I want to implement a web-based IM service on the lines Meebo. Might sound ambitious but that adds to the fun of it.
My research suggests XMPP would be a good protocol for the IM since it can talk to proprietary protocols as well. Am I right? What else would I need to complete this?
Could Google App Engine(GAE) fit in to this project? Can GAE be used to create and host the whole service? That would simplify matters significantly.Also,GAE does support XMPP.
I know what I want to make, need to know the best way to make it.
Thanks!
Suvir
GAE has an XMPP API that lets your app send and receive XMPP messages. The real sticking point with making a real time chat app using only GAE is that you can't push updates to the client. So your client would have to continually poll the server to see if there were any new messages. One way around this is to operate a comet server outside of GAE to forward the pushes to the client.
wikipedia page on comet techniques
Google App Engine allows you to use stateless HTTP requests and XMPP, but not TCP sockets. Thus you're limited to any IM services which use the former.
For an example of using the XMPP service, see Using the XMPP service:
For our example app, we're going to
write the Amazing Crowd Guru. The
Amazing Crowd Guru is a veritable
oracle, who can answer any question
you might pose it over XMPP. Writing
an omniscient computer program is no
small task, but thanks to a little
behind-the-scenes trickery, we're
going to get our users to do all the
work of answering questions for us.
Related
First question here so go easy on me.
The producer and endpoints can be sockets/websockets/http(s). These requests will then be processed and sent to subscribed consumers or sent to a queue and routed based on message priority and/or user skill. I would also like to store all the messages and transactions and have options to retry and schedule them.
I know appengine does not support sockets right now, buts its available to trusted testers as of sdk 1.7.5 so that might work in future. This application will not be serving the client pages so the channel api won't work and i don't see any websocket server support, i can work around that i suppose.
On the other hand if i use ec2 then all of those issues go away, but i'll need to scale the application myself, and i'll have to manager the database. I know AWS has other options like SQS, SNS, Beanstalk and simpleDB that could handle the queues, notifications and scaling.
I want to use appengine as it seems like the easier platform to develop for. I know i am not the first person to try to build something like this so i wanted to find out what your experiences were.
Does camel work well with appengine? I know a lot of camel components use threads, jms, jndi which dont work on appengine, were you successful on still using camel on appengine without these. And from my description of what i want the app to do is it possible on appengine or am i better of using ec2. Also has anyone tried doing this with AWS beanstalk.
I have spent a decent amount of time googling around but could not find anything concrete. I have the sample camel app running on appengine, so i know camel works, Just want to make sure the other features i talked about will too. I am new to camel and just learning so sorry if the answer is already obvious or if the questions are vague, any help is appreciated.
Thanks for any insight here!
This question is cross-posted on bitcoin.stackexchange, stackoverflow and bitcointalks.
I'm planning to build an application on Google App Engine that will heavily make use of Bitcoin trading. I've been Googling along a little but I couldn't find whether it is possible to run Bitcoin itself on App Engine (with Java). I have some experience with App Engine, but limited to a pure web-app centered usage.
I've read about a few people that have made applications using Bitcoin with App Engine as well that are hosting Bitcoin separately on an Amazon EC2 instance.
So, does anyone here either has experience with running Bitcoin in App Engine for Java or would anyone have an idea how this could possibly be done?
I know there are a lot of Bitcoin applications out there, I'd like to know how these manage their Bitcoin traffic.
I'm trying to avoid needing a separate Amazon service running all the time next to App Engine.
In fact, receiving Bitcoin can easily be done by using passive APIs like blockexplorer or blockchain, so I'm considering to find a reliable API to handle my outgoing payments. But this approach causes extreme dependency on this API service, which I actually want to avoid as much as possible.
I think you summed up the possiblities already.
depend on an external service providing notifications for
transactions and sending them i would advise against this.
have a second server running permanently and connect to it using json-rpc
running any type of p2p node on app engine will fail, because of the threading limitations on GAE.
a third possibility would be to use a stratum/electrum supernode, that way you are dependant on a 3rd party service, but at least it is well documented and you can set up one yourself easily. AFAIK, stratum is based on http.
source: i programmed a GAE app dealing with bitcoins about 6 monts ago. (using the second server approach)
I would like to build a mobile application with the following requirements:
The mobile client applications should request and recieve data from a database on a server.
