Category Archives: Programming & Development
Custom Web.Config Wrapper Class ASP .NET
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Configuration; namespace AIS.Common { public class ConfigValues { #region appSettings public static string SomeStringOne { get { return getval("SomeStringOne "); } } public static string SomeStringTwo { get { return getval("SomeStringTwo "); } } public static string Env { get { return getval("env"); } } //keep in mind case sensitivity public static string LastManualRefresh { get { return getval("date_last_manual_refresh"); } } //useful for manual site refresh/reload public static double SomeDouble { get { return Convert.ToDouble(getval("some_static_double")); } } #endregion #region connectionStrings - update web.config env variable to toggle between dev and prd public static string YourDBOneConnectionString { get { return getcstr("win_web_db"); } } //also read only implementation like above, but illustrates environment variable usage specific in web.config useful if you have many environments public static string YourDBTwoConnectionString { get { if (Env.ToLower().ToString() != "filesystem") { return getcstr("static_string" + Env.ToLower().ToString()); } return ""; } } #endregion /// <summary> /// Retrieve Connection String for specified provided key /// </summary> /// <param name="key"></param> /// <returns></returns> private static string getcstr(string key) { try { return ConfigurationManager.ConnectionStrings[key].ConnectionString; } catch (Exception ex) { Shared.HandleError(ex); //TODO: change to throw error event handle instead of direct call for reusability return "Error retrieving value"; } } /// <summary> /// Retrieve appSettings value for provided specified key /// </summary> /// <param name="key"></param> /// <returns></returns> private static string getval(string key) { try { return ConfigurationManager.AppSettings[key]; } catch (Exception ex) { Shared.HandleError(ex); //TODO: change to throw error event handle instead of direct call for reusability return "Error retrieving value"; } } } }
Custom URLRewriting with XML and Global.asax
utilizes my custom DocParser class here https://ronniediaz.com/2013/08/23/parse-xml-to-dynamic-expandoobject-c-net-4-0/
void Application_BeginRequest(object sender, EventArgs e) { //string path = Request.Url.ToString(); string path = Request.Path; if (Regex.IsMatch(path.ToLower(), ".*[.](jpg|png|gif|css|js|pdf|ico|woff|svg|eot|ttf)$")) { //var h = Regex.Replace(path.ToLower(), ".*/(.*)/(.*)$", "~/$1/$2", RegexOptions.Singleline); //Context.RewritePath(path); return; } //TODO: authorize user/request DocParser dp = new DocParser(Server.MapPath("~/rewrite.xml")); var rules = dp.GetElements("*/rule"); foreach (var r in rules) { if (string.IsNullOrEmpty(r.match_url)) { Shared.HandleError("Global.asax::null or empty match_url encountered"); } if (string.IsNullOrEmpty(r.action_url)) { Shared.HandleError("Global.asax::null or empty action_url encountered"); } if (Regex.IsMatch(path, r.match_url,RegexOptions.IgnoreCase)) { List<object> qsvars = new List<object>(); foreach (Match m in Regex.Matches(path, r.match_url, RegexOptions.IgnoreCase)) { for (int i=1;i<m.Groups.Count;i++) { qsvars.Add(m.Groups[i].Value); } } //Context.RewritePath(string.Format(r.action_url,qsvars.ToArray()) + "&rewrite=1"); Context.RewritePath(string.Format(r.action_url, qsvars.ToArray())); } } }
rewrite.xml examples
<?xml version="1.0" encoding="utf-8" ?> <rules> <rule match_url="^/home" action_url="~/home.aspx" /> <rule match_url="^/login" action_url="~/default.aspx" /> <rule match_url="^/register" action_url="~/welcome/register.aspx" /> <rule match_url="^/logout" action_url="~/logout.aspx" /> <rule match_url="^/default/(.*)" action_url="~/default.aspx?q={0}" /> <rule match_url="^/test/(.*)/(.*)" action_url="~/test.aspx?q={0}&r={1}" /> </rules>
Common functions asp .net static shared library
references custom encryption class here https://ronniediaz.com/2011/01/13/quick-net-encryption-reference/
