1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469
use crate::{client::ClientImpl, GraphQLQuery, QueryBody, QueryError, Response}; #[cfg(feature = "observable")] use futures::{channel::mpsc::Receiver, task::Context, Stream}; use serde::{de::DeserializeOwned, Serialize}; use std::{ any::{Any, TypeId}, collections::HashMap, fmt, pin::Pin, sync::Arc, task::Poll }; #[cfg(target_arch = "wasm32")] use wasm_bindgen::JsValue; use std::marker::PhantomData; /// The result type returned by exchanges pub type ExchangeResult<R> = Result<OperationResult<R>, QueryError>; /// The main trait that must be implemented by exchanges #[async_trait] pub trait Exchange: Send + Sync + 'static { /// Process a query operation. /// /// Note that this can return early, perhaps partial results to subscriptions via `client.push_result()`, /// but this will do nothing for regular requests. The exchange should have a workflow in the style of: /// Determine if this exchange can return a result -> Delegate to `next` if not -> Perform processing on the delegated result -> Return result /// /// For examples, see the built-in exchanges. /// /// # Arguments /// /// * `operation` - the operation to be handled. /// * `client` - the client object for rerunning queries and pushing results if applicable. /// /// # Returns /// /// * `Ok(Response)` if the operation was completed successfully /// * `Err(YourError)` if there was an error anywhere. Errors from `next` should be passed through. /// This will be displayed to the user, so make sure the error messages are reasonable. async fn run<Q: GraphQLQuery, C: Client>( &self, operation: Operation<Q::Variables>, client: C ) -> ExchangeResult<Q::ResponseData>; } /// An exchange factory. This must be passed to the ClientBuilder by the user, /// so it should take only necessary parameters. /// /// In a scenario that doesn't require additional configuration this should just be a zero size struct pub trait ExchangeFactory<TNext: Exchange> { type Output: Exchange; /// Build the exchange using the provided `next` exchange. If a query isn't handled /// it should be delegated to this exchange. fn build(self, next: TNext) -> Self::Output; } /// Internal struct used in codegen pub trait QueryInfo<TVars> { /// Recursively creates the selection for the given set of variables. /// The variables are used to fill in non-const argument values. fn selection(variables: &TVars) -> Vec<FieldSelector>; } /// The type of the operation. This corresponds directly to the GraphQL syntax, /// `query`, `mutation` and `subscription`. #[derive(PartialEq, Debug, Clone)] pub enum OperationType { Query, Mutation, Subscription } impl OperationType { pub fn to_str(&self) -> &'static str { match self { OperationType::Query => "Query", OperationType::Mutation => "Mutation", OperationType::Subscription => "Subscription" } } } impl From<u8> for OperationType { fn from(u: u8) -> Self { match u { 1 => OperationType::Mutation, 2 => OperationType::Subscription, _ => OperationType::Query } } } impl ToString for OperationType { fn to_string(&self) -> String { let str = match self { OperationType::Query => "Query", OperationType::Mutation => "Mutation", OperationType::Subscription => "Subscription" }; str.to_string() } } /// The request policy of the request. /// /// * `CacheFirst` - Prefers results from the cache, if it's not found it is fetched /// * `CacheOnly` - Only fetches results from the cache, if it's not found it will simply return `None` for the data /// * `NetworkOnly` - Only fetches results from the network and ignores the cache. /// * `CacheAndNetwork` - Returns the result from the cache if it exists, but also refetch from the network and push the result to a subscription. /// This acts the same as CacheFirst without subscriptions, but has overhead. #[repr(u8)] #[derive(Debug, Clone, PartialEq)] pub enum RequestPolicy { /// Prefers results from the cache, if it's not found it is fetched CacheFirst = 1, /// Only fetches results from the cache, if it's not found it will simply return `None` for the data CacheOnly = 2, /// Only fetches results from the network and ignores the cache. NetworkOnly = 3, /// Returns the result from the cache if it exists, but also refetch from the network /// and push the result to a subscription. This acts the same as CacheFirst without /// subscriptions, but has overhead. CacheAndNetwork = 4 } impl From<u8> for RequestPolicy { fn from(value: u8) -> Self { match value { 1 => RequestPolicy::CacheFirst, 2 => RequestPolicy::CacheOnly, 3 => RequestPolicy::NetworkOnly, 4 => RequestPolicy::CacheAndNetwork, _ => unreachable!