Problem with System.Net.Dns.GetHostEntry(dnsServer) on .NET 4.0 - dns

I have been using the following code for months (without problem) in a .NET 2.0/3.5 environment:
string server="192.168.1.3";
IPHostEntry ipe = System.Net.Dns.GetHostEntry(server);
IPAddress ipa = ipe.AddressList[0];
IPEndPoint ipep = new IPEndPoint(ipa, (int)UdpServices.Domain);
Here, server is hardcoded to an IP address, but in my application it could potentially be something like "server.test.com".
When converting my project to .NET 4.0, this code stopped working when directly passing an IP address (still works with a hostname). It crashes with this exception:
System.Net.Sockets.SocketException was unhandled
Message=The requested name is valid, but no data of the requested type was found
Source=System
ErrorCode=11004
NativeErrorCode=11004
StackTrace:
at System.Net.Dns.InternalGetHostByAddress(IPAddress address, Boolean includeIPv6)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress)
Because all I need is the resulting IPEndPoint, I can work around the issue by using IPAddress.Parse to generate the IPAddress object, but I want to know if any of you know why this behaviour changed in .NET 4.0? (If we can't resolve the hostname from the IP address, an exception is now thrown).

Microsoft answered this here:
this was purposely changed to more
consistently represent name resolution
failures. If you have input strings
that you just want to convert to
IPAddresses, it is recommended that
you use IPAddress.TryParse or
Dns.GetHostAddresses

Related

Opening SqlConnection inside TransactionScope error

We have been trying to use a SqlConnection within a TransactionScope. When we build the site and try this database call we run into an error:
A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
The error involved occurs on the line cnn.Open().
using (var scope = new TransactionScope())
using (var cnn = new SqlConnection(connectionString))
{
cnn.Open();
int result = cnn.QuerySingle<int>("SELECT 1");
Console.WriteLine(result);
}
We created a console application to figure out what was wrong and discovered that by changing our connection string keyword 'Pooling' from 'false' to 'true' allows this to run in the console application and successfully return our result.
We made the same change to our site connection string, the same error as before returns.
Is there any reason this code is not working?
I was under the assumption that the web.config was law, as viewing the file through the Kudu service showed my expected connection string, but apparently this isn't the case in Azure.
I discovered that Azure Publish Profile is overriding our web.config connection string, this override still contained 'Pooling=false'.
Removing this now allows our code to run as intended.
This blog post explains more:
"When this code runs on a developer’s local machine, the value returned will be the one from the web.config file. However when this code runs in Windows Azure Web Sites, the value returned will instead be overridden with the value entered in the portal"

