Create RavenDB index based on dynamic properties - c#

In RavenDB 4.2, I want to create an Index/Map based on a dynamic object. Better put, on dynamic properties which are not known at compile-time.
Here is an example of the raw JSON I'm ingesting:
{
"id": "A",
"detections":
[
{
"steps": [
{
"object": {
"id": "A1",
"target": {
"domain_name": "foobar.com"
}
},
"object": {
"id": "A2",
"target": {
"ipv4": "127.0.0.1"
}
}
}
]
}
]
}
The above sample is ingested from a 3rd party and stored in a RavenDB collection. Roughly translated, the following model has the challenge:
public class Step
{
public string Id { get; set; }
public DateTime When {get; set;}
public dynamic Object { get; set; } // aware that it's not handy naming
}
The pickle in this is that the object.target.X property name is dynamic. They cannot be strong-typed and can be a lot of things, like: domain_name, ipv4, ipv6, dns, shoe_size, hair_colour etc. This is why the entire steps.object is ingested and stored as either System.Object or dynamic.
My objective is to basically do a SelectMany() on each object.target and extract the property name (key) and value. This would make my RavenDB Index something like this:
public class StepsIndex : AbstractIndexCreationTask<Models.Step, StepsIndex.Result>
{
public class Result
{
public DateTime When { get; set; }
public string TargetKey { get; set; }
public string TargetValue { get; set; }
// ... removed other properties for brevity
}
public StepsIndex()
{
Map = steps =>
from block in blocks
from detection in blocks.Detections
from step in detection.Steps
select new Result
{
// extract property name (key), like 'domain_name'
TargetKey = step.Object.target.GetType().GetProperties()[0].Name,
// extract property value, like 'foobar.com'
TargetValue = step.Object.target.GetType().GetProperty(s.Object.target.GetType().GetProperties()[0].Name).GetValue(s.Object.target, null)
};
}
}
Unfortunately this doesn't work due to step.Object being dynamic and resulting in the following error during compile-time:
Error [CS1963] An expression tree may not contain a dynamic operation
Second option I've tried is to cast it to JSON in the expression, which also fails because Raven's projection is not aware of Newtonsoft.Json during runtime:
// Error CS0103: The name 'JObject' does not exist in the current context
// Error CS0103: The name 'JsonConvert' does not exist in the current context
TargetKey = JObject.Parse(JsonConvert.SerializeObject(ass.Object))["target"][0].Value<string>(),
A third option I thought of was perhaps changing the dynamic Object to System.Object Object, but haven't found a neat way to extract the property key/values without knowning the property.
The question: how can I extract these dynamic property keys and values and Map them to a RavenDB index?

RavenDB allows to index dynamic fields:
See:
https://ravendb.net/docs/article-page/4.2/Csharp/indexes/using-dynamic-fields
https://github.com/ravendb/book/blob/v4.0/Ch10/Ch10.md#dynamic-data

