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How to partial update mongodb document in Web Api Patch request

I want to partial update fileds of my document that changed in the patch request and in every request the field probably changed for example one time Balance will be charged another time AccountHolder and others.
I want to update each specific field in single method not create a method for the number of fields .
Note: there is nothing in IDto interface, I use it just for separating Dtos from other classes.
UpdateAccountDto.cs
public class UpdateAccountDto : IDto
{
public string Id { get; set; } = string.Empty;
public string AccountId { get; set; } = string.Empty;
public string AccountHolder { get; set; } = string.Empty;
public string AccountType { get; set; } = string.Empty;
public decimal Balance { get; set; }
}
Account.cs my entity
public class Account
{
[BsonId]
[BsonRepresentation(BsonType.ObjectId)]
public string Id { get; set; } = string.Empty;
[BsonElement("account_id")]
public string AccountId { get; set; } = string.Empty;
[BsonElement("account_holder")]
public string AccountHolder { get; set; } = string.Empty;
[BsonElement("account_type")]
public string AccountType { get; set; } = string.Empty;
[BsonRepresentation(BsonType.Decimal128)]
[BsonElement("balance")]
public decimal Balance { get; set; }
}
My endpoint
[HttpPatch("UpdatePartialAccount")]
public async Task<ActionResult> UpdatePartialAccount([FromQuery]string id,[FromBody] JsonPatchDocument<UpdateAccountDto>? document)
{
if (document is null)
return BadRequest();
var updateAccountDto = document.ToDto();
document.ApplyTo(updateAccountDto, ModelState);
if (!ModelState.IsValid)
return BadRequest();
var entity = updateAccountDto.ToEntity<Account>();
entity.Id = id;
await _accountRepository.PartialUpdateAsync(entity);
return NoContent();
}
PartialUpdateAsync method
public async Task<UpdateResult> PartialUpdateAsync(Account account)
{
//var filter = Builders<Account>.Filter.Eq(a => a.Id, account.Id);
//var update = Builders<Account>.Update.Set()
//Partial update
}

Your question are actually not very clear, but I guess you may want to know the field settings corresponding to JsonPatchDocument and the operation of updating the Mongodb database.
Regarding the field setting of JsonPatchDocument, you can refer to the official document to use it. For example:
[HttpPatch("UpdatePartialAccount")]
public async Task<ActionResult> UpdatePartialAccount([FromQuery] string id, [FromBody] JsonPatchDocument<UpdateAccountDto>? document)
{
if (document is null)
return BadRequest();
var dto = new UpdateAccountDto() { AccountId = "DAccount1" };
document.ApplyTo(dto, ModelState);
//.....
}
Suppose you do a Replace operation on it:
[
{
"operationType": 2,
"path": "/accountHolder",
"op": "replace",
"value": "TestHolder"
}
]
At this point your dto will become:
Please confirm the content of dto and then match with Account to update the database(I'm not sure how you map to Account, but I used AutoMapper). For example:
public async Task UpdateAsync(Account account)
{
await _account.UpdateOneAsync(c => c.AccountId == account.AccountId, account.AccountHolder);
}
For more operations on updating the database, you can check this link.
Hope this can help you.

Mapping problem, object reference not set to an instance

I got a small problem here. I got a course class and a User. I want to show all the Users inside a Course through the API.
the error i get,
'Object reference not set to an instance of an object.'
And this is my controller method,
var objList = _courseRepo.GetUsers(CourseId);
if (objList == null)
{
return NotFound();
}
var objToShow = new List<ViewCourseDetailsDTO>();
foreach (var obj in objList)
{
objToShow.Add(_mapper.Map<ViewCourseDetailsDTO>(obj));
}
return Ok(objToShow);
The Error i got is inside the Foreach-loop. It says that i need to create an object...
This is how my DTO classes looks like,
public class ViewCourseDetailsDTO
{
public int CourseId { get; set; }
public string CourseTitle { get; set; };
public ICollection<UserDTO>? Users { get; set; } = new List<UserDTO>();
}
And this one,
public class UserDTO
{
public string ID { get; set; }
public string UserName { get; set; }
public string Name { get; set; }
}
Do you think i have to break out the UserDTO somehow? Is it Therefore u think ?
if you want to see my CourseRepository than its here,
public ICollection<Course> GetUsers(int courseId)
{
return _db.Course.Where(c => c.CourseId == courseId).Include(a => a.Users).ToList();
}
Would be really grateful if you could help me out here.

