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//! A modern GraphQL Client with common built-in features //! as well as the ability to extend its functionality through exchanges //! //! # Getting Started //! //! The first step is to write some queries in `.graphql` files and then add the following to your //! `build.rs` (create it if necessary): //! //! ```ignore //! use artemis_build::CodegenBuilder; //! //! fn main() { //! CodegenBuilder::new() //! .introspect_schema("http://localhost:8080/graphql", None, Vec::new()) //! .unwrap() //! .add_query("queries/x.graphql") //! .with_out_dir("src/queries") //! .build() //! .unwrap(); //! } //! ``` //! //! Afterwards, you can use the crate in your application as such: //! //! ``` //! # tokio_test::block_on(async { //! use artemis::Client; //! use artemis_test::get_conference::{GetConference, get_conference::Variables}; //! //! let client = Client::builder("http://localhost:8080/graphql") //! .with_default_exchanges() //! .build(); //! //! let result = client.query(GetConference, Variables { id: "1".to_string() }).await.unwrap(); //! assert!(result.data.is_some()); //! # }); //! ``` //! //! For more info see the relevant method and struct documentation. //! //! # Build //! //! This crate uses code generation to take your GraphQL files and turn them into //! strongly typed Rust modules. These contain the query struct, a zero-size type //! such as `GetConference`, as well as a submodule containing the `Variables`, //! any input types, the `ResponseData` type and any involved output types. //! //! Having a strongly typed compile time representation with additional info //! (such as the `__typename` of all involved types and an abstract selection tree) //! means that the work the CPU has to do at runtime is very minimal, //! only amounting to serialization, deserialization and simple lookups using //! the statically generated data. //! //! For details on how to use the query builder, see [artemis-build](../artemis_build/index.html) //! //! # Exchanges //! //! Exchanges are like a bi-directional middleware. //! They act on both the incoming and outgoing queries, //! passing them on if they can't return a result themselves. //! //! There are three default exchanges, called in this order: //! //! ## DedupExchange //! //! The deduplication exchange (`DedupExchange`) filters out unnecessary queries //! by combining multiple identical queries into one. It does so by keeping track //! of in-flight queries and, instead of firing off another identical query, //! waiting for their results instead. This reduces network traffic, //! especially in larger applications where the same query may be used in multiple //! places and run multiple times simultaneously as a result. //! //! ## CacheExchange //! //! The cache exchange is a very basic, un-normalized cache which eagerly invalidates queries. //! It's focused on simplicity and correctness of data, so if a query uses any of the same types //! as a mutation it will always be invalidated by it. This means that especially if you //! have large amounts of different entities of the same type, this can become expensive quickly. //! For a more advanced normalized cache that invalidates only directly related entities //! see the `artemis-normalized-cache` crate. //! //! ## FetchExchange //! //! The fetch exchange will serialize the query, send it over the network and deserialize the response. //! This works on x86 using `reqwest`, or `fetch` if you're using WASM. //! This should be your last exchange in the chain, as it never forwards a query. //! //! # WASM //! //! WASM support requires some minor boilerplate in your code. //! First, there's a `wasm` module in your queries. this contains an automatically generated enum //! containing all your queries. This is used for transmitting type data across the WASM //! boundary. //! //! Second, you have to use the [wasm_client! macro](../artemis_codegen_proc_macro/macro.wasm_client!.html) //! to generate a WASM interop client that has hard-coded types for your queries, again, to //! eliminate the unsupported generics and transmit type data across the boundary. //! The queries type passed to the macro must