Related

Web API 2 - Implementing a PATCH

I currently have a Web API that implements a RESTFul API. The model for my API looks like this:
public class Member
{
public string FirstName { get; set; }
public string LastName { get; set; }
public DateTime Created { get; set; }
public DateTime BirthDate { get; set; }
public bool IsDeleted { get; set; }
}
I've implemented a PUT method for updating a row similar to this (for brevity, I've omitted some non-relevant stuff):
[Route("{id}")]
[HttpPut]
public async System.Threading.Tasks.Task<HttpResponseMessage> UpdateRow(int id,
[FromBody]Models.Member model)
{
// Do some error checking
// ...
// ...
var myDatabaseEntity = new BusinessLayer.Member(id);
myDatabaseEntity.FirstName = model.FirstName;
myDatabaseEntity.LastName = model.LastName;
myDatabaseEntity.Created = model.Created;
myDatabaseEntity.BirthDate = model.BirthDate;
myDatabaseEntity.IsDeleted = model.IsDeleted;
await myDatabaseEntity.SaveAsync();
}
Using PostMan, I can send the following JSON and everything works fine:
{
firstName: "Sara",
lastName: "Smith",
created: "2018/05/10",
birthDate: "1977/09/12",
isDeleted: false
}
If I send this as my body to http://localhost:8311/api/v1/Member/12 as a PUT request, the record in my data with ID of 12 gets updated to what you see in the JSON.
What I would like to do though is implement a PATCH verb where I can do partial updates. If Sara gets married, I would like to be able to send this JSON:
{
lastName: "Jones"
}
I would like to be able to send just that JSON and update JUST the LastName field and leave all the other fields alone.
I tried this:
[Route("{id}")]
[HttpPatch]
public async System.Threading.Tasks.Task<HttpResponseMessage> UpdateRow(int id,
[FromBody]Models.Member model)
{
}
My problem is that this returns all the fields in the model object (all of them are nulls except the LastName field), which makes sense since I am saying I want a Models.Member object. What I would like to know is if there is a way to detect which properties have actually been sent in the JSON request so I can update just those fields?
I hope this helps using Microsoft JsonPatchDocument:
.Net Core 2.1 Patch Action into a Controller:
[HttpPatch("{id}")]
public IActionResult Patch(int id, [FromBody]JsonPatchDocument<Node> value)
{
try
{
//nodes collection is an in memory list of nodes for this example
var result = nodes.FirstOrDefault(n => n.Id == id);
if (result == null)
{
return BadRequest();
}
value.ApplyTo(result, ModelState);//result gets the values from the patch request
return NoContent();
}
catch (Exception ex)
{
return StatusCode(StatusCodes.Status500InternalServerError, ex);
}
}
Node Model class:
[DataContract(Name ="Node")]
public class Node
{
[DataMember(Name = "id")]
public int Id { get; set; }
[DataMember(Name = "node_id")]
public int Node_id { get; set; }
[DataMember(Name = "name")]
public string Name { get; set; }
[DataMember(Name = "full_name")]
public string Full_name { get; set; }
}
A valid Patch JSon to update just the "full_name" and the "node_id" properties will be an array of operations like:
[
{ "op": "replace", "path": "full_name", "value": "NewNameWithPatch"},
{ "op": "replace", "path": "node_id", "value": 10}
]
As you can see "op" is the operation you would like to perform, the most common one is "replace" which will just set the existing value of that property for the new one, but there are others:
[
{ "op": "test", "path": "property_name", "value": "value" },
{ "op": "remove", "path": "property_name" },
{ "op": "add", "path": "property_name", "value": [ "value1", "value2" ] },
{ "op": "replace", "path": "property_name", "value": 12 },
{ "op": "move", "from": "property_name", "path": "other_property_name" },
{ "op": "copy", "from": "property_name", "path": "other_property_name" }
]
Here is an extensions method I built based on the Patch ("replace") specification in C# using reflection that you can use to serialize any object to perform a Patch ("replace") operation, you can also pass the desired Encoding and it will return the HttpContent (StringContent) ready to be sent to httpClient.PatchAsync(endPoint, httpContent):
public static StringContent ToPatchJsonContent(this object node, Encoding enc = null)
{
List<PatchObject> patchObjectsCollection = new List<PatchObject>();
foreach (var prop in node.GetType().GetProperties())
{
var patch = new PatchObject{ Op = "replace", Path = prop.Name , Value = prop.GetValue(node) };
patchObjectsCollection.Add(patch);
}
MemoryStream payloadStream = new MemoryStream();
DataContractJsonSerializer serializer = new DataContractJsonSerializer(patchObjectsCollection.GetType());
serializer.WriteObject(payloadStream, patchObjectsCollection);
Encoding encoding = enc ?? Encoding.UTF8;
var content = new StringContent(Encoding.UTF8.GetString(payloadStream.ToArray()), encoding, "application/json");
return content;
}
}
Noticed that tt also uses this class I created to serialize the PatchObject using DataContractJsonSerializer:
[DataContract(Name = "PatchObject")]
class PatchObject
{
[DataMember(Name = "op")]
public string Op { get; set; }
[DataMember(Name = "path")]
public string Path { get; set; }
[DataMember(Name = "value")]
public object Value { get; set; }
}
A C# example of how to use the extension method and invoking the Patch request using HttpClient:
var nodeToPatch = new { Name = "TestPatch", Private = true };//You can use anonymous type
HttpContent content = nodeToPatch.ToPatchJsonContent();//Invoke the extension method to serialize the object
HttpClient httpClient = new HttpClient();
string endPoint = "https://localhost:44320/api/nodes/1";
var response = httpClient.PatchAsync(endPoint, content).Result;
Thanks
PATCH operations aren't usually defined using the same model as the POST or PUT operations exactly for that reason: How do you differentiate between a null, and a don't change. From the IETF:
With PATCH, however, the enclosed entity contains a set of
instructions describing how a resource currently residing on the
origin server should be modified to produce a new version.
You can look here for their PATCH suggestion, but sumarilly is:
[
{ "op": "test", "path": "/a/b/c", "value": "foo" },
{ "op": "remove", "path": "/a/b/c" },
{ "op": "add", "path": "/a/b/c", "value": [ "foo", "bar" ] },
{ "op": "replace", "path": "/a/b/c", "value": 42 },
{ "op": "move", "from": "/a/b/c", "path": "/a/b/d" },
{ "op": "copy", "from": "/a/b/d", "path": "/a/b/e" }
]
#Tipx's answer re using PATCH is spot on, but as you've probably already found, actually achieving that in a statically typed language like C# is a non-trivial exercise.
