async_graphql/
context.rs

1//! Query context.
2
3use std::{
4    any::{Any, TypeId},
5    collections::HashMap,
6    fmt::{self, Debug, Display, Formatter},
7    ops::Deref,
8    sync::{Arc, Mutex},
9};
10
11use async_graphql_parser::types::ConstDirective;
12use async_graphql_value::{Value as InputValue, Variables};
13use fnv::FnvHashMap;
14use serde::{
15    ser::{SerializeSeq, Serializer},
16    Serialize,
17};
18
19use crate::{
20    extensions::Extensions,
21    parser::types::{
22        Directive, Field, FragmentDefinition, OperationDefinition, Selection, SelectionSet,
23    },
24    schema::{IntrospectionMode, SchemaEnv},
25    Error, InputType, Lookahead, Name, OneofObjectType, PathSegment, Pos, Positioned, Result,
26    ServerError, ServerResult, UploadValue, Value,
27};
28
29/// Data related functions of the context.
30pub trait DataContext<'a> {
31    /// Gets the global data defined in the `Context` or `Schema`.
32    ///
33    /// If both `Schema` and `Query` have the same data type, the data in the
34    /// `Query` is obtained.
35    ///
36    /// # Errors
37    ///
38    /// Returns a `Error` if the specified type data does not exist.
39    fn data<D: Any + Send + Sync>(&self) -> Result<&'a D>;
40
41    /// Gets the global data defined in the `Context` or `Schema`.
42    ///
43    /// # Panics
44    ///
45    /// It will panic if the specified data type does not exist.
46    fn data_unchecked<D: Any + Send + Sync>(&self) -> &'a D;
47
48    /// Gets the global data defined in the `Context` or `Schema` or `None` if
49    /// the specified type data does not exist.
50    fn data_opt<D: Any + Send + Sync>(&self) -> Option<&'a D>;
51}
52
53/// Schema/Context data.
54///
55/// This is a type map, allowing you to store anything inside it.
56#[derive(Default)]
57pub struct Data(FnvHashMap<TypeId, Box<dyn Any + Sync + Send>>);
58
59impl Deref for Data {
60    type Target = FnvHashMap<TypeId, Box<dyn Any + Sync + Send>>;
61
62    fn deref(&self) -> &Self::Target {
63        &self.0
64    }
65}
66
67impl Data {
68    /// Insert data.
69    pub fn insert<D: Any + Send + Sync>(&mut self, data: D) {
70        self.0.insert(TypeId::of::<D>(), Box::new(data));
71    }
72
73    pub(crate) fn merge(&mut self, other: Data) {
74        self.0.extend(other.0);
75    }
76}
77
78impl Debug for Data {
79    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
80        f.debug_tuple("Data").finish()
81    }
82}
83
84/// Context for `SelectionSet`
85pub type ContextSelectionSet<'a> = ContextBase<'a, &'a Positioned<SelectionSet>>;
86
87/// Context object for resolve field
88pub type Context<'a> = ContextBase<'a, &'a Positioned<Field>>;
89
90/// Context object for execute directive.
91pub type ContextDirective<'a> = ContextBase<'a, &'a Positioned<Directive>>;
92
93/// A segment in the path to the current query.
94///
95/// This is a borrowed form of [`PathSegment`](enum.PathSegment.html) used
96/// during execution instead of passed back when errors occur.
97#[derive(Debug, Clone, Copy, Serialize)]
98#[serde(untagged)]
99pub enum QueryPathSegment<'a> {
100    /// We are currently resolving an element in a list.
101    Index(usize),
102    /// We are currently resolving a field in an object.
103    Name(&'a str),
104}
105
106/// A path to the current query.
107///
108/// The path is stored as a kind of reverse linked list.
109#[derive(Debug, Clone, Copy)]
110pub struct QueryPathNode<'a> {
111    /// The parent node to this, if there is one.
112    pub parent: Option<&'a QueryPathNode<'a>>,
113
114    /// The current path segment being resolved.
