I have an asp.net mvc application that take a while to load on my production server. I would like to write a script to call my pages every 10 minutes to avoid the pages from being scrapped on the server, which would then cause the server to reload them.
I was thinking of using a SQL Server stored procedure to call my pages every 10 minutes to keep the pages alive.
I've read that I can do this using CLR, but I am not sure how. Does anyone have an example of how to call webpages in a SQL Stored Procedure using CLR?
I have no idea why you would want to use a stored procedure for this.
Just write a simple console application to "call" the page. Then use a scheduled task to run the console application.
Code untested but something like this should work.
You'll probably also need TRUSTWORTHY SET.
ALTER DATABASE Foo SET TRUSTWORTHY ON;
Code:
public partial class WebProc
{
[SqlFunction()]
public static string WebQuery()
{
WebRequest request = HttpWebRequest.Create("http://www.google.com");
WebResponse response = request.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader (dataStream);
string responseFromServer = reader.ReadToEnd();
return responseFromServer;
}
}
I have no idea why you would want to use a stored procedure for this.
Just write a simple console application to "call" the page. Then use a scheduled task to run the console application.
You could do that (of course) but that's not what the question was asking ;)
Jafin's answer is correct for the question.
The best answer (IMHO) would be to fix your production server (i.e. reconfigure the settings) so that it doesn't "scrap" your pages every 10 minutes.
Why use a jackhammer (console app or .net inside the database or whatever) when a regular one will do?
Related
I'm hosting a WEB API App on Azure and I'm noticing some latency on a file operation.
What I'm doing is:
Post File
Write file on disk
Execute operations on file
The problem is that it takes A LOT of time to simply "take" this file, this is my code:
[HttpPost]
[Route("api/Test/Debug")]
public async Task Debug()
{
var sw = Stopwatch.StartNew();
var httpRequest = HttpContext.Current.Request;
var postedFile = httpRequest.Files[0];
return Ok(sw.ElapsedMilliseconds);
}
As you can see it's really simple but it takes also 3 seconds to get the "postedFile" element.
Is there any way to optimize this? Any other way to increase performance? Is this file already stored in some temp dir so that I can access it without having to write him down and then delete it?
thanks in advance
I needed a audio conversion library. After already pulling my hair..I have given up on the fact that there is no such audio library out there..every library out there has some or the other problem.
The only option left is ffmpeg which is the best but unfortunately you cannot use it in asp.net (not directly I mean). Every user on the website that will convert a file; will launch an exe?; I think I will hit the server memory max soon.
Bottom Line: I will try using ffmpeg.exe and see how many users it can support simultaneously.
I went to the ffmpeg website and in the windows download section I found 3 different version; static, shared and dev.
Does any one know which would be the best? All packed in one exe (static) or dll's separely and exe small, wrt using it in asp.net?
PS: any one has a good library out there..would be great if you can share.
Static builds provide one self-contained .exe file for each program (ffmpeg, ffprobe, ffplay).
Shared builds provide each library as a separate .dll file (avcodec, avdevice, avfilter, etc.), and .exe files that depend on those libraries for each program
Dev packages provide the headers and .lib/.dll.a files required to use the .dll files in other programs.
ffMpeg is the best library out there from what I have used but I wouldn't recommend trying to call it directly from asp.net.
What I have done, is accepted the upload, stored it on the server, or S3 in my case, then have a worker role (if using something like Azure) and a process that continuously looks and monitors for new files to convert.
If you needed a realtime like solution, you could update flags in your database and have an AJAX solution to poll the database to keep providing progress updates, then a link to download once the conversion is complete.
Personally my approach would be
Azure Web Roles
Azure Worker Role
ServiceBus
The WorkerRole starts up and is monitoring the ServiceBus Queue for messages.
The ASP.NET site uploads and stores the file in S3 or Azure
The ASP.NET site then records information in your DB if needed and sends a message to the ServiceBus queue.
The WorkerRole picks this up and converts.
AJAX will be needed on the ASP.NET site if you want a realtime monitoring solution. Otherwise you could send an email when complete if needed.
Using a queuing process also helps you with load as when you are under heavy load people just wait a little longer and it doesn't grind everything to a halt. Also you can scale out your worker roles as needed to balance loads, should it ever become too much for one server.