In the case where you're using a PATCH to represent a set of partial updates for a single domain entity (e.g. to update the first name and last name only for a contact with many more properties) you need to do something along the lines of looping each instruction in the 'PATCH' request and then applying that instruction to an instance of your class.
Applying an individual instruction will then comprise of
Finding the property of the instance that matches the name in the
instruction, or handling property names you weren't expecting
For an update: Trying to parse the value submitted in the patch into the instance property and handling the error if e.g. the instance property is a bool but the patch instruction contains a date
Deciding what to do with Add instructions as you can't add new properties to a statically typed C# class. One approach is to say that Add means "set the value of the instance's property only if property's existing value is null"
For Web API 2 on the full .NET Framework the JSONPatch github project looks to make a stab at providing this code, although it doesn't look like there's been a lot of development on that repo recently and the readme does state:
This is still very much an early project, don't use it in production
yet unless you understand the source and don't mind fixing a few bugs
;)
Things are simpler on .NET Core as that has a set of functionality to support this in the Microsoft.AspNetCore.JsonPatch namespace.
The rather useful jsonpatch.com site also lists out a few more options for Patch in .NET:
Asp.Net Core JsonPatch (Microsoft official implementation)
Ramone (a framework for consuming REST services, includes a JSON Patch implementation)
JsonPatch (Adds JSON Patch support to ASP.NET Web API)
Starcounter (In-memory Application Engine, uses JSON Patch with OT for client-server sync)
Nancy.JsonPatch (Adds JSON Patch support to NancyFX)
Manatee.Json (JSON-everything, including JSON Patch)
I need to add this functionality to an existing Web API 2 project of ours, so I'll update this answer if I find anything else that's useful while doing that.
I wanted to achieve exactly the same thing, but used a different method to others described here. I've created a working repo using this if you want to check it out:
https://github.com/emab/patch-example
If you have the following two models:
Database model
public class WeatherDBModel
{
[Key]
public int Id { get; set; }
public string City { get; set; }
public string Country { get; set; }
public double Temperature { get; set; }
public double WindSpeed { get; set; }
public double Rain { get; set; }
public Weather(int id, string city, string country, double temperature, double windSpeed, double rain)
{
Id = id;
City = city;
Country = country;
Temperature = temperature;
WindSpeed = windSpeed;
Rain = rain;
}
}
Update model
Containing exact names of database model properties. Includes properties which can be updated
public class WeatherUpdateModel
{
public string? City { get; set; }
public string? Country { get; set; }
public double Temperature { get; set; }
public double WindSpeed { get; set; }
public double Rain { get; set; }
}
This update model is sent to the service layer along with the id of the object you'd like to update.
You can then implement the following method in your repository layer which maps any non-null values from the updateModel into an existing entity if it has been found:
public Weather Update(int id, WeatherUpdate updateObject)
{
// find existing entity
var existingEntity = _context.Weather.Find(id);
// handle not found
if (existingEntity == null)
{
throw new EntityNotFoundException(id);
}
// iterate through all of the properties of the update object
// in this example it includes all properties apart from `id`
foreach (PropertyInfo prop in updateObject.GetType().GetProperties())
{
// check if the property has been set in the updateObject
// if it is null we ignore it. If you want to allow null values to be set, you could add a flag to the update object to allow specific nulls
if (prop.GetValue(updateObject) != null)
{
// if it has been set update the existing entity value
existingEntity.GetType().GetProperty(prop.Name)?.SetValue(existingEntity, prop.GetValue(updateObject));
}
}
_context.SaveChanges();
return existingEntity;
}
Using this method you can change your models without worrying about the update logic, as long as you ensure that the UpdateModel is kept up-to-date with the database model.
If a property of your object was omitted in your JSON, ASP.NET won't "set" that property on the object, the property will have its default value. In order to know which properties were sent with the JSON object you need to have a way to detect which properties of the object were set.
In order to detect which properties have "actually been sent" with the JSON object, you can modify your Member class to contain a collection of property names that were "set". Then, for all properties that you want to be able to know if they were sent in the JSON object make that when the property is set the name of the property should be added to the collection of set properties.
public class Member
{
private string _firstName;
private string _lastName;
...
private bool _isDeleted;
public string FirstName
{
get => _firstName;
set
{
_firstName = value;
_setProperties.Add(nameof(FirstName));
}
}
public string LastName
{
get => _lastName;
set
{
_lastName = value;
_setProperties.Add(nameof(LastName));
}
}
...
public bool IsDeleted
{
get => _isDeleted;
set
{
_isDeleted= value;
_setProperties.Add(nameof(IsDeleted));
}
}
private readonly HashSet<string> _setProperties = new HashSet<string>();
public HashSet<string> GetTheSetProperties()
{
return new HashSet<string>(_setProperties);
}
}
In the UpdateRow method you can now check whether a property was sent in the JSON by checking if it is in the _setProperties collection. So if you want to see if the LastName was sent in the JSON just do
bool lastNameWasInJson = model.Contains(nameof(model.LastName));
Following up to Avid Learners approach. I found this easy to add to an existing PUT method.
Alternatively to avoid loading twice you could apply update operations and then before saving apply the patch, but I'd rather load twice and have simple code.
public ResultModel Patch(UpdateModel model)
{
var record = LoadAsUpdateModel(model.Id);
if (record == null) return null;
foreach(var propertyName in model.SetProperties())
{
var property = model.GetType().GetProperty(propertyName);
property.SetValue(record, property.GetValue(model));
}
return Update(record);
}

