I have the following get-method:
public async Task<TModel> Get(string id)
{
var filter = Builders<TModel>.Filter.Eq("_id",id);
var result = await _collection.FindAsync(filter);
return result.FirstOrDefault();
}
My Model is defined like this:
public class Entity
{
[BsonId]
[BsonRepresentation(BsonType.ObjectId)]
public string Id { get; set; }
...
}
If I test this method I get 404 (Not found) back.
What I already checked:
The id parameter has the right id.
Used id exists in database.
_collection is the correct IMongoCollection.
MongoDB server is running and collection exits.
Connection string, credentials and permissions to connect to the MongoDB server is correct (other crud methods are working).
What other troubleshooting steps can I do? What could be the error?
Thank you for your help!
In the Entity class the _id field is defined to be ObjectId, but in the Get function it is string. MongoDB matches are type-sensitive, so you'll need to convert the string to an ObjectId first.
Related
I have the following class
public class UpdateUserRequest
{
public string Id {get;set;}
public string FirstName {get;set;}
public string LastName {get;set;}
public int Age {get;set;}
}
And I have the following endpoint:
[HttpPut]
[Route("/[controller]/update/user/{userId}")]
public IActionResult Update(UpdateUserRequest update, string userId)
{
// code logic to update a user
// etc...
}
If I run my project with that code swagger generates the proper documentation. The problem is that I want to modify my endpoint and instead of taking a UpdateUserRequest update I will like to take a object update. In other words this is how I would like my endpoint to look like:
[HttpPut]
[Route("/[controller]/update/user/{userId}")]
public IActionResult Update(object update, string userId)
{
// code logic to update a user
// etc...
}
The reason why I want to accept an object instead of an UpdateUserRequest is because I will like to enable my API to only update the properties that are sent through the request. In other words if the user sends:
{ "FirstName":"Tono" }
Then I will only update the property FirstName. without making the other properties null!
How can I tell swagger to generate documentation as if the method where to take UpdateUserRequest parameter when in fact it is accepting an object? When I place an object as a parameter swagger displays this:
How can I have it display json with the format of a UpdateUserRequest?
One solution I have found is to do something like this:
app.Use(async (context, next) =>
{
// if its an update?
if (context.Request.Method == "PUT")
{
// enable buffering in order to see raw object
context.Request.EnableBuffering();
using MemoryStream memoryStream = new MemoryStream();
// save body to memory
await context.Request.Body.CopyToAsync(memoryStream);
// convert it to json
var rawJson = System.Text.Encoding.UTF8.GetString(memoryStream.ToArray());
// save raw json on current context.
context.Items.Add("rawJson", rawJson);
// later that json could be from current context
// reset the position
context.Request.Body.Position = 0;
}
await next();
);
But this is kind of an ugly hack when I just need a different swagger documentation.
I need to get the most recent document in a Cosmos DB container using an IQueryable query.
The SQL query corresponding to what I want to do is:
SELECT top 1 * FROM c order by c._ts
What I have available is an IQueryable provided by a generic repository. The repository creates the IQueryable like this:
var queryable = container.GetItemLinqQueryable<TEntity>(false, null, requestOption);
And the Entity (in IQueryable) does NOT contain a field that maps to "_ts":
public class Entity {
public string id { get; set; }
public Name { get; set; }
}
Here is the code that I need to write, but there is a missing timestamp field:
var queryable = await _repo.GetAsync(partitionKey);
var query = queryable.OrderByDescending(e => e.{The Missing _ts field}).Take(1);
Is there a way to write such a LINQ query?
Note: I am using .NET Cosmos DB SDK (v3).
Add the ts attribute on your Entity class something like below. Now you can query on Timestamp.
[Newtonsoft.Json.JsonConverter(typeof(Microsoft.Azure.Documents.UnixDateTimeConverter))]
[Newtonsoft.Json.JsonProperty(PropertyName="_ts")]
private virtual DateTime Timestamp { get; }
Adding _ts attribute plainly throws error when ingesting the data without setting the value for TimeStamp field(Default value is "01/01/0001" for DateTime). It works fine when fetching data, but when ingesting we will run into issues. Solution is to use a nullable type which will work both for insertion, retrieval.
