configuration page for mvc 5 application - c#

I'm developing an ASP.NET application using the MVC 5 framework. This application will ultimately be deployed on-premise. Therefore, users need to be able to install and configure the application before they can start using it. I need them to be able to specify things like the database name (MSSQL), the locations of various supporting services, and certain credentials like API keys for third-party services.
In a few MVC 5 applications I've used, these settings could be managed through a form. So I thought of creating a Configurations controller with GET and POST Edit actions. So the user can install the app, and then go to http://myServer/myApp/Config and specify the various settings there.
What I'm not sure about is where those settings would then be stored. Would it be the web.config file, or a settings.xml file, or the database?
Here's the strange thing... I already have a working solution with web.config that uses the below code:
public class ConfigController : Controller
{
// GET: Config/Edit/5
[HttpGet]
public ActionResult Edit()
{
ViewBag.DatabaseServer = WebConfigurationManager.AppSettings["DatabaseServer"];
ViewBag.DatabaseName = WebConfigurationManager.AppSettings["DatabaseName"];
ViewBag.PusherClientID = WebConfigurationManager.AppSettings["ClientID"];
ViewBag.PusherAPIKey = WebConfigurationManager.AppSettings["APIKey"];
return View();
}
// POST: Config/Edit/5
[HttpPost]
public ActionResult Edit(FormCollection collection)
{
WebConfigurationManager.AppSettings.Set("DatabaseServer", collection.Get("databaseserver"));
WebConfigurationManager.AppSettings.Set("DatabaseName", collection.Get("databasename"));
WebConfigurationManager.AppSettings.Set("ClientID", collection.Get("pusherclientid"));
WebConfigurationManager.AppSettings.Set("APIKey", collection.Get("pusherapikey"));
return RedirectToAction("Edit");
}
}
And my web.config file:
<appSettings>
...
<add key="DatabaseServer" value="localhost\sqlexpress" />
<add key="DatabaseName" value="MyDatabase" />
<add key="ClientID" value="testID" />
<add key="APIKey" value="testkey" />
</appSettings>
I can change these variables on a form on edit.cshtml and they persist fine. Two problems:
I can't figure out where they go. I'm told they go in web.config but I checked both web.config files inside my app and none of them have the updated values. On the form, I update ClientID to "123" but in web.config it still says "testID" which is the original default value.
I'm told that updating web.config will cause the app pool to restart. Yet that doesn't seem to be the case here...
Can someone explain what is going on?

You are missing,
WebConfigurationManager.Save();
in your post to edit.
The changes you are making are only being applied at run time. The reason you are not causing the app pool to restart is because you have not committed your changes.
Here is a reference I found: modify the web config at run-time
Do Note that in the long run as stated in the referenced link you should not store settings that are edited frequently in your web config. Use an XML or json file to store those settings and load them as needed.

Unless you call the Save method on the configuration, It won't be persisted to the physical file(Web.config). That means, you will still be able to read the app setting entry values you set until the app pool recycles. But if your app pool recycle/IIS get restarted, you will loose whatever you set to the AppSettings.
Save method writes the config settings to the current XML configuration file.
Keep in mind that, the user or process that writes config file entries must have the following permissions:
Write permission on the configuration file and directory at the current configuration hierarchy level.
Read permissions on all the configuration files.
If you really want to persist the app settings entries to the files, you can do this
[HttpPost]
public ActionResult Edit(FormCollection collection)
{
var config = WebConfigurationManager.OpenWebConfiguration("~");
var db = config.AppSettings.Settings["DatabaseServerName"];
if (db != null)
{
config.AppSettings.Settings["DatabaseServerName"].Value = id;
}
else
{
var dbEntry=new KeyValueConfigurationElement("DatabaseServerName",id);
config.AppSettings.Settings.Add(dbEntry);
}
config.Save();
// to do : Redirect to a success action (PRG pattern)
}
In your case, to set the db server name & api keys, you should be calling the Save method so that they are persisted in the file and will be available later even after the app pool restarts.

Related

How do you pull values from a linked App.config in Web application when Web.config exists?

I have a mvc .NET web application written in C# and I have a web.config file associated with it for web specific configuration values. I also have a windows service application that will be running on the server in the background that has a App.config associated with it. I have linked the file within the web application and can see the file with updated values. But I am unable to use those values in my controller to display them to the UI. Is there a way to make a call to the app.config values to use in the controller and views of the web application? Right now it seems like they are coming in null due to them not being in the web.config.
Any help is apprecaited.
As long as permissions are worked out, you should be able to open the shared config file thusly:
var map = new ExeConfigurationFileMap();
//TODO: resolve this path in whatever way makes sense for your situation.
map.ExeConfigFilename = #"C:\MyConfig.config";
var config = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
//do something with config, e.g. config.AppSettings.Settings["Blah"];
Otherwise, you can do something like put shared settings into machine.config, but it's typically wise not to mess with that file.

