GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.
It is a single API face for different clients like mobile, desktop apps, tablets. Tests in the test folder. You can add your own GraphQL unit tests to this project.
GraphQL project consists of a MainSchema. In the MainSchema there is QueryContainer that hosts all queries. Out of the box, there are queries for RolesOrganization Units and Users. Mvc projects. So both ASP. Startup for MVC project. There is also GraphQL Playground included in the project. In debug mode, all GraphQL exceptions are being sent to the client but in release mode exceptions are not being sent to the client.
By default, GraphQL is disabled. Core project and set GraphQL. You can change the default endpoint of the GraphQL. To do this, open the Startup. Mvc project for MVC. In the Configure method, find the line app. And set the path parameter like below. It is included AspNet Zero but disabled by default. The default GraphQL Playground endpoints are.
There is also a desktop version of the GraphQL Playground. The desktop app is the same as the web version but includes these additional features:. By default, GraphQL Playground is disabled. To enable it, open WebConsts. GraphQL class. You can change the default endpoint of the GraphQL Playground. To do this, open Startup. Mvc for MVC. To be able to run the queries that requires authentication, you need to open Playground on your browser, open settings tab and change the request.
This is needed for cookie authentication. On the other hand, Playground uses polling to update the schema and refreshes the schema every 2 seconds. You can also safely disable this option to not see flooding XHR requests on your browser's network tab. Playground gives you the advantage of writing the queries with intellisense and see the results on your browser.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.
There I have Tags which have an unique aliasa value which can be of different types and some properties. To take care of the different value types, I have defined an interface containing alias and properties as well as 4 implementations with a differently typed value field. In the interface implementation in CI want to use ResolveType as suggested in the graphql-dotnet getting started docs.
This seems to be because of the 4 constructor parameters in the interface definition which is according to the example in the docs.
If I remove them and return new StringTag etc. I got it working by using the parameterless constructor and returning the resolved object like this:. To be able to resolve your TagInterface type you will need to use some form of Dependency Injection. You may also need to register those Tag types using RegisterType on Schema if they are not publicly exposed somewhere else in your Schema. Often when you are working with an interface type the concrete types are not exposed on the root types or any of their children.
Learn more. Asked 2 years, 5 months ago. Active 1 year, 7 months ago. Viewed 3k times. I am new to GraphQL and I'm currently trying to build an api for a existing library. Bool: return booleanTag; case EDataType. Byte: case EDataType. Sbyte: case EDataType. Short: case EDataType. Ushort: case EDataType. Int: case EDataType. Uint: case EDataType. Long: case EDataType. Ulong: return integerTag; case EDataType.
Double: case EDataType. Float: case EDataType. Bool: return from t in PossibleTypes where t is BooleanTag select t. First ; case EDataType. Ulong: return from t in PossibleTypes where t is IntegerTag select t.On this page, you'll learn all you need to know about the GraphQL type system and how it describes what data can be queried.
Since GraphQL can be used with any backend framework or programming language, we'll stay away from implementation-specific details and talk only about the concepts. If you've seen a GraphQL query before, you know that the GraphQL query language is basically about selecting fields on objects.
So, for example, in the following query:. Because the shape of a GraphQL query closely matches the result, you can predict what the query will return without knowing that much about the server. But it's useful to have an exact description of the data we can ask for - what fields can we select?
What kinds of objects might they return? What fields are available on those sub-objects? That's where the schema comes in. Every GraphQL service defines a set of types which completely describe the set of possible data you can query on that service. Then, when queries come in, they are validated and executed against that schema.
In the GraphQL schema language, we might represent it like this:. The language is pretty readable, but let's go over it so that we can have a shared vocabulary:. Every field on a GraphQL object type can have zero or more arguments, for example the length field below:.
In this case, the length field has one defined argument, unit. Arguments can be either required or optional. When an argument is optional, we can define a default value - if the unit argument is not passed, it will be set to METER by default. Most types in your schema will just be normal object types, but there are two types that are special within a schema:. Every GraphQL service has a query type and may or may not have a mutation type.
These types are the same as a regular object type, but they are special because they define the entry point of every GraphQL query. So if you see a query that looks like:. That means that the GraphQL service needs to have a Query type with hero and droid fields:. Mutations work in a similar way - you define fields on the Mutation type, and those are available as the root mutation fields you can call in your query.
It's important to remember that other than the special status of being the "entry point" into the schema, the Query and Mutation types are the same as any other GraphQL object type, and their fields work exactly the same way. A GraphQL object type has a name and fields, but at some point those fields have to resolve to some concrete data.
That's where the scalar types come in: they represent the leaves of the query. In the following query, the name and appearsIn fields will resolve to scalar types:. We know this because those fields don't have any sub-fields - they are the leaves of the query. In most GraphQL service implementations, there is also a way to specify custom scalar types. For example, we could define a Date type:.
Then it's up to our implementation to define how that type should be serialized, deserialized, and validated. For example, you could specify that the Date type should always be serialized into an integer timestamp, and your client should know to expect that format for any date fields.This tutorial is the continuity of the previous part of this tutorial.
Which can be confirmed from viewing the installed nuget package as shown below:. Now, Finally after doing all this, In Startup. So, that's all we need to do in our coding part.
