async-graphql/src/context.rs
2020-03-03 19:15:18 +08:00

120 lines
3.3 KiB
Rust

use crate::registry::Registry;
use crate::{ErrorWithPosition, GQLInputValue, QueryError, Result};
use fnv::FnvHasher;
use graphql_parser::query::{Field, SelectionSet, Value};
use std::any::{Any, TypeId};
use std::collections::HashMap;
use std::hash::BuildHasherDefault;
use std::ops::{Deref, DerefMut};
#[derive(Default)]
pub struct Variables(HashMap<String, serde_json::Value>);
impl Deref for Variables {
type Target = HashMap<String, serde_json::Value>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for Variables {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
#[derive(Default)]
pub struct Data(HashMap<TypeId, Box<dyn Any + Sync + Send>, BuildHasherDefault<FnvHasher>>);
impl Data {
pub fn insert<D: Any + Send + Sync>(&mut self, data: D) {
self.0.insert(TypeId::of::<D>(), Box::new(data));
}
pub fn remove<D: Any + Send + Sync>(&mut self) {
self.0.remove(&TypeId::of::<D>());
}
}
pub type ContextSelectionSet<'a> = ContextBase<'a, &'a SelectionSet>;
pub type Context<'a> = ContextBase<'a, &'a Field>;
pub struct ContextBase<'a, T> {
pub(crate) item: T,
pub(crate) data: Option<&'a Data>,
pub(crate) variables: Option<&'a Variables>,
pub(crate) registry: &'a Registry,
}
impl<'a, T> Deref for ContextBase<'a, T> {
type Target = T;
fn deref(&self) -> &Self::Target {
&self.item
}
}
impl<'a, T> ContextBase<'a, T> {
#[doc(hidden)]
pub fn with_item<R>(&self, item: R) -> ContextBase<'a, R> {
ContextBase {
item,
data: self.data,
variables: self.variables,
registry: self.registry.clone(),
}
}
pub fn data<D: Any + Send + Sync>(&self) -> Option<&D> {
self.data.and_then(|data| {
data.0
.get(&TypeId::of::<D>())
.and_then(|d| d.downcast_ref::<D>())
})
}
}
impl<'a> ContextBase<'a, &'a Field> {
#[doc(hidden)]
pub fn param_value<T: GQLInputValue>(&self, name: &str) -> Result<T> {
let value = self
.arguments
.iter()
.find(|(n, _)| n == name)
.map(|(_, v)| v)
.cloned();
if let Some(Value::Variable(var_name)) = &value {
if let Some(vars) = &self.variables {
if let Some(var_value) = vars.get(&*var_name).cloned() {
let res =
GQLInputValue::parse_from_json(var_value.clone()).ok_or_else(|| {
QueryError::ExpectedJsonType {
expect: T::qualified_type_name(),
actual: var_value,
}
.with_position(self.item.position)
})?;
return Ok(res);
}
}
return Err(QueryError::VarNotDefined {
var_name: var_name.clone(),
}
.into());
};
let value = value.unwrap_or(Value::Null);
let res = GQLInputValue::parse(value.clone()).ok_or_else(|| {
QueryError::ExpectedType {
expect: T::qualified_type_name(),
actual: value,
}
.with_position(self.item.position)
})?;
Ok(res)
}
}