I am trying to update a row in a (typed) MongoDB collection with the C# driver. When handling data of that particular collection of type MongoCollection<User>, I tend to avoid retrieving sensitive data from the collection (salt, password hash, etc.)
Now I am trying to update a User instance. However, I never actually retrieved sensitive data in the first place, so I guess this data would be default(byte[]) in the retrieved model instance (as far as I can tell) before I apply modifications and submit the new data to the collection.
Maybe I am overseeing something trivial in the MongoDB C# driver how I can use MongoCollection<T>.Save(T item) without updating specific properties such as User.PasswordHash or User.PasswordSalt? Should I retrieve the full record first, update "safe" properties there, and write it back? Or is there a fancy option to exclude certain fields from the update?
Thanks in advance
Save(someValue) is for the case where you want the resulting record to be or become the full object (someValue) you passed in.
You can use
var query = Query.EQ("_id","123");
var sortBy = SortBy.Null;
var update = Update.Inc("LoginCount",1).Set("LastLogin",DateTime.UtcNow); // some update, you can chain a series of update commands here
MongoCollection<User>.FindAndModify(query,sortby,update);
method.
Using FindAndModify you can specify exactly which fields in an existing record to change and leave the rest alone.
You can see an example here.
The only thing you need from the existing record would be its _id, the 2 secret fields need not be loaded or ever mapped back into your POCO object.
It´s possible to add more criterias in the Where-statement. Like this:
var db = ReferenceTreeDb.Database;
var packageCol = db.GetCollection<Package>("dotnetpackage");
var filter = Builders<Package>.Filter.Where(_ => _.packageName == packageItem.PackageName.ToLower() && _.isLatestVersion);
var update = Builders<Package>.Update.Set(_ => _.isLatestVersion, false);
var options = new FindOneAndUpdateOptions<Package>();
packageCol.FindOneAndUpdate(filter, update, options);
Had the same problem and since I wanted to have 1 generic method for all types and didn't want to create my own implementation using Reflection, I end up with the following generic solution (simplified to show all in one method):
Task<bool> Update(string Id, T item)
{
var serializerSettings = new JsonSerializerSettings()
{
NullValueHandling = NullValueHandling.Ignore,
DefaultValueHandling = DefaultValueHandling.Ignore
};
var bson = new BsonDocument() { { "$set", BsonDocument.Parse(JsonConvert.SerializeObject(item, serializerSettings)) } };
await database.GetCollection<T>(collectionName).UpdateOneAsync(Builders<T>.Filter.Eq("Id", Id), bson);
}
Notes:
Make sure all fields that must not update are set to default value.
If you need to set field to default value, you need to either use DefaultValueHandling.Include, or write custom method for that update
When performance matters, write custom update methods using Builders<T>.Update
P.S.: It's obviously should have been implemented by MongoDB .Net Driver, however I couldn't find it anywhere in the docs, maybe I just looked the wrong way.
Well there are many ways to updated value in mongodb.
Below is one of the simplest way I choose to update a field value in mongodb collection.
public string UpdateData()
{
string data = string.Empty;
string param= "{$set: { name:'Developerrr New' } }";
string filter= "{ 'name' : 'Developerrr '}";
try
{
//******get connections values from web.config file*****
var connectionString = ConfigurationManager.AppSettings["connectionString"];
var databseName = ConfigurationManager.AppSettings["database"];
var tableName = ConfigurationManager.AppSettings["table"];
//******Connect to mongodb**********
var client = new MongoClient(connectionString);
var dataBases = client.GetDatabase(databseName);
var dataCollection = dataBases.GetCollection<BsonDocument>(tableName);
//****** convert filter and updating value to BsonDocument*******
BsonDocument filterDoc = BsonDocument.Parse(filter);
BsonDocument document = BsonDocument.Parse(param);
//********Update value using UpdateOne method*****
dataCollection.UpdateOne(filterDoc, document);
data = "Success";
}
catch (Exception err)
{
data = "Failed - " + err;
}
return data;
}
Hoping this will help you :)
Related
How i can combine type C# filled model and mongo language for create update request?
i try this but get types error:
var update = new ObjectUpdateDefinition<User>(user) & Builders<User>.Update.Inc(f => f.FindCount, 1);
FullCode:
var user = new Model
{
Email = email,
Language = language,
Password = password,
// +17 fields
};
// how i can convert all fields to set? and join with query Inc (like AllFieldToSet)?
var update = user.AllFieldToSet() & Builders<User>.Update.Inc(f => f.FindCount, 1);
Models.FindOneAndUpdate<Model>(
f => f.Email == email,
update,
new FindOneAndUpdateOptions<Model> {IsUpsert = true});
Firstly I would begin to ask why do you update so many fields at once, this can have a significant effect on performance and scalability, especially when your collection has indexes, replication and/or sharding involved. Whenever you have to update an indexed field it needs to update the index as well.