115    pub segment: QueryPathSegment<'a>,
116}
117
118impl serde::Serialize for QueryPathNode<'_> {
119    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
120        let mut seq = serializer.serialize_seq(None)?;
121        self.try_for_each(|segment| seq.serialize_element(segment))?;
122        seq.end()
123    }
124}
125
126impl Display for QueryPathNode<'_> {
127    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
128        let mut first = true;
129        self.try_for_each(|segment| {
130            if !first {
131                write!(f, ".")?;
132            }
133            first = false;
134
135            match segment {
136                QueryPathSegment::Index(idx) => write!(f, "{}", *idx),
137                QueryPathSegment::Name(name) => write!(f, "{}", name),
138            }
139        })
140    }
141}
142
143impl<'a> QueryPathNode<'a> {
144    /// Get the current field name.
145    ///
146    /// This traverses all the parents of the node until it finds one that is a
147    /// field name.
148    pub fn field_name(&self) -> &str {
149        std::iter::once(self)
150            .chain(self.parents())
151            .find_map(|node| match node.segment {
152                QueryPathSegment::Name(name) => Some(name),
153                QueryPathSegment::Index(_) => None,
154            })
155            .unwrap()
156    }
157
158    /// Get the path represented by `Vec<String>`; numbers will be stringified.
159    #[must_use]
160    pub fn to_string_vec(self) -> Vec<String> {
161        let mut res = Vec::new();
162        self.for_each(|s| {
163            res.push(match s {
164                QueryPathSegment::Name(name) => (*name).to_string(),
165                QueryPathSegment::Index(idx) => idx.to_string(),
166            });
167        });
168        res
169    }
170
171    /// Iterate over the parents of the node.
172    pub fn parents(&self) -> Parents<'_> {
173        Parents(self)
174    }
175
176    pub(crate) fn for_each<F: FnMut(&QueryPathSegment<'a>)>(&self, mut f: F) {
177        let _ = self.try_for_each::<std::convert::Infallible, _>(|segment| {
178            f(segment);
179            Ok(())
180        });
181    }
182
183    pub(crate) fn try_for_each<E, F: FnMut(&QueryPathSegment<'a>) -> Result<(), E>>(
184        &self,
185        mut f: F,
186    ) -> Result<(), E> {
187        self.try_for_each_ref(&mut f)
188    }
189
190    fn try_for_each_ref<E, F: FnMut(&QueryPathSegment<'a>) -> Result<(), E>>(
191        &self,
192        f: &mut F,
193    ) -> Result<(), E> {
194        if let Some(parent) = &self.parent {
195            parent.try_for_each_ref(f)?;
196        }
197        f(&self.segment)
198    }
199}
200
201/// An iterator over the parents of a
202/// [`QueryPathNode`](struct.QueryPathNode.html).
203#[derive(Debug, Clone)]
204pub struct Parents<'a>(&'a QueryPathNode<'a>);
205
206impl<'a> Parents<'a> {
207    /// Get the current query path node, which the next call to `next` will get
208    /// the parents of.
209    #[must_use]
210    pub fn current(&self) -> &'a QueryPathNode<'a> {
211        self.0
212    }
213}
214
215impl<'a> Iterator for Parents<'a> {
216    type Item = &'a QueryPathNode<'a>;
217
218    fn next(&mut self) -> Option<Self::Item> {
219        let parent = self.0.parent;
220        if let Some(parent) = parent {
221            self.0 = parent;
222        }
223        parent
224    }
225}
226
227impl std::iter::FusedIterator for Parents<'_> {}
228
229/// Query context.
230///
231/// **This type is not stable and should not be used directly.**
232#[derive(Clone)]
233pub struct ContextBase<'a, T> {
234    /// The current path node being resolved.
235    pub path_node: Option<QueryPathNode<'a>>,
236    /// If `true` means the current field is for introspection.
