I am implementing a custom IBsonSerializer with the official MongoDB driver (C#). I am in the situation where I must serialize and deserialize a Guid.
If I implement the Serialize method as follow, it works:
public void Serialize(BsonWriter bsonWriter, Type nominalType, object value, IBsonSerializationOptions options)
{
BsonBinaryData data = new BsonBinaryData(value, GuidRepresentation.CSharpLegacy);
bsonWriter.WriteBinaryData(data);
}
However I don't want the Guid representation to be CSharpLegacy, I want to use the standard representation. But if I change the Guid representation in that code, I get the following error:
MongoDB.Bson.BsonSerializationException: The GuidRepresentation for the writer is CSharpLegacy, which requires the subType argument to be UuidLegacy, not UuidStandard.
How do I serialize a Guid value using the standard representation?
Old question but in case someone finds it on google like I did...
Do this once:
BsonDefaults.GuidRepresentation = GuidRepresentation.Standard;
For example, in a Web Application/Web API, your Global.asax.cs file is best place to add it once
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
BsonDefaults.GuidRepresentation = GuidRepresentation.Standard;
//Other code...below
}
}
If you don't want to modify the global setting BsonDefaults.GuidRepresentation (and you shouldn't, because modifying globals is a bad pattern), you can specify the setting when you create your collection:
IMongoDatabase db = ???;
string collectionName = ???;
var collectionSettings = new MongoCollectionSettings {
GuidRepresentation = GuidRepresentation.Standard
};
var collection = db.GetCollection<BsonDocument>(collectionName, collectionSettings);
Then any GUIDs written to the collection will be in the standard format.
Note that when you read records from the database, you will get a System.FormatException if the GUID format in the database is different from the format in your collection settings.
It looks like what's happening is when you are not explicitly passing the GuidRepresentation to BsonBinaryData constructor, it defaults to passing GuidRepresentation.Unspecified and that ultimately maps to GuidRepresentation.Legacy (see this line in the source)
So you need to explicitly pass the guidRepresentation as a third argument to BsonBinaryData set to GuidRepresentation.Standard.
edit: As was later pointed out, you can set BsonDefaults.GuidRepresentation = GuidRepresentation.Standard if that's what you always want to use.
Related
Imagine myAPICreate requires a JSON string.
public void put(Collection<SinkRecord> collection) {
for (SinkRecord record : collection) {
JSONObject recordJson = toJSON(record.value());
String recordJsonString = recordJson.toString();
myAPICreate(recordJsonString);
}
}
toJSON is a helper I have defined which just takes the record and returns a JSONObject.
JSONObject json = new JSONObject()
.put("a", record.getString("a"))
.put("b", record.getString("b"))
.put("c", record.getString("c"));
I feel like I might be doing a lot of redundant work here. Is it necessary to have the code in put convert it to JSON or is there a way to use the converters so that record already comes in as JSON or a JSON string? Then I can just pass myAPICreate(record.value().toString()) without having to manually do it?
When you create a SinkRecord, you have a key & value schema w/ a key and value Object. Those objects should be Struct instances that must be created with the matching Schema
In the Connector configuration, you would then use JSONConverter (or other converter) to get the serialized output
With the help of other Stackoverflow users, I have gone some way to my solution but have come to a halt.
I would like to build some generic classes in an app_code .cshtml file eg one would be to return property values from documents from a function eg
public static string docFieldValue(int docID,string strPropertyName){
var umbracoHelper = new Umbraco.Web.UmbracoHelper(Umbraco.Web.UmbracoContext.Current);
var strValue = "";
try{
strValue = umbracoHelper.Content(docID).GetPropertyValue(strPropertyName).ToString();
}
catch(Exception ex){
strValue = "Error - invalid document field name (" + strPropertyName + ")";
}
var nContent = new HtmlString(strValue);
return nContent;
}
This works ok for returning one field (ie property) from a document. However, if I wanted to return 2 or more, ideally, I would store the returned node in a variable or class and then be able to fetch property values repeatedly without having to look up the document with each call
ie without calling
umbracoHelper.Content(docID).GetPropertyValue(strPropertyName).ToString();
with different strPropertyName parameters each time, as I assume that will mean multiple reads from the database).
I tried to build a class, with its properties to hold the returned node
using Umbraco.Web;
using Umbraco.Core.Models;
...
public static Umbraco.Web.UmbracoHelper umbracoHelper = new Umbraco.Web.UmbracoHelper(Umbraco.Web.UmbracoContext.Current);
public static IPublishedContent docNode;
...
docNode = umbracoHelper.Content(docID);
but this crashed the code. Can I store the node in a property on a class, and if so, what type is it?
First of all, using a .cshtml file is unnecessary, use a .cs file instead :-) CSHTML files are for Razor code and HTML and stuff, CS files are for "pure" C#. That might also explain why your last idea crashes.
Second of all, UmbracoHelper uses Umbracos own cache, which means that the database is NOT touched with every request. I would at least define the umbracoHelper object outside of the method (so it gets reused every time the method is called instead of reinitialised).
Also, beware that property values can contain all kinds of other object types than strings.
