In my ASP.NET MVC 5 application I'm trying to access the Request.InputStream property but I get the following exception:
System.NullReferenceException: Object reference not set to an instance of an object.
at Telerik.Web.UI.Upload.RequestParser.MergeArrays(Byte[] array1, Byte[] array2)
at Telerik.Web.UI.Upload.RequestParser.get_FirstBoundary()
at Telerik.Web.UI.Upload.RequestParser..ctor(Byte[] boundary, Encoding encoding, RequestStateStore requestStateStore)
at Telerik.Web.UI.Upload.ProgressWorkerRequest.get_Parser()
at Telerik.Web.UI.Upload.ProgressWorkerRequest.UpdateProgress(Byte[] buffer, Int32 validBytes
at Telerik.Web.UI.Upload.ProgressWorkerRequest.GetPreloadedEntityBody()
at System.Web.HttpRequest.GetEntireRawContent()
at System.Web.HttpRequest.get_InputStream()
As you can see, the exception is thrown by a Telerik component. I'm indeed using Telerik web controls in my project but none of them are related to this controller. The exception occurs even if I generate a request using a tool. Looks to me like Telerik somehow injected this ProgressWorkerRequest object into my HttpRequest.
Any clues on how to get rid of it?
It doesn't have to be related to your controller. It is related to the process that the Telerik uploader is conducting and is not something to "get rid of". Basically, it is telling you that the Telerik uploader process didn't complete because it didn't find what it was expecting to.
Since Telerik controls are generally straightforward to use, you should only need something like this to get the input stream for your file:
public ActionResult UploadFile(IEnumerable<HttpPostedFileBase> fileUploader)
{
if (Request.Files.Count == 1)
{
string fileName = Request.Files[0].FileName;
Stream s = Request.Files[0].InputStream;
int size = Request.Files[0].ContentLength;
byte[] myFile = new byte[length];
s.Read(myFile, 0, size);
// Now, myFile should have the file, in bytes
}
}
If you are not getting the file, I would ensure the application has the permissions via the account it is acting under (either yours, or a service account, if a web application) to the resource you are pointing at.
Related
I am getting this error occasionally with the MSSQLServer sink. I can't see what's wrong with this guid. Any ideas? I've verified in every place I can find the data type of the source guid is "Guid" not a string. I'm just a bit mystified.
Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).Couldn't store <"7526f485-ec2d-4ec8-bd73-12a7d1c49a5d"> in UserId Column. Expected type is Guid.
The guid in this example is:
7526f485-ec2d-4ec8-bd73-12a7d1c49a5d
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
seems to match the template to me?
Further details:
This is an occasional issue, but when it arises it arises a lot. It seems to be tied to specific Guids. Most Guids are fine, but a small subset have this issue. Our app logs thousands of messages a day, but these messages are not logged (because of the issue) so it is difficult for me to track down exactly where the specific logs that are causing this error come from. However, we use a centralized logging method that is run something like this. This test passes for me, but it mirrors the setup and code we use for logging generally, which normally succeeds. As I said, this is an intermittent issue:
[Fact]
public void Foobar()
{
// arrange
var columnOptions = new ColumnOptions
{
AdditionalColumns = new Collection<SqlColumn>
{
new SqlColumn {DataType = SqlDbType.UniqueIdentifier, ColumnName = "UserId"},
},
};
columnOptions.Store.Remove(StandardColumn.MessageTemplate);
columnOptions.Store.Remove(StandardColumn.Properties);
columnOptions.Store.Remove(StandardColumn.LogEvent);
columnOptions.Properties.ExcludeAdditionalProperties = true;
var badGuid = new Guid("7526f485-ec2d-4ec8-bd73-12a7d1c49a5d");
var connectionString = "Server=(localdb)\\MSSQLLocalDB;Database=SomeDb;Trusted_Connection=True;MultipleActiveResultSets=true";
var logConfiguration = new LoggerConfiguration()
.MinimumLevel.Information()
.Enrich.FromLogContext()
.WriteTo.MSSqlServer(connectionString, "Logs",
restrictedToMinimumLevel: LogEventLevel.Information, autoCreateSqlTable: false,
columnOptions: columnOptions)
.WriteTo.Console(restrictedToMinimumLevel: LogEventLevel.Information);
Log.Logger = logConfiguration.CreateLogger();
// Suspect the issue is with this line
LogContext.PushProperty("UserId", badGuid);
// Best practice would be to do something like this:
// using (LogContext.PushProperty("UserId", badGuid)
// {
Log.Logger.Information(new FormatException("Foobar"),"This is a test");
// }
Log.CloseAndFlush();
}
One thing I have noticed since constructing this test code is that the "PushProperty" for the UserId property is not captured and disposed. Since behaviour is "undefined" in this case, I am inclined to fix it anyway and see if the problem goes away.
full stack:
2020-04-20T08:38:17.5145399Z Exception while emitting periodic batch from Serilog.Sinks.MSSqlServer.MSSqlServerSink: System.ArgumentException: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).Couldn't store <"7526f485-ec2d-4ec8-bd73-12a7d1c49a5d"> in UserId Column. Expected type is Guid.