be the enum generated as mentioned above. //! //! Documentation of the JavaScript types and methods can be found in the TypeScript //! definitions that are output when you build your WASM. //! //! # Features //! //! * `default-exchanges` **(default)** - Include default exchanges and the related builder method //! * `observable` **(default)** - Include support for observable and all related types. Includes //! `tokio` on x86. //#![warn(missing_docs)] //#![deny(warnings)] #[macro_use] extern crate serde; #[macro_use] extern crate async_trait; use std::{collections::HashMap, fmt, fmt::Display}; use types::*; pub mod client; pub mod default_exchanges; mod error; pub(crate) mod types; pub mod utils; #[doc(inline)] pub use artemis_codegen_proc_macro::wasm_client; pub use client::{Client, ClientBuilder}; pub use error::QueryError; use serde::{de::DeserializeOwned, Serialize}; #[cfg(feature = "observable")] pub use types::Observable; pub use types::{ DebugInfo, ExtensionMap, Extensions, HeaderPair, QueryOptions, RequestPolicy, ResultSource }; #[cfg(target_arch = "wasm32")] pub use utils::wasm; /// Types used by custom exchanges. Regular users probably don't need these. pub mod exchange { pub use crate::types::{ Client, Exchange, ExchangeFactory, ExchangeResult, Extension, Operation, OperationMeta, OperationOptions, OperationResult, OperationType }; } /// Types used only by the code generator. Exchanges may use these, but they shouldn't /// be created/implemented manually. pub mod codegen { pub use crate::types::{FieldSelector, QueryInfo}; } /// The form in which queries are sent over HTTP in most implementations. This will be built using the [GraphQLQuery](./trait.GraphQLQuery.html) trait normally. #[derive(Debug, Serialize, Clone)] pub struct QueryBody<Variables: Serialize + Send + Sync + Clone> { /// The values for the variables. They must match those declared in the queries. This should be the `Variables` struct from the generated module corresponding to the query. pub variables: Variables, /// The GraphQL query, as a string. pub query: &'static str, /// The GraphQL operation name, as a string. #[serde(rename = "operationName")] pub operation_name: &'static str } /// A convenience trait that can be used to build a GraphQL request body. /// This will be implemented for you by codegen. It is implemented on the struct you place the derive on. pub trait GraphQLQuery: Send + Sync + 'static { /// The shape of the variables expected by the query. This should be a generated struct most of the time. type Variables: Serialize + Send + Sync + Clone + 'static; /// The top-level shape of the response data (the `data` field in the GraphQL response). In practice this should be generated, since it is hard to write by hand without error. type ResponseData: Serialize + DeserializeOwned + Send + Sync + Clone + 'static + QueryInfo<Self::Variables>; /// Produce a GraphQL query struct that can be JSON serialized and sent to a GraphQL API. fn build_query(variables: Self::Variables) -> (QueryBody<Self::Variables>, OperationMeta); fn selection(variables: &Self::Variables) -> Vec<FieldSelector> { <Self::ResponseData as QueryInfo<Self::Variables>>::selection(variables) } } /// The generic shape taken by the responses of GraphQL APIs. /// /// This will generally be used with the `ResponseData` struct from a derived module. /// /// [Spec](https://github.com/facebook/graphql/blob/master/spec/Section%207%20--%20Response.md) /// /// ``` /// # use serde_json::json; /// # use serde::Deserialize; /// # use artemis::GraphQLQuery; /// # /// # #[derive(Debug, Deserialize, PartialEq, Clone)] /// # struct User { /// # id: i32, /// # } /// # /// # #[derive(Debug, Deserialize, PartialEq, Clone)] /// # struct Dog { /// # name: String /// # } /// # /// # #[derive(Debug, Deserialize, PartialEq, Clone)] /// # struct ResponseData { /// # users: Vec<User>, /// # dogs: Vec<Dog>, /// # } /// # /// # fn main() -> Result<(), Box<dyn std::error::Error>> { /// use artemis::Response; /// /// let body: Response<ResponseData> = serde_json::from_value(json!