In the future I will probably want to build a web application for the same database.
For communication between the clients and the server I would like to use Google Protocol Buffers.
So I have the following questions:
How does one set up a server to take request and respond with anything other than html. I think that using RPC sounds nice, but I have no clue how to set it up on a server.
I need to find a good web hosting service which will allow me to set up a database and a server that can serve both Google Protocol Buffers and regular web pages with data.
Before I get to making the web app, is there any more lightweight solution that might be better just for communicating with the clients (maybe even a home made tiny server), and how hard would it be to do it with a full scale web server from the start?
Please point me in the right direction so I know what to read up on.
I'm not necessarily looking for specific names of web hosting services but rather an idea what kind of services are available that might meet my needs. I've worked a little bit with django, Spring and Java EE so if there's any solution involving those that would be great, however I'm not afraid of learning something new.
Thanks in advance
Simon
if you still mean http, that is pretty trivial - you simply set an appropriate content-type, and write your data to the response stream. The exact how depends on your web framework and tools, but this is no different to (say) serving generated images on the fly. HTTP requests function fine for messaging scenarios - as simple as making an http request (typically POST) with a protobuf (etc) body, and processing the response in the same way.
can't comment
a web app can be lightweight; certainly more-so than having to configure a non-http service/daemon. The "lightweight" option would be raw sockets, but that is harder to deploy, and you'll have to be more picky choosing a host. Unless you absolutely need this level of terseness (i.e. dropping the http headers and writing your own transport to get close to the wire), just stick with http - it'll be a lot easier to get going and maintain
For info, I have a blog post on doing this with ASP.NET MVC; this isn't intended to mean "do this" (heck, use whatever tools help you) - simply, it is meant to show the kind of thing necessary.
use case: 5 - 30 users simultaniously on a chat.
is it a good idea / is it possible to code this on google app engine?
Until the Channel API is released, you'll have to use polling to do this. When that API is released, App Engine will be (IMO, caveat that I work on the team) a great tool for this.
Note that with 1.3.6 you can use the Channel API for local development so you can at least get started implementing something, though it won't work in prod.
maybe it's a stupid question, but couldn't the GAE Application forward incoming messages to all known clients when they are posted to the server?
Why would that not work?
Laures
I would like to write a client application for Android that uses the Google App Engine as a database backend. My Android client would connect to the App Engine to save information, then it would connect later for reports. Is it possible to use the App Engine as a backend like this?
If you're looking for something like the remote api that the App Engine has in python, then you'll be disappointed to find it missing in Java.
That said, absolutely nothing stops your from hitting your app and posting data either through POST / JSON / XML / any other format you can think of. The same thing goes for getting your reports back.
If security is a concern, the OAuth protocol allows you to authenticate to app engine from your android device.
This is an aside, but as far as reporting is concerned, you might not find the app engine a very suitable platform for reporting type apps. Just make sure you understand its limitations - the lack of joins, 1000 object limit, no sum / average, necessary indexes, etc. It's certainly not impossible, but do think carefully about how you're going to model your data.
Yes, it is possible.
Without more details in your question, any more details in the answer would be speculation.
Yes, its very much possible. It's something I am also currently working on.
My code uses HTTP GET and HTTP POST and I am using a RESTful service on the GAE.
I'm sorry I can't provide any code because I am still learning however the library I'm using is called RESTLET. They have libraries for both GAE and Android however I'm only using RESTLET on the GAE and I'm just using the HTTP library in the Android SDK for the client.
http://www.restlet.org/
The version you require is 2.0 M6 and not the stable release.
No.
In your response to Laurence, you said you want a direct DB connetion. A client cannot connect directly to the GAE datastore. You must write web handlers to interface between the client and your data. It doesn't have to be much, but it must be something.
Yes, it is very possible. You would not connect directly to the GAE database though. A better architecture would be to make your app hit a URL that writes to the DB. For example, you could set up a Struts 2 action that takes the values of your query parameters and then mutates and validates them as necessary before persisting them.