---> System.FormatException: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).
at System.Guid.GuidResult.SetFailure(Boolean overflow, String failureMessageID)
at System.Guid.TryParseExactD(ReadOnlySpan`1 guidString, GuidResult& result)
at System.Guid.TryParseGuid(ReadOnlySpan`1 guidString, GuidResult& result)
at System.Guid..ctor(String g)
at System.Data.Common.ObjectStorage.Set(Int32 recordNo, Object value)
at System.Data.DataColumn.set_Item(Int32 record, Object value)
--- End of inner exception stack trace ---
at System.Data.DataColumn.set_Item(Int32 record, Object value)
at System.Data.DataRow.set_Item(DataColumn column, Object value)
at Serilog.Sinks.MSSqlServer.MSSqlServerSink.FillDataTable(IEnumerable`1 events)
at Serilog.Sinks.MSSqlServer.MSSqlServerSink.EmitBatchAsync(IEnumerable`1 events)
at Serilog.Sinks.PeriodicBatching.PeriodicBatchingSink.OnTick()
RESOLUTION
This issue was caused because someone created a log message with a placeholder that had the same name as our custom data column, but was passing in a string version of a guid instead of one typed as a guid.
Very simple example:
var badGuid = "7526f485-ec2d-4ec8-bd73-12a7d1c49a5d";
var badGuidConverted = Guid.Parse(badGuid); // just proving the guid is actually valid.
var goodGuid = Guid.NewGuid();
using (LogContext.PushProperty("UserId",goodGuid))
{
Log.Logger.Information("This is a problem with my other user {userid} that will crash serilog. This message will never end up in the database.", badGuid);
}
The quick fix is to edit the message template to change the placeholder from {userid} to something else.
Since our code was centralized around the place where the PushProperty occurs, I put some checks in there to monitor for this and throw a more useful error message in the future when someone does this again.
I don't see anything obvious in the specific code above that would cause the issue. The fact that you call PushProperty before setting up Serilog would be something I would change (i.e. set up Serilog first, then call PushProperty) but that doesn't seem to be the root cause of the issue you're having.
My guess, is that you have some code paths that are logging the UserId as a string, instead of a Guid. Serilog is expecting a Guid value type, so if you give it a string representation of a Guid it won't work and will give you that type of exception.
Maybe somewhere in the codebase you're calling .ToString on the UserId before logging? Or perhaps using string interpolation e.g. Log.Information("User is {UserId}", $"{UserId}");?
For example:
var badGuid = "7526f485-ec2d- 4ec8-bd73-12a7d1c49a5d";
LogContext.PushProperty("UserId", badGuid);
Log.Information(new FormatException("Foobar"), "This is a test");
Or even just logging a message with the UserId property directly:
var badGuid = "7526f485-ec2d-4ec8-bd73-12a7d1c49a5d";
Log.Information("The {UserId} is doing work", badGuid);
Both snippets above would throw the same exception you're having, because they use string values rather than real Guid values.
Is there any way in Struts2 by which I can get list of namespaces in my App ?
I want this as set or list at runtime .
I am using Struts2 RestActionMapper plugin.
When there invalid namespace is specified for valid action, Struts is throwing namespace error.
But I could not redirected to standard error page when this error occurs. I tried almost all options e.g.global error mapping default namespace etc . Nothing worked. So thought it would be great if I could get list of namespaces in my app, thus i could have checked invalid namespace against my list of valid namespaces and accordingly I could have thrown generic error which would finally result in my standard error page.
I am looking for how to get list of all namespaces in my project.
So basically I want to do something like this.
validNamespaces = getNamespaces();
if(validNamespaces.contains(namespaceRetrivedFromRestPlugin))
{Sysout("This is valid namespace.")}
else
{Sysout("Invalid namespace");}
This is possible, though like Steven has pretty much stated, I'm not convinced that this is the right approach to the problem you state of redirecting to an error page. But, I'll leave that part up to you and use this space to answer the namespace question.
