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#![feature(use_extern_macros)] #[macro_use] extern crate log; #[macro_use] extern crate rocket; extern crate serde; extern crate serde_json; use std::ops::{Deref, DerefMut}; use std::io::Read; use rocket::outcome::IntoOutcome; use rocket::request::Request; use rocket::data::{self, Data, FromData}; use rocket::response::{self, Responder, content}; use rocket::http::Status; use serde::{Serialize, Serializer}; use serde::de::{Deserialize, DeserializeOwned, Deserializer}; pub use serde_json::error::Error as SerdeError; pub use serde_json::json_internal; /// Like [`from_reader`] but eagerly reads the content of the reader to a string /// and delegates to `from_str`. /// /// [`from_reader`]: https://docs.serde.rs/serde_json/fn.from_reader.html fn from_reader_eager<R, T>(mut reader: R) -> serde_json::Result<T> where R: Read, T: DeserializeOwned { let mut s = String::with_capacity(512); if let Err(io_err) = reader.read_to_string(&mut s) { // Error::io is private to serde_json. Do not use outside of Rocket. return Err(SerdeError::io(io_err)); } serde_json::from_str(&s) } /// The JSON type: implements `FromData` and `Responder`, allowing you to easily /// consume and respond with JSON. /// /// ## Receiving JSON /// /// If you're receiving JSON data, simply add a `data` parameter to your route /// arguments and ensure the type of the parameter is a `Json<T>`, where `T` is /// some type you'd like to parse from JSON. `T` must implement `Deserialize` or /// `DeserializeOwned` from [Serde](https://github.com/serde-rs/json). The data /// is parsed from the HTTP request body. /// /// ```rust,ignore /// #[post("/users/", format = "application/json", data = "<user>")] /// fn new_user(user: Json<User>) { /// ... /// } /// ``` /// /// You don't _need_ to use `format = "application/json"`, but it _may_ be what /// you want. Using `format = application/json` means that any request that /// doesn't specify "application/json" as its `Content-Type` header value will /// not be routed to the handler. /// /// ## Sending JSON /// /// If you're responding with JSON data, return a `Json<T>` type, where `T` /// implements `Serialize` from [Serde](https://github.com/serde-rs/json). The /// content type of the response is set to `application/json` automatically. /// /// ```rust,ignore /// #[get("/users/<id>")] /// fn user(id: usize) -> Json<User> { /// let user_from_id = User::from(id); /// ... /// Json(user_from_id) /// } /// ``` /// /// ## Incoming Data Limits /// /// The default size limit for incoming JSON data is 1MiB. Setting a limit /// protects your application from denial of service (DOS) attacks and from /// resource exhaustion through high memory consumption. The limit can be /// increased by setting the `limits.json` configuration parameter. For /// instance, to increase the JSON limit to 5MiB for all environments, you may /// add the following to your `Rocket.toml`: /// /// ```toml /// [global.limits] /// json = 5242880 /// ``` #[derive(Debug)] pub struct Json<T>(pub T); impl<T> Json<T> { /// Consumes the JSON wrapper and returns the wrapped item. /// /// # Example /// ```rust /// # use rocket_lenient_json::Json; /// let string = "Hello".to_string(); /// let my_json = Json(string); /// assert_eq!(my_json.into_inner(), "Hello".to_string()); /// ``` #[inline(always)] pub fn into_inner(self) -> T { self.0 } } /// Default limit for JSON is 1MB. const LIMIT: u64 = 1 << 20; impl<T: DeserializeOwned> FromData for Json<T> { type Error = SerdeError; fn from_data(request: &Request, data: Data) -> data::Outcome<Self, SerdeError> { let size_limit = request.limits().get("json").unwrap_or(LIMIT); from_reader_eager(data.open().take(size_limit)) .map(|val| Json(val)) .map_err(|e| { error_!("Couldn't parse JSON body: {:?}", e); e }) .into_outcome(Status::BadRequest) } } /// Serializes the wrapped value into JSON. Returns a response with Content-Type /// JSON and a fixed-size body with the serialized value. If serialization /// fails, an `Err` of `Status::InternalServerError` is returned. impl<T: Serialize> Responder<'static> for Json<T> { fn respond_to(self, req: &Request) -> response::Result<'static> { serde_json::to_string(&self.0).map(|string| { content::Json(string).respond_to(req).unwrap() }).map_err(|e| { error_!("JSON failed to serialize: {:?