What is the most sensible way to save an entry from a public to private database using CloudKit
There is a similar question answered: here, but I didn't quite understand the solution in those words. I don't necessarily need code answers (though always appreciated), but the linked question confused me here:
That recordType would then have a field of type CKReference in which you save your user ID
Does it mean public entry has an array of references to all the users who saved it?
Currently I'm just creating a brand-new entry in the users private database based on the public one they chose to save. When I fetch public items I first query the saved items and cross reference so I can e.g. set the 'star' button to filled or unfilled. It feels very verbose and wrong, I would like to know how people manage this.
Example:
An app with two tabs/views - 'public' and 'private'. The public view is a list of strings (from the public database) and a star icon showing whether the user saved it or not, and the private view shows entries that are saved.
Thanks
Yes, that's their solution. If you want to keep your own, just create a copy of the record in your private db. In my code I create models for each record type with;
let publicDB: CKDatabase
let privateDB: CKDatabase
var saveToDB : CKDatabase
then;
... other code retrieved record R from public DB
now;
saveToDB = privateDB
saveToDB.save(R, completionHandler:
{
(record, error) -> Void in
if (error != nil)
{
// ... error handling...
completion(error)
}
else
{
completion(nil)
}
})
Related
When we pass our DbContext an object whose values have not changed, and try to perform an Update we get a 500 internal server error.
A user may open a dialog box to edit a record, change a value, change it back and then send the record to the database. Also we provide a Backup and Restore function and when the records are restored, some of them will not have changed since the backup was performed.
I was under the impression that a PUT would delete and re-create the record so I didn't feel there would be a problem.
For example, having checked that the Activity exists my ActivityController is as follows:
var activityEntityFromRepo = _activityRepository.GetActivity(id);
// Map(source object (Dto), destination object (Entity))
_mapper.Map(activityForUpdateDto, activityEntityFromRepo);
_activityRepository.UpdateActivity(activityEntityFromRepo);
// Save the updated Activity entity, added to the DbContext, to the SQL database.
if (await _activityRepository.SaveChangesAsync())
{
var activityFromRepo = _activityRepository.GetActivity(id);
if (activityFromRepo == null)
{
return NotFound("Updated Activity could not be found");
}
var activity = _mapper.Map<ActivityDto>(activityFromRepo);
return Ok(activity);
}
else
{
// The save failed.
var message = $"Could not update Activity {id} in the database.";
_logger.LogWarning(message);
throw new Exception(message);
};
My ActivityRepository is as follows:
public void UpdateActivity(Activity activity)
{
_context.Activities.Update(activity);
}
If any of the fields have changed then we don't get the error. Do I have to check every record for equality before the PUT? It seems unnecessary.
Perhaps I have missed something obvious. Any suggestions very welcome.
There is a lot of code missing here.
In your code you call your SaveChangesAsync (not the EF SaveChangesAsync).
Probably (but there is not the code to be sure) your SaveChangesAsync is something that returns false if there is an exception (and is not a good pattern because you "loose" the exception info) or if DbSet.SaveChangesAsync returns 0.
I think (but there is a lot of missing code) that this is your case. If you don't make any changes, SaveChangesAsync returns 0.
EDIT
The System.Exception is raised by your code (last line). EF never throws System.Exception.
I'm having an issue trying to convert an object to json. The error is a Newtonsoft.Json.JsonSerializationException:
Self referencing loop detected for property 'Project' with type 'System.Data.Entity.DynamicProxies.Project_F29F70EF89942F6344C5B0A3A7910EF55268857CD0ECC4A484776B2F4394EF79'. Path '[0].Categories[0]'.
The problem is that the object (it's actually a list of objects) has a property which is another object that refers back to the first object:
public partial class Project
{
...
public virtual ICollection<Category> Categories { get; set; }
...
}
public partial class Category
{
...
public virtual Project Project { get; set; }
...
}
This is all fine and dandy as far as Entity Framework is concerned, but to convert this to json would result in an infinite regress, hence the exception.
