more thing to learn), but if I have to, I definitely will. I know that some people use gevent as a replacement of the node server. Others, decide to write a small nodejs which they connect to the rest of their stack. I would probably do this.
Another option, is to use an js XMPP library like Strophe which I don't think has a flash fallback. Also, I would need to research what this means for my server.
I have read several of the Stackoverflow answer on how to do comet and django - hence why it seems that there are several options.
The question is:
If I want to have the advantage of Socket IO behavior (with the fallbacks) and I want to push realtime data to the web client (which is being fed to the server through XMPP), and use Django what is my best option?
Update: The XMPP server that I use is ejabberd, which also supports BOSH. I realize that I could use Strophe.js and thus my communication would go over a type of long polling http connection instead of websockets. As far as I can tell, there are some XMPP over Websockets open source library, but AFAIK the community is not as active as the SocketIO one.
Update 2: Browsers that I need to support are only modern browsers. I guess this means that Flash fallback will not be that important, which is leaning me towards strophe.js.
I think once you get your hands dirty with some node you'll find that straying from Node for socket.io is going to be much harder. There are very easy to use xmpp modules in node ready to go (see https://github.com/astro/node-xmpp). Remember, node is all javascript, so you're probably familiar with programming in it already.
Personally, I've had some memory leak issues using node 0.6 or higher. Node 0.4 worked without those issues. If you are new to github (as I was before playing with Node) here is how you would get going with a node server.
Getting Node
Login to your linux box and favorite directory (I'll assume /)
git clone https://github.com/joyent/node.git
cd /node
git tag -l (this will list all available version of node)
git checkout v0.6.16 (this will checkout 0.6.16 version of node, you could replace that with v0.4.12 for example if you have memory issues)
./configure
make
make install
You'll need certain development tools to build it such as g++, but at this point you'll have a working node command.
Installing Node Modules like xmpp
Node has a nice amount of modules where most things have already been written for you. There is a search facility at http://search.npmjs.org or you can access all modules directly from your shell by using the npm command. NPM is nodes tool for installing and managing node modules. You can type npm search xmpp to search for all xmpp modules, for instance. To install a basic xmpp library for node you would do npm install node-xmpp. By the way, most github node module pages will include instructions on the front page readme file.
Keeping Node Running in Production
This threw me when I first started out. If you have any errors that are not caught node will simply die. So, you can either
1. Make sure there are no errors whatsoever or they are all caught (unlikely because even Node itself will error)
2. Use the uncaughtException handler to catch these problems. You would use code like this in your program
process.addListener("uncaughtException", function (err) {
util.log("Uncaught exception: " + err);
console.log(err.stack);
console.log(typeof(this));
// maybe email me?
});
Be Extra Safe and Use Forever
Even with the uncaughtException issue your program in production might die. Memory running out, segfaults, who knows what. That's where it pays to use something like the wonderful Node module called "Forever" (see https://github.com/nodejitsu/forever). You can type npm install forever -g to install forever. Note the -g option which puts forever in the GLOBAL node module directory. Without -g it puts the node module in the current working directory. You'll then be able to type something like (assuming your node program was called my_program.js) forever start my_program.js and then the Forever program will make sure that if it dies it gets restarted.
Not sure why you'd need Flash fallback if you're going to do BOSH (XEP-0124, XEP-0206), which is what strophe.js does. If you don't need to support IE7, you can do CORS from strophe.js, and you don't even need a proxy for same-origin. IE6 will work because it's insecure, and IE8+ support a just-barely-working form of CORS.
To get information from django through XMPP to your client, make a component connection (XEP-0114) to your server using your favorite Python XMPP library, such as SleekXMPP from your Django app. Arrange for that connection to be relatively long-lived, for performance (i.e. don't create a new one for each client connection). Send protocol as needed.
You didn't mention what XMPP server you're using. XMPP servers that don't support BOSH are getting rare, but if you've got one, you might need Punjab as a BOSH-to-XMPP proxy, or you might want to switch to a newer server, such as Prosody.
