GraphQL How would I write a query to find by first name

Question

I am trying to understand Graph QL and have a basic example working. e.g. if I pass in this query I get back the match with the id.

query {
  person(id:\"4090D8F         


        

Answer 1

You would need to either change the field you have here to make the id parameter optional or create a new field (maybe called persons or people) and add a new parameter that you parse into your data repository. Personally, I would favour doing the latter and create a new field. For example:

public PersonQuery(ShoppingData data)
{
    Field<PersonType>( /* snip */ );

    //Note this is now returning a list of persons
    Field<ListGraphType<PersonType>>(
        "people", //The new field name
        description: "A list of people",
        arguments: new QueryArguments(
            new QueryArgument<NonNullGraphType<StringGraphType>>
            {
                Name = "firstName", //The parameter to filter on first name
                Description = "The first name of the person"
            }),
        resolve: ctx =>
        {
            //You will need to write this new method
            return data.GetByFirstName(ctx.GetArgument<string>("firstName"));
        });
}

And now you just need to write the GetByFirstName method yourself. The query would now look like this:

query {
  people(firstName:"Andrew")
  {
    firstname
    surname
  }
}

Now you may find that GetByFirstName isn't enough and you also want a surname parameter too, and for them to be optional, so you could do something like this:

Field<ListGraphType<PersonType>>(
    "people",
    description: "A list of people",
    arguments: new QueryArguments(
        new QueryArgument<StringGraphType>
        {
            Name = "firstName", //The parameter to filter on first name
            Description = "The first name of the person"
        },
        new QueryArgument<StringGraphType>
        {
            Name = "surname",
            Description = "The surname of the person"
        }),
    resolve: ctx =>
    {
        //You will need to write this new method
        return data.SearchPeople(
            ctx.GetArgument<string>("firstName"), 
            ctx.GetArgument<string>("surame"));
    });