[Newtonsoft.Json.JsonConverter(typeof(Microsoft.Azure.Documents.UnixDateTimeConverter))]
[Newtonsoft.Json.JsonProperty(NullValueHandling=Newtonsoft.Json.NullValueHandling.Ignore, PropertyName="_ts")]
public DateTime? LastModified { get; }
The key here is NullValueHandling.Ignore and nullable type (DataTime?). If we have these values, Cosmos will internally update the _ts field when we insert or merge. So, no need to set the value in our code during ingestion. Querying for documents will fetch the value as usual.
The above will cause an issue if you try to fetch an element and update some properties of that element. Now if you try to push this element to cosmos, it will not update the latest modified time because we already have the value set in _ts.
To overcome this, add shouldserialize method.
private bool ShouldSerializeLastModified()
{
// never update last modified timestamp when updating entries in cosmos. Let cosmos do that for us.
return false;
}
Reference: https://learn.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.databaseproperties.lastmodified?view=azure-dotnet
https://learn.microsoft.com/en-us/dotnet/desktop/winforms/controls/defining-default-values-with-the-shouldserialize-and-reset-methods?view=netframeworkdesktop-4.8
Maybe I'm missing something really simple out here but gonna ask anyways.....
I am using Xamarin forms (.NET Standard project), MVVMLight, Realm DB and ZXing Barcode Scanner.
I have a realmobject like so...
public class Participant : RealmObject
{
public string FirstName {get; set;}
public string LastName {get; set;}
public string Email {get; set;}
public string RegistrationCode {get; set;}
//More properties skipped out for brevity
}
I have the corresponding viewmodel as follows:
public class ParticipantViewModel
{
Realm RealmInstance
public ParticipantViewModel()
{
RealmInstance = Realms.Realm.GetInstance();
RefreshParticipants();
}
private async Task RefreshParticipants()
{
//I have code here that GETS the list of Participants from an API and saves to the device.
//I am using the above-defined RealmInstance to save to IQueryable<Participant> Participants
}
}
All the above works fine and I have no issues with this. In the same viewmodel, I am also able to fire up the ZXing Scanner and scan a bar code representing a RegistrationCode.
This, in turn, populates the below property (also in the viewmodel) once scanned...
private ZXing.Result result;
public ZXing.Result Result
{
get { return result; }
set { Set(() => Result, ref result, value); }
}
and calls the below method (wired up via the ScanResultCommand) to fetch the participant bearing the scanned RegistrationCode.
private async Task ScanResults()
{
if (Result != null && !String.IsNullOrWhiteSpace(Result.Text))
{
string regCode = Result.Text;
await CloseScanner();
SelectedParticipant = Participants.FirstOrDefault(p => p.RegistrationCode.Equals(regCode, StringComparison.OrdinalIgnoreCase));
if (SelectedParticipant != null)
{
//Show details for the scanned Participant with regCode
}
else
{
//Display not found message
}
}
}
I keep getting the below error....
System.Exception: Realm accessed from incorrect thread.
generated by the line below....
SelectedParticipant = Participants.FirstOrDefault(p => p.RegistrationCode.Equals(regCode, StringComparison.OrdinalIgnoreCase));
I'm not sure how this is an incorrect thread but any ideas on how I can get around to fetching the scanned participant either from the already populated IQueryable or from the Realm representation directly would be greatly appreciated.
Thanks
Yes, you're getting a realm instance in the constructor, and then using it from an async task (or thread). You can only access a realm from the thread in which you obtained the reference. Since you're only using a default instance, you should be able to simply obtain a local reference within the function (or thread) where you use it. Try using
Realm LocalInstance = Realms.Realm.GetInstance();
at the top of the function and use that. You'll need to recreate the Participants query to use the same instance as its source too. This will be the case wherever you use async tasks (threads), so either change all to get hold of the default instance on entry or reduce the number of threads that access the realm.
Incidentally I'm surprised you don't get a similar access error from within
RefreshParticipants() - maybe you're not actually accessing data via RealmInstance from there.
I just read this post by Dave Ward (http://encosia.com/using-jquery-to-post-frombody-parameters-to-web-api/), and I'm trying to throw together a simple web api controller that will accept a viewmodel, and something just isn't clicking for me.