Return JSON from MongoDb without $date

I am using MongoDb with C# in a WebApi app. My data does not lend well to mapped data types due to the dynamic nature of the document stored. For example, here is an example of some data. Note the Data section with values that can either be arrays or a single string (Technician):
{
"_id" : "5a59129d16d5c42f7444b83d",
"CreatedDate" : "2018-01-09T20:30:19.455Z",
"Data" : {
"AlcoholTest" : [
{
"Technician" : [
"STT",
"BAT"
],
"TestReason" : "not well"
}
]
}
}
When I attempt to return the data like above, I get this instead:
{
"_id": {
"$oid": "5a59129d16d5c42f7444b83d"
},
"CreatedDate": {
"$date": 1515529819455
},
"Data": {
"AlcoholTest": [
{
"Technician": [
"STT",
"BAT"
],
"TestReason": "drunk"
}
]
}
}
Here is the code I'm using:
public object FindById(string id)
{
var filter = new BsonDocument { { "_id", ObjectId.Parse(id) } };
var result = _collection2.Find(filter);
var note = result.Any() ? result.First() : null;
var json = note.ToJson(new JsonWriterSettings{OutputMode = JsonOutputMode.Strict});
return JObject.Parse(json);
}
I can't just return the note object since Newtonsoft does not know how to convert those $data and $oid into valid types and returns a parsing error.
When I attempted to use MongoDb mapping classes in .NET, this is what my class looked like (I'm not including the BsonClassMap.RegisterClassMap stuff for simplicity):
public class Note
{
public string Id { get; set; }
public DateTime? CreatedDate { get; set; }
public IDictionary<string, IList<IDictionary<string, object>>> Data { get; set; }
}
When I tried this code, the Newtonsoft did not know how to handle the case where the object in IList<IDictionary<string, object>> could be an array or string and saved some rather nasty JArray and JObject data instead.
So here are my questions:
Is there a way to make the above C# code return identical JSON as what is represented in the Mongo database (or what the UI is sending and expecting to get back)?
Or is there a way to map my Data document using .NET types that would allow me to use MongoDb mapping classes that accepts either string values, arrays, or both?
I ended up using a different approach for save vs get. For saving, I converted a generic object to BsonDocument, and saved it as it. This resulted in the data format I was expecting (first data format my above question).
I used a strongly-typed collection to get data from the MongoDB so I could avoid the second data format from my question above. To get the data returned in the correct format, I changed this property from
public IDictionary<string, IList<IDictionary<string, IList<string>>>> Data { get; set; }
to
public IDictionary<string, object> Data { get; set; }
This gave me the correctly formatted data I needed. Having two MongoDb collections for getting vs saving was not ideal, but it eliminated my original hack to parse the dictionary BsonDocument into my strongly-typed POCO.