Here is my code:
public async Task<HttpResponseMessage> GetProjects()
{
var projects = _projectService.GetProjects().ToList();
string jsonString = JsonConvert.SerializeObject(projects); // <-- Offending line
return Request.CreateResponse(HttpStatusCode.OK, jsonString);
}
I've looked online for solutions to this and I found this stackoverflow post:
JSON.NET Error Self referencing loop detected for type
They suggest three solutions, none of which work:
1) Ignore the circular reference:
public async Task<HttpResponseMessage> GetProjects()
{
var projects = _projectService.GetProjects().ToList();
JsonSerializerSettings settings = new JsonSerializerSettings()
{
ReferenceLoopHandling = ReferenceLoopHandling.Ignore
};
string jsonString = JsonConvert.SerializeObject(projects, settings);
return Request.CreateResponse(HttpStatusCode.OK, jsonString);
}
This resulted in the call to SerializeObject(...) hanging for a bit then throwing a System.OutOfMemoryException (which tells me the circular references were NOT being ignored).
Mind you, the author of this proposed solution at stackoverflow says to set the ignore setting in WebApiConfig.cs but I tried that and it has no effect.
He also says:
"If you want to use this fix in a non-api ASP.NET project, you can add the above line to Global.asax.cs, but first add: var config = GlobalConfiguration.Configuration;"
Mine's a web API with no global file so I shouldn't have to do this.
I also don't want to ignore circular references because I don't want to lose data.
2) Preserve the circular reference:
public async Task<HttpResponseMessage> GetProjects()
{
var projects = _projectService.GetProjects().ToList();
JsonSerializerSettings settings = new JsonSerializerSettings()
{
ReferenceLoopHandling = ReferenceLoopHandling.Serialize,
PreserveReferencesHandling = PreserveReferencesHandling.Objects
};
string jsonString = JsonConvert.SerializeObject(projects, settings);
return Request.CreateResponse(HttpStatusCode.OK, jsonString);
}
This just resulted in the request timing out because it would just hang.
Again, the author says to put this in WebApiConfig.cs, but again this had no effect.
3) Add ignore/preserve reference attributes to the objects and properties:
Ignoring Categories:
public partial class Project
{
...
[JsonIgnore]
public virtual ICollection<Category> Categories { get; set; }
...
}
This has no effect. I hover over the project list and see that it still has categories, and each category still has an instance of the project. I still get the same exception.
Again, even if this worked, I don't want to ignore the categories.
Preserve Categories:
[JsonObject(IsReference = true)]
public partial class Project
{
...
public virtual ICollection<Category> Categories { get; set; }
...
}
Again, same results.
Even if this method worked, the attributes wouldn't be preserved. I'd be doing it on Entity Framework classes which are re-generated automatically every time I recompile. (Is there a way to tell it to set these attributes in the model? Can I set them on the other half of the partial class?)
Alternatively, I'm open to suggestions other than converting to json and sending back in the response. Is there another way to get the data back to the client?
What would be the fix to this problem? Thanks.
Briefly
The best way to fix this problem is to create completely brand-new Models (xxxModel, xxxViewModel, xxxResponse, etc..) on Presentation layer which will be returned to end-users. Than just cast one object to another using AutoMapper or your own custom methods.
Keep your database entities separate from real world!
In detail
There are so many problems that you will encounter:
Disclosure of sensitive data. Your database entity could/will contain sensitive data which end-users shouldn't receive;
Performance issues and waste of RAM and CPU. It would be better to load only those properties that end-users is required, instead all;
Serialization problems. EF entities almost always contain Navigation properties which will be serialized together in case lazy-loading enabled. Imagine dozens related entities, which will be lazy-loaded when your composite root is being serialized. It will cause dozens unexpected requests to database;
Fragility. Any changes related your EF entities will affect on Presentation Layer and on end-users. For instance, in case with API, new added property just extend response, but deleted or renamed will break logic in your customers' application.
There are a lot of other problems, just be careful.
I would recommend not Serializing Entity Framework classes and creating a specific class that only inherits from Object and has only the data you need
After struggling to create Realm object in App Group, I seem to have hit the next issue.
