One of our applications is exhibiting poor network behavior on Vista due to the new network stack's auto-tuning functionality. I'm working on tracking down why the problem's happening, but in the meantime, it'd be wonderful if we could simply disable auto-tuning on our application for the time being. Is there any way to do so programmatically, ideally just on a per-application basis? The only solution I've found is to use an elevated command-prompt—not an acceptable solution for our users.
Try setting the SO_RCVBUF socket option on your applications TCP socket. This should override the auto-tuned receive window with the value you supply (see).
Related
Sorry if this is a dumb question that's already been asked, but I don't even know what terms to best search for.
I have a situation where a cloud app would deliver a SPA (single page app) to a client web browser. Multiple clients would connect at once and would all work within the same network. An example would be an app a business uses to work together - all within the same physical space (all on the same network).
A concern is that the internet connection could be spotty. I know I can store the client changes locally and then push them all to the server once the connection is restored. The problem, however, is that some of the clients (display systems) will need to show up-to-date data from other clients (mobile input systems). If the internet goes down for a minute or two it would be unacceptable.
My current line of thinking is that the local network would need some kind of "ThinServer" that all the clients would connect to. This ThinServer would then work as a proxy for the main cloud server. If the internet breaks then the ThinServer would take over the job of syncing data. Since all the clients would be full SPAs the only thing moving around would be the data - so the ThinServer would really just need to sync DB info (it probably wouldn't need to host the full SPA - though, that wouldn't be a bad thing).
However, a full dedicated server is obviously a big hurdle for most companies to setup.
So the question is, is there any kind of tech that would allow a web page to act as a web server? Could a business be instructed to go to thinserver.coolapp.com in a browser on any one of their machines? This "webpage" would then say, "All clients in this network should connect to 192.168.1.74:2000" (which would be the IP:port of the machine running this page). All the clients would then connect to this new "server" and that server would act as a data coordinator if the internet ever went down.
In other words, I really don't like the idea of a complicated server setup. A simple URL to start the service would be all that is needed.
I suppose the only option might have to be a binary program that would need to be installed? It's not an ideal solution - but perhaps the only one? If so, are their any programs out there that are single click web servers? I've tried MAMP, LAMP, etc, but all of them are designed for the developer. Any others that are more streamlined?
Thanks for any ideas!
There are a couple of fundamental ways you can approach this. The first is to host a server in a browser as you suggest. Some example projects:
http://www.peer-server.com
https://addons.mozilla.org/en-US/firefox/addon/browser-server/
Another is to use WebRTC peer to peer communication to allow the browsers share information between each other (you could have them all share date or have one act as a 'master' etc deepening not he architecture you wanted). Its likely not going to be that different under the skin, but your application design may be better suited to a more 'peer to peer' model or a more 'client server' one depending on what you need. An example 'peer to peer' project:
https://developer.mozilla.org/en-US/docs/Web/Guide/API/WebRTC/Peer-to-peer_communications_with_WebRTC
I have not used any of the above personally but I would say, from using similar browser extension mechanisms in the past, that you need to check the browser requirements before you decide if they can do what you want. The top one above is Chrome based (I believe) and the second one is Firefox. The peer to peer one contains a list of compatible browser functions, but is effectively Firefox and Chrome based also (see the table in the link). If you are in an environment where you can dictate the browser type and plugins etc then this may be ok for you.
The concept is definitely very interesting (peer to peer web servers) and it is great if you have the time to explore it. However, if you have an immediate business requirement, it might be that a simple on site server based approach may actually be more reliable, support a wider variety of browser and actually be easier to maintain (as the skills required are quite commonly available).
BTW, I should have said - 'WebRTC' is probably a good search term for you, in answer to the first line of your question.
httprelay.io v.s. WebRTC
Pros:
Simple to use
Fast
Supported by all browsers and HTTP clients
Can be used with the not stable network
Opensource and cross-platform
Cons:
Need to run a server instance
No data streaming is supported (yet)
So I'm building a web app, and I want to emulate a network failure in browser to see if the client side javascript handles it gracefully. I know I can just disconnect my network connection, but that also disconnects my email, pandora, skype, all things that are marginally vital to my non-productivity. Is there an easy way to kill network communication for just one tab in either of these browser? Or (I'm in linux) can I block a single pid from network communication while still allowing the rest (even if it's the same program) through?