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.Security; using System.Text; using System.Net; using System.IO; namespace AIS.Common { public static class Shared { //TODO: add local, dev, prd public static string basehref { get { return HttpContext.Current.Request.ApplicationPath; } } //TODO: change to json serialized object reference to prevent manipulation of pipe delimeters public static string SetSecureQueryString(object o) { string ct = Crypto.Rijndael.Encrypt(o.ToString(), "static_or_dynamic_string"); return HttpUtility.UrlEncode(ct); } //TODO: change to json (same as above) public static string SetSecureQueryString(object a, object b, object c, object d, object e, object f, object g, object h) { string ct = Crypto.Rijndael.Encrypt(a.ToString() + "|" + b.ToString() + "|" + c.ToString() + "|" + d.ToString() + "|" + e.ToString() + "|" + f.ToString() + "|" + g.ToString() + "|" + h.ToString(), "livestream"); return HttpUtility.UrlEncode(ct); } public static string GetSecureQueryString(string q) { try { //automatically decodes querystring in request return Crypto.Rijndael.Decrypt(q, "static_or_dynamic_string"); } catch (Exception ex) { return ""; } } //retrieves content from web url and returns as string public static string DownloadString(string url, NetworkCredential nc=null) { System.Net.WebClient wc = new WebClient(); if (nc != null) { wc.UseDefaultCredentials = true; wc.Credentials = nc; } return wc.DownloadString(url); } //http://mayur.gondaliya.com/programming-languages/c-sharp/samples/fetching-url-contents-into-a-string-using-httpwebrequest-72.html //same as above function, different approach with more detail public static string DownloadPage(string url) { const int bufSizeMax = 65536; // max read buffer size conserves memory const int bufSizeMin = 8192; // min size prevents numerous small reads StringBuilder sb; // A WebException is thrown if HTTP request fails try { // Create an HttpWebRequest using WebRequest.Create (see .NET docs)! HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Method = WebRequestMethods.Http.Get; // Execute the request and obtain the response stream HttpWebResponse response = (HttpWebResponse)request.GetResponse(); Stream responseStream = response.GetResponseStream(); // Content-Length header is not trustable, but makes a good hint. // Responses longer than int size will throw an exception here! int length = (int)response.ContentLength; // Use Content-Length if between bufSizeMax and bufSizeMin int bufSize = bufSizeMin; if (length > bufSize) bufSize = length > bufSizeMax ? bufSizeMax : length; // Allocate buffer and StringBuilder for reading response byte[] buf = new byte[bufSize]; sb = new StringBuilder(bufSize); // Read response stream until end while ((length = responseStream.Read(buf, 0, buf.Length)) != 0) sb.Append(Encoding.UTF8.GetString(buf, 0, length)); return sb.ToString(); } catch (Exception ex) { sb = new StringBuilder(ex.Message); return sb.ToString(); } } //one approach using filesystem. will only work depending on permissions otherwise url parsing is needed public static string GetCurrentPageName() { string spath = System.Web.HttpContext.Current.Request.Url.AbsolutePath; System.IO.FileInfo oInfo = new System.IO.FileInfo(spath); string spagename = oInfo.Name; return spagename; } //get titlecase string public static string GetTitleCase(object str) { try { return System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(str.ToString().ToLower()); } catch (Exception ex) { Shared.HandleError(ex); return "Other"; } } #region handleerror public static void HandleError(Exception ex) { HandleError(ex.ToString()); } //TODO: send error to error handler public static void HandleError(string details) { SendEmail(details); } public static void HandleError(Page p, Exception ex) { HandleError(p, ex.ToString()); } public static void HandleError(Page p, string details) { //MessageBox.Show(hwnd, details); SendEmail(details); } //TODO: replace with call to error manager or hook to event for compatibility public static void SendEmail(string details) { //throw new HttpUnhandledException(details); if (Shared.GetCurrentPageName().Replace("/", "") != "error.aspx") //TODO: remove. temporary resolution for unhandled session timeouts. PROTOTYPE { //HttpContext.Current.Response.Redirect("~/error.aspx"); //TODO: global error log and local } } #endregion } }
Could not load type System.ServiceModel.Activation.HttpModule’ from assembly ‘System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=
If you already have .Net 4.0 installed and install a program that brings in an earlier version of .Net, or manually install an earlier version of .Net afterwards, you may get an exception page that matches the title of this article.
This is a simple fix, outlined in detail in MSDN article referenced at the bottom.
Navigate to:
%windir%\Microsoft.NET\Framework\v4.0.30319 %windir%\Microsoft.NET\Framework64\v4.0.30319 (on a 64-bit computer)
Run:
aspnet_regiis.exe /iru
That’s it!
ubuntu lts 12 xrdp rdp setup on Amazon Cloud AWS(12.04.3 precise pangolin)
Consolidated from multiple sources to exclude erroneous steps.
Tested on Amazon Web Services fresh Ubuntu LTS 12.04.3 instance.