There are multiple solutions:
ReplaceOne:
Inc only increments the value, this can be done manually in the model: FindCount++
Manually build the update operator: Just manually build using the builder they provided
Write your own extension using reflection Personally I like type safety but you can use this extension that I wrote (you will just have to extend it and build in null checks, etc.)
public static class UpdateBuilderExtensions
{
public static UpdateDefinition<TDocument> SetAll<TDocument, TModel>(this UpdateDefinition<TDocument> updateBuilder, TModel value, params string[] excludeProperties)
{
foreach (var property in value.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance).Where(x => excludeProperties?.Contains(x.Name) == false))
updateBuilder = Builders<TDocument>.Update.Combine(updateBuilder.Set(property.Name, property.GetValue(value)));
return updateBuilder;
}
}
Usage of it:
You have to exclude properties that have been set already and you have to exclude the BsondId field (if you do not set it manually)
var update = Builders<User>.Update.Inc(x => x.FindCount, 1).SetAll(model, nameof(model.Id), nameof(model.FindCount));
Models.UpdateOne(x => x.Email== "some-email", update, new UpdateOptions
{
IsUpsert = true
});
My result set is not sorting. How do I set up OrderBy for type System.Linq.GroupedEnumerable
I've converted an application from Core 1.1 to 2.2. Everything ported over fine except one piece of logic that:
1) takes a response from a service call maps it to a GroupedEnumerable
2) takes the grouped set and passes it to a function that maps it to an object of type System.Linq.Enumerable.SelectEnumerableIterator.
The resulting object is properly populated but not sorted. I have tried the order by in the function parameter call and as a separate process afterwards.
//response = {myService.myClient.SearchNominationsResponse}
//groupedSet = {System.Linq.GroupedEnumerable<ServiceClients.myClient.NominationObject, long>}
//result = {System.Linq.Enumerable.SelectEnumerableIterator<System.Linq.IGrouping<long, ServiceClients.myClient.NominationObject>, app.ViewModels.EvaluationSummary>}
public IEnumerable<EvaluationSummary> GetEvaluationSummaries(string sortBy, string sortOrder, Filter filter = null)
{
var request = Mapper.MapSearchNominationRequest(filter);
request.IsDetailed = false;
var response = myService.SearchNominationsAsync(request).GetAwaiter().GetResult();
var groupedSet = response.mySet.GroupBy(n => n.SetId);
// I get a proper result but it is not sorted
var result = groupedSet.Select(
g => Mapper.MapEvaluationSummary(
g.OrderBy(g2 => sortBy + " " + sortOrder)
.Last()));
// Still not sorting
result = result.OrderBy(r => sortBy + sortOrder);
return result;
}
public EvaluationSummary MapEvaluationSummary(SetObject setIn)
{
var eval = new EvaluationSummary
{
setDate = setIn.Date,
setId = setIn.Id,
setTypeId = setIn.TypeId,
setTypeDescription = setIn.TypeDescription,
setStatusId = setIn.StatusId,
setStatusDescription = setIn.StatusDescription,
setBy = setIn.Manager,
setEmployee = setIn.employee
};
}
So in my view I have columns that list Date, Id, setEmployee. I can click on these values to issue a sort pattern and I can see that the sortBy and sortOrder variables are being passed in with proper values but the sorting is not happening.
I expect 'William' to appear before 'Bill' and then Bill to appear before 'William' when toggling the employee column header in my view.
Based off of the previous answers, I'm still not sure if I can substitute a property name in the LINQ with a variable. To fix my problem and move on I've implemented JS logic to sort my table headers. We had a custom JS that we use to format tables in our apps but it seems the sort functionality never worked. Anyway not an answer to my question but this is how I solved the problem:
Logic can be found at:
http://www.kryogenix.org/code/browser/sorttable/
-HaYen
I have a Mongo database with lots of documents. All of the documents have a field called "source" which contains the origin name for the document. But a lot of old documents have this field containing "null" (because I hadn't have source by that time) string value. I want to select all those documents and fix this problem by replacing their "source = "null"" values by new values parsed from another fields of the aforementioned documents.
Here's what I'm doing to fix the this:
public void FixAllSources() {
Task.Run(async ()=> {
var filter = Builders<BsonDocument>.Filter.And(new List<FilterDefinition<BsonDocument>>() {
Builders<BsonDocument>.Filter.Exists("url"),
Builders<BsonDocument>.Filter.Ne("url", BsonNull.Value),
Builders<BsonDocument>.Filter.Eq("source", "null")
});
var result = await m_NewsCollection.FindAsync(filter);
var list = result.ToList();
list.ForEach(bson => {
bson["source"] = Utils.ConvertUrlToSource(bson["url"].AsString);
});
});
}
as you can see, I'm fetching all those documents and replacing their source field by a new value. So now I've got a List of correct BsonDocuments which I need to put back into the database.
Unfortunately, I'm stuck on this. The problem is that all of the "Update" methods require filters and I have no idea what filters should I pass there. I just need to put back all those updated documents, and that's it.