This code will have to be in a Struts2-created object for the injection to work.
private Configuration configuration;
#Inject
public void setConfiguration(Configuration config) {
this.configuration = config;
}
protected Set<String> getNamespaces() {
Set<String> namespaces = Collections.emptySet();
Map<String, Map<String, ActionConfig>> allActionConfigs = this.configuration.getRuntimeConfiguration().getActionConfigs();
if (allActionConfigs != null) {
namespaces = allActionConfigs.keySet();
}
return namespaces;
}
The configuration can also be obtained from a ConfigurationManager. Also, you would obviously want to store these in a variable rather than calling above method over and over. If your object is, say, an interceptor, then you could call this method from the init() method and store it in a class-level variable.
I'm trying to generate a sitemap dynamically for a large web site with thousands of pages.
Yes, I have considered generating the sitemap file offline and simply serving it statically, and I might end up doing exactly that. But I think this is a generally useful question:
How can I stream large data from a DB in Wicket?
I followed the instructions at the Wicket SEO page, and was able to get a dynamic sitemap implementation working using a DataProvider. But it doesn't scale- it runs out of memory when it calls my DataProvider's iterator() method with a count arg equal to the total number of objects I'm returning, rather than iterating over them in chunks.
I think the solution lies somewhere with WebResource/ResourceStreamingRequestTarget. But those classes expect an IResourceStream, which ultimately boils down to providing an InputStream implementation, which deals in bytes, rather than DB records. I wouldn't know how to implement the length() method in such a case, as that would require visiting every record ahead of time to compute the overall length.
From the doc of the IResourceStream.length() method:
/**
* Gets the size of this resource in bytes
*
* TODO 1.5: rename to lengthInBytes() or let it return some sort of size object
*
* #return The size of this resource in the number of bytes, or -1 if unknown
*/
long length();
So I think it would be ok if your IResourceStream implementation tells that the length is unknown and you stream the data directly as you get the records from the database.
You could return -1, indicating an unknown length, or you could write the result in a memory buffer or disk, before rendering it to the client.
You could also use this file as a cache, so that you don't need to regenerate it every time this resource is requested (remember you have to handle concurrent requests, though). Dedicated caching solutions (e.g. memcache, ehcache, etc.) can also be considered.
It may be cleaner than publishing a static file, although static files are probably better if performance is critical.
I ended up using an AbsractResourceStreamWriter subclass:
public class SitemapStreamWriter extends AbstractResourceStreamWriter
{
#Override
public void write(OutputStream output)
{
String HEAD = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
"<urlset xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\"\n" +
" xmlns:wicket=\"http://wicket.apache.org/dtds.data/wicket-xhtml1.4-strict.dtd\">\n";
try
{
output.write(HEAD.getBytes());
// write out a <loc> entry for each of my pages here
output.write("</urlset>\n".getBytes());
}
catch (IOException e)
{
throw new RuntimeException(e.getMessage(), e);
}
}
}
I have a site where I allow members to upload photos. In the MVC Controller I take the FormCollection as the parameter to the Action. I then read the first file as type HttpPostedFileBase. I use this to generate thumbnails. This all works fine.
In addition to allowing members to upload their own photos, I would like to use the System.Net.WebClient to import photos myself.
I am trying to generalize the method that processes the uploaded photo (file) so that it can take a general Stream object instead of the specific HttpPostedFileBase.
I am trying to base everything off of Stream since the HttpPostedFileBase has an InputStream property that contains the stream of the file and the WebClient has an OpenRead method that returns Stream.
However, by going with Stream over HttpPostedFileBase, it looks like I am loosing ContentType and ContentLength properties which I use for validating the file.
Not having worked with binary stream before, is there a way to get the ContentType and ContentLength from a Stream? Or is there a way to create a HttpPostedFileBase object using the Stream?
You're right to look at it from a raw stream perspective because then you can create one method that handles streams and therefore many scenarios from which they come.
In the file upload scenario, the stream you're acquiring is on a separate property from the content-type. Sometimes magic numbers (also a great source here) can be used to detect the data type by the stream header bytes but this might be overkill since the data is already available to you through other means (i.e. the Content-Type header, or the .ext file extension, etc).
You can measure the byte length of the stream just by virtue of reading it so you don't really need the Content-Length header: the browser just finds it useful to know what size of file to expect in advance.
If your WebClient is accessing a resource URI on the Internet, it will know the file extension like http://www.example.com/image.gif and that can be a good file type identifier.
Since the file info is already available to you, why not open up one more argument on your custom processing method to accept a content type string identifier like:
public static class Custom {
// Works with a stream from any source and a content type string indentifier.
static public void SavePicture(Stream inStream, string contentIdentifer) {
// Parse and recognize contentIdentifer to know the kind of file.
// Read the bytes of the file in the stream (while counting them).
// Write the bytes to wherever the destination is (e.g. disk)
// Example:
long totalBytesSeen = 0L;
byte[] bytes = new byte[1024]; //1K buffer to store bytes.