EDIT
This is an example of the entire class file - my example namespace is Umbraco7 and my example class name is Helpers:
using Umbraco.Web;
namespace Umbraco7
{
public class Helpers
{
private static UmbracoHelper umbracoHelper = new UmbracoHelper(UmbracoContext.Current);
private static dynamic docNode;
public static string docFieldValue(int docID, string strPropertyName)
{
docNode = umbracoHelper.Content(docID);
return docNode.GetPropertyValue(strPropertyName).ToString();
}
}
}
This is an example how the function is called inside a View (.cshtml file inside Views folder):
#Helpers.docFieldValue(1076, "introduction")
Helpers, again, is the class name I chose. It can be "anything" you want. I've just tested this and it works.
I suggest you read up on general ASP.NET MVC and Razor development, since this is not very Umbraco specific.
According to EclipseLink/Examples/JPA/MappingSelectionCriteria I can make some filtering on OneToOne or OneToMany relationships. To do that I have to implement DescriptorCustomizer.
My question is: Can I do some conditional filtering with this technique and how? I mean, in the example of mentioned link we can write something like this
public class ConfigureBsFilter implements DescriptorCustomizer {
public void customize(ClassDescriptor descriptor) throws Exception {
OneToManyMapping mapping = (OneToManyMapping) descriptor
.getMappingForAttributeName("bs");
ExpressionBuilder eb = new ExpressionBuilder(mapping
.getReferenceClass());
Expression fkExp = eb.getField("A_ID").equal(eb.getParameter("A_ID"));
Expression activeExp = eb.get("active").equal(true);
mapping.setSelectionCriteria(fkExp.and(activeExp));
}
}
But what if in the expression
Expression activeExp = eb.get("active").equal(true);
the "active" is not always true but have to be set at runtime by some parameter. Can I do that and how?
Looking at wiki.eclipse.org/Using_Advanced_Query_API_(ELUG) you could use a query redirector on the ForeignReferenceMapping#getSelectionQuery() so that your query redirector can dynamically clone the query and add filters as required. Passing parameters to the redirector will need to be creative though, such as storing them on the thread context or in the session's properties map.
I am trying to initialize an Entity object (ADO.NET EF Object), but it does not allow me to choose what connection string I want to use. I need to change connection string in order to give different access levels to users.
There are no overrides in the Entities Object, just a parameterless constructor.
If anyone can give me any pointers, it is appreciated.
If you have used the designer to generate an .edmx file for you, you will have something like below:
public MyEntities() : base("name=MyEntities", "MyEntities")
{
this.ContextOptions.LazyLoadingEnabled = true;
OnContextCreated();
}
This will by default, get the connection string from your configuration file.
What you could do in this case is set the connection string
public partial class MyEntities
{
partial void OnContextCreated()
{
//Dynamically Building a Connection String
this.Connection.ConnectionString = "myconnectionstring";
}
}
Bear in mind though that this will first use the base constructor to pull the connection string from config, then set it with your custom version, basically overriding the connection string. This is typically good when you always want a default connection string.
Another option if you want a bit more control, is pass the connection string in via the constructor as shown below:
public partial class MyEntities
{
public MyEntities(string connectionString) :
base(connectionString,"MyEntities")
{
this.OnContextCreated();
}
}
Now you are passing in the connection string down to the base class and this is the only one it will use. This does mean however that you will most often need to supply this each time.
Hope this helps...
I want to use EF Code first for a database that I'm currently accessing using plain old ADO.NET with stored procedures.
In my database I have some nvarchar(MAX) columns that should be mapped to and from a Dictionary<string, string>.
When saved to database, it is an XML formatted string. I use this technique to allow internationalization of e.g. a name of a product in an online store. I don't know how many languages any given user want to translate to so I can't have a Name column for each language.
I also wanted to avoid storing the values in a seperate table, so I ended up with the Dictionary - XML approach.
The way I do it now, is to just treat any of these columns as a string whenever I interact with the database. I have a custom mapper function that can turn the XML into a Dictionary, and back to XML.
But I can't seem to find a way to do this with EF Code first? Any ideas?
You can add a property that will return your Dictionary<,> as a XML string and then remove the mapping for your Dictionary<,> property.
[NotMapped]
public Dictionary<string,string> MyDictionary
{
get; set;
}
public string DictionaryAsXml
{
get
{
return ToXml(MyDictionary);
}
set
{
MyDictionary = FromXml(value);
}
}
If you don't want to expose your DictionaryAsXml property have a look at this blog post. It shows how you can persist private and protected properties.
I had some difficulties with the xml conversion in VB.NET. Therefore I took advantage of newtonsoft.json to serialize the dictionary to a JSON string and back.
Public Property JsonDict As String
Get
If MyDict Is Nothing Then
Return Nothing
Else
Return JsonConvert.SerializeObject(MyDict)
End If
End Get
Set(value As String)
If value Is Nothing Then
MyDict = Nothing
Else
MyDict = JsonConvert.DeserializeObject(Of Dictionary(Of Single, Single))(value)
End If
End Set
End Property
<NotMapped>
Public Property MyDict As Dictionary(Of Single, Single)