I'd appreciate any help :)
p.s.
I've came up with an ugly solution like this:
list.ForEach(bson => {
bson["source"] = Utils.ConvertUrlToSource(bson["url"].AsString);
try {
m_NewsCollection.UpdateOne( new BsonDocument("unixtime", bson["unixtime"]), new BsonDocument {{"$set", bson}},
new UpdateOptions {IsUpsert = true});
}
catch (Exception e) {
WriteLine(e.StackTrace);
}
});
It works for now. But I'd still like to know the better one in case I need to do something like this again. So I'm not putting my own solution as an answer
I need to read certain fields in documents from Mongo. I filtered out a document using the Filter.EQ() method but how can I find and store a field in that document? This is my code:
public void human_radioButton_Checked(object sender, RoutedEventArgs e)
{
Upload human = new Upload(); //opens connection to the database and collection
var filter = Builders<BsonDocument>.Filter.Eq("name", "Human");
race_desc description = new race_desc();
description.desc = Convert.ToString(filter);
desc_textBox.Text = description.desc;
However, this doesn't work since I didn't grab any fields, just the document. So how can I read a field called 'A' and store it into an object?
Thanks
When you define a filter using the Builders<BsonDocument>.Filter here, you merely define a filter that you can use/execute in a query. Much like storing a SQL string in a string variable.
What you missed here is executing the filter and actually retrieve the data. According to Mongodb C# driver doc:
var collection = _database.GetCollection<BsonDocument>("restaurants");
var filter = Builders<BsonDocument>.Filter.Eq("borough", "Manhattan");
var result = await collection.Find(filter).ToListAsync();
Then you can iterate the results and access the properties like
foreach(var result in results)
{
//do something here with result.your_property
}
And if you just want the first of the result
var result = (await collection.Find(filter).ToListAsync()).FirstOrDefault();
Now if you want to cast the BsonDocument you got now to your own class deserialize document using BsonSerializer:
var myObj = BsonSerializer.Deserialize<YourType>(result);
You can also map it to your own class:
var yourClass = new YourType();
yourClass.Stuff= result["Stuff"].ToString();
I can query a single document from the Azure DocumentDB like this:
var response = await client.ReadDocumentAsync( documentUri );
If the document does not exist, this will throw a DocumentClientException. In my program I have a situation where the document may or may not exist. Is there any way to query for the document without using try-catch and without doing two round trips to the server, first to query for the document and second to retrieve the document should it exist?
Sadly there is no other way, either you handle the exception or you make 2 calls, if you pick the second path, here is one performance-driven way of checking for document existence:
public bool ExistsDocument(string id)
{
var client = new DocumentClient(DatabaseUri, DatabaseKey);
var collectionUri = UriFactory.CreateDocumentCollectionUri("dbName", "collectioName");
var query = client.CreateDocumentQuery<Microsoft.Azure.Documents.Document>(collectionUri, new FeedOptions() { MaxItemCount = 1 });
return query.Where(x => x.Id == id).Select(x=>x.Id).AsEnumerable().Any(); //using Linq
}
The client should be shared among all your DB-accesing methods, but I created it there to have a auto-suficient example.
The new FeedOptions () {MaxItemCount = 1} will make sure the query will be optimized for 1 result (we don't really need more).
The Select(x=>x.Id) will make sure no other data is returned, if you don't specify it and the document exists, it will query and return all it's info.
You're specifically querying for a given document, and ReadDocumentAsync will throw that DocumentClientException when it can't find the specific document (returning a 404 in the status code). This is documented here. By catching the exception (and seeing that it's a 404), you wouldn't need two round trips.
To get around dealing with this exception, you'd need to make a query instead of a discrete read, by using CreateDocumentQuery(). Then, you'll simply get a result set you can enumerate through (even if that result set is empty). For example:
var collLink = UriFactory.CreateDocumentCollectionUri(databaseId, collectionId);
var querySpec = new SqlQuerySpec { <querytext> };
var itr = client.CreateDocumentQuery(collLink, querySpec).AsDocumentQuery();
var response = await itr.ExecuteNextAsync<Document>();
foreach (var doc in response.AsEnumerable())
{
// ...
}
With this approach, you'll just get no responses. In your specific case, where you'll be adding a WHERE clause to query a specific document by its id, you'll either get zero results or one result.
With CosmosDB SDK ver. 3 it's possible. You can check if an item exists in a container and get it by using Container.ReadItemStreamAsync<T>(string id, PartitionKey key) and checking response.StatusCode:
using var response = await container.ReadItemStreamAsync(id, new PartitionKey(key));
if (response.StatusCode == HttpStatusCode.NotFound)
{
return null;
}
if (!response.IsSuccessStatusCode)
{
throw new Exception(response.ErrorMessage);
}
using var streamReader = new StreamReader(response.Content);
var content = await streamReader.ReadToEndAsync();
var item = JsonConvert.DeserializeObject(content, stateType);
This approach has a drawback, however. You need to deserialize the item by hand.