237    pub(crate) is_for_introspection: bool,
238    #[doc(hidden)]
239    pub item: T,
240    #[doc(hidden)]
241    pub schema_env: &'a SchemaEnv,
242    #[doc(hidden)]
243    pub query_env: &'a QueryEnv,
244    #[doc(hidden)]
245    pub execute_data: Option<&'a Data>,
246}
247
248#[doc(hidden)]
249pub struct QueryEnvInner {
250    pub extensions: Extensions,
251    pub variables: Variables,
252    pub operation_name: Option<String>,
253    pub operation: Positioned<OperationDefinition>,
254    pub fragments: HashMap<Name, Positioned<FragmentDefinition>>,
255    pub uploads: Vec<UploadValue>,
256    pub session_data: Arc<Data>,
257    pub query_data: Arc<Data>,
258    pub http_headers: Mutex<http::HeaderMap>,
259    pub introspection_mode: IntrospectionMode,
260    pub errors: Mutex<Vec<ServerError>>,
261}
262
263#[doc(hidden)]
264#[derive(Clone)]
265pub struct QueryEnv(Arc<QueryEnvInner>);
266
267impl Deref for QueryEnv {
268    type Target = QueryEnvInner;
269
270    fn deref(&self) -> &Self::Target {
271        &self.0
272    }
273}
274
275impl QueryEnv {
276    #[doc(hidden)]
277    pub fn new(inner: QueryEnvInner) -> QueryEnv {
278        QueryEnv(Arc::new(inner))
279    }
280
281    #[doc(hidden)]
282    pub fn create_context<'a, T>(
283        &'a self,
284        schema_env: &'a SchemaEnv,
285        path_node: Option<QueryPathNode<'a>>,
286        item: T,
287        execute_data: Option<&'a Data>,
288    ) -> ContextBase<'a, T> {
289        ContextBase {
290            path_node,
291            is_for_introspection: false,
292            item,
293            schema_env,
294            query_env: self,
295            execute_data,
296        }
297    }
298}
299
300impl<'a, T> DataContext<'a> for ContextBase<'a, T> {
301    fn data<D: Any + Send + Sync>(&self) -> Result<&'a D> {
302        ContextBase::data::<D>(self)
303    }
304
305    fn data_unchecked<D: Any + Send + Sync>(&self) -> &'a D {
306        ContextBase::data_unchecked::<D>(self)
307    }
308
309    fn data_opt<D: Any + Send + Sync>(&self) -> Option<&'a D> {
310        ContextBase::data_opt::<D>(self)
311    }
312}
313
314impl<'a, T> ContextBase<'a, T> {
315    #[doc(hidden)]
316    pub fn with_field(
317        &'a self,
318        field: &'a Positioned<Field>,
319    ) -> ContextBase<'a, &'a Positioned<Field>> {
320        ContextBase {
321            path_node: Some(QueryPathNode {
322                parent: self.path_node.as_ref(),
323                segment: QueryPathSegment::Name(&field.node.response_key().node),
324            }),
325            is_for_introspection: self.is_for_introspection,
326            item: field,
327            schema_env: self.schema_env,
328            query_env: self.query_env,
329            execute_data: self.execute_data,
330        }
331    }
332
333    #[doc(hidden)]
334    pub fn with_selection_set(
335        &self,
336        selection_set: &'a Positioned<SelectionSet>,
337    ) -> ContextBase<'a, &'a Positioned<SelectionSet>> {
338        ContextBase {
339            path_node: self.path_node,
340            is_for_introspection: self.is_for_introspection,
341            item: selection_set,
342            schema_env: self.schema_env,
343            query_env: self.query_env,
344            execute_data: self.execute_data,
345        }
346    }
347
348    #[doc(hidden)]
349    pub fn set_error_path(&self, error: ServerError) -> ServerError {
350        if let Some(node) = self.path_node {
351            let mut path = Vec::new();
352            node.for_each(|current_node| {
353                path.push(match current_node {
354                    QueryPathSegment::Name(name) => PathSegment::Field((*name).to_string()),
355                    QueryPathSegment::Index(idx) => PathSegment::Index(*idx),
356                })
357            });
358            ServerError { path, ..error }
359        } else {
360            error
361        }
362    }
363
364    /// Report a resolver error.
365    ///
366    /// When implementing `OutputType`, if an error occurs, call this function
367    /// to report this error and return `Value::Null`.
368    pub fn add_error(&self, error: ServerError) {
369        self.query_env.errors.lock().unwrap().push(error);
370    }
371
372    /// Gets the global data defined in the `Context` or `Schema`.
373    ///
374    /// If both `Schema` and `Query` have the same data type, the data in the
375    /// `Query` is obtained.
376    ///
377    /// # Errors
378    ///
379    /// Returns a `Error` if the specified type data does not exist.
