I'm attempting to query my db using Enumerable.Contains inside a SqlExpressionVisitor.Whereclause. When the lambda is compiled, I'm getting a null reference exception.
When the visitor makes it to foreach (Object e in inArgs) (currently line 1067) inside SqlExpressionVisitor.VisitArrayMethodCall, it chokes because inArgs is null. The following is my sample that causes the error. I don't understand lambdas/expressions well enough to know why this is happening.
So my questions is, am I not using the Where clause properly or is this a bug?
class Program
{
static void Main(string[] args)
{
var connectionFactory = new OrmLiteConnectionFactory(#"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|Database1.mdf;Integrated Security=True;User Instance=True", SqlServerDialect.Provider);
SetupDb(connectionFactory);
using (var db = connectionFactory.OpenDbConnection())
{
var numbersToSelect = new int[2] { 1, 2 };
db.Select<SomeObject>(e => e.Where(o => numbersToSelect.Contains(o.Number)));
}
}
static void SetupDb(IDbConnectionFactory connectionFactory)
{
using (var db = connectionFactory.OpenDbConnection())
{
db.DropTable<SomeObject>();
db.CreateTable<SomeObject>();
db.Insert(new SomeObject { Number = 1 });
db.Insert(new SomeObject { Number = 2 });
db.Insert(new SomeObject { Number = 3 });
db.Insert(new SomeObject { Number = 4 });
db.Insert(new SomeObject { Number = 5 });
}
}
}
class SomeObject
{
public int Number { get; set; }
}
After a little more digging, it turns out calling the compiled method is returning an int[] which causes the cast to object[] to be null. Casting to IEnumerable fixes my specific issue.
Changed
var getter = lambda.Compile();
var inArgs = getter() as object[];
to
var getter = lambda.Compile();
var inArgs = getter() as IEnumerable;
Not sure what sort of implications this has though (if any). Still looking for some guidance.
Instead of using Contains, use Sql.In
db.Select<SomeObject>(e => e.Where(o => Sql.In(o.Number,numbersToSelect)));
Turns out it was a bug. It's been fixed for the sqlite visitor and the sql visitor as of commit 9f0b0e8 Thanks #mythz.
Related
Using Azure's DocumentDb and the .NET API, I have the following method which works great for retrieving lists of entire documents:
public async Task<IEnumerable<T>> GetItemsAsync<T>(Expression<Func<T, bool>> predicate)
{
IDocumentQuery<T> query = _Client.CreateDocumentQuery<T>(
UriFactory.CreateDocumentCollectionUri(_DatabaseId, _Collection),
new FeedOptions { MaxItemCount = -1 })
.Where(predicate)
.AsDocumentQuery();
List<T> results = new List<T>();
while (query.HasMoreResults)
{
var item = await query.ExecuteNextAsync<T>();
results.AddRange(item);
}
return results;
}
Now, I don't always want to return the entire document (especially considering the DocumentDb RU pricing model), so I thought I should be able to add a .Select projection like so:
public async Task<List<TResult>> GetItemsAsync<T, TResult>(Expression<Func<T, bool>> predicate, Expression<Func<T, TResult>> select)
{
IDocumentQuery<TResult> query = _Client.CreateDocumentQuery<T>(
UriFactory.CreateDocumentCollectionUri(_DatabaseId, _Collection),
new FeedOptions { MaxItemCount = -1 })
.Where(predicate)
.Select(select)
.AsDocumentQuery();
List<TResult> results = new List<TResult>();
while (query.HasMoreResults)
{
var item = await query.ExecuteNextAsync<TResult>();
results.AddRange(item);
}
return results;
}
Usage:
var rez = await _docs.GetItemsAsync<ApolloAssetDoc, Guid?>(x => x.MyVal == 5, x => x.ID);
But the second method always return 0 results. Obviously I'm barking up the wrong tree.