Wohooo I found it, damnit!
On my controller, i forgot to put in mapper here,
public CourseController(ICourseRepository courseRepo, IMapper mapper)
{
_courseRepo = courseRepo;
_mapper = mapper;
}
I had injected it correct at the top but forgot to put it inside there ^

DynamoDB - How to implement Optimistic Locking using ServiceStack.Aws

Currently, I am using ServiceStack.Aws v5.9.0 to communicate with DynamoDB. I have used PutItem for both creating and updating an item without anticipating data loss in case of concurrency handling.
public class Customer
{
[HashKey]
public int CustomerId { get; set; }
[AutoIncrement]
public int SubId { get; set; }
public string CustomerType { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
...//and hundreds of fields here
}
public class CustomerDynamo
{
private readonly IPocoDynamo db;
//Constructor
public CustomerDynamo()
{
var dynamoClient = new AmazonDynamoDBClient(_region);
var entityType = typeof(Customer);
var tableName = entityType.Name;
entityType.AddAttributes(new AliasAttribute(name: tableName));
db = new PocoDynamo(dynamoClient) { ConsistentRead = true }.RegisterTable(tableType: entityType);
}
public Customer Update(Customer customer)
{
customer.ModifiedDate = DateTime.UtcNow;
db.PutItem(customer);
return customer;
}
}
The above Update method is called in every service/async task that needs to update the data of the customer.
Refer to this article of AWS I decided to implement the Optimistic Locking to save my life from the issue of concurrency requests.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBContext.VersionSupport.html
Assume that the VersionNumber will be the key for Optimistic Locking. So I added the VersionNumber into the Customer model.
public class Customer
{
[HashKey]
public int CustomerId { get; set; }
[AutoIncrement]
public int SubId { get; set; }
public string CustomerType { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
...//and hundreds of fields here
[DynamoDBVersion]
public int? VersionNumber { get; set; }
}
The result is VersionNumber not updated while it should be automatically incremented. I think it is just because the PutItem will override the whole existing item. Is this correct?
I think I need to change from PutItem to UpdateItem in the Update method. The question is how can I generate the expression dynamically to be used with the UpdateItem?
Thanks in advance for any help!
Updates:
Thanks #mythz for the useful information about DynamoDBVersion attribute. Then I tried to remove the DynamoDBVersion and using the UpdateExpression of PocoDynamo as below
public Customer Update(Customer customer)
{
customer.ModifiedDate = DateTime.UtcNow;
var expression = db.UpdateExpression<Customer>(customer.CustomerId).Set(() => customer);
expression.ExpressionAttributeNames = new Dictionary<string, string>()
{
{ "#Version", "VersionNumber" }
};
expression.ExpressionAttributeValues = new Dictionary<string, AttributeValue>()
{
{ ":incr", new AttributeValue { N = "1" } },
{ ":zero", new AttributeValue { N = "0" } }
};
expression.UpdateExpression = "SET #Version = if_not_exists(#Version, :zero) + :incr";
if (customer.VersionNumber.HasValue)
{
expression.Condition(c => c.VersionNumber == customer.VersionNumber);
}
var success = db.UpdateItem(expression);
}
But the changes are not saved except the VersionNumber

The [DynamoDBVersion] is an AWS Object Persistence Model attribute for usage with AWS's DynamoDBContext not for PocoDynamo. i.e. the only [DynamoDB*] attributes PocoDynamo utilizes are [DynamoDBHashKey] and [DynamoDBRangeKey] all other [DynamoDB*] attributes are intended for AWS's Object Persistence Model libraries.
When needed you can access AWS's IAmazonDynamoDB with:
var db = new PocoDynamo(awsDb);
var awsDb = db.DynamoDb;
Here are docs on PocoDynamo's UpdateItem APIs that may be relevant.

Separate Model with List

I want to return a list of links to a web page when it loads. Right now I have a model called SsoLink.cs bound to the page. I would like to return a list, so I have created another model called SsoLinks.cs that has a List. In my helper function, I keep getting "object not set to an instance of an object".
SsoLink.cs
public class SsoLink
{
public enum TypesOfLinks
{
[Display(Name="Please Select a Type")]
Types,
Collaboration,
[Display(Name="Backups & Storage")]
Backups_Storage,
Development,
[Display(Name="Cloud Services")]
Cloud_Services,
[Display(Name="Human Resources")]
Human_Resources,
Analytics
}
public string Id { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public string Owner { get; set; }
public string OwnerEmail { get; set; }
public string LinkDescription { get; set; }
public TypesOfLinks LinkType { get; set; }
}
SsoLinks.cs
public class SsoLinks
{
public List<SsoLink> Links {get; set;}
}
GetLinksHelper.cs
public partial class SsoLinkHelper
{
public static SsoLinks GetLinks()
{
var ssoList = new SsoLinks();
try
{
//search the index for all sso entries
var searchResponse = _client.Search<SsoLink>(s => s
.Index(_ssoLinkIndex)
.Size(500)
.Query(q => q
.MatchAll()
)
);
if (searchResponse.Documents.Count == 0)
{
return ssoList;
}
ssoList.Links.AddRange(searchResponse.Hits.Select(hit => new SsoLink() {Id = hit.Source.Id, Name = hit.Source.Name, Url = hit.Source.Url, Owner = hit.Source.Owner}));
return ssoList;
}
catch (Exception e)
{
Log.Error(e, "Web.Helpers.SsoLinkHelper.GetLinks");
return ssoList;
}
}
}
While debugging, It is failing at SsoLinks.Links.AddRange(etc). How can I add a new SsoLink to the ssoList for every item found in my query?
Edit: Here is a screenshot of the error while debugging.