First of all, full disclosure: I work for a company called PubNub, which I'm going to mention shortly.
There are a whole range of hosted bidirectional messaging services (sometimes called IaaS - Infrastructure as a Service) that I think are worth considering. They are Pusher, Firebase, Flotype, PubNub, and others. I'm reasonably confident you could use any of them for what you want to accomplish. Firebase has a built-in database that ties right into their service, which is a pretty cool feature, but probably not useful for your particular use case (I assume you already have a database on your backend).
I can't speak too heavily about our competitors, but as far as you wanting a JavaScript library on the frontend that communicates with your Python backend, we (PubNub) provide a very similar api in both languages and that communicate on the same databus in the cloud. So you can send messages with Python and catch them with JavaScript, or vice-versa. We even wrote a PubNub-hosted version of socket.io, which you could use instead of our vanilla JavaScript api, and would still tie into your Django backend in about 10 lines of code.
Finally, the nice thing about using an IaaS (or at least us; again I'm not certain about the others) is that we handle that tricky scaling problem for you. If you reach the point of a million simultaneous users and need to push something to them in real-time, you'll find that's no problem.
We are using real-time push as well with Django and Celery. When I first created the architecture, I also researched my options. Eventually, I decided that I'd rather focus on getting the app just right rather then on fiddling around with devops work. There are several services out there that offer hosted real-time push technology that can be easily integrated with any app.
I chose PubNub and I couldn't be happier. They support socket.io for the client side and have a Python lib I use from Django and Celery workers. They also have SDKs you could use from native mobile apps.
I know, you already have a working setup in place. But I'm betting that the time it will take you to replace your current setup with such a hosted solution would be less than the time it will take you to find a good solution for what you're looking for and implement it. Also keep in mind maintenance costs down the road (esp if you opt for a lib which is not well maintained).
True, you will be paying for the service, but they price is very reasonable and you will be getting a solid service with nice perks like colocation.
I'm not affiliated with that company, just a happy customer. There are other similar services out there.
I'm working on a WebApp using backbone.js and socket.io on the client side, and Django on the server side. I'd like to do "push" from the server when data changes (just like in a chat app). I came across two implementation of socket.io in Python with a Django integration that looked promising:
django-socketio which is based on gevent and gevent-socketio
Tornado-based integrations that use torandio2 such as tornadio-with-django and django-tornadio
Both gevent and tornado have very good performance, so I'm not interested in other async connection frameworks. The only other requirement is the use of SSL for the connection - no plain text transmission.
So between these two approached, which would be the easiest to implement? Is there a good subscription-based framework for tornadio2 similar to how django-socketio does it for gevent?
Another option I came across is django-serverpush, which is also based on TornadIO2. It better integrates with Django than the other TornadIO2 apps, but the implementation still needs some improvement before it becomes production-ready.
At the time of writing this answer, django-socketio still hasn't been fully upgraded to work with the latest socket.io.
Tornado/TornadIO2 on the other hand are well maintained, and with a few custom extensions I was able to get them up and running very nicely. After I launch my product, I'm hoping to spend some time to open-source my modifications. Until then, I'd be happy to answer any questions on how to get this running.
Honestly I'd say they're pretty similar. This is more of an opinion. For performance I think gevent has more performance based on what I've read, but you should do your own tests to find out which has highest performance.
I'm looking for a simple POP3 and/or IMAP server for unit testing my application.
Requirements are:
no root privileges required to make it fully functional,
may store it's data in whichever directory I choose,
compliant to RFCs,
possibility to add e-mails by hand.
I've tried Dovecot, but it seems too complicated and running it without special system account is fairly impossible.
I know Mozilla should have one for Thunderbird testing, but only one I have found was for newsgroups.
Why not use (or create) a mock server and use that to test the functionality? This will return the correct responses to the various commands so you can be sure that your code will work correctly when you connect it to a real server.
That way you're not reliant on a 3rd party service for this aspect of your testing.
http://quintanasoft.com/dumbster/
http://www.icegreen.com/greenmail/
And probably many more. You start them in Your test so You don't have to create any system accounts.