Create index with multi field mapping syntax with NEST 2.x

I just can't seem to get the syntax correct for multi field mapping in NEST 2.0--if that's the correct terminology. Every example I've found for mapping seems to be <= the 1.x version of NEST. I'm new to Elasticsearch and NEST, and I've been reading their documentation, but the NEST documentation hasn't been completely updated for 2.x.
Basically, I don't need to index or store the entire type. Some fields I need for indexing only, some fields I'll need to index and retrieve, and some I don't need for indexing, just for retrieval.
MyType
{
// Index this & allow for retrieval.
int Id { get; set; }
// Index this & allow for retrieval.
// **Also**, in my searching & sorting, I need to sort on this **entire** field, not just individual tokens.
string CompanyName { get; set; }
// Don't index this for searching, but do store for display.
DateTime CreatedDate { get; set; }
// Index this for searching BUT NOT for retrieval/displaying.
string CompanyDescription { get; set; }
// Nest this.
List<MyChildType> Locations { get; set; }
}
MyChildType
{
// Index this & allow for retrieval.
string LocationName { get; set; }
// etc. other properties.
}
I've have been able to index the entire object and child as-is using the following as an example:
client.Index(item, i => i.Index(indexName));
However, the actual object is a lot larger than this, and I really don't need most of it. I've found this, which looks like what I think I want to do, but in an older version: multi field mapping elasticsearch
I think "mapping" is what I'm going for, but like I said, I'm new to Elasticsearch and NEST and I'm trying to learn the terminology.
Be gentle! :) It's my first time to ask a question on SO. Thanks!
In addition to Colin's and Selçuk's answers, you can also fully control the mapping through the fluent (and object initializer syntax) mapping API. Here's an example based on your requirements
void Main()
{
var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var connectionSettings = new ConnectionSettings(pool);
var client = new ElasticClient(connectionSettings);
client.Map<MyType>(m => m
.Index("index-name")
.AutoMap()
.Properties(p => p
.String(s => s
.Name(n => n.CompanyName)
.Fields(f => f
.String(ss => ss
.Name("raw")
.NotAnalyzed()
)
)
)
.Date(d => d
.Name(n => n.CreatedDate)
.Index(NonStringIndexOption.No)
)
.String(s => s
.Name(n => n.CompanyDescription)
.Store(false)
)
.Nested<MyChildType>(n => n
.Name(nn => nn.Locations.First())
.AutoMap()
.Properties(pp => pp
/* properties of MyChildType */
)
)
)
);
}
public class MyType
{
// Index this & allow for retrieval.
public int Id { get; set; }
// Index this & allow for retrieval.
// **Also**, in my searching & sorting, I need to sort on this **entire** field, not just individual tokens.
public string CompanyName { get; set; }
// Don't index this for searching, but do store for display.
public DateTime CreatedDate { get; set; }
// Index this for searching BUT NOT for retrieval/displaying.
public string CompanyDescription { get; set; }
// Nest this.
public List<MyChildType> Locations { get; set; }
}
public class MyChildType
{
// Index this & allow for retrieval.
public string LocationName { get; set; }
// etc. other properties.
}
This produces the mapping
{
"properties": {
"id": {
"type": "integer"
},
"companyName": {
"type": "string",
"fields": {
"raw": {
"type": "string",
"index": "not_analyzed"
}
}
},
"createdDate": {
"type": "date",
"index": "no"
},
"companyDescription": {
"type": "string",
"store": false
},
"locations": {
"type": "nested",
"properties": {
"locationName": {
"type": "string"
}
}
}
}
}
Calling .AutoMap() causes NEST to infer the mapping based on the property types and any attributes applied to them. Then .Properties() overrides any of the inferred mappings. For example
CompanyName is mapped as a multi_field with the field companyName analyzed using the standard analyzer and companyName.raw not analyzed. You can reference the latter in your queries using .Field(f => f.CompanyName.Suffix("raw"))
Locations is mapped as a nested type (automapping by default would infer this as an object type mapping). You can then define any specific mappings for MyChildType using .Properties() inside of the Nested<MyChildType>() call.
As far as I can see, you don't have any complex types that you are trying map. So you can easily use NEST attributes to map your objects.
Check this out:
[Nest.ElasticsearchType]
public class MyType
{
// Index this & allow for retrieval.
[Nest.Number(Store=true)]
int Id { get; set; }
// Index this & allow for retrieval.
