C# 2008
I have developed an application that need to connect to a web server in order to work. If the web server goes offline. The the app will have to be notified so that the user using the app can know what happened.
This application will be downloaded from the internet from our clients web site. So hundreds or thousands of users could have it.
I was thinking about pinging the web server maybe every 5 seconds. However, with 100's or 1000's apps would overload the web server.
Someone has told me about ESB would be right for this problem. The way I am thinking to use this, and I am not totally sure. Is to have every app to subscribe to the ESB. If the web server goes offline it will send a message to all the apps.
However, I understand that ESB is very big and complex and maybe this is overkill for my problem.
Am I understanding correctly.
If ESB is not the correct choice is there another design pattern I could use?
Many thanks
It sounds inappropriately out of scope to spec an ESB for this simple purpose. Why not just have the client machines figure it out as they periodically need to access the website? Instead of pinging the web server over and over, in the course of their normal activities they will need to access the web server for any normal reason, if they get an error response they can branch down the "web server is down" code path.
An ESB sounds like the wrong solution.
Two possibilities come to mind:
(1) If the user doesn't need to know they're offline in real-time, defer detection to usual error handling when you try and access the server.
(2) If you must know real time, use a small proxy at each client site so that only the proxies need to ping your server, not every desktop.
Related
Im currently in the process of switching to google compute engine for my web hosting because my current provider performance has been deteriorating over time. Giving me more flexibility to upgrade as I need to.
Ive got my website setup and working on the engine. But the next steps need to go smoothly to ensure my customers don't experience any downtime.
I have a few things I need to work out:
- Does google have a way of managing email addresses at your own domain? Then I can just send or receive from gmail.com or another email client on my domain? Or do I have to setup a email server in my VM? If so is there any way to setup a cpanel like management software on it?
- To my understanding I should just have to call my current provider to ask them for my SSL certificates and for them to switch my domain over to google and then point it to my VM? or is there something I'm missing here?
Are there any simple ways to ensure my server says secure when I'm managing it myself other then just updating packages manually? Like a website I can use to track known security problems with the packages I have installed?
Edit:
Please read Dan Cornilescu's comment on this question about setting up your own custom domain email. He said it can possibly be managed using google apps.
On the topic of SSL/Domains I called my current provider and they said they would help me switch over if its what I decided. They also upgrading my hosting plan and things seem better now and are comparable to the performance I was getting on my google VM so Ill be trying that for now.
Is it possible to build a realtime app using AngularJs with a mysql database?
I've been reading thousands of tutorials, but they are all focused on express, nodejs, etc.. didn't found any documentation on wheter it's possible or not. I tried to take a look at the socket.io docs, but still didn't found anything relevant to this question.
I didn't tried anything yet because of this. I use a webApp based on AngularJs on a apache server (local).
Where should i start to be able to build a real time app using these tools i have?
Do i really need to use a node/express server?
What are the main consideration i need to do before taking this step?
Is there any documentation i should read?
I need to do this real time because it involves product orders, call center, ticket system, etc.. So everytime there is a new ticket is opened/changed, new order arrives, etc.. I need to make the user aware of this, without the need to refresh the page.
Or if someone could give me a further explanation of this concept and how to get started, it will be great.
You can run angular on top of any backend, although most examples push towards REST. If you want your app to feel like a real time application, using WebSockets is a likely improvement.
WebSockets play nice with Angular, look at https://github.com/wilk/ng-websocket for example. A back-end in Node will work, but many other backend techs will do equally well.
Here is a decent tutorial using MySQL, NodeJS, and Angular: https://codeforgeek.com/2015/03/real-time-app-socket-io/
I recommend that you keep using a webserver like Apache (my personal preference is Nginx). You can proxy API and socket requests to Node, and serve static resources for the app from a folder.
Check out https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html if you stay with Apache. Check out http://nginx.org/en/docs/http/websocket.html is you go for nginx.
Without a webserver, you'll have to either:
serve your static resources with Node (polluting your server project with client code), or
work with different ports, risking the app becomes unusable in client environments, or
work with different domains, giving you a CORS head-ache.
Although I don't have much experience with Node, MySQL with Node.js should help you out a bit.
You'll want to move away from Apache if you want to do websocket stuff with Socket.io
Yes, it is possible to create a software with AngularJS in the front end and any other server side language that speaks to MySQL. Few months back I worked on a software with Java Spring Framework in the backend with MySQL database and AngularJS with bootstrap in the front end. You could start by following the MVC pattern, where your views can be served as AngularJS and your Controller can be in any server side code, with MySQL database.