Here you can see the screen as shown below:. The above screen i. Playground is a place where we can test our query. Let us now try to get the list of users from the server. Here, we are getting the list of users with entities id, name and address. But, what if we need only id, and name Entities.
For that we need to specify it in the request query itself which is shown below:. Here we only got id, and name from the list of users. What if we want to use postman instead? The answer is no we don't. Playground is just for easy testing purpose. If we had to use postman, the same step can be carried out by writing it under raw tab which is shown below:.
NET Core. Thankyou for reading this article. If you encountered with any type of problem with this process. Please feel free to comment in the comment section of this article. Id, type: typeof IdGraphType. Description "Id property from the user object. Description "Name property from the user object. Description "Address property from the user object. AddGraphTypes ServiceLifetime. Scoped. Integrating and Using Identity In Asp. Serialization and Deserialization In C Sharp. Creating Service In C Sharp.For example:.
A Schema is created by supplying the root types of each type of operation, query and mutation optional. A schema definition is then supplied to the validator and executor.
Subscribe to RSS
The leaf values of any request and input values to arguments are Scalars or Enums and are defined with a name and a series of serialization functions used to ensure validity. Almost all of the GraphQL types you define will be object types.
Object types have a name, but most importantly describe their fields. When two types need to refer to each other, or a type needs to refer to itself in a field, you can use a function expression aka a closure or a thunk to supply the fields lazily. Note that resolver functions are provided the source object as the first parameter. However, if a resolver function is not provided, then the default resolver is used, which looks for a method on source of the same name as the field. If found, the method is called with args, context, info.
Since it is a method on sourcethat value can always be referenced with this. When a field can return one of a heterogeneous set of types, a Interface type is used to describe what types are possible, what fields are in common across all types, as well as a function to determine which type is actually used when the field is resolved. When a field can return one of a heterogeneous set of types, a Union type is used to describe what types are possible as well as providing a function to determine which type is actually used when the field is resolved.
Some leaf values of requests and input values are Enums. GraphQL serializes Enum values as strings, however internally Enums can be represented by any kind of type, often integers. Note: If a value is not provided in a definition, the name of the enum value will be used as its internal value. An input object defines a structured collection of fields which may be supplied to a field argument. A list is a kind of type marker, a wrapping type which points to another type. Lists are often created within the context of defining the fields of an object type.
A non-null is a kind of type marker, a wrapping type which points to another type. Non-null types enforce that their values are never null and can ensure an error is raised if this ever occurs during a request. It is useful for fields which you can make a strong guarantee on non-nullability, for example usually the id field of a database row will never be null.
Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have a simple enum I am trying to include in my GraphQL type and am receiving teh following error:. I had a very hard time getting this to work as well. Official documentation definitely seems to be lacking in this regard.
The way I got it to work was based on something I found in this article. One other thing to mention that I ran into with EnumTypes that I wasn't expecting. If you are using an enum as a parameter, do what you did above where you ingest it as an IntGraphType and then cast it to your enum type NewsType category.
If you are going to do that, then the category property on the object passed to the server needs to be a string. Here's a quick way to do this for your case. Basically you don't use the default lambda expression Field. Instead actually write out a resolver yourself and convert the enum to the proper type. This is helping GraphQL to convert the type properly into the type you want to return.
Quick Start Guide
Learn more. Asked 1 year, 1 month ago. Active 4 months ago. Viewed times. Description "Id of a news item. Description "Title of a new item. Description "Description of a news item. Description "Author of a news item. Description "Category of the news item.
GetMostRecent newsType, count. GregH GregH 4, 1 1 gold badge 23 23 silver badges 72 72 bronze badges. Active Oldest Votes. Category ; If your enum was a string, you could do the same for that as well. Hardik Goel Hardik Goel 21 2 2 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.
Post as a guest Name. Email Required, but never shown. The Overflow Blog. Featured on Meta. Feedback on Q2 Community Roadmap. Technical site integration observational experiment live on Stack Overflow. Question Close Updates: Phase 1. Dark Mode Beta - help us root out low-contrast and un-converted bits.This guide will help you get a GraphQL project up and running so you can start experimenting.
We'll cover the following:.
Be sure to include the -AllowPrereleaseVersions flag. NET is still in beta. The properties your model defines are automatically registered as fields on the object graph and can be queried in any order when a Person requested. In GraphQL, we return the object back to GraphQL and let it handle which properties to render to the requestor based on their query.
Here we've chosen to use the special [QueryRoot] attribute to indicate that the action is both a query and exists at the top most level of our object graph. See the section on declaring field paths for a complete set of options and recommendations. We need to register GraphQL to the application instance.
This registers it for dependency injection and sets up the HTTP route to allow it to receive requests. Note: Calling. NET http pipeline.
Be sure to call it at an appropriate point. For instance, if you need authorization support in GraphQL. UseGraphQL will need to be called after. Jump In! Overview Quick Start Code Examples. Introduction What is GraphQL?
Made for ASP. NET Developers.GraphQL Tutorial #13 - Type Relations
Logging Structured Logging Standard Events. Development Concerns Debugging Unit Testing. We'll cover the following: Create a new ASP. NET Nuget Package. Write some code to create a Person model object and a PersonController to deliver it.