SqlDataProvider connection string in Suave on Azure

I can't get SqlDataProvider to work when executed in a fsx script which is running in an Azure Web Site.
I have started from the samples that Tomas Petrecek has here: https://github.com/tpetricek/Dojo-Suave-FsHome.
In short it is a FSX script that is executed using the IIS httpPlatformHandler so that all http requests to my Azure Web site is forwarded to my F# script.
The F# Script use Suave to handle the requests.
When I tried adding some database access to my HTTP handlers I got into problems.
The problematic code looks like this:
[<Literal>]
let connStr = "Server=(localdb)\\v11.0;Initial Catalog=My_Database;Integrated Security=true;"
[<Literal>]
let resolutionFolder = __SOURCE_DIRECTORY__
FSharp.Data.Sql.Common.QueryEvents.SqlQueryEvent |> Event.add (printfn "Executing SQL: %s")
// the following line fails when executing in azure
type db = SqlDataProvider<connStr, Common.DatabaseProviderTypes.MSSQLSERVER, ResolutionPath = resolutionFolder>
let saveData someDataToSave =
let ctx = db.GetDataContext(Environment.GetEnvironmentVariable("SQLAZURECONNSTR_QUERIES"))
.....
/// code using the context here
This works just fine when I run it locally, but when I deploy it to the azure site it will fail at the line where the type dbis created.
The error message is (line 70 is the line that has the type db = ...:
D:\home\site\wwwroot\app.fsx(70,11): error FS3033: The type provider
'FSharp.Data.Sql.SqlTypeProvider' reported an error: A network-related
or instance-specific error occurred while establishing a connection to
SQL Server. The server was not found or was not accessible. Verify
that the instance name is correct and that SQL Server is configured to
allow remote connections. (provider: SQL Network Interfaces, error: 52
- Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database
Runtime feature is enabled.)
The design-time database in the connStr is not available in the azure site, but I thought this is why we have the GetDataContext overload that takes a connection string to be used at run-time?
Is it because it is running as a script and not as compiled code that it is trying to access the database when creating the TypeProvider?
If yes, does it mean that my only option is to compile and provide the database code as a compiled assembly that I load and use in my Suave FSX script?
Reading the connection string from a config file does not work very well as this is in a azure site. I really need to get the connection string from an environment variable (which is set in the azure management interface).
Hmm, this is a bit unfortunate - as #Fyodor mentioned in the comments, the problem is that the script-based deployment to Azure actually compiles the script on the Azure machine - and so you need to have a statically-resolved connection string that works on Azure.
There are two options:
Use compiled project instead. If you compile your F# code locally and deploy the compiled code to Azure it will work. Sadly, there are no good samples for that.
Do some clever trick to make the connection string accessible to the script at compile time.
Send a PR to the SQL provider so that you can give it the name of an environment variable and it reads the connection string from there.
I think (3) would actually be quite nice and useful feature.
I'm not necessarily sure what the best way to do (2) would be. But I think you might be able to modify app.azure.fsx so that it creates a file (say connection.fsx) that contains something like:
module Connection
let [<Literal>] ConnString = "<Contents of SQLAZURECONNSTR_QUERIES>"
Then app.fsx could load this script and use Connection.ConnString in the argument of SQL type provider.

Error 2007 - SQLyog

Good Morning,
I am trying to connect to a Mysql Data base using SqlYog, I have created a new connection and I have entered all the necessary informations (login,password & port). But when I click “ok”, I get this error message (Error 2007 : Protocol mismatch; server version = 1, client version = 10) . I have pinged the data base and it responds me successfully !!!
Could you please tell me how can I solve this problem, I need to access to the data base urgently.
Thanks a lot.
This is usually due to using a very old MySQL server (before 3.22.x) which has a different protocol version.
You can take a look at this link to see what all server versions are supported.
To check your server protocol version, go to the MySQL command line and type:
SHOW VARIABLES LIKE "%version%"
SQLyog supports only the protocol version 10.