A customer of mine asked me a better and faster solution to update it's real estate web site as he and his employees don't want to connect to the web site and update one by one the ads as they don't want to loose time waiting the normal latency of the internet.
I firstly solved the issue by building a PHP script that imported an Excel file into the web site's MySQL database and it worked greatly. But the problem were pictures that have still to be uploaded separately. I then wrote a PHP script that uploaded the pictures using ajax and drag&drop so the user could select multiple pictures and upload them at once. And this worked too, but the customer is still not completely satisfied as he says this solution is quite 'patched'.
I then thought about a desktop application - a kind of local database (could be SQLite) - that the user keeps updated locally and only at the end of the day the app connects to the remote server and updates the db and uploads the pictures.
My question is: what EASY desktop high level programming language I could use to do the job? Do you know any RAD (visual IDE) programming language able to connect to a remote mySQL server and upload data via a simple custom GUI?
I tried RealBasic and PureBasic but I did not work it out. I thought about building the app in PHP and then convert it to EXE but I did not tried yet.
Please don't suggest me Java, C or Delphy as I'm looking for something very easy.
Thank you
Have you considered a client side javascript/html app that syncs with the server, since you're already familiar with the platform? If one browser better supports what you want to do (Firefox has some extension perhaps vs Chrome, or whatever), than mandate that to run this app (rather than worrying about being portable across browsers).
All of the browsers can have client side storage now, and you can just do things locally, and finally push them to the server "all at once".
If your client is using a Windows platform, you could use IronPython (.NET), VB.NET, or C#. These all allow you to create windows/forms visually in Visual Studio. If you're not already familiar with the .NET platform I'm not sure how 'easy' this will be, but I think that's going to be true for most other platforms as well.
That being said, it sounds like your existing solution is probably the best idea - perhaps if you can make your solution feel less like a "patch" they will be satisfied.
No reason you can't use Purebasic if that's what you're comfortable with. There are HTTP file upload examples on the PB forums.
I've used Purebasic for years but I'd recommend spending the time to get to know C#/.NET - it's a world of difference and once you learn it stuff like this is pretty easy.
This is question is about whether this will hypothetically work for a project I'm working on:
Flash .swf plays in browser
User sends SMS text message to SMS Server.
SMS Server updates MySQL Database value.
Flash connects to MySQL database and checks value.
Technically right now, I know I have to do research, but the biggest thing is "Flash needs to do something once it hits X amount of SMS text messages". Anything that I can cut out of that process would be great, but I think that's the best way.
The SMS part is a mystery to me, but after looking at another post, it seems like with http://www.twilio.com/ or something similar I can have a MySQL database receive SMS data.
Getting Flash to connect to MySQL I've heard is possible, but that's not really the part I'm worried about.
Suggestions or tips?
Flash cannot connect to MySQL directly.
It can "ask" a server side programming language to though.
Basically you use HTTP or AMF remoting to connect to a PHP class or file which in turn interrogates the database.
any ideas on what I need to create a touchscreen restaurant ordering system?
I've got the touch UI understood and implemented 100%.
What I can't figure out is how to implement the "Send order to
kitchen" and "Call waiter" functions.
Each table will have a "client" computer running an air app. Calling the "Send order to kitchen" and "Call waiter" functions from the "client" computer should make the "client" communicate with a different "kitchen" computer over wifi.
I'm sure this can be done, I just don't know what I need.
I've read about UDP but I'm not sure that's it.
Any ideas?
With real time data delivery, a streaming server is useful, like you mentioned. Adobe offers a free service for that:
http://labs.adobe.com/technologies/cirrus/
If you think dealing with that might be somewhat over your head, you can always use a standard, locally accessible web server like PHP/MySQL. It would even allow you to archive closed orders with say, an "order_status" database field in MySQL.
The host AIR application could periodically ping the server for "open" records and push an alert if it sees any new records. When an order goes out, you'd obviously send a separate request back to the web server to update a particular record as closed.
Additionally, clients would send their order requests to the web server for inserting new records into the database... with each new record receiving a unique id (primary key).
I personally would go for option 2 for the sake of a database implementation.
For an easy Windows PHP/MySQL installation: http://www.wampserver.com/
Don't over complicate it.
An AIR application can run a ServerSocket that other AIR apps can push and pull messages from. You only need to write and read Sockets.
We even have cross-platform implementations of this, where either server or client is a native Android or iPhone app.
It works well as long as you can read / write servers and you are on the same network.
Good luck!
Juan