Here is how I run ffMpeg from C# (you will need to change the parameters for your requirements)
String params = string.Format("-i {0} -s 640x360 {1}", input.Path, "C:\\FilePath\\file.mp4");
RunProcess(params);
private string RunProcess(string Parameters)
{
//create a process info
ProcessStartInfo oInfo = new ProcessStartInfo(this._ffExe, Parameters);
oInfo.UseShellExecute = false;
oInfo.CreateNoWindow = true;
oInfo.RedirectStandardOutput = true;
oInfo.RedirectStandardError = true;
//Create the output and streamreader to get the output
string output = null; StreamReader srOutput = null;
//try the process
try
{
//run the process
Process proc = System.Diagnostics.Process.Start(oInfo);
proc.ErrorDataReceived += new DataReceivedEventHandler(proc_ErrorDataReceived);
proc.OutputDataReceived += new DataReceivedEventHandler(proc_OutputDataReceived);
proc.BeginOutputReadLine();
proc.BeginErrorReadLine();
proc.WaitForExit();
proc.Close();
proc.Dispose();
}
catch (Exception)
{
// Capture Error
}
finally
{
//now, if we succeeded, close out the streamreader
if (srOutput != null)
{
srOutput.Close();
srOutput.Dispose();
}
}
return output;
}
I see a couple of DataContext connection string questions. I'm going to try to differentiate this one a bit:
How does one construct a generic connection string to a database, localhost | User-PC\User | Some database... (it is hosted/managed by Microsoft SQL 2008)
I notice that it is IDisposable. So if I have multiple users hitting my site, my code can only access the database one instance at a time, and has to wait until each instance is disposed, in order for the data to be consistent for each user?
Is it possible, by any chance, to somehow enable LINQ in F#-Interactive, and connect to the database from there? I cannot figure out how to enable/load the System.Data dll into fsi. Maybe that is unique to my installation, or it is a common thread? (ie, my installation also does not recognize windows.base.dll--I have to manually get it from programs\reference assemblies).
Anyhow, I've pretty much conclusively discovered that
let x = new System.Data.Linq.DataContext("localhost")
...does not work.
1) How does one construct a generic connection string to a database?
There is no generic way to construct a connection string. The best thing to do is to keep the connection string in some configuration file where you can change it depending on your configuration (the name of SQL Server machine, authentication options, whether it is a file-based database or normal). There is a web site with examples for most of the options.
2) I notice that it is IDisposable. So if I have multiple users hitting my site, my code can only access the database one instance at a time [...]?
No, this is not how DataContext works. The DataContext does not keep a live connection to the server that would block anybody else from using the SQL server. It keeps some state (i.e. cached entities that were already obtained) and it uses optimistic concurrency to make sure that the state is consistent (you can use transactions to prevent other connections, if that's what you want).
3) Is it possible, by any chance, to somehow enable LINQ in F#-Interactive [...]?
That shouldn't be a problem. You can reference assemblies using #r "foo.dll" in F# interactive. The typical approach for F# 2.0 is to generate the data context using C# tools and then just reference it (for F# 3.0, things are easier because you can just use type provider).
If you generate LINQ to SQL data context for Northwind in C#, the F# Interactive use would look like this:
#r #"<whatever_path>\Northwind.dll"
#r "System.Data.Linq.dll"
open Northwind
open Microsoft.FSharp.Linq
let connStr = #"Data Source=.\SQLEXPRESS;AttachDbFilename=<path>\NORTHWND.MDF;" +
#"Integrated Security=True;User Instance=True"
let operation () =
// Using 'use' to make sure it gets disposed at the end
use db = new NorthwindDataContext(connStr)
// do something with the database
There actually is a somewhat generic way to construct a connection string:
open System.Data.Common
open System.Data.SqlClient
let providerName = "System.Data.SqlClient"
let factory = DbProviderFactories.GetFactory(providerName)
let cnBuilder = factory.CreateConnectionStringBuilder() :?> SqlConnectionStringBuilder
cnBuilder.DataSource <- "localhost"
cnBuilder.InitialCatalog <- "MyDatabase"
cnBuilder.IntegratedSecurity <- true
let connStr = cnBuilder.ConnectionString
My approach was to have 1 connection string and then use that for all of my DataContext connections. So this code builds the EntityConnectionString based on MyConnString:
protected override MyEntities CreateObjectContext()
{
string ConnString =ConfigurationManager.ConnectionStrings["MyConnString"];
string seConn = ConfigurationManager.ConnectionStrings["MyEntities"].ToString();
EntityConnectionStringBuilder ecsb = new EntityConnectionStringBuilder(seConn);
ecsb.ProviderConnectionString = ConnString;
EntityConnection ec = new EntityConnection(ecsb.ToString());
ScheduleEntities ctx = new ScheduleEntities(ec);
return ctx;
}
i have to call an executable in the client machine in asp.net and get the return parameters, i been looking for an example but i couldn't find it.
it this possible to recover the output parameters from one exe in JavaScript?
i know that can i write:
var WshShell = new ActiveXObject("WScript.Shell");
var oExec = WshShell.Exec("My.exe");
but the clients executable returns 0 or 1 that values are the ones i need to collect
Thanks in advance
Browser-based JavaScript can't call executable files on client machines; to do so would be a catastrophic security problem. If you have to run an executable on the client machine, consider asking the user to install a .NET application, an ActiveX control, or something like Java if you want to be platform-independent.
