Develop Reference

Confirm a Folder Exists on a Web Server from a C# Desktop Application

I am trying to confirm that a folder has been uploaded to my Website folder so that it can be accessed by a Desktop application. I keep getting an error that states that there is a URI format error on the connection string. There is no shortage of 'solutions' on the general internet but I cannot get anything to work, even ones on this site (of which I am a member for many years). Forward slashes, back slashes, no slashes ... on and on. I am thoroughly confused. The following seems to be a simple and correct code, but it does not work either even though it is a direct copy of a solution that was offered as correct! The passed string 's' is the name of the folder I am trying to look for. A polite simple answer, perhaps with an example, is my desperate request. Thank You.
private bool CheckFiles(string s)
{
bool exists = System.IO.Directory.Exists(#"\\\\http:/www.myserver.com/sites/"+ s);
return exists;
}

System.IO.Directory.Exists checks for a directory in the file system. The address that is provided as a parameter is a http-URL that is not supported by file system access.
If you want to check for the presence of the folder on a webserver, you need to use a http client to "talk" to the server. Send a GET or HEAD request to the URL. If this returns a 200 (ok), the folder exists, if it returns 404 (not found), it doesn't.
As you are using .NET Framework 4.5 (or 4.0), you can use WebClient or better HttpClient for this. The following should give you an idea of how to check for the folder:
using (var http = new HttpClient())
{
using (var req = new HttpWebRequest(HttpMethod.Head, "https://..."))
{
using (var resp = http.Send(req))
{
// This is a very broad condition;
// you can also check the StatusCode property against HttpStatusCode.NotFound
return resp.IsSuccessStatusCode;
}
}
}

Is it possible to have more than one parse client configured in a single app?

So I have a few different parse servers setup.
One server is just to capture error logs from various applications (I have a LOT out there) in nice uniformed database.
So I might have a specific standalone data migration tool that if it encounters an error, will write out the exception into this Error_log parse table/class. No problem there.
But, if I have an app that uses a Parse Database for itself, I have not been able to figure out how to let it work on it's own parse server configuration for it's own stuff, but write out error logs to this other Parse server instance.
Yes... I could go through the trouble of writing out something via the REST api just for writing out logs,but I am I trying to avoid that and stick with native parse APIs for the particular platform I am on because of the benefits that the APIs give over REST (like save eventually for the none .NET stuff).
EDIT
Some clarification was requested so here I go...
On the app side of things (c# for this example but the same holds true for iOS etc)… I do the usual initialization of the Parse client as such …
ParseClient.Initialize(new ParseClient.Configuration
{
ApplicationId = "MyAppID",
WindowsKey = "MyDotNetKey",
Server = "www.myparseserver.com/app1"
});
So for all calls to save a parse object go through that parse client connection
But what I need to do would be something like this ….
//Main App cloud database
ParseClient1.Initialize(new ParseClient.Configuration
{
ApplicationId = "MyAppID",
WindowsKey = "MyDotNetKey",
Server = "www.myparseserver.com/app1"
});
ParseClient2.Initialize(new ParseClient.Configuration
{
ApplicationId = "MyAppID",
WindowsKey = "MyDotNetKey",
Server = "www.myparseserver.com/errorcollection"
});
try{
ParseConfig config = null;
config = await ParseConfig.GetAsync().ParseClient1;
} catch (Exception ex){
ParseObject MyError = new ParseObject("Error_Log");
MyError["Application"] = "My First App-App2";
MyError["Error"] = ex.message;
await MyError.Save().ParseClient2;
}
Yes - this is all fake code... my point is I want to be able to have multiple ParseClient instances in one app.
Now... I can simply write a routine that writes out errors that resets the ParseClient.Initialization to the error parse server instance and then redo it back to the original (primary app data) instance when it's done... but that is just asking for trouble in a multi threaded environment and will cause conflicts if some other thread in the app goes to write out parse data right at the moment the error method resets the init.
If ParseClient were IDisposable I could probably do that using :
ParseClient ParseErrorServer = new ParseClient();
ParseErrorServer.ApplicationId = "hmmm";
ParseErrorServer.WindwosKey= "hmmm";
ParseErrorServer.Server= "www.hmmm.com/errorcollection";
using ParseErrorServer {
//Do The Work
}
Is that clear as mud yet? ;P

Without alteration I believe none of the Parse SDKs have the ability to initialise multiple instances.
In the iOS SDK for example, is possible to make a new instance (say with a different server url) upon restarting the app but you cannot have multiple. There has also been discussion on the iOS SDK about being able to change the configuration without restart but no one has implemented this yet.
We would happily review a PR for this, however it would require a major and complex overhaul as you would have to manage cache, users etc across multiple instances.

