pub struct ContextBase<'a, T> {
    pub path_node: Option<QueryPathNode<'a>>,
    /* private fields */
}
Expand description

Query context.

This type is not stable and should not be used directly.

Fields

path_node: Option<QueryPathNode<'a>>

The current path node being resolved.

Implementations

Report a resolver error.

When implementing OutputType, if an error occurs, call this function to report this error and return Value::Null.

Gets the global data defined in the Context or Schema.

If both Schema and Query have the same data type, the data in the Query is obtained.

Errors

Returns a Error if the specified type data does not exist.

Gets the global data defined in the Context or Schema.

Panics

It will panic if the specified data type does not exist.

Gets the global data defined in the Context or Schema or None if the specified type data does not exist.

Returns whether the HTTP header key is currently set on the response

Examples
use ::http::header::ACCESS_CONTROL_ALLOW_ORIGIN;
use async_graphql::*;

struct Query;

#[Object]
impl Query {
    async fn greet(&self, ctx: &Context<'_>) -> String {
        let header_exists = ctx.http_header_contains("Access-Control-Allow-Origin");
        assert!(!header_exists);

        ctx.insert_http_header(ACCESS_CONTROL_ALLOW_ORIGIN, "*");

        let header_exists = ctx.http_header_contains("Access-Control-Allow-Origin");
        assert!(header_exists);

        String::from("Hello world")
    }
}

Sets a HTTP header to response.

If the header was not currently set on the response, then None is returned.

If the response already contained this header then the new value is associated with this key and all the previous values are removed, however only a the first previous value is returned.

See http::HeaderMap for more details on the underlying implementation

Examples
use ::http::{header::ACCESS_CONTROL_ALLOW_ORIGIN, HeaderValue};
use async_graphql::*;

struct Query;

#[Object]
impl Query {
    async fn greet(&self, ctx: &Context<'_>) -> String {
        // Headers can be inserted using the `http` constants
        let was_in_headers = ctx.insert_http_header(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
        assert_eq!(was_in_headers, None);

        // They can also be inserted using &str
        let was_in_headers = ctx.insert_http_header("Custom-Header", "1234");
        assert_eq!(was_in_headers, None);

        // If multiple headers with the same key are `inserted` then the most recent
        // one overwrites the previous. If you want multiple headers for the same key, use
        // `append_http_header` for subsequent headers
        let was_in_headers = ctx.insert_http_header("Custom-Header", "Hello World");
        assert_eq!(was_in_headers, Some(HeaderValue::from_static("1234")));

        String::from("Hello world")
    }
}

Sets a HTTP header to response.

If the header was not currently set on the response, then false is returned.

If the response did have this header then the new value is appended to the end of the list of values currently associated with the key, however the key is not updated (which is important for types that can be == without being identical).

See http::HeaderMap for more details on the underlying implementation

Examples
use ::http::header::SET_COOKIE;
use async_graphql::*;

struct Query;

#[Object]
impl Query {
    async fn greet(&self, ctx: &Context<'_>) -> String {
        // Insert the first instance of the header
        ctx.insert_http_header(SET_COOKIE, "Chocolate Chip");

        // Subsequent values should be appended
        let header_already_exists = ctx.append_http_header("Set-Cookie", "Macadamia");
        assert!(header_already_exists);

        String::from("Hello world")
    }
}

Creates a uniform interface to inspect the forthcoming selections.

Examples
use async_graphql::*;

#[derive(SimpleObject)]
struct Detail {
    c: i32,
    d: i32,
}

#[derive(SimpleObject)]
struct MyObj {
    a: i32,
    b: i32,
    detail: Detail,
}

struct Query;

#[Object]
impl Query {
    async fn obj(&self, ctx: &Context<'_>) -> MyObj {
        if ctx.look_ahead().field("a").exists() {
            // This is a query like `obj { a }`
        } else if ctx.look_ahead().field("detail").field("c").exists() {
            // This is a query like `obj { detail { c } }`
        } else {
            // This query doesn't have `a`
        }
        unimplemented!()
    }
}

Get the current field.

Examples
use async_graphql::*;

#[derive(SimpleObject)]
struct MyObj {
    a: i32,
    b: i32,
    c: i32,
}

pub struct Query;

#[Object]
impl Query {
    async fn obj(&self, ctx: &Context<'_>) -> MyObj {
        let fields = ctx
            .field()
            .selection_set()
            .map(|field| field.name())
            .collect::<Vec<_>>();
        assert_eq!(fields, vec!["a", "b", "c"]);
        MyObj { a: 1, b: 2, c: 3 }
    }
}

let schema = Schema::new(Query, EmptyMutation, EmptySubscription);
assert!(schema.execute("{ obj { a b c }}").await.is_ok());
assert!(schema.execute("{ obj { a ... { b c } }}").await.is_ok());
assert!(schema
    .execute("{ obj { a ... BC }} fragment BC on MyObj { b c }")
    .await
    .is_ok());

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Gets the global data defined in the Context or Schema. Read more
Gets the global data defined in the Context or Schema. Read more
Gets the global data defined in the Context or Schema or None if the specified type data does not exist. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
Attaches the current Context to this type, returning a WithContext wrapper. Read more
Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more
Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Should always be Self
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more