({ /// "data": { /// "users": [{"id": 13}], /// "dogs": [{"name": "Strelka"}], /// }, /// "errors": [], /// }))?; /// /// let expected: Response<ResponseData> = Response { /// data: Some(ResponseData { /// users: vec![User { id: 13 }], /// dogs: vec![Dog { name: "Strelka".to_owned() }], /// }), /// errors: Some(vec![]), /// debug_info: None /// }; /// /// assert_eq!(body, expected); /// /// # Ok(()) /// # } /// ``` #[derive(Debug, Serialize, Deserialize, PartialEq, Clone)] pub struct Response<Data: Clone> { /// The debug info if in test config, an empty struct otherwise #[serde(skip_deserializing, rename = "debugInfo")] pub debug_info: Option<DebugInfo>, /// The absent, partial or complete response data. pub data: Option<Data>, /// The top-level errors returned by the server. pub errors: Option<Vec<Error>> } /// An element in the top-level `errors` array of a response body. /// /// This tries to be as close to the spec as possible. /// /// [Spec](https://github.com/facebook/graphql/blob/master/spec/Section%207%20--%20Response.md) /// /// /// ``` /// # use serde_json::json; /// # use serde::Deserialize; /// # use artemis::GraphQLQuery; /// # /// # #[derive(Debug, Deserialize, PartialEq, Clone)] /// # struct ResponseData { /// # something: i32 /// # } /// # /// # fn main() -> Result<(), Box<dyn std::error::Error>> { /// use artemis::*; /// /// let body: Response<ResponseData> = serde_json::from_value(json!({ /// "data": null, /// "errors": [ /// { /// "message": "The server crashed. Sorry.", /// "locations": [{ "line": 1, "column": 1 }] /// }, /// { /// "message": "Seismic activity detected", /// "path": ["underground", 20] /// }, /// ], /// }))?; /// /// let expected: Response<ResponseData> = Response { /// data: None, /// errors: Some(vec![ /// Error { /// message: "The server crashed. Sorry.".to_owned(), /// locations: Some(vec![ /// Location { /// line: 1, /// column: 1, /// } /// ]), /// path: None, /// extensions: None, /// }, /// Error { /// message: "Seismic activity detected".to_owned(), /// locations: None, /// path: Some(vec![ /// PathFragment::Key("underground".into()), /// PathFragment::Index(20), /// ]), /// extensions: None, /// }, /// ]), /// debug_info: None /// }; /// /// assert_eq!(body, expected); /// /// # Ok(()) /// # } /// ``` #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)] pub struct Error { /// The human-readable error message. This is the only required field. pub message: String, /// Which locations in the query the error applies to. pub locations: Option<Vec<Location>>, /// Which path in the query the error applies to, e.g. `["users", 0, "email"]`. pub path: Option<Vec<PathFragment>>, /// Additional errors. Their exact format is defined by the server. pub extensions: Option<HashMap<String, serde_json::Value>> } impl Display for Error { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { // Use `/` as a separator like JSON Pointer. let path = self .path .as_ref() .map(|fragments| { fragments .iter() .fold(String::new(), |mut acc, item| { acc.push_str(&format!("{}/", item)); acc }) .trim_end_matches('/') .to_string() }) .unwrap_or_else(|| "<query>".to_string()); // Get the location of the error. We'll use just the first location for this. let loc = self .locations .as_ref() .and_then(|locations| locations.iter().next()) .cloned() .unwrap_or_else(Location::default); write!(f, "{}:{}:{}: {}", path, loc.line, loc.column, self.message) } } /// Part of a path in a query. It can be an object key or an array index. See [Error](./struct.Error.html). #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)] #[serde(untagged)] pub enum PathFragment { /// A key inside an object Key(String), /// An index inside an array Index(i32) } /// Represents a location inside a query string. Used in errors. See [Error](./struct.Error.html). #[derive(Debug, Clone, Copy, Default, Serialize, Deserialize, PartialEq)] pub struct Location { /// The line number in the query string where the error originated (starting from 1). pub line: i32, /// The column number in the query string where the error originated (starting from 1). pub column: i32 } impl Display for PathFragment { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match *self { PathFragment::Key(ref key) => write!(f, "{}", key), PathFragment::Index(ref idx) => write!(f, "{}", idx) } } }