Kafka consumer (using kafka-net) fetching all messages from the beginning by default

I'm building a Kafka consumer for my .net proyect. I'm using kafka-net (A native c# client fro Apache Kafka mady by James Roland).
The problem I have is that this code (based on the documentation) fetches all messages from the beginning by default:
private void StartKafkaConsumer(string ipKafka, string portKafka, string topicKafka)
{
string topic = topicKafka;
Uri uri = new Uri($"http://{ipKafka}:{portKafka}");
var options = new KafkaOptions(uri);
using (var router = new BrokerRouter(options))
{
using (var consumer = new Consumer(new ConsumerOptions(topic, router)))
{
foreach (var message in consumer.Consume())
{
Console.WriteLine(Encoding.UTF8.GetString(message.Value));
}
}
}
}
...
StartKafkaConsumer("localhost", "9092", "test"); //this fetches messages sent weeks ago, since the creation of the 'test' topic
Basically, this code does the same than this command:
.\bin\windows\kafka-console-consumer.bat --bootstrap-server localhost:9092 --topic test --from-beginning
All I want to do is to fetch messages from the time the client gets connected to the Apache server, not from the beginning. I know it's possible since I tried the last command without the "--from-beginning" part and it worked.
Any suggestion would be appreciated.

Look at the ConsumerOptions methods. There should be an option to set a property/config value:
auto.offset.reset
Set the above property/config to latest. At that point, anytime you connect with an unknown/new consumer group id, the consumer will default to start at the latest offset.
If, however, the consumer group id was already known (i.e., had already consumed at least once from that topic/partition), it will attempt to get the last committed offset + 1. If that offset is unavailable, because maybe it has gone past the retention threshold, then it will default to latest.
Here's more detailed documentation:
https://kafka.apache.org/documentation/#newconsumerconfigs

FtpWebRequest ignores wrong password after previous successful connection using correct password

I have run into an issue when working with FtpWebRequest class in C#.
When I try to upload a file to an FTP server using correct credentials for the first time and then wrong credentials (user name the same but wrong password) for the second time, there is no exception thrown and the file is still UPLOADED to the FTP server. Please consider the following code:
using System;
using System.Net;
internal class Program
{
private static void Main(string[] args)
{
var uri = new Uri("ftp://ftp.dlptest.com/TestFile.txt");
var method = WebRequestMethods.Ftp.UploadFile;
//Here I'm uploading the test file using correct credentials
var correctCredentials =
new NetworkCredential("dlpuser#dlptest.com", "fwRhzAnR1vgig8s");
DoFtpRequest(uri, correctCredentials, method);
//Here I'm uploading the test file using wrong credentials.
//I expect some exception to be thrown and the file not being
//uploaded to the server, neither is the case.
var wrongCredentials =
new NetworkCredential("dlpuser#dlptest.com", "WRONG_PASWORD");
DoFtpRequest(uri, wrongCredentials, method);
}
public static FtpWebResponse DoFtpRequest(
Uri uri, NetworkCredential credentials, string method)
{
var request = (FtpWebRequest)WebRequest.Create(uri);
request.Credentials = credentials;
request.Method = method;
return (FtpWebResponse)request.GetResponse();
}
}
Here I am using a public ftp server ftp://ftp.dlptest.com/ that I found here https://dlptest.com/ftp-test/ which you can use to test this code.
As you can see first I try to upload a file with correct credentials and then with wrong credentials (using the same user name but changing the password).
But the file is still uploaded to the server. If I try to use wrong credentials first, the exception is thrown, and everything works as expected.
Do you know what's going on? Is this a bug of the framework? What are my options to deal with this issue, because it causes problems with the program I'm working on now?

FtpWebRequest uses a connection pool under the hood. See FTP multiple files in C# without reestablishing connection.
Keys to that connection pool are only hostname, port number, username and optional connection group name.
Your second request reuses a connection from the first request and never uses the wrong password. It's because these two requests use the same connection pool, as they differ by a password only, which is not part of the key.
While, if you swap the requests, the first request does not succeed, its connection is closed and does not make it to the pool. The second request has to start with a new connection, and it will use its correct password.
To isolate the requests you can:
Use a unique FtpWebRequest.ConnectionGroupName for different requests to make them use different connection pools.
Or disable FtpWebRequest.KeepAlive to disable connection pooling altogether.

