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// Copyright 2020 Oxide Computer Company /*! * Interface for implementing HTTP endpoint handler functions. * * For information about supported endpoint function signatures, argument types, * extractors, and return types, see the top-level documentation for this crate. * As documented there, we support several different sets of function arguments * and return types. * * We allow for variation in the function arguments not so much for programmer * convenience (since parsing the query string or JSON body could be implemented * in a line or two of code each, with the right helper functions) but rather so * that the type signature of the handler function can be programmatically * analyzed to generate an OpenAPI snippet for this endpoint. This approach of * treating the server implementation as the source of truth for the API * specification ensures that--at least in many important ways--the * implementation cannot diverge from the spec. * * Just like we want API input types to be represented in function arguments, we * want API response types to be represented in function return values so that * OpenAPI tooling can identify them at build time. The more specific a type * returned by the handler function, the more can be validated at build-time, * and the more specific an OpenAPI schema can be generated from the source * alone. * * We go through considerable effort below to make this interface possible. * Both the interface (primarily) and the implementation (less so) are inspired * by Actix-Web. The Actix implementation is significantly more general (and * commensurately complex). It would be possible to implement richer facilities * here, like extractors for backend server state, headers, and so on; allowing * for server and request parameters to be omitted; and so on; but those other * facilities don't seem that valuable right now since they largely don't affect * OpenAPI document generation. */ use super::error::HttpError; use super::http_util::http_extract_path_params; use super::http_util::http_read_body; use super::http_util::CONTENT_TYPE_JSON; use super::server::DropshotState; use crate::api_description::ApiEndpointParameter; use crate::api_description::ApiEndpointParameterLocation; use crate::api_description::ApiEndpointResponse; use crate::api_description::ApiSchemaGenerator; use crate::pagination::PaginationParams; use async_trait::async_trait; use futures::lock::Mutex; use http::StatusCode; use hyper::Body; use hyper::Request; use hyper::Response; use schemars::JsonSchema; use serde::de::DeserializeOwned; use serde::Serialize; use slog::Logger; use std::cmp::min; use std::collections::BTreeMap; use std::convert::TryFrom; use std::fmt::Debug; use std::fmt::Formatter; use std::fmt::Result as FmtResult; use std::future::Future; use std::marker::PhantomData; use std::num::NonZeroUsize; use std::sync::Arc; /** * Type alias for the result returned by HTTP handler functions. */ pub type HttpHandlerResult = Result<Response<Body>, HttpError>; /** * Handle for various interfaces useful during request processing. */ /* * TODO-cleanup What's the right way to package up "request"? The only time we * need it to be mutable is when we're reading the body (e.g., as part of the * JSON extractor). In order to support that, we wrap it in something that * supports interior mutability. It also needs to be thread-safe, since we're * using async/await. That brings us to Arc<Mutex<...>>, but it seems like * overkill since it will only really be used by one thread at a time (at all, * let alone mutably) and there will never be contention on the Mutex. */ pub struct RequestContext { /** shared server state */ pub server: Arc<DropshotState>, /** HTTP request details */ pub request: Arc<Mutex<Request<Body>>>, /** HTTP request routing variables */ pub path_variables: BTreeMap<String, String>, /** unique id assigned to this request */ pub request_id: String, /** logger for this specific request */ pub log: Logger, } impl RequestContext { /** * Returns the appropriate count of items to return for a paginated request * * This first looks at any client-requested limit and clamps it based on