Using Amazon S3 SDK Pre-signedURL function

Today i was just exploring the amazon sdk. While using the presignedurl function of amazon sdk(C#), i was just curious that what is the server response time , zone. The amazon s3 returns the time in UTC. so simple but i was just curious that if we input time in GMT and it automatically convert it according to requestee IP time zone. i have tried to confirm but first i checked with UTC and it works 100% correctly. The second try i did is that i sent a GMT time and it works too. The amazon convert GMT to UTC according to client location. The sample code look like:


public string GetPreSignedURL(string bucketName, string key)
{
string url = string.Empty;
try
{
AmazonS3 client = Amazon.AWSClientFactory.CreateAmazonS3Client("ur access key", "secret key");

GetPreSignedUrlRequest request = new GetPreSignedUrlRequest().WithProtocol(Protocol.HTTPS).WithBucketName(bucketName).WithKey(key).WithExpires(DateTime.UtcNow.AddMinutes(1));
url = client.GetPreSignedURL(request);
}
catch { }
return url;
}

Increase IIS 5 connection limit on windows

On a non server edition of window operating system, we often got the error.
There are too many people accessing the Web site at this time.
OR
HTTP 403.9 - Access Forbidden: Too many users are connected
Internet Information Services

To increase the connection limit, go to :
1 - Go to directory c:\inetpub\AdminScripts
2 - Execute the following command.
adsutil set w3svc/MaxConnections 40

Read or Write on Registry in C#

Registry is a special place where applications stores its setting. Although Isolated storage for .net is a preferred way for storing
application settings yet registry has its own benefit. Normally it is difficult to find application created registry entries(if created carefully).
Below is a sample C# code.

//It will create a new subkey if not already created. otherwise it opens the existing one with write access.
RegistryKey objRegistryKey = Registry.CurrentUser.CreateSubKey("App_Name");
//Suppose i want to save last open time when application opened.
objRegistryKey.SetValue("LastOpenTime", DateTime.Now.ToString());


To get the value from registry, you use
string lastOpenDT = objRegistryKey.GetValue("LastOpenTime") as string;

The GetValue return the object type. you can than cast to the appropriate type.


Don't forget to add Microsoft.Win32 namespace.

For further reading,you can see the following two classess at msdn.
Registry,RegistryKey class.

multiple submit buttons and the enter key

As you know it is the limitation of asp.net that it has only one form, so if you have another section which needs enter key submission, than you can use default button as used below.
The defaultButton property of Panel or Form is used to ensure Enter Key Submission. Typically people used to Enter Key submission and if it is disabled, it might be annoying certain times.

The defaultButton really provides a way to handle Enter Keys for respective portions of the page when the focus is there.

Example:

<form defaultbutton="button1" runat="server">
<asp:textbox id="textbox1" runat="server"/>
<asp:textbox id="textbox2" runat="server"/>
<asp:button id="button1" text="Button1" runat="server"/>

<asp:panel defaultbutton="button2" runat="server">
<asp:textbox id="textbox3" runat="server"/>
<asp:button id="button2" runat="server"/>
</asp:panel>
</form>

Extract links from html in C#

private List ExtractLinks(string html)
{
List links = new List();

string startSquence = "<a";
string endSequence = "</a>";

html = html.ToLower();

while (html.IndexOf("<a") != -1)
{
int start = html.IndexOf(startSquence) ;
int end = html.IndexOf(endSequence, start+startSquence.Length);

//Extract the link, and add it to the list
if (end > start)
{
string link = html.Substring(start, end + endSequence.Length - start);

//Check b
if (link.Substring(1).IndexOf(startSquence) != -1)
{
html = html.Substring(start + startSquence.Length);
continue;
}

if (link != string.Empty)
{
links.Add(link);
}
}
else if (end < start)
{
html = html.Substring(start + startSquence.Length);
continue;
}
//Trim the raw data
html = html.Substring(end + endSequence.Length);
}
return links;
}

how to modify web.config in asp.net using C#

You can modify web.config at run time. For exmaple to add a property in app settings section of web.config, you can use the following c# code

Configuration myConfiguration = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
myConfiguration.AppSettings.Settings.Add("CommentsLimit", "10");
myConfiguration.Save();


To update the existing property:
Configuration myConfiguration = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
myConfiguration.AppSettings.Settings["CommentsLimit"].Value = "20";
myConfiguration.Save();

virtual keyword in C#

If a base class method is to be overriden, it is defined using the keyword virtual
The class member method may be overriden even if the virtual keyword is not used, but its usage makes the code more transparent & meaningful.

When the override keyword is used to override the virtual method, in a scenario where the base class method is required in a child class along with the overriden method, then the base keyword may be used to access the parent class member. The following example will be helpful to understand.

public class Shape
{
string name;
public virtual void SetName(string name)
{ this.name = name; }
}


public class Circle : Shape
{
//This method is being overriden
public override void SetName(string name)
{
base.SetName("circle"); //We are calling parent class method
}
}