ASP.NET cleanest way to invalidate cache across applications

I have two ASP.NET applications running on the same server and sharing the same database. One is the front-end, developed with MVC, that caches data to avoid database calls to retrieve the same objects. The other is the back-end, developed with WebForms, that is used to manage CRUD operations.
I'd like to invalidate the front-end cache when a back-end operation occur. I don't need a refined mechanism... back-end will be used only sporadically and could invalidate ALL cached objects.
I've come across some solutions, but they're not very clean solutions... like, putting a flag on a db settings table, using a shared configuration file, calling a front-end web service from the back-end application. Every solution needs to be applied every time a front-end page is called, so I need it to be less resource consuming as possibile.
I don't want to use memcached or AppFabric or similar 'cause I think they're overkill for my basic needs.
Thank you very much!
You can just make an action that will invalidate cache. You can pass it a secret token to check if the request comes from your other web application for security.
So it will look like this:
public ActionResult Invalidate(string key)
{
if (key == ConfigurationManager.AppSettings["ApplicationSecurityKey"])
{
_cacheService.Invalidate();
return Content("ok");
}
return null;
}
In both web.config files of both projects you will have:
<appSettings>
<add key="ApplicationSecurityKey" value="SomeVerySecureValue" />
</appsettings>
And you can call it from your other web application like this:
WebClient client = new WebClient();
client.QueryString.Add("key", ConfigurationManager.AppSettings["ApplicationSecurityKey"]);
string response = client.DownloadString(url)

Program cannot find app.config

// Set LastRun to now
config.AppSettings.Settings["LastRun"].Value = DateTime.Now.ToString();
// Save all settings
config.Save(ConfigurationSaveMode.Modified);
This code was working fine in my development server but not in my production server. It seems like my program is unable to communicate with my app.config file. I have checked all the "obvious" . . Any ideas ... ?
From your code example, I cannot tell how your config variable is initialized. But, from the comments, you have a web app. Unless you are attempting to load a specific app.config file, the web app will attempt to get AppSettings from web.config.
It's not a good idea to programatically change the values of web.config. Changing web.config will cause an application restart.
If you have a different app.config for storing this type of information, that would be better than trying to change web.config. But you'll have to specifically load the file, something like this:
Configuration config = WebConfigurationManager.OpenWebConfiguration("yourPath\app.config");
ConfigurationManager.OpenExeConfiguration() is intended for use within an executable application not a web app. Try using WebConfigurationManager as shown above.
You find some more information in this SO question/answers.
More information can be found in this SO question/answer.

How to check whether or not a folder is exist on the server through WCF

I want to know that is there any property or method by which i come to know that a folder is there on the server.
just like if i have this in my web.config:
<appSettings>
<add key="ImagePath" value="http://server1:801/ImageById/"/>
</appSettings>
and i am getting this key like this:
var URL = System.Configuration.ConfigurationManager.AppSettings["ImagePath"].ToString();
Now i want to know that how to access imageById on the server and save something into this.
just like below:
if("Folder exist on this server URL that is ImageById")
{
save images to the folder thorugh code of WCF as the folder has write permission.
}
and i want this functionality in WCF not in ASP.NET.
please help.
if(Directory.Exists(Server.MapPath("ImabgeById")))
{
save images to the folder thorugh code of WCF as the folder has write permission.
}
also this can be of help
How to get working path of a wcf application?
You can use System.IO.Directory.Exists(path) - you simply need to ensure that your WCF service is operating under credentials with adequate permissions to get to the folder in question (otherwise you will encounter an exception).