Edit: Shoot, I just realized that I'm working on localhost, and that may not apply for what I'm asking for.
Does menu file -> work without connection works for you? It should be in the firefox menu.
You could always use invalid proxy settings! I recall some plugins that let you easily change proxy profiles so you could even have a profile for "dead proxy" and enable ot whenever you want no Internet.
Turns out there are more sophisticated options: a dedicated site blocker for Chrome. That way you could still use other sites that help your non-productivity while still blocking the desired one!
I'm coding an extension for a customer, one of the requirements is that the extension also works offline because internet services are not that reliable, my customer's business can't stop but can deal with "stale" data, thats a nice tradeoff I guess.
Therefore, I want to code some kind of distributed cache as an extension to synchronize local data among the N nodes that will be connected running the same application and thus synchronize with the real database, hosted on the internet.
In order to achieve that I imagined that I would need to make a network broadcast and listen to incoming broadcasts, then every node that starts to run my application will broadcast it's IP address and become available as a new node for the distributed cache, failover is very important here.
I googled some possibilities I initially thought but none of them will work, I guess. The first was to do it just with HTTP, the second was to use Google Native Client to write C++ code that could run network code and thus do the broadcast, but it has limitations. Right now I'm thinking to use Java Applets but I don't really know if they have some limitations related to networking or if Chrome Extensions has any limitation with Java Applets.
Any ideas on how to do it? Using some of the stuff I suggested or another approach?
You could create an NPAPI extension, which would not be restricted by Chrome at all.
I'm building a client-server application and I am looking at adding failover to the client so that when a server is down it will try to connect to another available server. Are there any standards or specifications covering server failover? I'd rather adopt an existing standard than implement my own mechanism.
I don't there is, or needs to be any. It's pretty straight forward and all depends on how you can connect to your sever, but basically you need to keep sending pings/keepalives/heartbeats whatever you want to call em, and when a fail occurs (or n fails in a row, if you want) change a switch in your config.
Typically, the above would be running as a separate service on the client machine. Altenativly, you could create a method execution handler which handles thr execution of all server calls you make, and on Communication failure, in your 'catch' block, flick your switch in config
You're question is very general. here are some general answers:
Google for Fault Tolerant Computing
Google for High Availability Solutions
This is usually handled at either the load balancer or the server level. This isn't something you normally do in code at the client.
Typically, you multihome the servers each having their own IP + one that is shared between all of them. Further, they communicate with each other over tcp for the heartbeat to know which is the Active node in an Active / Passive cluster.
I can't tell what type of servers you have, but most of the windows servers can do this natively.
You might consider asking the question at serverfault to see how to properly configure your servers to support this.
I'm bored cause my development server is down and I'm running the command prompt to ping the server indefinitely so that I'll see when they stop timing out and know that I can work again. In the meantime I wanted to make an Air app that will do this for me, so I can have it chirp or alarm or do something when it starts to be able to connect to the server.
So I need to start with having AIR do the ping, does anyone know how to do this? I can't find any help on it. I can't use the HTTPService because whatever it is that is broken (think it's the VPN), our dev web site is still up.
Thanks
Otherwise you can use the NativeProcess class of the AIR 2.0 beta, and use the ping command of your operating system.
You can find informations on how to use it here.
According to the docs, SocketMonitor, descending from ServiceMonitor will check basic availability, but not a true ping. If you want to truly "ping" the server, you would need to use a socket an implement the protocol, This link to the Wikipedia article might help.
The AIR SDK offers some classes (URLMonitor, SocketMonitor) to handle this:
http://livedocs.adobe.com/flex/3/html/help.html?content=network_connectivity_1.html