Any idea what the correct way to return a list of either dynamic objects for queries where more than one property is selected (eg "SELECT d.id, d.MyVal FROM Items d WHERE d.DocType=0")or a simple list where only a single property is selected (eg "SELECT d.id FROM Items d WHERE d.DocType=0")?
I could repro the issue, if there is no [JsonProperty(PropertyName = "id")] for ID property in the entity Class. If it is not included, please have a try to use the following code:
public class ApolloAssetDoc
{
[JsonProperty(PropertyName = "id")]
public Guid ID { get; set; }
public string MyVal { get; set; }
}
Note: The field is case sensitive.
How do you model bind an array from the URI with GET in ASP.NET Core 1 Web API (implicitly or explicitly)?
In ASP.NET Web API pre Core 1, this worked:
[HttpGet]
public void Method([FromUri] IEnumerable<int> ints) { ... }
How do you do this in ASP.NET Web API Core 1 (aka ASP.NET 5 aka ASP.NET vNext)? The docs have nothing.
The FromUriAttribute class combines the FromRouteAttribute and FromQueryAttribute classes. Depending the configuration of your routes / the request being sent, you should be able to replace your attribute with one of those.
However, there is a shim available which will give you the FromUriAttribute class. Install the "Microsoft.AspNet.Mvc.WebApiCompatShim" NuGet package through the package explorer, or add it directly to your project.json file:
"dependencies": {
"Microsoft.AspNet.Mvc.WebApiCompatShim": "6.0.0-rc1-final"
}
While it is a little old, I've found that this article does a pretty good job of explaining some of the changes.
Binding
If you're looking to bind comma separated values for the array ("/api/values?ints=1,2,3"), you will need a custom binder just as before. This is an adapted version of Mrchief's solution for use in ASP.NET Core.
public class CommaDelimitedArrayModelBinder : IModelBinder
{
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext.ModelMetadata.IsEnumerableType)
{
var key = bindingContext.ModelName;
var value = bindingContext.ValueProvider.GetValue(key).ToString();
if (!string.IsNullOrWhiteSpace(value))
{
var elementType = bindingContext.ModelType.GetTypeInfo().GenericTypeArguments[0];
var converter = TypeDescriptor.GetConverter(elementType);
var values = value.Split(new[] { "," }, StringSplitOptions.RemoveEmptyEntries)
.Select(x => converter.ConvertFromString(x.Trim()))
.ToArray();
var typedValues = Array.CreateInstance(elementType, values.Length);
values.CopyTo(typedValues, 0);
bindingContext.Result = ModelBindingResult.Success(typedValues);
}
else
{
// change this line to null if you prefer nulls to empty arrays
bindingContext.Result = ModelBindingResult.Success(Array.CreateInstance(bindingContext.ModelType.GetElementType(), 0));
}
return TaskCache.CompletedTask;
}
return TaskCache.CompletedTask;
}
}
You can either specify the model binder to be used for all collections in Startup.cs:
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddMvc().AddMvcOptions(opts =>
{
opts.ModelBinders.Insert(0, new CommaDelimitedArrayModelBinder());
});
}
Or specify it once in your API call:
[HttpGet]
public void Method([ModelBinder(BinderType = typeof(CommaDelimitedArrayModelBinder))] IEnumerable<int> ints)
ASP.NET Core 1.1 Answer
#WillRay's answer is a little outdated. I have written an 'IModelBinder' and 'IModelBinderProvider'. The first can be used with the [ModelBinder(BinderType = typeof(DelimitedArrayModelBinder))] attribute, while the second can be used to apply the model binder globally as I've show below.