Deploying an HttpHandler web service

I am trying to build a webservice that manipulates http requests POST and GET.
Here is a sample:
public class CodebookHttpHandler: IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
if (context.Request.HttpMethod == "POST")
{
//DoHttpPostLogic();
}
else if (context.Request.HttpMethod == "GET")
{
//DoHttpGetLogic();
}
}
...
public void DoHttpPostLogic()
{
...
}
public void DoHttpGetLogic()
{
...
}
I need to deploy this but I am struggling how to start. Most online references show making a website, but really, all I want to do is respond when an HttpPost is sent. I don't know what to put in the website, just want that code to run.
Edit:
I am following this site as its exactly what I'm trying to do.
I have the website set up, I have the code for the handler in a .cs file, i have edited the web.config to add the handler for the file extension I need. Now I am at the step 3 where you tell IIS about this extension and map it to ASP.NET. Also I am using IIS 7 so interface is slightly different than the screenshots. This is the problem I have:
1) Go to website
2) Go to handler mappings
3) Go Add Script Map
4) request path - put the extension I want to handle
5) Executable- it seems i am told to set aspnet_isapi.dll here. Maybe this is incorrect?
6) Give name
7) Hit OK button:
Add Script Map
Do you want to allow this ISAPI extension? Click "Yes" to add the extension with an "Allowed" entry to the ISAPI and CGI Restrictions list or to update an existing extension entry to "Allowed" in the ISAPI and CGI Restrictions list.
Yes No Cancel
8) Hit Yes
Add Script Map
The specified module required by this handler is not in the modules list. If you are adding a script map handler mapping, the IsapiModule or the CgiModule must be in the modules list.
OK
edit 2: Have just figured out that that managed handler had something to do with handlers witten in managed code, script map was to help configuring an executable and module mapping to work with http Modules. So I should be using option 1 - Add Managed Handler.
I know what my request path is for the file extension... and I know name (can call it whatever I like), so it must be the Type field I am struggling with. In the applications folder (in IIS) so far I just have the MyHandler.cs and web.config (Of course also a file with the extension I am trying to create the handler for!)
edit3: progress
So now I have the code and the web.config set up I test to see If I can browse to the filename.CustomExtension file:
HTTP Error 404.3 - Not Found
The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.
So in IIS7 I go to Handler Mappings and add it in. See this MSDN example, it is exactly what I am trying to follow
The class looks like this:
using System.Web;
namespace HandlerAttempt2
{
public class MyHandler : IHttpHandler
{
public MyHandler()
{
//TODO: Add constructor logic here
}
public void ProcessRequest(HttpContext context)
{
var objResponse = context.Response;
objResponse.Write("<html><body><h1>It just worked");
objResponse.Write("</body></html>");
}
public bool IsReusable
{
get
{
return true;
}
}
}
}
I add the Handler in as follows:
Request path: *.whatever
Type: MyHandler (class name - this appears correct as per example!)
Name: whatever
Try to browse to the custom file again (this is in app pool as Integrated):
HTTP Error 500.21 - Internal Server Error
Handler "whatever" has a bad module "ManagedPipelineHandler" in its module list
Try to browse to the custom file again (this is in app pool as CLASSIC):
HTTP Error 404.17 - Not Found
The requested content appears to be script and will not be served by the static file handler.
Direct Questions
1) Does the website need to be in CLASSIC or INTEGRATED mode? I don't find any reference of this in the online material, whether it should be either.
2) Do I have to compile the MyHandler.cs to a .dll, or can I just leave it as .cs? Does it need to be in a bin folder, or just anywhere in root?
RE your questions:
I don't know the answer to the first one (CLASSIC or INTEGRATED); but I can help with the second...
Yes you'll need to compile it first. I have never tried deploying dll's to anywhere other than the bin, given that that's the standard I would be suspect in putting them anywhere else even if it did work.
The way I deploy HttpHandlers is quiet straight forward - all the hard work's done in web.config, I'v enever had to go into IIS to change any settings.
For a start, for the http request to be handled by ASP.NET you need to use a request suffix that's already piped to ASP.NET - like .aspx or ashx. If you want to use something else you will need to config IIS to do this, as per your managed handler img above.
I tend to use .ashx e.g: http://localhost/foo/my/httphandler/does/this.ashx
All you need to do (assuming you've compiled athe HttpHandler into a DLL and deployed it to the site) is add the necessary config.
<configuration>
<system.web>
<httpHandlers>
<add verb="*"
path="*.ashx"
type="MyApp.PublishingSystem.HttpHandlers.GroovyHandler, MyApp.PublishingSystem" />
</httpHandlers>
</system.web>
</configuration>
Obviously (?) you can change / restrict the scope using the path, e.g:
path="*.ashx"
path="*ListWidgets.ashx"
path="*Admin/ListWidgets.ashx"
More info here: http://msdn.microsoft.com/en-us/library/ms820032.aspx
An important gotcha to look out for is the order in which you declare your HttpHandlers in the config; from what I remember ones declared first take precedent. So in this example...
<add verb="*" path="*foo.ashx" type="MyApp.PublishingSystem.HttpHandlers.FooHandler, MyApp.PublishingSystem" />
<add verb="*" path="*.ashx" type="MyApp.PublishingSystem.HttpHandlers.GroovyHandler, MyApp.PublishingSystem" />
...the groovy handler will handle all HttpRequests except any that end in foo.ashx
By the way, I make use of HttpHanldrs in my open source .net CMS / app framework, you might find some helpful code there (?): http://morphfolia.codeplex.com/
Make sure the app pool's .NET Framework Version is set correctly...
I deployed a .NET 4.0 web app on a .NET 2.0 app pool and got this error. Set the app pool to v4.X and the ashx was served like a champ.

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