Microsoft Dynamics CRM SDK CRMServiceClient connection string cache bug

Caching behavior of the last Dynamics SDK is driving me crazy.
First, if you want to use CrmServiceClient to access different environments you have to use the parameter RequireNewInstance=True; in the connection string. If not, every instance of CrmServiceClient will use the same connection, even if you create and dispose instances to different environments.
Now, even if you use the RequireNewInstance=True; in the connection string I found that cache still occurs in some scenarios.
var client1 = new CrmServiceClient("RequireNewInstance=True;
Url=https://myCompany.crm.dynamics.com;
Username=myUser#myCompany.onmicrosoft.com; Password=myPassowrd;
AuthType=Office365");
//Now, client 2 points to a url that doesn’t exists:
var client2 = new CrmServiceClient("RequireNewInstance=True;
Url=https://xxx.crm.dynamics.com; Username=myUser#myCompany.onmicrosoft.com;
Password=myPassowrd; AuthType=Office365");
The client2 keeps using the first connection string, so you cannot determine if the new connection string is correct.
Any ideas how to test Dynamics Crm connections strings correctly in my asp.net application?

Late reply, but the behavior you're seeing is because when you're specifying an erroneous URL the discovery service is used to ascertain which instance to connect to.
To prevent this specify SkipDiscovery=True in your connection string:
var connectionString2 = #"AuthType=Office365;Url=https://FAKE.crm.dynamics.com;Username=USERNAME;Password=PASSWORD;RequireNewInstance=True;SkipDiscovery=True;";
Edit: SkipDiscovery is true by default starting with 9.0.7, kudos to #mwardm

I think I found the problem. It seems to only happens on Dynamics 365 online trials, that was the reason we were getting inconsistent results depending on the environment.
Apparently, the url doesn't need to be completely valid to establish a connection to a CRM online trial environment, as long as the credentials are valid and the url structure is kept.
Let's consider the following example:
var client1 = new CrmServiceClient("RequireNewInstance=True;
Url=https://fake.crm.dynamics.com;
Username=myUser#myCompany.onmicrosoft.com; Password=myPassowrd;
AuthType=Office365");
In this case I can substitute the "fake" part of the url with whatever I want, but still execute requests correctly using the CrmServiceClient service.
If I try to do this with another environment (e.g. 2015, on premise, not-trial crm online, etc.), the IsReady property of the CrmServiceClient would return false and I would get an error in the LastCrmError property.
Very weird behavior, and difficult to pinpoint.
Now that I think I understand the inconsistent behavior I know that finally it will not affect our clients, so I will mark this response as the answer even if I still do not know why we have different behavior between a trial and a normal environment..

I agree choosing to reuse the existing connection if you don't include RequireNewInstance=true seems counter-intuitive, but I can't reproduce what you're seeing. If I try the following from LinqPad crmSvcClient2 will print out errors and then throw a null ref on the Execute call (8.2.0.2 version of the SDK). With this version of the SDK you'll want to always check LastCrmError after connecting to see if the connection failed.
var connectionString = #"AuthType=Office365;Url=https://REAL.crm.dynamics.com;Username=USERNAME;Password=PASSWORD;RequireNewInstance=True;";
var connectionString2 = #"AuthType=Office365;Url=https://FAKE.crm.dynamics.com;Username=USERNAME;Password=PASSWORD;RequireNewInstance=True;";
using (var crmSvcClient = new CrmServiceClient(connectionString))
{
"crmSvcClient".Dump();
crmSvcClient.LastCrmError.Dump();
((WhoAmIResponse)crmSvcClient.Execute(new WhoAmIRequest())).OrganizationId.Dump();
crmSvcClient.ConnectedOrgFriendlyName.Dump();
}
using (var crmSvcClient2 = new CrmServiceClient(connectionString2))
{
"crmSvcClient2".Dump();
crmSvcClient2.LastCrmError.Dump();
((WhoAmIResponse)crmSvcClient2.Execute(new WhoAmIRequest())).OrganizationId.Dump();
crmSvcClient2.ConnectedOrgFriendlyName.Dump();
}