the * server-configured maximum page size. If the client did not request any * particular limit, this function returns the server-configured default * page size. */ pub fn page_limit<ScanParams, PageSelector>( &self, pag_params: &PaginationParams<ScanParams, PageSelector>, ) -> Result<NonZeroUsize, HttpError> where ScanParams: DeserializeOwned, PageSelector: DeserializeOwned + Serialize, { let server_config = &self.server.config; Ok(pag_params .limit /* * Convert the client-provided limit from a NonZeroU64 to a * usize. That's because internally, we want the limit to be a * "usize" so we can use functions like `iter.take()` with it (as an * example). We could put "usize" in the public interface, but that * would cause the server's exported interface to change when it was * built differently, although that's arguably correct. Instead, we * essentially validate here that the client gave us a value that we * can support. */ .map(|limit_nzu64| usize::try_from(limit_nzu64.get())) .transpose() .map_err(|_| { HttpError::for_bad_request( None, String::from("unsupported pagination limit: too large"), ) })? /* * Compare the client-provided limit to the configured max for the * server and take the smaller one. */ .map(|limit_usize| { let limit_nzusize = NonZeroUsize::new(limit_usize).unwrap(); min(limit_nzusize, server_config.page_max_nitems) }) /* * If no limit was provided by the client, use the configured * default. */ .unwrap_or(server_config.page_default_nitems)) } } /** * `Extractor` defines an interface allowing a type to be constructed from a * `RequestContext`. Unlike most traits, `Extractor` essentially defines only a * constructor function, not instance functions. * * The extractors that we provide (`Query`, `Path`, `TypedBody`) implement * `Extractor` in order to construct themselves from the request. For example, * `Extractor` is implemented for `Query<Q>` with a function that reads the * query string from the request, parses it, and constructs a `Query<Q>` with * it. * * We also define implementations of `Extractor` for tuples of types that * themselves implement `Extractor`. See the implementation of * `HttpRouteHandler` for more on why this needed. */ #[async_trait] pub trait Extractor: Send + Sync + Sized { /** * Construct an instance of this type from a `RequestContext`. */ async fn from_request( rqctx: Arc<RequestContext>, ) -> Result<Self, HttpError>; fn metadata() -> Vec<ApiEndpointParameter>; } /** * `impl_derived_for_tuple!` defines implementations of `Extractor` for tuples * whose elements themselves implement `Extractor`. */ macro_rules! impl_extractor_for_tuple { ($( $T:ident),*) => { #[async_trait] impl< $($T: Extractor + 'static,)* > Extractor for ($($T,)*) { async fn from_request(_rqctx: Arc<RequestContext>) -> Result<( $($T,)* ), HttpError> { Ok( ($($T::from_request(Arc::clone(&_rqctx)).await?,)* ) ) } fn metadata() -> Vec<ApiEndpointParameter> { #[allow(unused_mut)] let mut v = vec![]; $( v.append(&mut $T::metadata()); )* v } } }} impl_extractor_for_tuple!(); impl_extractor_for_tuple!(T1); impl_extractor_for_tuple!(T1, T2); impl_extractor_for_tuple!(T1, T2, T3); /** * `HttpHandlerFunc` is a trait providing a single function, `handle_request()`, * which takes an HTTP request and produces an HTTP response (or * `HttpError`). * * As described above, handler functions can have a number of different * signatures. They all consume a reference to the current request context. * They may also consume some number of extractor arguments. The * `HttpHandlerFunc` trait is parametrized by the type `FuncParams`, which is * expected to be a tuple describing these extractor arguments. * * Below, we define implementations of `HttpHandlerFunc` for various function * types. In this way, we can treat functions with different signatures as * different kinds of `HttpHandlerFunc`. However, since the signature shows up * in the `FuncParams` type parameter, we'll need additional abstraction to * treat different handlers interchangeably. See `RouteHandler` below. */ #[async_trait] pub trait HttpHandlerFunc<FuncParams, ResponseType>: Send + Sync + 'static where FuncParams: Extractor, ResponseType: HttpResponse + Send + Sync + 'static, { async fn handle_request( &self, rqctx: Arc<RequestContext>, p: FuncParams, ) -> HttpHandlerResult; } /** * Defines an implementation of the `HttpHandlerFunc` trait for functions * matching one of the supported signatures for HTTP endpoint handler functions. * We use a macro to do this because we need to provide different * implementations for functions that take 0 arguments, 1 argument, 2 arguments, * etc., but the implementations are almost identical. */ /* * For background: as the module-level documentation explains, we want to * support API endpoint handler functions that vary in their signature so that * the signature can accurately reflect details about their expected input and * output instead of a generic `Request -> Response` description. The * `HttpHandlerFunc` trait defines an interface for invoking one of these * functions. This macro defines an implementation of `HttpHandlerFunc` that * says how to take any of these HTTP endpoint handler function and provide that * uniform interface for callers. The implementation essentially does three * things: * * 1. Converts the uniform arguments of `handle_request()` into the appropriate * arguments for the underlying function. This is easier than it sounds at * this point because we require that one of the arguments be a tuple whose * types correspond to the argument types for the function, so we just need * to unpack them from the tuple into function arguments. * * 2. Converts a call to the `handle_request()` method into a call to the * underlying function. * * 3. Converts the return type of the underlying function into the uniform * return type expected by callers of `handle_request()`. This, too, is * easier than it sounds because we require that the return value implement * `HttpResponse`. * * As mentioned above, we're implementing the trait `HttpHandlerFunc` on _any_ * type `FuncType` that matches the trait bounds below. In particular, it must * take a request context argument and whatever other type parameters have been * passed to this macro. * * The function's return type deserves further explanation. (Actually, these * functions all return a `Future`, but for convenience when we say "return * type" in the comments here we're referring to the output type of the returned * future.) Again, as described above, we'd like to allow HTTP endpoint * functions to return a variety of different return types that are ultimately * converted into `Result<Response<Body>, HttpError>`. To do that, the trait * bounds below say that the function must produce a `Result<ResponseType, * HttpError>` where `ResponseType` is a type that implements `HttpResponse`. * We provide a few implementations of the trait `HttpTypedResponse` that * includes a HTTP status code and structured output. In addition we allow for * functions to hand-craft a `Response<Body>`. For both we implement * `HttpResponse` (trivially in the latter case). * * 1. Handler function * | * | returns: * v * 2. Result<ResponseType, HttpError> * | * | This may fail with an HttpError which we return immediately. * | On success, this will be Ok(ResponseType) for some specific * | ResponseType that implements HttpResponse. We'll end up * | invoking: * v * 3. ResponseType::to_result() * | * | This is a type-specific conversion from `ResponseType` into * | `Response<Body>` that's allowed to fail with an `HttpError`. * v * 4. Result<Response<Body>, HttpError> * * Note that the handler function may fail due to an internal error *or* the * conversion to JSON may successively fail in the call to * `serde_json::to_string()`. * * The `HttpResponse` trait lets us handle both generic responses via * `Response<Body>` as well as more structured responses via structures * implementing `HttpResponse<Body = Type>`. The latter gives us a typed * structure as well as response code that we use to generate rich OpenAPI * content. * * Note: the macro parameters really ought to be `$i:literal` and `$T:ident`, * however that causes us to run afoul of issue dtolnay/async-trait#46. The * workaround is to make both parameters `tt` (token tree). */ macro_rules! impl_HttpHandlerFunc_for_func_with_params { ($(($i:tt, $T:tt)),*) => { #[async_trait] impl<FuncType, FutureType, ResponseType, $($T,)*> HttpHandlerFunc<($($T,)*), ResponseType> for FuncType where FuncType: Fn(Arc<RequestContext>, $($T,)*) -> FutureType + Send + Sync + 'static, FutureType: Future<Output = Result<ResponseType, HttpError>> + Send + 'static, ResponseType: HttpResponse + Send + Sync + 'static, $($T: Extractor + Send + Sync + 'static,)* { async fn handle_request( &self, rqctx: Arc<RequestContext>, _param_tuple: ($($T,)*) ) -> HttpHandlerResult { let response: ResponseType = (self)(rqctx, $(_param_tuple.