Decided upon ubuntu vs centOS simply to avoid having to compile xrdp and manage dependencies manually. Chose 3rd party linux over Amazon AMI in this case for benefit of included repos, use cases and support in their respective communities (ubuntuforums, etc), as well as not having to compile xrdp in Amazon AMI.
sudo useradd -m {name} passwd {name} #you may want to consider setting a root passwd in case you mess up sudoers. if you make a mistake with sudoers terminate your instance and relaunch 🙂 ... or you could mount the HD with another system if it's unencrypted and modify sudoers passwd root #edit /etc/sudoers.d and add your new user {name} ALL=(ALL) ALL #edit sshd /etc/ssh/sshd_config disable root login and allow password authentication (if you like) service ssh restart #http://www.liberiangeek.net/2012/05/connect-to-ubuntu-12-04-precise-pangolin-via-windows-remote-desktop/ sudo apt-get install xrdp sudo apt-get install gnome-session-fallback #two options, 2d unity no longer available, previously echo "gnome-session --session=ubuntu-2d" > ~/.xsession #http://askubuntu.com/questions/247501/i-get-failed-to-load-session-ubuntu-2d-when-using-xrdp echo gnome-session --session=gnome-fallback > ~/.xsession #make sure your user has permission to this file if you have to create it with sudo etc chown {name}:{name} .xsession #http://www.filiwiese.com/installing-gnome-on-ubuntu-12-04-precise-pangolin/ sudo add-apt-repository ppa:gnome3-team/gnome3 sudo apt-get update sudo apt-get install gnome-shell #http://askubuntu.com/questions/251041/how-to-install-lightdm-set-defaults sudo apt-get install lightdm #http://askubuntu.com/questions/71126/how-do-i-set-the-gnome-classic-login-to-be-the-default-with-autologin sudo /usr/lib/lightdm/lightdm-set-defaults -s gnome-fallback
Don’t forget AWS Firewall:
22 (SSH) your ip/32
MSSQL User Defined Functions vs Stored Procedures
I received this question earlier today, and thought it was a valid question often misunderstood, and deserving of a small write-up:
“Should a User Defined Function be your first choice instead of a Stored Procedure?”
While there are many pros and cons of each not covered in this write-up (review your versions on MSDN for details), including some features which may not be apparent until you have an issue to troubleshoot (such as sp_who filtering), you can generally ask yourself a single question up front that can help you determine which you should use.
Simply, if the db functionality you need to implement in the function/procedure requires
any DML (insert/update/delete), then go with a stored procedure. Advanced selects and/or filters are best left up to views/table valued functions.
Additionally, do not be afraid to use a combination of functions and procedures especially if there is a goal of re-usability, in accordance with the design considering the planned growth of your db as your software & db architecture permits. On that note, consider and test the performance differences of these implementations, as a compiled/cached function/procedure containing more logic internally may outperform one utilizing logic that is spread throughout.
References
SP_who filtering UDF vs SP, http://stackoverflow.com/questions/2567141/use-sql-to-filter-the-results-of-a-stored-procedure
Data Manipulation Language, http://en.wikipedia.org/wiki/Data_manipulation_language
(Some) Differences (about.com), http://databases.about.com/od/sqlserver/a/procs_vs_functs.htm
(Some) Differences (stackoverflow), http://stackoverflow.com/questions/2039936/difference-between-stored-procedures-and-user-defined-functions
mssql aes function encrypt decrypt in microsoft sql
Simple symmetric encryption in MSSQL. Copied from MS references below:
USE AdventureWorks2012; --If there is no master key, create one now. IF NOT EXISTS (SELECT * FROM sys.symmetric_keys WHERE symmetric_key_id = 101) CREATE MASTER KEY ENCRYPTION BY PASSWORD = '23987hxJKL95QYV4369#ghf0%lekjg5k3fd117r$$#1946kcj$n44ncjhdlj' GO CREATE CERTIFICATE Sales09 WITH SUBJECT = 'Customer Credit Card Numbers'; GO CREATE SYMMETRIC KEY CreditCards_Key11 WITH ALGORITHM = AES_256 ENCRYPTION BY CERTIFICATE Sales09; GO -- Create a column in which to store the encrypted data. ALTER TABLE Sales.CreditCard ADD CardNumber_Encrypted varbinary(128); GO -- Open the symmetric key with which to encrypt the data. OPEN SYMMETRIC KEY CreditCards_Key11 DECRYPTION BY CERTIFICATE Sales09; -- Encrypt the value in column CardNumber using the -- symmetric key CreditCards_Key11. -- Save the result in column CardNumber_Encrypted. UPDATE Sales.CreditCard SET CardNumber_Encrypted = EncryptByKey(Key_GUID('CreditCards_Key11') , CardNumber, 1, HashBytes('SHA1', CONVERT( varbinary , CreditCardID))); GO -- Verify the encryption. -- First, open the symmetric key with which to decrypt the data. OPEN SYMMETRIC KEY CreditCards_Key11 DECRYPTION BY CERTIFICATE Sales09; GO -- Now list the original card number, the encrypted card number, -- and the decrypted ciphertext. If the decryption worked, -- the original number will match the decrypted number. SELECT CardNumber, CardNumber_Encrypted AS 'Encrypted card number', CONVERT(nvarchar, DecryptByKey(CardNumber_Encrypted, 1 , HashBytes('SHA1', CONVERT(varbinary, CreditCardID)))) AS 'Decrypted card number' FROM Sales.CreditCard; GO
References:
asp .net repeater itemcommand command name common repeater control item operations
This is only one small snippet illustrating some functionality. I will add to this blog from my previous usage with Repeater control over time or per request.