I want my viewmodel to be an object with a couple DateTime properties:
public class DateRange
{
public DateTime Start { get; set; }
public DateTime End { get; set; }
}
Without changing anything in the stock web api project, I edit my values controller to this:
public IEnumerable<float> Get()
{
DateRange range = new DateRange()
{
Start = DateTime.Now.AddDays(-1),
End = DateTime.Now
};
return Repo.Get(range);
}
// GET api/values/5
public IEnumerable<float> Get(DateRange id)
{
return Repo.Get(range);
}
However, when I try to use this controller, I get this error:
Multiple actions were found that match the request:
System.Collections.Generic.IEnumerable1[System.Single] Get() on type FEPIWebService.Controllers.ValuesController
System.Collections.Generic.IEnumerable1[System.Single] Get(FEPIWebService.Models.DateRange) on type FEPIWebService.Controllers.ValuesController
This message appears when I hit
/api/values
or
/api/values?start=01/01/2013&end=02/02/2013
How can I solve the ambiguity between the first and second get actions?
For further credit, if I had this action
public void Post(DateRange value)
{
}
how could I post the Start and End properties to that object using jQuery so that modelbinding would build up the DateRange parameter?
Thanks!
Chris
The answer is in detail described here: Routing and Action Selection. The Extract
With that background, here is the action selection algorithm.
Create a list of all actions on the controller that match the HTTP request method.
If the route dictionary has an "action" entry, remove actions whose name does not match this value.
Try to match action parameters to the URI, as follows:
For each action, get a list of the parameters that are a simple type, where the binding gets the parameter from the URI. Exclude
optional parameters.
From this list, try to find a match for each parameter name, either in the route dictionary or in the URI query string. Matches are
case insensitive and do not depend on the parameter order.
Select an action where every parameter in the list has a match in the URI.
If more that one action meets these criteria, pick the one with the most parameter matches.
4.Ignore actions with the [NonAction] attribute.
Other words, The ID parameter you are using, is not SimpleType, so it does not help to decide which of your Get methods to use. Usually the Id is integer or guid..., then both methods could live side by side
If both of them would return IList<float>, solution could be to omit one of them:
public IEnumerable<float> Get([FromUri]DateRange id)
{
range = range ?? new DateRange()
{
Start = DateTime.Now.AddDays(-1),
End = DateTime.Now
};
return Repo.Get(range);
}
And now both will work
/api/values
or
/api/values?Start=2011-01-01&End=2014-01-01
I have an EF object called SportDivision. For simplicity's sake, I won't include every field, just the ones that are relevant:
[Table("SportDivision", Schema = "dbo")]
public class SportDivision: BaseReferenceEntity
{
public int Id { get; set; }
public string Name { get; set; }
public int SportId { get; set; }
[ForeignKey("SportId")]
public virtual Sport Sport { get; set; }
}
So it has a SportId and it's a foreign key that points to the table Sport.
Now, I can't just use an EF object in my views, so I have a model class that's mapped to SportDivision called SportDivisionModel:
public class SportDivisionModel: BaseReferenceModel
{
public int Id { get; set; }
public string Name { get; set; }
public int SportId { get; set; }
//Read only fields
public string Sport { get; set; }
}
I use automapper to transfer data from SportDivision to SportDivisionModel and vice versa. The mapping looks like this:
Mapper.CreateMap<SportDivision, SportDivisionModel>()
.ForMember(x => x.Sport, c => c.MapFrom(e => e.Sport.Name));
Mapper.CreateMap<SportDivisionModel, SportDivision>();
And I have a genericized service that CRUDs and translates data from entity to model or model to entity. Everything works fine except on Create, of which the function is shown below:
public TModel Create<TModel, TEntity>(TModel entry)
where TModel : BaseReferenceModel
where TEntity : BaseReferenceEntity
{
var dm = ServiceLocator.Current.GetInstance<ICrudService<TEntity>>();
var raw = Mapper.Map<TModel, TEntity>(entry);
var created = dm.CreateOrUpdate(raw);
return Mapper.Map<TEntity, TModel>(dm.FindById(created.Id));
}
In the very last line, where you see dm.FindById(created.Id), it returns a SportDivisionModel object with no Sport name. A null reference exception is found in .ForMember(x => x.Sport, c => c.MapFrom(e => e.Sport.Name));. It didn't load Sport after the entry was just created in the database.
I've debugged the code, and I see that the entry with a valid SportId is entered into the SportDivision table of my database, but when I try and bring it over to my MVC application, it doesn't get all the information.