$i,)*).await?; response.to_result() } } }} impl_HttpHandlerFunc_for_func_with_params!(); impl_HttpHandlerFunc_for_func_with_params!((0, T0)); impl_HttpHandlerFunc_for_func_with_params!((0, T1), (1, T2)); impl_HttpHandlerFunc_for_func_with_params!((0, T1), (1, T2), (2, T3)); /** * `RouteHandler` abstracts an `HttpHandlerFunc<FuncParams, ResponseType>` in a * way that allows callers to invoke the handler without knowing the handler's * function signature. * * The "Route" in `RouteHandler` refers to the fact that this structure is used * to record that a specific handler has been attached to a specific HTTP route. */ #[async_trait] pub trait RouteHandler: Debug + Send + Sync { /** * Returns a description of this handler. This might be a function name, * for example. This is not guaranteed to be unique. */ fn label(&self) -> &str; /** * Handle an incoming HTTP request. */ async fn handle_request(&self, rqctx: RequestContext) -> HttpHandlerResult; } /** * `HttpRouteHandler` is the only type that implements `RouteHandler`. The * reason both exist is that we need `HttpRouteHandler::new()` to consume an * arbitrary kind of `HttpHandlerFunc<FuncParams>` and return an object that's * _not_ parametrized by `FuncParams`. In fact, the resulting * `HttpRouteHandler` _is_ parametrized by `FuncParams`, but we returned it * as a `RouteHandler` that does not have those type parameters, allowing the * caller to ignore the differences between different handler function type * signatures. */ pub struct HttpRouteHandler<HandlerType, FuncParams, ResponseType> where HandlerType: HttpHandlerFunc<FuncParams, ResponseType>, FuncParams: Extractor, ResponseType: HttpResponse + Send + Sync + 'static, { /** the actual HttpHandlerFunc used to implement this route */ handler: HandlerType, /** debugging label for the handler */ label: String, /** * In order to define `new()` below, we need a type parameter `HandlerType` * that implements `HttpHandlerFunc<FuncParams>`, which means we also need a * `FuncParams` type parameter. However, this type parameter would be * unconstrained, which makes Rust upset. Use of PhantomData<FuncParams> * here causes the compiler to behave as though this struct referred to a * `FuncParams`, which allows us to use the type parameter below. */ phantom: PhantomData<(FuncParams, ResponseType)>, } impl<HandlerType, FuncParams, ResponseType> Debug for HttpRouteHandler<HandlerType, FuncParams, ResponseType> where HandlerType: HttpHandlerFunc<FuncParams, ResponseType>, FuncParams: Extractor, ResponseType: HttpResponse + Send + Sync + 'static, { fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult { write!(f, "handler: {}", self.label) } } #[async_trait] impl<HandlerType, FuncParams, ResponseType> RouteHandler for HttpRouteHandler<HandlerType, FuncParams, ResponseType> where HandlerType: HttpHandlerFunc<FuncParams, ResponseType>, FuncParams: Extractor + 'static, ResponseType: HttpResponse + Send + Sync + 'static, { fn label(&self) -> &str { &self.label } async fn handle_request( &self, rqctx_raw: RequestContext, ) -> HttpHandlerResult { /* * This is where the magic happens: in the code below, `funcparams` has * type `FuncParams`, which is a tuple type describing the extractor * arguments to the handler function. This could be `()`, `(Query<Q>)`, * `(TypedBody<J>)`, `(Query<Q>, TypedBody<J>)`, or any other * combination of extractors we decide to support in the future. * Whatever it is must implement `Extractor`, which means we can invoke * `Extractor::from_request()` to construct the argument tuple, * generally from information available in the `request` object. We * pass this down to