.AddMvc(options =>
{
// Add to global model binders so you don't need to use the [ModelBinder] attribute.
var arrayModelBinderProvider = options.ModelBinderProviders.OfType<ArrayModelBinderProvider>().First();
options.ModelBinderProviders.Insert(
options.ModelBinderProviders.IndexOf(arrayModelBinderProvider),
new DelimitedArrayModelBinderProvider());
})
public class DelimitedArrayModelBinderProvider : IModelBinderProvider
{
public IModelBinder GetBinder(ModelBinderProviderContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (context.Metadata.IsEnumerableType && !context.Metadata.ElementMetadata.IsComplexType)
{
return new DelimitedArrayModelBinder();
}
return null;
}
}
public class DelimitedArrayModelBinder : IModelBinder
{
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
var modelName = bindingContext.ModelName;
var valueProviderResult = bindingContext.ValueProvider.GetValue(modelName);
var values = valueProviderResult
.ToString()
.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
var elementType = bindingContext.ModelType.GetTypeInfo().GenericTypeArguments[0];
if (values.Length == 0)
{
bindingContext.Result = ModelBindingResult.Success(Array.CreateInstance(elementType, 0));
}
else
{
var converter = TypeDescriptor.GetConverter(elementType);
var typedArray = Array.CreateInstance(elementType, values.Length);
try
{
for (int i = 0; i < values.Length; ++i)
{
var value = values[i];
var convertedValue = converter.ConvertFromString(value);
typedArray.SetValue(convertedValue, i);
}
}
catch (Exception exception)
{
bindingContext.ModelState.TryAddModelError(
modelName,
exception,
bindingContext.ModelMetadata);
}
bindingContext.Result = ModelBindingResult.Success(typedArray);
}
return Task.CompletedTask;
}
}
There are some changes in the .NET Core 3.
Microsoft has split out the functionality from the AddMvc method (source).
As AddMvc also includes support for View Controllers, Razor Views and etc. If you don't need to use them in your project (like in an API), you might consider using services.AddControllers() which is for Web API controllers.
So, updated code will look like this:
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers()
.AddMvcOptions(opt =>
{
var mbp = opt.ModelBinderProviders.OfType<ArrayModelBinderProvider>().First();
opt.ModelBinderProviders.Insert(opt.ModelBinderProviders.IndexOf(mbp), new DelimitedArrayModelBinderProvider());
});
}
We are migrating our SProc based solution over to ORMLite, and so far has been pretty painless. Today I wrote the following method:
public AppUser GetAppUserByUserID(int app_user_id)
{
var dbFactory = new OrmLiteConnectionFactory(this.ConnectionString, SqlServerOrmLiteDialectProvider.Instance);
AppUser item = null;
var rh = new RedisHelper();
var id= CacheIDHelper.GetAppUserID( app_user_id );
item = rh.Get<AppUser>(id);
if (item == null)
{
try
{
using (var db = dbFactory.OpenDbConnection())
{
item = db.Single<AppUser>("application_user_id={0}", app_user_id);
rh.Set<AppUser>(item, id);
}
}
catch (Exception ex)
{
APLog.error(ex, "Error retrieving user!");
}
}
return item;
}
I have remove some of the extraneous fields, but they are basically:
[Alias("application_user")]
public class AppUser : APBaseObject
{
[Alias("application_user_id")]
[AutoIncrement]
public int? UserID
{
get;
set;
}
[Alias("application_user_guid")]
public string UserGUID
{
get;
set;
}
//MORE FIELDS here.
}
The challenge is that they only field that is populate is the ID field, AND I already know that ID because I am passing it into the method.
I did get the last SQL called and ran that against the DB directly and all of the fields were being referenced correctly.
I stepped through the code in the debugger, and everything came back correctly, except that the only field returned was the ID.
Thoughts?
I had a similar issue which was caused by my class methods not mapping to the db properly. My exact issue was caused by a nullable int field in the db and the class method was defined as an 'int' instead of 'int?'.
Perhaps you have a similar issue?
Basically I have following architecture:
Website-project (1)
Domain-project (2)
Api-project (3)
Dependencies:
1 uses 2 and 3
3 uses 2
2 uses nothing
In my Api-project I define a concrete implementation of ServiceStack.Webhost.Endpoints.AppHostBase, eg ApiAppHost:
public sealed class ApiAppHost : AppHostBase
{
private ApiAppHost()
: base("Description", typeof (ApiAppHost).Assembly) {}
public override void Configure(Container container)
{
this.SetConfig(new EndpointHostConfig
{
ServiceStackHandlerFactoryPath = "api"
});
this.Routes.Add<Foo>("/foo", "POST");
}
public static void Initialize()
{
var instance = new ApiAppHost();
instance.Init();
}
}
This is pretty straight-forward.