() } } } /// A key-value pair used for custom headers. pub struct HeaderPair(pub String, pub String); /// An internal struct used in codegen. /// This represents the recursive selection of a query and is used for normalization. #[derive(Clone)] pub enum FieldSelector { /// field name, arguments Scalar(&'static str, String), /// field_name, arguments, typename, inner selection Object(&'static str, String, &'static str, Vec<FieldSelector>), /// field name, arguments, inner selection by type Union( &'static str, String, Arc<dyn Fn(&str) -> Vec<FieldSelector>> ) } impl fmt::Debug for FieldSelector { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match self { FieldSelector::Scalar(field_name, args) => { write!(f, "Scalar(field name: {}, args: {})", field_name, args) } FieldSelector::Object(field_name, args, typename, _) => write!( f, "Object(field name: {}, args: {}, typename: {})", field_name, args, typename ), FieldSelector::Union(field_name, args, _) => { write!(f, "Union(field name: {}, args: {})", field_name, args) } } } } /// Metadata for an operation #[derive(Clone, Debug, PartialEq)] pub struct OperationMeta { /// The query key before being hashed with the variables pub query_key: u32, /// The type of the operation, query, mutation or subscription pub operation_type: OperationType, /// A list of types that are returned by the query pub involved_types: Vec<&'static str> } /// Options for the operation. /// This is just an internal representation of the union between `QueryOptions` and `ClientOptions`. #[derive(Clone)] pub struct OperationOptions { /// The url that should be used when fetching pub url: String, /// Extra headers that should be applied when fetching pub extra_headers: Option<Arc<dyn Fn() -> Vec<HeaderPair> + Send + Sync>>, /// The request policy of the query. Exchanges should respect this. pub request_policy: RequestPolicy, /// Extensions that can contain extra configuration for exchanges. pub extensions: Option<Extensions>, /// The fetch function passed by JavaScript code #[cfg(target_arch = "wasm32")] pub fetch: Option<js_sys::Function> } // SAFETY: JavaScript doesn't have multi-threading // The only non-send value is the pointer in JsValue unsafe impl Send for OperationOptions {} // SAFETY: JavaScript doesn't have multi-threading // The only non-send value is the pointer in JsValue unsafe impl Sync for OperationOptions {} /// A query operation. One of these is fired for each direct query, as well as for query reruns. #[derive(Clone)] pub struct Operation<V: Serialize + Clone + Send + Sync> { /// The unique key of the operation. This will identify a unique combination of query and /// variables. /// This means calling the same query with the same variables will produce the same key, /// regardless of where the operation originates pub key: u64, /// Operation metadata such as the query key pub meta: OperationMeta, /// The query body. This will be serialized by the fetch implementation but may also be used /// to get a reference to the query variables. pub query: QueryBody<V>, /// The options of the operation. This is an OR union of `QueryOptions` and `ClientOptions`. pub options: OperationOptions } /// The source of the result (cache or network). /// Used for debugging. #[derive(Clone, Debug, PartialEq, Copy, Serialize)] pub enum ResultSource { Cache, Network } /// Debug info used for... well, debugging. #[derive(Clone, Debug, PartialEq, Serialize)] pub struct DebugInfo { /// The source of the result, cache or network pub source: ResultSource, /// Whether the query was actually run (`false`) or combined with another query in a deduplication exchange (`true`) #[serde(rename = "didDedup")] pub did_dedup: bool } /// The result of a successful operation. #[derive(Clone, Debug, PartialEq)] pub struct OperationResult<R: DeserializeOwned + Send + Sync + Clone> { /// The key of the operation passed back by the last exchange pub key: u64, /// The metadata of the operation passed back by the last exchange pub meta: OperationMeta, /// The deserialized response pub response: Response<R> } /// An observable result. This implements `Stream` and unsubscribes on drop. /// It will receive early (partial or stale) results, as well as refreshing when the query is /// rerun after being invalidated by mutations. #[cfg(feature = "observable")] pub struct Observable<T, M: Exchange> { inner: Receiver<Arc<dyn Any + Send + Sync>>, client: Arc<ClientImpl<M>>, key: u64, index: usize, t: PhantomData<T> } #[cfg(feature = "observable")] impl<T: Clone, M: Exchange> Observable<T, M> { pub(crate) fn new( key: u64, inner: Receiver<Arc<dyn Any + Send + Sync>>, client: Arc<ClientImpl<M>>, index: usize ) -> Self { Observable { inner, client, key, index, t: PhantomData } } } #[cfg(feature = "observable")] impl<T: Clone, M: Exchange> Observable<T, M> { /// Manually cause the client to rerun this query. /// Note this doesn't invalidate any caching, so if the query is in the cache it will simply be re-read pub fn rerun(&self) { self.client.rerun_query(self.key); } } #[cfg(feature = "observable")] impl<T, M: Exchange> Stream for Observable<T, M> where T: 'static + Unpin + Clone { type Item = T; fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { let inner = &mut self.get_mut().inner; let