the `HttpHandlerFunc`, for which there's a * different implementation for each value of `FuncParams`. The * `HttpHandlerFunc` for each `FuncParams` just pulls the arguments out * of the `funcparams` tuple and makes them actual function arguments * for the actual handler function. From this point down, all of this * is resolved statically.makes them actual function arguments for the * actual handler function. From this point down, all of this is * resolved statically. */ let rqctx = Arc::new(rqctx_raw); let funcparams = Extractor::from_request(Arc::clone(&rqctx)).await?; let future = self.handler.handle_request(rqctx, funcparams); future.await } } /* * Public interfaces */ impl<HandlerType, FuncParams, ResponseType> HttpRouteHandler<HandlerType, FuncParams, ResponseType> where HandlerType: HttpHandlerFunc<FuncParams, ResponseType>, FuncParams: Extractor + 'static, ResponseType: HttpResponse + Send + Sync + 'static, { /** * Given a function matching one of the supported API handler function * signatures, return a RouteHandler that can be used to respond to HTTP * requests using this function. */ pub fn new(handler: HandlerType) -> Box<dyn RouteHandler> { HttpRouteHandler::new_with_name(handler, "<unlabeled handler>") } /** * Given a function matching one of the supported API handler function * signatures, return a RouteHandler that can be used to respond to HTTP * requests using this function. */ pub fn new_with_name( handler: HandlerType, label: &str, ) -> Box<dyn RouteHandler> { Box::new(HttpRouteHandler { label: label.to_string(), handler, phantom: PhantomData, }) } } /* * Extractors */ /* * Query: query string extractor */ /** * `Query<QueryType>` is an extractor used to deserialize an instance of * `QueryType` from an HTTP request's query string. `QueryType` is any * structure of yours that implements `serde::Deserialize`. See this module's * documentation for more information. */ pub struct Query<QueryType: DeserializeOwned + JsonSchema + Send + Sync> { inner: QueryType, } impl<QueryType: DeserializeOwned + JsonSchema + Send + Sync> Query<QueryType> { /* * TODO drop this in favor of Deref? + Display and Debug for convenience? */ pub fn into_inner(self) -> QueryType { self.inner } } /** * Given an HTTP request, pull out the query string and attempt to deserialize * it as an instance of `QueryType`. */ fn http_request_load_query<QueryType>( request: &Request<Body>, ) -> Result<Query<QueryType>, HttpError> where QueryType: DeserializeOwned + JsonSchema + Send + Sync, { let raw_query_string = request.uri().query().unwrap_or(""); /* * TODO-correctness: are query strings defined to be urlencoded in this way? */ match serde_urlencoded::from_str(raw_query_string) { Ok(q) => Ok(Query { inner: q, }), Err(e) => Err(HttpError::for_bad_request( None, format!("unable to parse query string: {}", e), )), } } /* * The `Extractor` implementation for Query<QueryType> describes how to construct * an instance of `Query<QueryType>` from an HTTP request: namely, by parsing * the query string to an instance of `QueryType`. * TODO-cleanup We shouldn't have to use the "'static" bound on `QueryType` * here. It seems like we ought to be able to use 'async_trait, but that * doesn't seem to be defined. */ #[async_trait] impl<QueryType> Extractor for Query<QueryType> where QueryType: JsonSchema + DeserializeOwned + Send + Sync + 'static, { async fn from_request( rqctx: Arc<RequestContext>, ) -> Result<Query<QueryType>, HttpError> { let request = rqctx.request.lock().await; http_request_load_query(&request) } fn metadata() -> Vec<ApiEndpointParameter> { QueryType::metadata(&ApiEndpointParameterLocation::Query) } } /* * Path: path parameter string extractor */ /** * `Path<PathType>` is an extractor used to deserialize an instance of * `PathType` from an HTTP request's path parameters. `PathType` is any * structure of yours that implements `serde::Deserialize`. See this module's * documentation for more information. */ pub struct Path<PathType: JsonSchema + Send + Sync> { inner: PathType, } impl<PathType: JsonSchema + Send + Sync> Path<PathType> { /* * TODO drop this in favor of Deref? + Display and Debug for convenience? */ pub fn into_inner(self) -> PathType { self.inner } } /* * The `Extractor` implementation for Path<PathType> describes how to construct * an instance of `Path<QueryType>` from an HTTP request: namely, by extracting * parameters from the query string. */ #[async_trait] impl<PathType> Extractor for Path<PathType> where PathType: DeserializeOwned + JsonSchema + Send + Sync + 'static, { async fn from_request( rqctx: Arc<RequestContext>, ) -> Result<Path<PathType>, HttpError> { let params: PathType = http_extract_path_params(&rqctx.path_variables)?; Ok(Path { inner: params, }) } fn metadata() -> Vec<ApiEndpointParameter> { PathType::metadata(&ApiEndpointParameterLocation::Path) } } /** * Convenience trait to generate parameter metadata from types implementing * `JsonSchema` for use with `Query` and `Path` `Extractors`. */ pub(crate) trait GetMetadata { fn metadata( loc: &ApiEndpointParameterLocation, ) -> Vec<ApiEndpointParameter>; } impl<ParamType> GetMetadata for ParamType where ParamType: JsonSchema, { fn metadata( loc: &ApiEndpointParameterLocation, ) -> Vec<ApiEndpointParameter> { /* * Generate the type for `ParamType` then pluck out each member of * the structure to encode as an individual parameter. */ let mut generator = schemars::gen::SchemaGenerator::new( schemars::gen::SchemaSettings::openapi3().with(|settings| { /* * Strip off any definitions prefix so that we can lookup * references simply. Ideally we would force no references to * be generated, but that doesn't seem to be an option. */ settings.definitions_path = String::new(); }), ); let schema = ParamType::json_schema(&mut generator); schema2parameters(loc, &schema, generator.definitions(), true) } } /** * This helper function produces a list of parameters. It is invoked * recursively with subschemas, which we will encounter in the case of enums * and structs that have been flattened into the containing structure. The * top-level structure must be flat--unflattened substructures will result * in an error. * * - `loc` is the input to GetMetadata::metadata, query or path parameters. * - `schema` is what we're processing. * - `definitions` is the map of referenced schemas created in the generation * step (as noted above, we would ideally just have these all inline). * - `required` defines whether parameters are required. In the case of an * enum (which results in an `any_of` subschema) we set this as `false` for * all subschemas. There doesn't seem to be a way to express in OpenAPI * collections of co-required or mutually exclusive parameters. */ fn schema2parameters( loc: &ApiEndpointParameterLocation, schema: &schemars::schema::Schema, definitions: &schemars::Map<String, schemars::schema::Schema>, required: bool, ) -> Vec<ApiEndpointParameter> { /* * We ignore schema.metadata, which includes things like doc comments, and * schema.extensions. We call these out explicitly rather than .. since we * match all other fields in the structure. */ match schema { /* We expect references to be on their own. */ schemars::schema::Schema::Object(schemars::schema::SchemaObject { metadata: _, instance_type: None, format: None, enum_values: None, const_value: None, subschemas: None, number: None, string: None, array: None, object: None, reference: Some(refstr), extensions: _, }) => match definitions.get(refstr) { // Recur on the referenced type. Some(refschema) => { schema2parameters(loc, refschema, definitions, required) } // This should not be possible. None => panic!("invalid reference {}", refstr), }, // Match objects and subschemas. schemars::schema::Schema::Object(schemars::schema::SchemaObject { metadata: _, // TODO: should be Some(schemars::schema::SingleOrVec::Single(_)) instance_type: _, format: None, enum_values: None, const_value: None, subschemas, number: None, string: None, array: None, object, reference: None, extensions: _, }) => { let mut parameters = vec![]; // If there's a local object, add its members to the list of // parameters. if let Some(object) = object { parameters.extend(object.properties.iter().map( |(name, schema)| { ApiEndpointParameter::new_named( loc, name.clone(), None, required && object.required.contains(name), ApiSchemaGenerator::Static(schema.clone()), vec![], ) }, )); } // We