380    pub fn data<D: Any + Send + Sync>(&self) -> Result<&'a D> {
381        self.data_opt::<D>().ok_or_else(|| {
382            Error::new(format!(
383                "Data `{}` does not exist.",
384                std::any::type_name::<D>()
385            ))
386        })
387    }
388
389    /// Gets the global data defined in the `Context` or `Schema`.
390    ///
391    /// # Panics
392    ///
393    /// It will panic if the specified data type does not exist.
394    pub fn data_unchecked<D: Any + Send + Sync>(&self) -> &'a D {
395        self.data_opt::<D>()
396            .unwrap_or_else(|| panic!("Data `{}` does not exist.", std::any::type_name::<D>()))
397    }
398
399    /// Gets the global data defined in the `Context` or `Schema` or `None` if
400    /// the specified type data does not exist.
401    pub fn data_opt<D: Any + Send + Sync>(&self) -> Option<&'a D> {
402        self.execute_data
403            .as_ref()
404            .and_then(|execute_data| execute_data.get(&TypeId::of::<D>()))
405            .or_else(|| self.query_env.query_data.0.get(&TypeId::of::<D>()))
406            .or_else(|| self.query_env.session_data.0.get(&TypeId::of::<D>()))
407            .or_else(|| self.schema_env.data.0.get(&TypeId::of::<D>()))
408            .and_then(|d| d.downcast_ref::<D>())
409    }
410
411    /// Returns whether the HTTP header `key` is currently set on the response
412    ///
413    /// # Examples
414    ///
415    /// ```no_run
416    /// use ::http::header::ACCESS_CONTROL_ALLOW_ORIGIN;
417    /// use async_graphql::*;
418    ///
419    /// struct Query;
420    ///
421    /// #[Object]
422    /// impl Query {
423    ///     async fn greet(&self, ctx: &Context<'_>) -> String {
424    ///         let header_exists = ctx.http_header_contains("Access-Control-Allow-Origin");
425    ///         assert!(!header_exists);
426    ///
427    ///         ctx.insert_http_header(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
428    ///
429    ///         let header_exists = ctx.http_header_contains("Access-Control-Allow-Origin");
430    ///         assert!(header_exists);
431    ///
432    ///         String::from("Hello world")
433    ///     }
434    /// }
435    /// ```
436    pub fn http_header_contains(&self, key: impl http::header::AsHeaderName) -> bool {
437        self.query_env
438            .http_headers
439            .lock()
440            .unwrap()
441            .contains_key(key)
442    }
443
444    /// Sets a HTTP header to response.
445    ///
446    /// If the header was not currently set on the response, then `None` is
447    /// returned.
448    ///
449    /// If the response already contained this header then the new value is
450    /// associated with this key and __all the previous values are
451    /// removed__, however only a the first previous value is returned.
452    ///
453    /// See [`http::HeaderMap`] for more details on the underlying
454    /// implementation
455    ///
456    /// # Examples
457    ///
458    /// ```no_run
459    /// use ::http::{header::ACCESS_CONTROL_ALLOW_ORIGIN, HeaderValue};
460    /// use async_graphql::*;
461    ///
462    /// struct Query;
463    ///
464    /// #[Object]
465    /// impl Query {
466    ///     async fn greet(&self, ctx: &Context<'_>) -> String {
467    ///         // Headers can be inserted using the `http` constants
468    ///         let was_in_headers = ctx.insert_http_header(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
469    ///         assert_eq!(was_in_headers, None);
470    ///
471    ///         // They can also be inserted using &str
472    ///         let was_in_headers = ctx.insert_http_header("Custom-Header", "1234");
473    ///         assert_eq!(was_in_headers, None);
474    ///
475    ///         // If multiple headers with the same key are `inserted` then the most recent
476    ///         // one overwrites the previous. If you want multiple headers for the same key, use
477    ///         // `append_http_header` for subsequent headers
478    ///         let was_in_headers = ctx.insert_http_header("Custom-Header", "Hello World");
479    ///         assert_eq!(was_in_headers, Some(HeaderValue::from_static("1234")));
480    ///
481    ///         String::from("Hello world")
482    ///     }
483    /// }
484    /// ```
485    pub fn insert_http_header(
486        &self,
487        name: impl http::header::IntoHeaderName,
488        value: impl TryInto<http::HeaderValue>,
489    ) -> Option<http::HeaderValue> {
490        if let Ok(value) = value.try_into() {
491            self.query_env
492                .http_headers
493                .lock()
494                .unwrap()
495                .insert(name, value)
496        } else {
497            None
498        }
499    }
500
501    /// Sets a HTTP header to response.