// Read one chunk of bytes at a time.
do
{
int num = inStream.Read(bytes, 0, 1024); // read up to 1024 bytes
// No bytes read means end of file.
if (num == 0)
break; // good bye
totalBytesSeen += num; //Actual length is accumulating.
/* Can check for "magic number" here, while reading this stream
* in the case the file extension or content-type cannot be trusted.
*/
/* Write logic here to write the byte buffer to
* disk or do what you want with them.
*/
} while (true);
}
}
Some useful filename parsing features are in the IO namespace:
using System.IO;
Use your custom method in the scenarios you mentioned like so:
From an HttpPostedFileBase instance named myPostedFile
Custom.SavePicture(myPostedFile.InputStream, myPostedFile.ContentType);
When using a WebClient instance named webClient1:
var imageFilename = "pic.gif";
var stream = webClient1.DownloadFile("http://www.example.com/images/", imageFilename)
//...
Custom.SavePicture(stream, Path.GetExtension(imageFilename));
Or even when processing a file from disk:
Custom.SavePicture(File.Open(pathToFile), Path.GetExtension(pathToFile));
Call the same custom method for any stream with a content identifer that you can parse and recognize.
I'm using ASP.NET MVC and have a long running process. Specifically I am generating a large PDF for the user to download.
I understand the basic concept:
Action method gets called
New thread started to generate process
Return a View that tells the user the (pdf) is being generated
Use AJAX to call the server and ask for progress
Once finished, present the file to the user for download.
The parts I don't fully understand are:
The management of the thread across separate AJAX calls. I will possibly need some way of finding the running thread and requesting a status. Is there a static context I can keep a reference to the thread in? I'm aware of the Data Caching in HttpContext.Application, would that be suitable for this?
And how to present the completed file. Do I create a temp file and present a download link? Or can I make a final AJAX call that returns the file?
It works!
Here's what I've done:
Step 1 & 2 - Action Method gets called, long running thread is started
When my action method gets called, it generates a unique ID. I then instantiate an instance of my PdfGenerator class, create a new thread that calls PdfGenerator.Generate and start it.
public class PdfGenerator
{
public string State;
public byte[] Data;
public void Generate()
{
// Generate PDF/Long running process
// Should update State as it goes
// ...
// Once finished, Data is populated with the binary byte[]
}
}
Once the thread has started (or before starting) the generator instance is stored in the cache:
HttpContext.Cache[guid] = generator;
I also attach the guid to the ViewData so that it can be reference in my view script.
Step 3 & 4 - Display and update status/progress view
Now that the thread is running and PDF generation has begun, I can display my progress view script. Using jQuery's $.getJSON I am able to poll a separate Action to find the status of the generation:
[OutputCache(Duration = 0, VaryByName = "none", NoStore = true)]
public JsonResult CheckPdfGenerationStatus(string guid)
{
// Get the generator from cache
var generator = HttpContext.Cache[guid] as PdfGenerator;
if (generator == null)
return Json(null);
else
return Json(generator.State);
}
My view script interprets the Json and displays the appropriate progress information.
Step 5 - Present file to user
Once the generation is completed, the generators state is set accordingly and when jQuery receives this information, it can either make available a link, or directly send the file using javascripts location.href.
The Action method that sets up and returns the file simply gets the generator out of the cache and returns the attached byte[]
public ContentResult DownloadPdf(string guid)
{
var generator = HttpContext.Cache[guid] as PdfGenerator;
if (generator == null)
return Content("Error");
if (generator.State == "Completed")
{
return Content(generator.Data);
}
else
{
return Content("Not finished yet");
}
}
My my actual work I've got more detailed state such as Initialised, Running and Completed. As well as a progress percentage (expressed as a decimal, 1.0 being complete).
So yeah, hope that helps anyone else trying to do something similar.
The Cashe is very well suitable for that. Only one thing is to make sure the item cached is never removed while the process is running (You can use ItemPriority.NotRemovable for that).
You can save the file on disk in a temp folder or you can keep it in cache for some time (it depends).
I personally don' like to pollute hard disk with files so I would keep the file in the cache (with MediumPriority for a couple of minutes). But if the file is large and can be generated often consider using a Database of file system instead.
On the client, when the last Ajax request returns result( can look like {progress: "100%", resultUrl: "http://your.url/Where/ToGet/TheFile.aspx?file=GUID-OR-CACHE-KEY"} ) you can redirect the browser to a URL provided.
It, in turn, will render that file as a binary result.
Client redirect can be done using Javascript like this:
location.href = response.resultUrl;
BTW, how do you generate PDF? NFOP?