might see subschemas here in the case of flattened enums // or flattened structures that have associated doc comments. if let Some(subschemas) = subschemas { match subschemas.as_ref() { // We expect any_of in the case of an enum. schemars::schema::SubschemaValidation { all_of: None, any_of: Some(schemas), one_of: None, not: None, if_schema: None, then_schema: None, else_schema: None, } => parameters.extend(schemas.iter().flat_map( |subschema| { // Note that all these parameters will be optional. schema2parameters( loc, subschema, definitions, false, ) }, )), // With an all_of, there should be a single element. We // typically see this in the case where there is a doc // comment on a structure as OpenAPI 3.0.x doesn't have // a description field directly on schemas. schemars::schema::SubschemaValidation { all_of: Some(schemas), any_of: None, one_of: None, not: None, if_schema: None, then_schema: None, else_schema: None, } if schemas.len() == 1 => parameters.extend( schemas.iter().flat_map(|subschema| { schema2parameters( loc, subschema, definitions, required, ) }), ), // We don't expect any other types of subschemas. invalid => panic!("invalid subschema {:#?}", invalid), } } parameters } /* * The generated schema should be an object. */ invalid => panic!("invalid type {:#?}", invalid), } } /* * JSON: json body extractor */ /** * `TypedBody<BodyType>` is an extractor used to deserialize an instance of * `BodyType` from an HTTP request body. `BodyType` is any structure of yours * that implements `serde::Deserialize`. See this module's documentation for * more information. */ pub struct TypedBody<BodyType: JsonSchema + DeserializeOwned + Send + Sync> { inner: BodyType, } impl<BodyType: JsonSchema + DeserializeOwned + Send + Sync> TypedBody<BodyType> { /* * TODO drop this in favor of Deref? + Display and Debug for convenience? */ pub fn into_inner(self) -> BodyType { self.inner } } /** * Given an HTTP request, attempt to read the body, parse it as JSON, and * deserialize an instance of `BodyType` from it. */ async fn http_request_load_json_body<BodyType>( rqctx: Arc<RequestContext>, ) -> Result<TypedBody<BodyType>, HttpError> where BodyType: JsonSchema + DeserializeOwned + Send + Sync, { let server = &rqctx.server; let mut request = rqctx.request.lock().await; let body_bytes = http_read_body( request.body_mut(), server.config.request_body_max_bytes, ) .await?; let value: Result<BodyType, serde_json::Error> = serde_json::from_slice(&body_bytes); match value { Ok(j) => Ok(TypedBody { inner: j, }), Err(e) => Err(HttpError::for_bad_request( None, format!("unable to parse body: {}", e), )), } } /* * The `Extractor` implementation for TypedBody<BodyType> describes how to * construct an instance of `TypedBody<BodyType>` from an HTTP request: namely, * by reading the request body and parsing it as JSON into type `BodyType`. * TODO-cleanup We shouldn't have to use the "'static" bound on `BodyType` here. * It seems like we ought to be able to use 'async_trait, but that doesn't seem * to be defined. */ #[async_trait] impl<BodyType> Extractor for TypedBody<BodyType> where BodyType: JsonSchema + DeserializeOwned + Send + Sync + 'static, { async fn from_request( rqctx: Arc<RequestContext>, ) -> Result<TypedBody<BodyType>, HttpError> { http_request_load_json_body(rqctx).await } fn metadata() -> Vec<ApiEndpointParameter> { vec![ApiEndpointParameter::new_body( None, true, ApiSchemaGenerator::Gen { name: BodyType::schema_name, schema: BodyType::json_schema, }, vec![], )] } } /* * Response Type Conversion * * See the discussion on macro `impl_HttpHandlerFunc_for_func_with_params` for a * great deal of context on this. */ /** * HttpResponse must produce a `Result<Response<Body>, HttpError>` and generate * the response metadata. Typically one should use `Response<Body>` or an * implementation of `HttpTypedResponse`. */ pub trait HttpResponse { /** * Generate the response to the HTTP call. */ fn to_result(self) -> HttpHandlerResult; /** * Extract status code and structure metadata for the non-error response. * Type information for errors is handled generically across all endpoints. */ fn metadata() -> ApiEndpointResponse; } /** * `Response<Body>` is