502    ///
503    /// If the header was not currently set on the response, then `false` is
504    /// returned.
505    ///
506    /// If the response did have this header then the new value is appended to
507    /// the end of the list of values currently associated with the key,
508    /// however the key is not updated _(which is important for types that
509    /// can be `==` without being identical)_.
510    ///
511    /// See [`http::HeaderMap`] for more details on the underlying
512    /// implementation
513    ///
514    /// # Examples
515    ///
516    /// ```no_run
517    /// use ::http::header::SET_COOKIE;
518    /// use async_graphql::*;
519    ///
520    /// struct Query;
521    ///
522    /// #[Object]
523    /// impl Query {
524    ///     async fn greet(&self, ctx: &Context<'_>) -> String {
525    ///         // Insert the first instance of the header
526    ///         ctx.insert_http_header(SET_COOKIE, "Chocolate Chip");
527    ///
528    ///         // Subsequent values should be appended
529    ///         let header_already_exists = ctx.append_http_header("Set-Cookie", "Macadamia");
530    ///         assert!(header_already_exists);
531    ///
532    ///         String::from("Hello world")
533    ///     }
534    /// }
535    /// ```
536    pub fn append_http_header(
537        &self,
538        name: impl http::header::IntoHeaderName,
539        value: impl TryInto<http::HeaderValue>,
540    ) -> bool {
541        if let Ok(value) = value.try_into() {
542            self.query_env
543                .http_headers
544                .lock()
545                .unwrap()
546                .append(name, value)
547        } else {
548            false
549        }
550    }
551
552    fn var_value(&self, name: &str, pos: Pos) -> ServerResult<Value> {
553        self.query_env
554            .operation
555            .node
556            .variable_definitions
557            .iter()
558            .find(|def| def.node.name.node == name)
559            .and_then(|def| {
560                self.query_env
561                    .variables
562                    .get(&def.node.name.node)
563                    .or_else(|| def.node.default_value())
564            })
565            .cloned()
566            .ok_or_else(|| {
567                ServerError::new(format!("Variable {} is not defined.", name), Some(pos))
568            })
569    }
570
571    pub(crate) fn resolve_input_value(&self, value: Positioned<InputValue>) -> ServerResult<Value> {
572        let pos = value.pos;
573        value
574            .node
575            .into_const_with(|name| self.var_value(&name, pos))
576    }
577
578    #[doc(hidden)]
579    fn get_param_value<Q: InputType>(
580        &self,
581        arguments: &[(Positioned<Name>, Positioned<InputValue>)],
582        name: &str,
583        default: Option<fn() -> Q>,
584    ) -> ServerResult<(Pos, Q)> {
585        let value = arguments
586            .iter()
587            .find(|(n, _)| n.node.as_str() == name)
588            .map(|(_, value)| value)
589            .cloned();
590        if value.is_none() {
591            if let Some(default) = default {
592                return Ok((Pos::default(), default()));
593            }
594        }
595        let (pos, value) = match value {
596            Some(value) => (value.pos, Some(self.resolve_input_value(value)?)),
597            None => (Pos::default(), None),
598        };
599        InputType::parse(value)
600            .map(|value| (pos, value))
601            .map_err(|e| e.into_server_error(pos))
602    }
603
604    #[doc(hidden)]
605    #[must_use]
606    pub fn with_index(&'a self, idx: usize) -> ContextBase<'a, T>
607    where
608        T: Copy,
609    {
610        ContextBase {
611            path_node: Some(QueryPathNode {
612                parent: self.path_node.as_ref(),
613                segment: QueryPathSegment::Index(idx),
614            }),
615            is_for_introspection: self.is_for_introspection,
616            item: self.item,
617            schema_env: self.schema_env,
618            query_env: self.query_env,
619            execute_data: self.execute_data,
620        }
621    }
622}
623
624impl<'a> ContextBase<'a, &'a Positioned<Field>> {
625    #[doc(hidden)]
626    pub fn param_value<T: InputType>(
627        &self,
628        name: &str,
629        default: Option<fn() -> T>,
630    ) -> ServerResult<(Pos, T)> {
631        self.get_param_value(&self.item.node.arguments, name, default)
632    }
633
634    #[doc(hidden)]
635    pub fn oneof_param_value<T: OneofObjectType>(&self) -> ServerResult<(Pos, T)> {
636        use indexmap::IndexMap;
637
638        let mut map = IndexMap::new();
639
640        for (name, value) in &self.item.node.arguments {
641            let value = self.resolve_input_value(value.clone())?;
642            map.insert(name.node.clone(), value);
643        }
644
645        InputType::parse(Some(Value::Object(map)))
646            .map(|value| (self.item.pos, value))
647            .map_err(|e| e.into_server_error(self.item.pos))
648    }
649
650    /// Creates a uniform interface to inspect the forthcoming selections.
