As per my understanding, when user visits a url of a SPA application, the whole application is downloaded including any static html,assets and javascript. Can someone please clarify what role does the host web server play from there on? If after download of all the assets, I turn off the web server the application does not work. But ideally, it should work because now all the code to create any views is with the client already in form of javascript files. Let's assume there are no API calls for data.
Yeah it will work
If the application is fully loaded in browser it will work even after you turned off or disconnect the web server
Web Server No Need after the client has downloaded all the assets
Is it possible to rename/move or delete files from a web application (ASP.Net MVC) that are on a server folder just like how you would do it locally? I would want the user to be able to upload say 30 files (from a scanner auto-feed) into a temporary folder on the server (cannot save it locally due to data security) and then allow the user to be able to rename /move before uploading them onto Azure blob storage.
I saw few examples - jquery file tree seemed good but not sure if it allows rename and moving. Please suggest solutions for working with the server folder. I intend to delete the server folder after I am done transferring files to Azure. TIA.
Yes, you can do this by giving the USER that is running the ASP.Net application (defaults to IUSR) permissions to write to that folder.
Be very careful though, as you're potentially opening your website for abuse when doing this.
See: https://www.iis.net/learn/get-started/planning-for-security/understanding-built-in-user-and-group-accounts-in-iis for how IIS users operate.
Currently, in order to push my website live I upload files to the server via FTP using FileZilla. If a user reloads the site when I'm pushing over the website DLL, they'll get a File is being used by another process type of error.
Are there any better pushover techniques I can make use of to get around this issue or any techniques that are generally better than using at FTP client to upload my site?
You can always upload an app_offline.htm file while you are deploying the new site. If you do this in an asp.net application the user will be directed to the app_offline.html file no matter what page they try to load/reload. When you're ready for them to access the site again you simply remove/delete/rename the file (i usually just rename it so it's a simple rename to get the site back into offline mode).
http://weblogs.asp.net/dotnetstories/archive/2011/09/24/take-an-asp-net-application-offline.aspx
If I make a change to the vb code in a classic asp page does the change get picked up automatically or is an iisreset needed?
Thanks
Quickest answer NO you do not need to reset IIS
Once the changed file is saved, the new code will run.
There's no need to reset IIS or build the project.
The ASP Script engine does maintain a cache of "compiled" scripts (where the results of parsing and tokenizing etc are stored. So that subsquent requests for the same ASP page can be processed more quickly. However the last modified date of the ASP file forms part of the cache identity of the cached page. Hence if the page has changed since the last request the cached item is dropped and a new one built when the next request arrives so it all works seemlessly.
So as the others very quickly said, you don't need an IISReset or even an App pool recycle.
It may be worth pointing out that as of IIS6 there are very very few circumstances where you would ever need to perform an IISReset. IISReset is massively draconian and high impact. Most of the time when such a "reset" is needed a simple re-cycle of the appropriate application pool will do which has a far more gentle touch.
Even back on IIS5 a close equivalent of a app pool recycle could be achieved with by restarting the appropriate COM+ application.
On Win 2003 Server (IIS6) most of the time, save the changes to the file and it works.
I have had caching problems when the files have been saved and then copied/moved to the final location which is a virtual folder in IIS.
For example:
Say C:\inetpub\wwwroot\myfolder\ is the physical path for the URL http:Myserver/myApp/
I save my files in C:\inetpub\wwwroot\test\ and everything works fine
Move/copy the files from 'test' to 'myfolder' overwriting existing files and when I access http:Myserver/myApp/ I see my old pages, not the updates.
I am trying to get a grasp on how to handle updates to a live, functioning ASP.NET (2.0 or greater) Application while there are users on the site.
For example, suppose SO is an ASP.NET Web Application project. The project code compiles down to the single .DLL in the BIN folder. Now, there are constantly users on SO, so what would happen to users' actions/sessions if you would use the Visual Studio .NET "Publish" feature (or just FTP everything again manually) while they are using the site?
Would creating an ASP.NET Web Site, instead, alleviate any problems that may or may not exist with the scenario above? I am beginning to develop a web site as a user-driven Web Application, and I want to make sure that my inexperience with this would not potentially annoy the [potentially] many users that I [want to] have 24/7.
EDIT: Sorry, I should have put this in a more exact context. Assume that this site is being hosted by a web hosting service with monthly fees. I won't be managing the server itself, just what the web host allows as a user of their services.
I create two Web sites in IIS. One is the production Web site, and the other is a static Web site with an HttpHandler that sends all requests to a single static "We're updating" HTML page served with an HTTP 503 Service Unavailable. Typically the update Web site is turned off. When it's time to update, we stop the production Web site, start the update Web site, and now we can fiddle with the production Web site all we want without worrying about DLLs being locked or worker processes needing to be spun down.
I started doing this because
App_Offline.htm really does not work well in Web Gardens, which we use.
App_Offline.htm serves its page as 404, which is bad if you're down for a meaningful period of time.
We can start the upgraded production Web site with modified settings (only listening on localhost), where we can do a last-minute acceptance/verification that everything is working before we flip the switch, turning off the update Web site and re-enabling the production Web site.
Things this does not solve include
Any maintenance that requires a restart of the server--you still have downtime where no page is served.
Any maintenance that diddles with the .NET runtime, like upgrading to the latest service pack.
Other approaches I've seen include
Having two servers. Send all load balancing requests to one server, upgrade the other one; then rinse and repeat. Most of us don't have this luxury.
Creating multiple bin directories, like bin-1.0.0.0 and bin-1.1.0.0 and telling ASP.NET which bin directory to use in the web.config file. (One advantage of this is that reverting to a previous binary is just editing a config file. A disadvantage is that it's harder to revert resources that don't end up in your binaries, like templates and images and such.) I don't remember how this actually worked--I think the application did some late assembly loading in its Global.asax based on its own web.config section (since you touched the web.config, the app had restarted, so it was okay).
If you find a better way, let me know!
Changing to the asp.net web site model won't have any effect, as the recycle will also happen, some of changes that trigger it for sure: web.config, global.asax, app_code.
After the recycle, user will still be logged in because asp.net will just validate the syntax. That is given you use a fixed machine key, otherwise it will change on each recycle. This is something you want to do anyway as other stuff can break if the key change across requests i.e. viewstate validation, embedded resources (decryption of the url fails).
If you can put the session out of process, like in sql server, you will avoid loosing the session. If you can't, your code will have to consider that. There are plenty of scenarios where you can avoid using session, and others were you can wrap it and re-retrieve the info if the session was cleaned. This should leave you with a handful specific cases that you know can give trouble to the users, so for those you do some of the suggestions others have already made.
One solution could be to deploy your application into a load balanced environment (web farm).
When deploying a new version you would use the load balancer to redirect requests to the server you are not deploying to.
App_offline.htm is great solution for this I think.
in SO we see application currently unavailable page when a deployment begins.
I am not sure how SO handles it.. But we usually put a holding page. So what ever the user has done (adding question or answering questions) does not get updated. As soon as he updates something he will see a holding page asking him to try after sometime.
And if I am the user I usually press the back button to make sure what I entered is saved in the browser history so that I can post later.
Some site use use are in clustered environment so I take one server offline and inform the load balancer that she will not be available and once I make sure that the new version is working fine I make it live.. I do the same thing for the next server.
Do we have any other option?
It is not a technical solution, but set up a scheduled maintenance window. You can annoucement in advance giving your user base fair warning that there is a possiblity that the application will not be available during that time frame.