Error with Azure service SSL in Development Fabric

I'm running into a problem with getting SSL to work in the Development Fabric. I'm running a clean install of Windows 8 Pro with Visual Studio 2012 Ultimate and the October 2012 Azure SDK for .NET. IIS8 is not installed, only IIS Express, which claims to support HTTPS so I'm hoping that's not the issue.
Running VS 12 as administrator, I've created a blank VS solution, added a new (.NET 4.5) cloud service with a new ASP.NET MVC 4 Internet web application project, and hit F5. Everything works fine. Then, when I add an SSL certificate to the web role and replace the HTTP endpoint (port 80) with an HTTPS endpoint (port 443, with the certificate), hitting F5 produces the following error message:
Windows Azure Tools for Microsoft Visual Studio
There was an error attaching the debugger to the role instance 'deployment18(32).WindowsAzureCloudService.Mvc4WebRole_IN_0' with Process Id: 4892'. Unable to attach. Access is denied.
Note, the last part ("Access is denied") comes in a few variations, a particularly pleasant one being "Catastrophic failure". :)
The only message in the VS Output window ('General' output) is:
Windows Azure Tools: Warning: Remapping private port 443 to 444 in role 'Mvc4WebRole' to avoid conflict during emulation.
The Compute Emulator UI is not much help; just before the instance disappears, this is the only console output that I get consistently (sometimes other messages appear, but sporadically every few runs; I'm not sure how to capture these):
[fabric] Role Instance: deployment18(33).WindowsAzureCloudService.Mvc4WebRole.0
[fabric] Role state Unknown
[fabric] Role state Suspended
[fabric] Role state Busy
[fabric] Role state Unhealthy
[fabric] Role state Stopped
The certificate was obtained from a CA and properly imported into the Local Machine/Personal/Certificates store as a .pfx with private key, extended properties, and marked as exportable, for what it's worth.
When I attempt to publish the service to Azure, I get one build (validation) warning about the database connection string (which I assume is irrelevant):
The connection string 'DefaultConnection' is using a local database '(LocalDb)\v11.0' in project 'Mvc4WebRole'. This connection string will not work when you run this application in Windows Azure. To access a different database, you should update the connection string in the web.config file.
Probably more important, the deployment actually fails with the following history in the Windows Azure Activity Log window:
9:00:25 AM - Warning: There are package validation warnings.
9:00:25 AM - Preparing deployment for WindowsAzureCloudService - 1/3/2013 8:59:55 AM with Subscription ID '<...>' using Service Management URL 'https://management.core.windows.net/'...
9:00:25 AM - Connecting...
9:00:26 AM - Object reference not set to an instance of an object.
9:00:26 AM - Deployment failed with a fatal error
Can someone help me troubleshoot this issue? I've rebooted a few times. ;)
Thanks in advance!
EDIT (Jan. 3, 4:44 PM): I have a few ideas that might help me make progress, but some are pretty drastic so any advice would be appreciated:
Is there a way to capture all the output from the Compute Emulator (Dev Fabric) to a log file so I can review it? (System.Diagnostic.Trace calls from my service won't help, since I don't even get as far as the RoleEntryPoint when using HTTPS!) I figured this out; see next edit.
That null pointer exception during the Azure deployment has me worried. Is it worthwhile to try reinstalling the Azure SDK, and if so, how should I go about doing a clean install of it?
Has anyone seen a problem of this sort disappear when switching to using full IIS for the emulator? (That seems unlikely since IIS vs. IIS Express should have no relevance to the Azure deployment.)
EDIT (Jan. 4, 10:15 AM): Bad news: I tried the suggestion to grant Read access to the certificates, but it didn't help in my case. Good news: I managed to capture one of those sporadic messages in the Compute Emulator UI before it shut down; it was a bit of info from some diagnostics. Not helpful in and of itself, but it revealed where the Development Fabric was storing its temporary files:
[Diagnostics] Information: C:\Users\Lars\AppData\Local\dftmp\Resources\0005155d-4592-40f4-812e-18793b26576c\directory\DiagnosticStore\Monitor
The GUID portion gets recreated for every deployment, and it is deleted when the deployment goes away (as it always does in my case). But in the parent directory ('dftmp'), there are a few helpful directories that I then monitored during a new deployment: DevFCLogs, DFAgentLogs, and IISConfiguratorLogs. I guess that answers the first question I had yesterday! :)
DFAgentLogs\DFAgent.log: (41KB) No useful information. A bunch of "Failure to read pipe" messages and failures to get the role/deployment instance ID, which I assume are just noise.
DevFCLogs\DevFabric--2013.01.04--<...>.log: (510 KB) No useful information. I skimmed the file and also searched for 'error', 'failure', 'not found', 'certificate', and 'Mvc4WebRole_IN_0'; none of those showed any hints of what was going on.
IISConfiguratorLogs\IISConfigurator.log: (6 KB) Now we're making progress!! :) Can someone tell me what this means? (In the meantime, I'm off ILSpy-hunting... fun fun...)
IISConfigurator Information: 0 : [00006356:00000005, 2013/01/04 16:07:08.915] Using IIS Express appdomain
(...)
IISConfigurator Information: 0 : [00006356:00000005, 2013/01/04 16:07:08.936] Adding binding 127.255.0.0:444: to site deployment18(40).WindowsAzureCloudService.Mvc4WebRole_IN_0_Web
IISConfigurator Information: 0 : [00006356:00000005, 2013/01/04 16:07:10.484] Caught exception
IISConfigurator Information: 0 : [00006356:00000005, 2013/01/04 16:07:10.487] Exception:System.Runtime.InteropServices.COMException (0x800401F3): Invalid class string (Exception from HRESULT: 0x800401F3 (CO_E_CLASSSTRING))
Server stack trace:
at Microsoft.Web.Administration.Interop.IAppHostProperty.get_Value()
at Microsoft.Web.Administration.ConfigurationElement.GetPropertyValue(IAppHostProperty property)
at Microsoft.Web.Administration.Binding.get_CertificateHash()
at Microsoft.Web.Administration.BindingCollection.Add(Binding binding)
at Microsoft.WindowsAzure.ServiceRuntime.IISConfigurator.WasManager.DeploySite(String roleId, WASite roleSite, String appPoolName, String sitePath, String iisLogsRootFolder, String failedRequestLogsRootFolder, List1 bindings, List1 protocols, FileManager fileManager, WAAppPool defaultAppPoolSettings, String roleGuid, String& appPoolSid, List`1 appPoolsAdded, String configPath)
EDIT (Jan. 4, 11 AM): ILSpy wasn't much help; the exception is being thrown at an interop point (we knew that already) while trying to get the hash of a certificate in order to set up the binding (we knew that too). Does anyone know what COM object would need to be registered in order to get a certificate hash for a binding in Microsoft.Web.Administration? Or how I could intercept the interop call to find out? Bonus points if you can tell me why this is happening in the first place. :)
I've had similar problem on two computers. On both cases installing IIS solved the problem.
It seems to be enough to just install the IIS (via add/remove Windows components). You don't need to start using it. The installation changes something and after that my IIS Express started working again with HTTPS from Visual Studio.
There is a discussion on similar issue on MSDN Social:
http://social.msdn.microsoft.com/Forums/nl-NL/windowsazuredevelopment/thread/ad362016-16f6-459a-8022-9307aa5f910e
And the issue has been also raised on Microsoft connect:
https://connect.microsoft.com/VisualStudio/feedback/details/758533
In my case the error in the log files was:
IISConfigurator Information: 0 : [00007644:00000007, 2013.01.17
00:39:18.523] Exception:System.Runtime.InteropServices.COMException
(0x800401F3): Invalid class string (Exception from HRESULT: 0x800401F3
(CO_E_CLASSSTRING))
I found the log files from C:\Users\\AppData\Local\dftmp\IISConfiguratorLogs directory.
When running locally with a private key cert for SSL, you'll need to give the user the emulator app is running under access to the private key. Open mmc.exe and add the Certificates >> Local Computer Snap-In to view your certificate. Right Click on the certificate, then All Tasks >> Manage Private Keys - then add IUSR and Network Service with at least read access.
For deployment to azure, you'll need to upload the certificate to the Cloud Service and make sure the certificate is valid for the domain.
Follow step 11 from http://www.microsoft.com/en-us/download/details.aspx?id=35448. From this SO post