poll = <Receiver<Arc<dyn Any + Send + Sync>> as Stream>::poll_next(Pin::new(inner), cx); match poll { Poll::Ready(Some(boxed)) => { let cast: &T = (&*boxed).downcast_ref::<T>().unwrap(); Poll::Ready(Some(cast.clone())) } Poll::Ready(None) => Poll::Ready(None), Poll::Pending => Poll::Pending } } } #[cfg(feature = "observable")] impl<T, M: Exchange> Drop for Observable<T, M> { fn drop(&mut self) { self.client.clear_observable(self.key, self.index) } } /// An extension that may be passed by the user to provide additional request options to a third-party exchange. /// This is only here to allow for JS interop - The implementor of the exchange must deserialize JavaScript input to the best of their ability. /// Note that this may involve complex operations such as converting `js_sys::Function` to Rust closures or other advanced deserialization. /// This is not a simple serde-like deserialization. /// /// An extension must always be `Clone`. /// /// # Example /// /// ``` /// use artemis::exchange::Extension; /// /// #[derive(Clone)] /// struct MyExtension(String); /// /// impl Extension for MyExtension { /// #[cfg(target_arch = "wasm32")] /// fn from_js(value: JsValue) -> Option<Self> { /// use wasm_bindgen::JsCast; /// /// let cast = value.dyn_into::<String>(); /// if let Ok(cast) = cast { /// Self(cast) /// } else { None } /// } /// } /// ``` pub trait Extension: Sized + Clone + Send + Sync + 'static { #[cfg(target_arch = "wasm32")] fn from_js(value: JsValue) -> Option<Self>; } /// A map of keyed extensions. /// The key is only used for JS interop, /// the Rust version uses the type as the key. /// /// This is usually instantiated by the [`ext![]`](./macro.ext!.html) macro. pub struct ExtensionMap { rust: HashMap<TypeId, Box<dyn Any>>, #[cfg(target_arch = "wasm32")] js: JsValue } // SAFETY: JavaScript doesn't have multi-threading // The only non-send value is the pointer in JsValue unsafe impl Send for ExtensionMap {} // SAFETY: JavaScript doesn't have multi-threading // The only non-send value is the pointer in JsValue unsafe impl Sync for ExtensionMap {} impl Default for ExtensionMap { fn default() -> Self { Self { rust: HashMap::new(), #[cfg(target_arch = "wasm32")] js: JsValue::NULL } } } impl ExtensionMap { /// Create a new extension map. /// This is usually just called by the [`ext![]`](./macro.ext!.html) macro. pub fn new() -> Self { Self::default() } /// Creates a new map from a JavaScript value. /// This is used internally but must be public due to use in the /// [`wasm_client!`](./macro.wasm_client!.html) macro. #[cfg(target_arch = "wasm32")] pub fn from_js(value: JsValue) -> Option<Self> { if value.is_object() { Some(Self { rust: HashMap::new(), js: value }) } else { None } } /// Insert a value into the map. /// This is usually called by the [`ext![]`](./macro.ext!.html) macro. pub fn insert<T: Extension>(&mut self, value: T) { self.rust.insert(TypeId::of::<T>(), Box::new(value)); } /// Get a value from the map. /// The key is only used to get the value out of the JavaScript object, /// if the extension was inserted on the Rust side it doesn't do anything. pub fn get<T: Extension, S: Into<String>>(&self, js_key: S) -> Option<T> { self.get_rust().or_else(|| self.get_js(js_key.into())) } #[cfg(target_arch = "wasm32")] fn get_js<T: Extension>(&self, js_key: String) -> Option<T> { let key: JsValue = js_key.into(); js_sys::Reflect::get(&self.js, &key) .ok() .and_then(|value| T::from_js(value)) } #[cfg(not(target_arch = "wasm32"))] fn get_js<T: Extension>(&self, _js_key: String) -> Option<T> { None } fn get_rust<T: Extension>(&self) -> Option<T> { self.rust .get(&TypeId::of::<T>()) .map(|boxed| (&*boxed).downcast_ref().unwrap()) .map(Clone::clone) } } /// A thread-safe wrapper around [ExtensionMap](./struct.ExtensionMap.html). pub type Extensions = Arc<ExtensionMap>; /// Options that can be passed to a query. /// This will be combined with `ClientOptions`, but `QueryOptions` takes precedence. #[derive(Default, Clone)] pub struct QueryOptions { /// The URL of your GraphQL Endpoint pub url: Option<String>, /// A function that returns extra headers. This is a function to allow for dynamic creation /// of things such as authorization headers pub extra_headers: Option<Arc<dyn Fn() -> Vec<HeaderPair> + Send + Sync>>, /// The policy to use for this request. See `RequestPolicy` pub request_policy: Option<RequestPolicy>, /// Extra extensions passed to the exchanges. Allows for configuration of custom exchanges. pub extensions: Option<Extensions> } /// Client trait passed to exchanges. Only exposes methods useful to exchanges pub trait Client: Clone + Send + Sync + 'static { /// Rerun a query with that key and push the result to all subscribers. fn rerun_query(&self, query_key: u64); /// Push a new result to any subscribers. fn push_result<R>(&self, query_key: u64, result: ExchangeResult<R>) where R: DeserializeOwned + Send + Sync + Clone + 'static; }