651    ///
652    /// # Examples
653    ///
654    /// ```no_run
655    /// use async_graphql::*;
656    ///
657    /// #[derive(SimpleObject)]
658    /// struct Detail {
659    ///     c: i32,
660    ///     d: i32,
661    /// }
662    ///
663    /// #[derive(SimpleObject)]
664    /// struct MyObj {
665    ///     a: i32,
666    ///     b: i32,
667    ///     detail: Detail,
668    /// }
669    ///
670    /// struct Query;
671    ///
672    /// #[Object]
673    /// impl Query {
674    ///     async fn obj(&self, ctx: &Context<'_>) -> MyObj {
675    ///         if ctx.look_ahead().field("a").exists() {
676    ///             // This is a query like `obj { a }`
677    ///         } else if ctx.look_ahead().field("detail").field("c").exists() {
678    ///             // This is a query like `obj { detail { c } }`
679    ///         } else {
680    ///             // This query doesn't have `a`
681    ///         }
682    ///         unimplemented!()
683    ///     }
684    /// }
685    /// ```
686    pub fn look_ahead(&self) -> Lookahead {
687        Lookahead::new(&self.query_env.fragments, &self.item.node, self)
688    }
689
690    /// Get the current field.
691    ///
692    /// # Examples
693    ///
694    /// ```rust
695    /// use async_graphql::*;
696    ///
697    /// #[derive(SimpleObject)]
698    /// struct MyObj {
699    ///     a: i32,
700    ///     b: i32,
701    ///     c: i32,
702    /// }
703    ///
704    /// pub struct Query;
705    ///
706    /// #[Object]
707    /// impl Query {
708    ///     async fn obj(&self, ctx: &Context<'_>) -> MyObj {
709    ///         let fields = ctx
710    ///             .field()
711    ///             .selection_set()
712    ///             .map(|field| field.name())
713    ///             .collect::<Vec<_>>();
714    ///         assert_eq!(fields, vec!["a", "b", "c"]);
715    ///         MyObj { a: 1, b: 2, c: 3 }
716    ///     }
717    /// }
718    ///
719    /// # tokio::runtime::Runtime::new().unwrap().block_on(async move {
720    /// let schema = Schema::new(Query, EmptyMutation, EmptySubscription);
721    /// assert!(schema.execute("{ obj { a b c }}").await.is_ok());
722    /// assert!(schema.execute("{ obj { a ... { b c } }}").await.is_ok());
723    /// assert!(schema
724    ///     .execute("{ obj { a ... BC }} fragment BC on MyObj { b c }")
725    ///     .await
726    ///     .is_ok());
727    /// # });
728    /// ```
729    pub fn field(&self) -> SelectionField {
730        SelectionField {
731            fragments: &self.query_env.fragments,
732            field: &self.item.node,
733            context: self,
734        }
735    }
736}
737
738impl<'a> ContextBase<'a, &'a Positioned<Directive>> {
739    #[doc(hidden)]
740    pub fn param_value<T: InputType>(
741        &self,
742        name: &str,
743        default: Option<fn() -> T>,
744    ) -> ServerResult<(Pos, T)> {
745        self.get_param_value(&self.item.node.arguments, name, default)
746    }
747}
748
749/// Selection field.