The null reference exception looks like it comes from ssoList.Links being null when calling AddRange on it, so it needs to be initialized to a new instance of List<SsoLink> before calling AddRange().

Russ's answer led me down the right path, I ended up just needing to change my view to:
#model List<SharedModels.Models.SsoLink>
rather than
#model SharedModels.Models.SsoLink
and do away with the SsoLinks model.

How to query LIST by passing parameter?

I am using Entity Framework 5.0 and I created my database from model. The below is the screenshot of the edmx diagram.
I am working towards to a below structure of data:
On given Client ID give me list of Theader which belongs to that ClientID and its TReports so I modeled my models as below:
public class TReportHeaderModel
{
public int ID { get; set; }
public int ClientID { get; set; }
public string THeaderTitle { get; set; }
public int RowNumber { get; set; }
public IList<TReportModel> TReports { get; set; }
}
public class TReportModel
{
public int ID { get; set; }
public string TReportName { get; set; }
public string URL { get; set; }
public int RowNumber { get; set; }
}
So when I query to get Theaders and its each report for given clientID:
I am listing the headers first for given clientID:
public IList<TReportHeaderModel> GetHeadersByClient(int ClientID)
{
using (var connection = new TReportEntitiesConnection())
{
var clientHeaders= (from st in connection.THeaders
where ClientID == st.ClientID
select new TReportHeaderModel
{
ID=st.ID,
THeaderTitle=st.THeaderTitle,
RowNumber=st.RowNumber
}).ToList();
return (clientHeaders);
}
}
And then to get the list of reports for each title and this is where I am stuck--->
public IList<TReportModel> GetChildReportsByHeader(int THeaderID)
{
using (var connection = new TReportEntitiesConnection())
{
// ....
}
}
Instead of separating it by get the headers by client first and then get the report by header id, is it possible to combine it in one method? sorry for the confusing explanation but I am new to LINQ Query so please understand.
The below is the ideal structure for the UI implemetation:
Client ID =2
Header 1
TReportName
URL
Header 2
TReportName
URL

is it possible to combine it in one method?
If I understand you correctly, this is what you're looking for:
using (var connection = new TReportEntitiesConnection())
{
var clientHeaders = (
from st in connection.THeaders
where ClientID == st.ClientID
select new TReportHeaderModel
{
ID=st.ID,
THeaderTitle = st.THeaderTitle,
RowNumber = st.RowNumber,
Reports = from r in st.TReports
select new TReportModel
{
ID = r.ID,
TReportName = r.TReportName,
URL = r.URL,
RowNumber = r.RowNumber,
}
}
).ToList();
}
return clientHeaders;
Note that for this to work, TReportHeaderModel.TReports should be IEnumerable<TReportModel>.

Normally I would suggest you separate the methods for getting your data and transforming your data into DTOs like this (And usually I have the connection defined at the class level, not at the method level because I will reuse the connection many times, and I prefer keeping my data accesses as lazy as possible):
TReportEntitiesConnection conn = new TReportEntitiesConnection();
Then I will create extension methods like so:
public static class MyExtensions
{
public IQueryable<THeader> ByClientId(this IQuerable<THeader> conn, int ClientID)
{
return conn
.Include(h=>h.Reports)
.Where(h=>h.ClientID==ClientID);
}
public TReportHeaderModel ToDto(this THeader t)
{
return new TReportHeaderModel
{
ID=t.ID,
ClientID=t.ClientID,
THeaderTitle=t.THeaderTitle,
RowNumber=t.RowNumber,
Reports=t.Reports.ToDto()
};
}
public TReportModel ToDto(this TReport r)
{
return new TReportModel
{
ID=r.ID,
TReportName=r.TReportName,
URL=r.URL,
RowNumber=r.RowNumber
};
}
public IEnumerable<TReportHeaderModel> ToDto(this IEnumerable<THeader> h)
{
return h.Select(x=>x.ToDto());
}
public IEnumerable<TReportModel> ToDto(this IEnumerable<TReport> r)
{
return r.Select(x=>x.ToDto());
}
}
Then you can use it like so:
var result=conn.THeaders.ByClientId(200).ToDto();
If you prefer not having your connection at the module level, that is easy too:
using(var connection = new TReportEntitiesConnection())
{
var result=connection.THeaders.ByClientId(200).ToDto();
}
(or use AutoMapper and skip all the manual Dto conversions)