Depending on what you're trying to do, you may not need to run an EXE on the client machine; you can do a LOT with standard cloud-type scenarios (JS or SilverLight on the client, Web services or WCF on the server). Without more information about your situation, however, it's impossible to tell.
EDIT: Based on your comments that you're using the ActiveXObject.Exec method, you can use the StdOut property of the WshScriptExec object that method returns. From MSDN's article on the StdOut property:
if (!oExec.StdOut.AtEndOfStream)
{
input += oExec.StdOut.Read(1);
//...
}
I am having some trouble with one of my ASP.NET 2.0 application's connection string. There are instances that I would get a ConnectionString Property Has not Been Initialized problem which occurs randomly and intermittently and without any reason.
My Connection string is actually coming from a webservice, because different kinds of users are provided with different sets of connection string depending on their user level.
What I have done so far goes like this:
I have a master page (mstr.page) and the corresponding code behind (mstr.page.vb).
In my master page, I retrieve initially the connection string and store the same into a session variable, i.e.
Session("ConnString") = "RetrievedConnectionString"
Now in one of my pages, let us say page1.aspx.vb, I use public shared functions from a class (named MyClass.vb) and use it in my page1.aspx.vb.
Some codes for reference:
[MyClass.vb]
Imports System.Web
NameSpace ClassNameSpace
Public Class Admin
Protected Shared da as New DataAccess()
Public Shared Function MYFunction() as String
'Execute some sql statements here, using the DataAccess
stringToReturn = Ctype(da.ExecuteScalar("SQLCommand"), String)
Return stringToReturn
End Function
End Class
End NameSpace
[DataAccessClass.vb]
Public Class DataAccess()
Private m_ConStr As String = ""
Public Sub New()
m_ConStr = HttpContext.Current.Session("ConnString")
End Sub
'Some methods for SQL statement execution (ExecuteQuery, ExecuteScalar)
End Class
[Page1.aspx.vb]
Imports ClassNameSpace
Protected Sub Page_Load(....) Handles Me.Load
Dim strValue as String = Admin.MyFunction()
End Sub
I have placed the code above to show you some rough idea of how things are going.
Basically, the function Admin.MyFunction() at times fails, because in the data access class, the connection string seems to have lost it's value (either blank or Nothing).
This has troubled me for quite some time already.
I hope someone can point me in the right direction to resolve this. Basically, I want my connection string which is retrieved by each user visiting the web application be maintained across all the time and be used anywhere. Session variable does not seem to be the best fit since when the ASP.NET recycles its process, the session is lost.
By the way, I am retrieving the connectionstring initially via the master page from a web service. I tried to place the same retrieve function in the Data Access class when conditions is that the session variable is lost, but I think my application cannot connect to the Web Service during the recycle process.
Any advice would be greatly appreciated on this.
Update on this:
I tried to use Session Variable and set the mode to State Server, but apparently some DLLs which I am using cannot be serialized, thus I am back to square one.
Is there a better way to do this?
One thing to check is if your Session is getting clobbered. If your using the (default) in-memory Session, then sessions die anytime an ASP.NET worker process is recycled. If this is causing your issue, you might have to look into using the ASP.NET SessionServer in IIS, or SQL Server as your Session storage.
I'd try to limit your use of the Session for this type of thing as much as possible. If you utilize the Web.Config for storing your connection strings, you can access it at anytime and it will not expire on you like the session.
You may also consider having a static data access class if it is the same for all users for the applications instance...
This is the exact same problem I was experiencing, and it turned out to be the session variables dying so the connection string couldn't be initialized properly.
Why cant your app use just one connection string? and why does the connection string need to come in through a webservice? that adds a huge amount of latency to the entire process. I assume it probably has to do something with data security in your database.
If you have to do this, I'd say, can't you have a fall back / default connectionstring? Wrap your code that attempts to pull it out of the session with some error handeling and if it fails revert to your default?
I would place your web service and web app in different app pools. Then increase the timeout length of your web apps pool.