// **Also**, in my searching & sorting, I need to sort on this **entire** field, not just individual tokens.
[Nest.String(Store = true, Index=Nest.FieldIndexOption.Analyzed, TermVector=Nest.TermVectorOption.WithPositionsOffsets)]
string CompanyName { get; set; }
// Don't index this for searching, but do store for display.
[Nest.Date(Store=true, Index=Nest.NonStringIndexOption.No)]
DateTime CreatedDate { get; set; }
// Index this for searching BUT NOT for retrieval/displaying.
[Nest.String(Store=false, Index=Nest.FieldIndexOption.Analyzed)]
string CompanyDescription { get; set; }
[Nest.Nested(Store=true, IncludeInAll=true)]
// Nest this.
List<MyChildType> Locations { get; set; }
}
[Nest.ElasticsearchType]
public class MyChildType
{
// Index this & allow for retrieval.
[Nest.String(Store=true, Index = Nest.FieldIndexOption.Analyzed)]
string LocationName { get; set; }
// etc. other properties.
}
After this declaration, to create this mapping in elasticsearch you need to make a call similar to:
var mappingResponse = elasticClient.Map<MyType>(m => m.AutoMap());
With AutoMap() call NEST will read your attributes from your POCO and create a mapping request accordingly.
Also see "Attribute Based Mapping" section from here.
Cheers!
At the time of writing, Nest does not offer a way to map a property in your class to multiple fields in your document mapping using built in attributes. However, it does provide the facilities needed to do anything with your mappings that you could do if you wrote the JSON yourself.
Here's a solution I've put together for my own needs. It shouldn't be hard to use it as the starting point for whatever you need to do.
First, here's an example of the mapping I want to generate
{
"product":{
"properties":{
"name":{
"type":"string",
"index":"not_analyzed",
"fields":{
"standard":{
"type":"string",
"analyzer":"standard"
}
}
}
}
}
}
The product document would then have the name field, which is indexed but not analyzed, and the name.standard field, which uses the standard analyzer.
The C# class that I generate the mapping from looks like this
[ElasticsearchType]
public class Product
{
[WantsStandardAnalysisField]
public string Name { get; set; }
}
Note the WantsStandardAnalysisField attribute. That's a custom attribute with no special properties added. Literally just:
public class WantsStandardAnalysisField : Attribute {}
If I were to use AutoMap as-is, my custom attribute would be ignored and I would get a mapping that has the name field, but not name.standard. Luckily, AutoMap accepts an instance of IPropertyVisitor. A base class called NoopPropertyVisitor implements the interface and does nothing at all, so you can subclass it and override only the methods you care about. When you use a property visitor with AutoMap, it will generate a document mapping for you but give you a chance to modify it before it gets sent to Elastic Search. All we need to do is look for properties marked with our custom attribute and add a field to them.
Here's an example that does that:
public class ProductPropertyVisitor : NoopPropertyVisitor
{
public override void Visit(IStringProperty type, PropertyInfo propertyInfo, ElasticsearchPropertyAttributeBase attribute)
{
base.Visit(type, propertyInfo, attribute);
var wsaf = propertyInfo.GetCustomAttribute<WantsStandardAnalysisField>();
if (wsaf != null)
{
type.Index = FieldIndexOption.NotAnalyzed;
type.Fields = new Properties
{
{
"standard",
new StringProperty
{
Index = FieldIndexOption.Analyzed,
Analyzer = "standard"
}
}
};
}
}
}
As you can see, we can do pretty much anything we want with the generated property, including turning off analysis for the main property and adding a new field with its own settings. For fun, you could add a couple properties to the custom attribute allowing you to specify the name of the field you want and the analyzer to use. You could even modify the code to see if the attribute has been added multiple times, letting you add as many fields as you want.
If you were to run this through any method that generates a mapping using AutoMap, such as:
new TypeMappingDescriptor<Product>().AutoMap(new ProductPropertyVisitor())
You'll get the desired multi-field mapping. Now you can customize mappings to your heart's content. Enjoy!
I think you have at least 2 possibilities to solve your problem:
On indexing: Create something like a metadata model, which is stored just for retrieving. See the _source field to limit the return to this field.
On searching: Specify the fields you want to query: if you don`t want to query the CreatedDate, just don't include it in your search.
In my case I am using both of these approaches to get very fast results :-)