750#[derive(Clone, Copy)]
751pub struct SelectionField<'a> {
752    pub(crate) fragments: &'a HashMap<Name, Positioned<FragmentDefinition>>,
753    pub(crate) field: &'a Field,
754    pub(crate) context: &'a Context<'a>,
755}
756
757impl<'a> SelectionField<'a> {
758    /// Get the name of this field.
759    #[inline]
760    pub fn name(&self) -> &'a str {
761        self.field.name.node.as_str()
762    }
763
764    /// Get the alias of this field.
765    #[inline]
766    pub fn alias(&self) -> Option<&'a str> {
767        self.field.alias.as_ref().map(|alias| alias.node.as_str())
768    }
769
770    /// Get the directives of this field.
771    pub fn directives(&self) -> ServerResult<Vec<ConstDirective>> {
772        let mut directives = Vec::with_capacity(self.field.directives.len());
773
774        for directive in &self.field.directives {
775            let directive = &directive.node;
776
777            let mut arguments = Vec::with_capacity(directive.arguments.len());
778            for (name, value) in &directive.arguments {
779                let pos = name.pos;
780                arguments.push((
781                    name.clone(),
782                    value.position_node(
783                        value
784                            .node
785                            .clone()
786                            .into_const_with(|name| self.context.var_value(&name, pos))?,
787                    ),
788                ));
789            }
790
791            directives.push(ConstDirective {
792                name: directive.name.clone(),
793                arguments,
794            });
795        }
796
797        Ok(directives)
798    }
799
800    /// Get the arguments of this field.
801    pub fn arguments(&self) -> ServerResult<Vec<(Name, Value)>> {
802        let mut arguments = Vec::with_capacity(self.field.arguments.len());
803        for (name, value) in &self.field.arguments {
804            let pos = name.pos;
805            arguments.push((
806                name.node.clone(),
807                value
808                    .clone()
809                    .node
810                    .into_const_with(|name| self.context.var_value(&name, pos))?,
811            ));
812        }
813        Ok(arguments)
814    }
815
816    /// Get all subfields of the current selection set.
817    pub fn selection_set(&self) -> impl Iterator<Item = SelectionField<'a>> {
818        SelectionFieldsIter {
819            fragments: self.fragments,
820            iter: vec![self.field.selection_set.node.items.iter()],
821            context: self.context,
822        }
823    }
824}
825
826impl Debug for SelectionField<'_> {
827    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
828        struct DebugSelectionSet<'a>(Vec<SelectionField<'a>>);
829
830        impl Debug for DebugSelectionSet<'_> {
831            fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
832                f.debug_list().entries(&self.0).finish()
833            }
834        }
835
836        f.debug_struct(self.name())
837            .field("name", &self.name())
838            .field(
839                "selection_set",
840                &DebugSelectionSet(self.selection_set().collect()),
841            )
842            .finish()
843    }
844}
845
846struct SelectionFieldsIter<'a> {
847    fragments: &'a HashMap<Name, Positioned<FragmentDefinition>>,
848    iter: Vec<std::slice::Iter<'a, Positioned<Selection>>>,
849    context: &'a Context<'a>,
850}
851
852impl<'a> Iterator for SelectionFieldsIter<'a> {
853    type Item = SelectionField<'a>;
854
855    fn next(&mut self) -> Option<Self::Item> {
856        loop {
857            let it = self.iter.last_mut()?;
858            let item = it.next();
859
860            match item {
861                Some(selection) => match &selection.node {
862                    Selection::Field(field) => {
863                        return Some(SelectionField {
864                            fragments: self.fragments,
865                            field: &field.node,
866                            context: self.context,
867                        });
868                    }
869                    Selection::FragmentSpread(fragment_spread) => {
870                        if let Some(fragment) =
871                            self.fragments.get(&fragment_spread.node.fragment_name.node)
872                        {
873                            self.iter
874                                .push(fragment.node.selection_set.node.items.iter());
875                        }
876                    }
877                    Selection::InlineFragment(inline_fragment) => {
878                        self.iter
879                            .push(inline_fragment.node.selection_set.node.items.iter());
880                    }
881                },
882                None => {
883                    self.iter.pop();
884                }
885            }
886        }
887    }
888}
async_graphql/context.rs

async_graphql/
context.rs