Objects that save into Realm with no issues when in Documents directory does not seem to save when in App Groups.
realm.transactionWithBlock { () -> Void in
let testModel = TestModel(test: "xyz")
self.realm.addObject(testModel)
}
Is this a known issue?
All mutations including adds must happen in a write transaction. Like this:
self.realm.transactionWithBlock() {
self.realm.addObject(testModel)
}
Accessing Out Arguments with WorkflowApplication when wf wait for response(bookmark OR idle) and not complete
I also used Tracking to retrieve the values, but instead of saving it to a database I come up with the following solution.
Make a Trackingparticipant and collect the data from an activity.
You can fine tune the tracking participant profile with a spefic tracking query.
I have added a public property Output to set the value of the data from the record.
public class CustomTrackingParticipant : TrackingParticipant
{
//TODO: Fine tune the profile with the correct query.
public IDictionary<String, object> Outputs { get; set; }
protected override void Track(TrackingRecord record, TimeSpan timeout)
{
if (record != null)
{
if (record is CustomTrackingRecord)
{
var customTrackingRecord = record as CustomTrackingRecord;
Outputs = customTrackingRecord.Data;
}
}
}
}
In your custom activity you can set the values you want to expose for tracking with a CustomTrackingRecord.
Here is a sample to give you an idea.
protected override void Execute(NativeActivityContext context)
{
var customRecord = new CustomTrackingRecord("QuestionActivityRecord");
customRecord.Data.Add("Question", Question.Get(context));
customRecord.Data.Add("Answers", Answers.Get(context).ToList());
context.Track(customRecord);
//This will create a bookmark with the display name and the workflow will go idle.
context.CreateBookmark(DisplayName, Callback, BookmarkOptions.None);
}
On the WorklfowApplication instance you can add the Tracking participant to the extensions.
workflowApplication.Extensions.Add(new CustomTrackingParticipant());
On the persistable idle event from the workflowApplication instance I subscribed with the following method.
In the method I get the tracking participant from the extensions.
Because we have set the outputs in the public property we can access them and set them in a member outside the workflow. See the following example.
private PersistableIdleAction PersistableIdle(WorkflowApplicationIdleEventArgs
workflowApplicationIdleEventArgs)
{
var ex = workflowApplicationIdleEventArgs.GetInstanceExtensions<CustomTrackingParticipant>();
Outputs = ex.First().Outputs;
return PersistableIdleAction.Unload;
}
I hope this example helped.
Even simpler: Use another workflow activity to store the value you are looking for somewhere (database, file, ...) before starting to wait for a response!
You could use Tracking.
required steps would be:
define a tracking profile which queries ActivityStates with the state closed
Implement an TrackingParticipant to save the OutArgument in process memory, a database or a file on disk
hook everything together
The link cotains all the information you will need to do this.
I am trying to make a simple plugin for MS Dynamics CRM 4.0 where send data of a salesorder in a SOAP message on the update of the order.
The strange thing is that I get this error every other time i try to save /(execute the plugin).
So when I update (any field) of a salesorder and then save I get the error:
The given key was not present in the dictionary.
When I save again right away after that(without even changing anything in between the two saves) it executes correctly and gives me all data I want. It is really every time the same thing: first save: error, second save: execute correctly.
Any ideas what this could be?
This is the first part of my code; where it actually gets the dataset of the salesorder in this case:
public class CompleteOrderPlugin : IPlugin
{
public void Execute(IPluginExecutionContext context)
{
DynamicEntity entity = null;
if (context.InputParameters.Properties.Contains(ParameterName.Target) &&
context.InputParameters.Properties[ParameterName.Target] is DynamicEntity)
{
entity = (DynamicEntity)context.InputParameters[ParameterName.Target];
if (entity.Name != EntityName.salesorder.ToString()) { return; }
}
else
{
return;
}
The rest is where I use values from attributes to fill my own variables.
I fixed this by first making a Post Image of the salesorder in the plugin regsitration tool and then using the values in the Post Image instead of the ones comming directly from the salesorder. This I did because on a update you get only the values that actually changed.