ViewModel with dynamic elements

I need to receive the next JSON in .NET
"currentData":
{
"Name": {"system": "wfdss", "canWrite": true },
"DiscoveryDateTime": { "system": "wfdss", "canWrite": true },
"Code": { "system": "code", "canWrite": false },
...
}
This elements are dynamics, it doesn't have default elements, so, how can I define a class doing that following next model:
public class currentData
{
//TODO
//<Data Element Name>: {
//data element system: <STRING of system>,
//the last system to update data element canWrite: <Boolean>
//true if requesting system may edit data element (based on ADS), otherwise false. }, ...
public List<Property> property { get; set; }
}
public class Property
{
public string system { get; set; }
public string canWrite { get; set; }
}
If you need to post dynamic structured Json to controller i have a bad news for you - you can't map it automattically in MVC. MVC model binding mechanism work only with stronly typed collecions - you must know structure.
One of the options that i can suggest you if use FormCollection and manually get values from it:
[HttpPost]
public JsonResult JsonAction(FormCollection collection)
{
string CurrentDataNameSystem = collection["currentData.Name.system"];
// and so on...
return Json(null);
}
Another option is to pass you dynamic json as string and then manually desirialize it:
[HttpPost]
public JsonResult JsonAction(string json)
{
//You probably want to try desirialize it to many different types you can wrap it with try catch
Newtonsoft.Json.JsonConvert.DeserializeObject<YourObjectType>(jsonString);
return Json(null);
}
Anyway my point is - you shouldn't mess with dynamic json unless you really need it in MVC.
I suggest you to creage object type that contain all the passible fields but make it all nullable so you can pass your Json and it will be mapped with Model binding MVC mechanism but some fields will be null.
I think the type format you are getting is an Object with a Dictionary.
So i think you need to Deserialize your Data into this.
public class ContainerObject
{
public Dictionary<String,Property> currentData { get; set; }
}

Alter Json or ExtensionDataObject

I have a Json service I cannot alter as it is not mine.
Their Json is a formatted in a way that parsing it is difficult. It looks something like this.
"people": {
"Joe Bob": {
"name": "Joe Bob",
"id": "12345"
},
"Bob Smith": {
"name": "Bob Smith",
"id": "54321"
}
},
I would really prefer this was laid out like a JSon array, however it presently is not.
I am wondering the best approach here. Should I alter the Json to look like an array before I parse it or load up the ExtensionData and parse it from that?
There are other items in the feed that I do not have issue with. Just stuck with this one section.
Thanks
You can use json.net to deserialize the data (the json you pasted, and doing only one parsing, without modifying anything).
using dynamic foo = JsonConvert.DeserializeObject<dynamic>(data)
than, you can iterate the list using foo.people, accessing the Name and Value.
you can create a class (if you know what the schema is, and to deserialize the data into a list of the given class such as:
public class People
{
[JsonProperty(PropertyName="people")]
public IDictionary<string, Person> Persons { get; set; }
}
public class Person
{
[JsonProperty(PropertyName="name")]
public string Name { get; set; }
[JsonProperty(PropertyName = "id")]
public string Id { get; set; }
}
and than call:
var obj = JsonConvert.DeserializeObject<People>(data);
foreach (var item in obj.Persons.Values)
{
//item is instance of Person
}
Another good and possible option will be:
How can I navigate any JSON tree in c#?

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