This only is an issue on create. If I simply get data from the database without creating it beforehand, or if I edit the information, then the Sport field in my model object does get populated. I don't know why this is happening, and I can't use the .Include in my generic service call (because not all BaseReferenceEntity classes have a foreign key pointing to Sport).
Please advise. Thanks in advance.
I must play Sherlock Holmes and try to derive what could be the content of CreateOrUpdate and FindById from the indications in your question:
You say that you don't use Include because of the generic service. I assume that you also don't use explicit loading (Load) because you would face the same problem that you cannot really make it generic.
Conclusion: Because the Sport navigation property in the SportDivision gets loaded in certain scenarios (Edit) this can only happen due to lazy loading. The conclusion is backed by the fact that the Sport property is marked as virtual.
Lazy loading relies on proxies. If your SportDivision entity is a proxy then
either loading the Sport entity works
or you get an exception telling you that the context is already disposed (if you have disposed the context)
Number 2 is not the case -> Conclusion: Number 1 must be the case if the pre-condition is fulfilled
But Number 1 also isn't the case (loading Sport does not work)
Conclusion: The pre-condition that your SportDivision entity is a proxy is not true.
So: SportDivision is not a proxy. Could this mean that you have lazy loading in the context disabled? No: Because you are saying that editing works it means that when you load entities from the database they are loaded as proxies and support lazy loading.
Editing works, lazy loading isn't disabled but creating a new entity does not work in the way that the Sport entity is loaded when you proceed to use the newly created entity.
Conclusion: Your newly created entity (returned from CreateOrUpdate) is not a proxy and CreateOrUpdate looks similar to this:
public TEntity CreateOrUpdate(TEntity raw) where TEntity : class
{
if (blabla)
; //update
else
{
context.Set<TEntity>().Add(raw);
context.SaveChanges();
return raw;
}
}
and FindById is just:
public TEntity FindById(int id)
{
return context.Set<TEntity>().Find(id);
}
Since you are passing raw directly into the Add method of the DbSet<T> the question raises where does raw come from and how is it created.
Obviously AutoMapper creates the entity after this line: var raw = Mapper.Map<TModel, TEntity>(entry);
How does Automapper create an entity? Probably by calling new TEntity or by using some reflection code like Activator.CreateInstance or...
It doesn't really matter how, but for sure AutoMapper doesn't instantiate an Entity Framework proxy which had to be created by:
var entity = context.Set<TEntity>().Create();
If all this is true, I feel totally screwed by AutoMapper and generic excesses. If all this wouldn't be generic we could solve the problem by:
context.Set<SportDivision>().Add(raw);
context.SaveChanges();
context.Entry(raw).Reference(r => r.Sport).Load();
Instead we must try some ugly tricks now:
context.Set<TEntity>().Add(raw);
context.SaveChanges();
context.Entry(raw).State = EntityState.Detached;
// We hope that raw is now really out of the context
raw = context.Set<TEntity>().Find(raw.Id);
// raw must be materialized as a new object -> Hurray! We have a proxy!
return raw;
(I'm really not sure if the Detached trick above does work. Aside from that you are forced to reload an entity from the database you just have created and saved which is stupid somehow.)
Potential trick number 2 (without reloading from DB but for the price of being a further step more ugly):
context.Set<TEntity>().Add(raw);
context.SaveChanges();
context.Entry(raw).State = EntityState.Detached;
// We hope that raw is now really out of the context
var anotherRaw = context.Set<TEntity>().Create(); // Proxy!
anotherRaw.Id = raw.Id;
context.Set<TEntity>().Attach(anotherRaw);
context.Entry(anotherRaw).CurrentValues.SetValues(raw);
context.Entry(anotherRaw).State = EntityState.Unchanged;
return anotherRaw; // Proxy! Lazy loading will work!
Does AutoMapper have a feature of a "custom allocator or instantiator" and can custom user data (a context) be supplied? Then there would be a chance to let AutoMapper call context.Set<TEntity>().Create();. Or is it possible to instantiate the object by hand, pass it to AutoMapper and AutoMapper just updates the object's properties?
BTW: The line...
context.Entry(anotherRaw).CurrentValues.SetValues(raw);
...is kind of EF's built-in "AutoMapper". The parameter of SetValues is a general System.Object (could be your ...Model object) and the method maps property values from the supplied object to properties of attached entities by identical property names. Maybe you can leverage this feature somehow instead of using the mapping from model to entity done by AutoMapper.