IIS Application pool identity

I am attempting to obtain a data feed from yahoo finance. I am doing this with the following code:
System.Net.WebRequest request = System.Net.WebRequest.Create(http://download.finance.yahoo.com/download/quotes.csv?format=sl&ext=.csv&symbols=^ftse,^ftmc,^ftas,^ftt1x,^dJA);
request.UseDefaultCredentials = true;
// set properties of the request
using (System.Net.WebResponse response = request.GetResponse())
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream()))
{
return reader.ReadToEnd();
}
}
I have placed this code into a console application and, using Console.WriteLine on the output I receive the information I require. I have used the 'Run as..' command to execute this using a specific domain account.
When I use this code from within a Page load I receive the following error message "No connection could be made because the target machine actively refused it 76.13.114.90:80".
This seems to suggest that the call is reaching yahoo (is this true?) and that there is something missing.
This would suggest there is an identity difference in the calls between the console application and application pool.
Environment is: Windows Server 2003, IIS 6.0, .net 4.0
"Target machine actively refused it" indicates that the TCP connection itself is not succeeding. This could be due to the fact that the Proxy settings when run under IIS are not the same as those that apply when you run in the console.
You can fix this by setting a WebProxy on your request, that points to the proxy server being used in the environment.
Yes, an active refusal is indication that the target machine is receiving the request and the information in the headers is either incorrect or insufficient to process the request. It is entirely possible that if you had to run this call using a "run as" command in console that the application pool's identity user does not have the appropriate permission or username. You can attempt to change the identity user to this specific domain account to see if that alleviates the problem, but you may have to isolate this particular function into its own application pool in order to protect the rest of the website from having this specification.

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