I'm trying to use templates from a remote server.
It seems ServletLoader is one of the options.
How can I set prefix like http://server-ip.com/pebble
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everyone! I am building a web application, i.e. a server-client application. For the interaction between the two, I have to define the URLs twice (hard-coded strings), both on the backend and the frontend, which makes future changes hard, because it would require changing the code in two places, rather than just one.
I am using Django and Angular and so I am looking for a way to specify the back end endpoints once, then ideally read them and use them for the Angular production build. Therefore changes to the endpoints will only require a new build, but no further changes.
Should these be defined in some .cfg file and be read by the back end on server startup and maybe somehow add them to the Angular's build process? Any suggestion would help because this redundancy comes in almost every webapp project and there has to be a more clever solution!
Thanks for the help in advance!
Here, it is the backend application that owns and defines url mappings to entities. It is possible that multiple clients can consume from the same API, like a web client, an Android client and an iOS client. In this setup, your backend is the point of truth for the url mappings, and client applications should be configured to use the url mappings defined in the backend application.
One possible way to do this is to serve defined urls in the backend on a path of the backend application, and have your client applications configure themselves using the data provided there. For example, if you use Django Rest Framework, by default, on the root path of the API ("/"), resources along with url mappings for the resources are served. You can use such a mechanism to configure your client applications on build time.
How many endpoints and how likely are you to alter them? Most likely you will always have to make more changes than just in 1 place as the reason behind changing an endpoint is normally you are trying to POST or GET new data structures. This would mean you will have to alter that request process anyway to handle the new data type or what was being posted.
Also, consider some of the publicly available api's out there - they don't give you an endpoint that serves a config file of available routes. When they make a change to their endpoints they usually create a versioned api so that consumers can upgrade in their own time.
In my opinion, unless you are planning a large scale web app, I wouldn't be too worried about trying to implement something like this.
I have a hypothetical web application which is split up into a microservice architecture like (as an example):
Clients A-C are web applications that serve HTML. Services 1-3 are the backend that handle CRUD and serve JSON. There are other clients (not pictured) that do not access Frontend Service - namely, native clients such as Android and iOS. I'm trying to figure out the best way to serve common frontend content (such as header/footer/css) across all web clients. The best way I can think of doing this is to create a Frontend Service that each web client can access to pull this common information. That way changing the common front end will be reflected in each application immediately without need to update versions, recompile or redeploy.
My question is what is the best way of doing this? I'm using Dropwizard to serve both the web clients and the services. The web clients serve Dropwizard Views (with freemarker templates) via Jetty. Is there a way to compose Dropwizard Views so that I can request a Header and a Footer view from Frontend Service and wrap these around each view returned from the Clients? Or am I going about this completely wrong? I know that Freemarker supports template inheritance but as far as I can tell this means the header/footer would have to live in each client or be pulled in from a common JAR (which would require updating version numbers and recompiling).
If you want to have content synchronized between all the microservices, in your case the header and footer, I'd suggest Zookeeper, it's designed for distributed orchestration and has more of a push model - i.e. you'd update the header in Zookeeper and all of your services would receive that update almost instantly.
I suggest the Curator library as it's much easier to work with than Zookeeper directly, the cache example might be a useful starting point.
You can also use Hazelcast as distributed Map/Cache. It is really easy to use (see code examples), but if you want some enterprise features you have to pay a lot.
Is it possible to communicate from a web browser(Loaded an HTM page from server) to an application running in the same server using AJAX. Need to send the request from browser using a button click and update the page with responses received from one another application running in the same server machine?
I am using HTML pages to create website and not using any PHP or ASP like server side scripting. In server machine data are manipulated using a C++ application.
I think you can use any sort of Javascript functions to do that. But you might need to use jQuery or similar frameworks to make your live easier. You might need to search for "Comet Programming" to know exactly how to do 2-way communication between client and server
Updated:
Well, this kind of stuff requires you to read a lot (if you have not already known). Basically, what you need is a server that can do long-polling (or eventsource, websockets). There are many open-source ones that might help you to get started. I can list a several good ones here. There are a lot more
http://www.ape-project.org/
http://cometd.org/
http://socket.io/
http://code.google.com/p/erlycomet/
http://faye.jcoglan.com/
So after you have the comet server up and running you will need to setup the client side (probably Javascript). For those listed projects, most of them come with the client side code to interact with the server (Except for erlycomet). Therefore, you can just use the examples provided and run a quick prototype. If you want to use your raspberry pi, you can use nodejs which provide a lot of ease for dealing with real-time communication (socket.io, faye). And lately, http://www.meteor.com/
I would think of the problem this way: you want to provide a web front end to an existing c++ application. To achieve this you need to think about how your web server communicates with your c++ application. Communication between the browser and web server can be thought of as a separate problem - as you say AJAX calls can be used, or maybe have a look at websockets.
Once you have your request in the web server you need to communicate it to the C++ application (and/or visa versa). This can be done a number of ways, e.g. sockets or RPC. I found this question here which has some good advice.
I'm currently writing a webservice (with node.js) for an AngularJS frontend which is hosted with node.js
It will later be available through a proxy under domain.com/api and therefore I don't need JSONP.
For local testing purposes i have my AngularJS app running on localhost:80 and my node.js backend on localhost:3000. Naturally I'm not able to query json requests. The easies
What would be the best setup to test my homepage locally without screwing to much in my setup?
I'm currently working on windows. Linux is also an option if it is easier.
Would it be possible to write a simple proxy for express that hosts both apps in the same domain?
You can use the hosts file to set the domain.com/api to localhost. This is done in /etc/hosts in Linux, but its present somewhere in Windows too. Another thing that helps me a lot is ssh tunneling. You can, for example, tunnel remote ports (where your backend is running) to localhost with ssh -L localPort:your.server:remotePort
It's not exactly what you asked for, but the easiest might be to have the node.js app serve the AngularJS app, too. It's quite efficient, certainly efficient enough to use for development.
If it's an expressjs app, you can just add
app.use(express['static'](__dirname + "/public"));
before your other routes to have it look for static files in ./public/
If your app is served by a template or build system that you can't easily reproduce in node.js, then another option would be to run nginx, apache or haproxy on some port (80 or 5000 or ...) and have that proxy to the current backend server for the app and port 3000 (the node.js app) for the API/data requests.
You might even be able to have your server currently running on port 80 do this.
As a final idea you could also setup the node.js app to proxy to port 80 for the "app files".
Edit - I just realized that both of your apps are written in node.js. Would it be possible to set it up so you run them separately in production but together in development? Put all the real functionality in modules and then have three separate "loaders" that start the apps, one together and then a loader for each individually.
Can anyone provide or link to a tutorial for adding django-socketio functionality to an existing Django site that uses Apache and mod_wsgi?
Can they work in parallel or does the runserver_socketio command need to handle all requests?
This Question is related but offers little practical information.
Thanks
You should be able to run the regular site behind a public facing server like Apache, with the runserver_socketio part just serving websockets on a separate port. As described in the question you linked to, you'll need to work out if it's possible to proxy websockets through your web server if that's a requirement for you, but as also mentioned the gevent server used by runserver_socketio is more than capable.
When running separate instances like this, the "out of band" functions won't work, as they depend on shared state:
django_socketio.broadcast(message)
django_socketio.broadcast_channel(message, channel)
django_socketio.send(session_id, message)
You'll also need to add the SOCKETIO_PORT to the regular Django project's settings so that it knows which port to use.