In many deployments, I prefer to use Repeater or ListView rather than Grids. The code pattern is the same, but the output is slightly different as well as some of the inherent features/functionality.
Notice the example below simulates table output similar to a Grid, or it may also be used for non-table type of output. Repeater is therefore IMO more adaptable to different needs, and allows more re-usability code patterns across projects.
page side:
<asp:Repeater ID="rptRobotsInFactories" runat="server" OnItemCommand="rptRobotsInFactories_ItemCommand"> <HeaderTemplate> <table> <tr> <td>factory name</td> <td>robot name</td> <td>factory location</td> <td>manufacture date</td> <td colspan="2">commands</td> </tr> </HeaderTemplate> <ItemTemplate> <tr> <td> <%# Eval("factoryname")%> <asp:TextBox ID="tbRobotName" runat="server" Text='<%# Eval("robotname")%>'></asp:TextBox> </td> <td> <%# Eval("factorylocation")%> </td> <td> <%# Eval("manufacturedate")%> </td> <td> <asp:LinkButton ID="lbtnRename" runat="server"> CommandName="rename" CommandArgument='<%# Eval("robotname")%>'>rename</asp:LinkButton> </td> <td> <asp:LinkButton ID="lbtnDeelte" runat="server"> CommandName="delete" CommandArgument="">delete</asp:LinkButton> </td> </tr> </ItemTemplate> </HeaderTemplate> <FooterTemplate> <!-- insert pager here if you like--> </table> </FooterTemplate> </asp:Repeater>
code behind:
//you can also intercept item databind as i've listed in another previous article on nested repeaters protected void rptRobotsInFactories_ItemCommand(object sender, RepeaterCommandEventArgs e) { if (e.CommandName == "rename") { string newname = ((TextBox)rptRobotsInFactories.Items[e.Item.ItemIndex].FindControl("tbFileName")).Text; //string newname = ((TextBox)e.Item.FindControl("tbFileName")).Text; //equal to the above //string index = (string)e.CommandArgument; //useful to pass in index values also. can split the values passed in or pass in class obj //var rif = ((List<robotinfactory>)rptRobotsInFactories.DataSource)[e.Item.ItemIndex]; //var rif = Session_RobotsInFactories().Select(r=>r.id==Convert.ToInt32(e.CommandArgument)); //compare to using viewstate/page repeater above string oldname = (string)e.CommandArgument; if ((newname.ToLower().Trim().Replace(" ","") != "") && (newname!=oldname)) { //dowork_rename(oldname,newname); } } else if (e.CommandName=="delete") { robotinfactory rif = ((List<robotinfactory>)rptRobotsInFactories.DataSource)[e.Item.ItemIndex]; //dowork_delete(rif.id); } } //added below funcs for clarity public class robotinfactory() { public string factoryname {get;set;} public string robotname {get;set;} public string factorylocation {get;set;} public string manufacturedate {get;set;} } protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { //these would normally load from your LINQ dbml SP, view, select statement, stored procedure etc var rifs = new List<robotinfactory>(); rifs.Add(new rif { factoryname="a", robotname="bob", factorylocation="florida", manufacturedate="7/1/2013" }); rifs.Add(new rif { factoryname="b", robotname="sam", factorylocation="not florida", manufacturedate="7/4/2013" }); rptRobotsInFactories.DataSource = rifs; rptRobotsInFactories.DataBind(); } }