Now I want to query my this.Routes (in combination with EndpointHostConfig.ServiceStackHandlerFactoryPath) from my Website-project to get the specific path for Foo.
How can I do that without creating an interceptor on my own? Does ServiceStack.Net provide anything which fits?
Currently I am doing something like this
public static class AppHostBaseExtensions
{
public static string GetUrl<TRequest>(this AppHostBase appHostBase)
{
var requestType = typeof (TRequest);
return appHostBase.GetUrl(requestType);
}
public static string GetUrl(this AppHostBase appHostBase, Type requestType)
{
var endpointHostConfig = appHostBase.Config;
var serviceStackHandlerFactoryPath = endpointHostConfig.ServiceStackHandlerFactoryPath;
var serviceRoutes = appHostBase.Routes as ServiceRoutes;
if (serviceRoutes == null)
{
throw new NotSupportedException("Property Routes of AppHostBase is not of type ServiceStack.ServiceHost.ServiceRoutes");
}
var restPaths = serviceRoutes.RestPaths;
var restPath = restPaths.FirstOrDefault(arg => arg.RequestType == requestType);
if (restPath == null)
{
return null;
}
var path = restPath.Path;
var virtualPath = "~/" + string.Concat(serviceStackHandlerFactoryPath, path); // bad, i know, but combining with 2 virtual paths ...
var absolutePath = VirtualPathUtility.ToAbsolute(virtualPath);
return absolutePath;
}
}
I know that it is wrong because of many issues (path-combining, not taking rest-paths into account, not taking rest-paths with placeholders into account), but it works as a start ...
Edit:
And this only works, if you register the route within Configure(Container) of your AppHostBase-implementation. It wont't work with the RestServiceAttribute-attribute ...
I am developing an e-commerce website that utilises db4o as the backend. All was well until last week when I came across a problem that I have been unable to solve. The code below is quite straight forward. I open a database file, save an object and then try to retrieve it. However I get nothing back. The "users" variable has a count of zero.
public class Program
{
private static string _connectionString = string.Format(#"c:\aaarrrr.db4o");
static void Main(string[] args)
{
TestUser container = new TestUser() { id = 1, Name = "Mohammad", Surname = "Rafiq" };
Db4oFactory.Configure().Diagnostic().AddListener(new DiagnosticToConsole());
using (var dbc = Db4oFactory.OpenFile(_connectionString))
{
dbc.Store(container);
}
IList<TestUser> users = null;
using (var dbc = Db4oFactory.OpenFile(_connectionString))
{
users = dbc.Query<TestUser>(x => x.id == 1).ToList();
}
if (users.Count > 0)
{
Console.WriteLine("{0} {1} with id of {2}", users.First().Name, users.First().Surname, users.First().id);
}
else
{
Console.WriteLine("\nNo data returned.");
}
Console.ReadLine();
}
}
public class TestUser
{
[Indexed]
private int _id = 0;
private string _name = string.Empty;
private string _surname = string.Empty;
public int id { get { return _id; } set { _id = value; } }
public string Name { get { return _name; } set { _name = value; } }
public string Surname { get { return _surname; } set { _surname = value; } }
}
I have attached db4o diagnostic listener and I see nothing in the console output. Everything seems fine. I know I am writing to the file because I can see the file size increase and the timestamp is also updated. I have checked all the project settings and they are all set to default. I am using .net 4, visual studio 2010 beta and windows 7. I have done some reading regarding reflection permission but I cant see how this applies here. Any help or ideas would be knidly appreciated.
After calling store(), you need to commit() before leaving the using{} statement. You closed your database before committing your changes.