}", e); Status::InternalServerError }) } } impl<T> Deref for Json<T> { type Target = T; #[inline(always)] fn deref<'a>(&'a self) -> &'a T { &self.0 } } impl<T> DerefMut for Json<T> { #[inline(always)] fn deref_mut<'a>(&'a mut self) -> &'a mut T { &mut self.0 } } /// An arbitrary JSON value. /// /// This structure wraps `serde`'s [`Value`] type. Importantly, unlike `Value`, /// this type implements [`Responder`], allowing a value of this type to be /// returned directly from a handler. /// /// [`Value`]: https://docs.rs/serde_json/1.0.2/serde_json/value/enum.Value.html /// [`Responder`]: /rocket/response/trait.Responder.html /// /// # `Responder` /// /// The `Responder` implementation for `JsonValue` serializes the represented /// value into a JSON string and sets the string as the body of a fixed-sized /// response with a `Content-Type` of `application/json`. /// /// # Usage /// /// A value of this type is constructed via the /// [`json!`](macro.json.html) macro. The macro and this type /// are typically used to construct JSON values in an ad-hoc fashion during /// request handling. This looks something like: /// /// ```rust,ignore /// use rocket_lenient_json::JsonValue; /// /// #[get("/item")] /// fn get_item() -> JsonValue { /// json!({ /// "id": 83, /// "values": [1, 2, 3, 4] /// }) /// } /// ``` #[derive(Debug, Clone, PartialEq, Default)] pub struct JsonValue(pub serde_json::Value); impl Serialize for JsonValue { fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> { self.0.serialize(serializer) } } impl<'de> Deserialize<'de> for JsonValue { fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> { serde_json::Value::deserialize(deserializer).map(JsonValue) } } impl JsonValue { #[inline(always)] fn into_inner(self) -> serde_json::Value { self.0 } } impl Deref for JsonValue { type Target = serde_json::Value; #[inline(always)] fn deref<'a>(&'a self) -> &'a Self::Target { &self.0 } } impl DerefMut for JsonValue { #[inline(always)] fn deref_mut<'a>(&'a mut self) -> &'a mut Self::Target { &mut self.0 } } impl Into<serde_json::Value> for JsonValue { #[inline(always)] fn into(self) -> serde_json::Value { self.into_inner() } } impl From<serde_json::Value> for JsonValue { #[inline(always)] fn from(value: serde_json::Value) -> JsonValue { JsonValue(value) } } /// Serializes the value into JSON. Returns a response with Content-Type JSON /// and a fixed-size body with the serialized value. impl<'a> Responder<'a> for JsonValue { #[inline] fn respond_to(self, req: &Request) -> response::Result<'a> { content::Json(self.0.to_string()).respond_to(req) } } /// A macro to create ad-hoc JSON serializable values using JSON syntax. /// /// # Usage /// /// To import the macro, add the `#[macro_use]` attribute to the `extern crate /// rocket_lenient_json` invocation: /// /// ```rust,ignore /// #[macro_use] extern crate rocket_lenient_json; /// ``` /// /// The return type of a `json!` invocation is /// [`JsonValue`](struct.JsonValue.html). A value created with /// this macro can be returned from a handler as follows: /// /// ```rust,ignore /// use rocket_lenient_json::JsonValue; /// /// #[get("/json")] /// fn get_json() -> JsonValue { /// json!({ /// "key": "value", /// "array": [1, 2, 3, 4] /// }) /// } /// ``` /// /// The `Responder` implementation for `JsonValue` serializes the value into a /// JSON string and sets it as the body of the response with a `Content-Type` of /// `application/json`. /// /// # Examples /// /// Create a simple JSON object with two keys: `"username"` and `"id"`: /// /// ```rust /// # #![allow(unused_variables)] /// # #[macro_use] extern crate rocket_lenient_json; /// # fn main() { /// let value = json!({ /// "username": "mjordan", /// "id": 23 /// }); /// # } /// ``` /// /// Create a more complex object with a nested object and array: /// /// ```rust /// # #![allow(unused_variables)] /// # #[macro_use] extern crate rocket_lenient_json; /// # fn main() { /// let value = json!({ /// "code": 200, /// "success": true, /// "payload": { /// "features": ["serde", "json"], /// "ids": [12, 121], /// }, /// }); /// # } /// ``` /// /// Variables or expressions can be interpolated into the JSON literal. Any type /// interpolated into an array element or object value must implement Serde's /// `Serialize` trait, while any type interpolated into a object key must /// implement `Into<String>`. /// /// ```rust /// # #![allow(unused_variables)] /// # #[macro_use] extern crate rocket_lenient_json; /// # fn main() { /// let code = 200; /// let features = vec!["serde", "json"]; /// /// let value = json!({ /// "code": code, /// "success": code == 200, /// "payload": { /// features[0]: features[1] /// } /// }); /// # } /// ``` /// /// Trailing commas are allowed inside both arrays and objects. /// /// ```rust /// # #![allow(unused_variables)] /// # #[macro_use] extern crate rocket_lenient_json; /// # fn main() { /// let value = json!([ /// "notice", /// "the", /// "trailing", /// "comma -->", /// ]); /// # } /// ``` #[macro_export] macro_rules! json { ($($json:tt)+) => { $crate::JsonValue(json_internal!($($json)+)) }; }