used for free-form responses. The implementation of * `to_result()` is trivial, and we don't have any typed metadata to return. */ impl HttpResponse for Response<Body> { fn to_result(self) -> HttpHandlerResult { Ok(self) } fn metadata() -> ApiEndpointResponse { ApiEndpointResponse { schema: None, success: None, description: None, } } } /* * Specific Response Types * * The `HttpTypedResponse` trait and the concrete types below are provided so * that handler functions can return types that indicate at compile time the * kind of HTTP response body they produce. */ /** * The `HttpTypedResponse` trait is used for all of the specific response types * that we provide. We use it in particular to encode the success status code * and the type information of the return value. */ pub trait HttpTypedResponse: Into<HttpHandlerResult> + Send + Sync + 'static { type Body: JsonSchema + Serialize; const STATUS_CODE: StatusCode; const DESCRIPTION: &'static str; /** * Convenience method to produce a response based on the input * `body_object` (whose specific type is defined by the implementing type) * and the STATUS_CODE specified by the implementing type. This is a default * trait method to allow callers to avoid redundant type specification. */ fn for_object(body_object: &Self::Body) -> HttpHandlerResult { let serialized = serde_json::to_string(&body_object) .map_err(|e| HttpError::for_internal_error(e.to_string()))?; Ok(Response::builder() .status(Self::STATUS_CODE) .header(http::header::CONTENT_TYPE, CONTENT_TYPE_JSON) .body(serialized.into())?) } } /** * Provide results and metadata generation for all implementing types. */ impl<T> HttpResponse for T where T: HttpTypedResponse, { fn to_result(self) -> HttpHandlerResult { self.into() } fn metadata() -> ApiEndpointResponse { ApiEndpointResponse { schema: Some(ApiSchemaGenerator::Gen { name: T::Body::schema_name, schema: T::Body::json_schema, }), success: Some(T::STATUS_CODE), description: Some(T::DESCRIPTION.to_string()), } } } /** * `HttpResponseCreated<T: Serialize>` wraps an object of any serializable type. * It denotes an HTTP 201 "Created" response whose body is generated by * serializing the object. */ /* * TODO-cleanup should ApiObject move into this submodule? It'd be nice if we * could restrict this to an ApiObject::View (by having T: ApiObject and the * field having type T::View). */ pub struct HttpResponseCreated< T: JsonSchema + Serialize + Send + Sync + 'static, >(pub T); impl<T: JsonSchema + Serialize + Send + Sync + 'static> HttpTypedResponse for HttpResponseCreated<T> { type Body = T; const STATUS_CODE: StatusCode = StatusCode::CREATED; const DESCRIPTION: &'static str = "successful creation"; } impl<T: JsonSchema + Serialize + Send + Sync + 'static> From<HttpResponseCreated<T>> for HttpHandlerResult { fn from(response: HttpResponseCreated<T>) -> HttpHandlerResult { /* TODO-correctness (or polish?): add Location header */ HttpResponseCreated::for_object(&response.0) } } /** * `HttpResponseAccepted<T: Serialize>` wraps an object of any * serializable type. It denotes an HTTP 202 "Accepted" response whose body is * generated by serializing the object. */ pub struct HttpResponseAccepted< T: JsonSchema + Serialize + Send + Sync + 'static, >(pub T); impl<T: JsonSchema + Serialize + Send + Sync + 'static> HttpTypedResponse for HttpResponseAccepted<T> { type Body = T; const STATUS_CODE: StatusCode = StatusCode::ACCEPTED; const DESCRIPTION: &'static str = "successfully enqueued operation"; } impl<T: JsonSchema + Serialize + Send + Sync + 'static> From<HttpResponseAccepted<T>> for HttpHandlerResult { fn from(response: HttpResponseAccepted<T>) -> HttpHandlerResult { HttpResponseAccepted::for_object(&response.0) } } /** * `HttpResponseOk<T: Serialize>` wraps an object of any serializable type. It * denotes an HTTP 200 "OK" response whose body is generated by serializing the * object. */ pub struct HttpResponseOk<T: JsonSchema + Serialize + Send + Sync + 'static>( pub T, ); impl<T: JsonSchema + Serialize + Send + Sync + 'static> HttpTypedResponse for HttpResponseOk<T> { type Body = T; const STATUS_CODE: StatusCode = StatusCode::OK; const DESCRIPTION: &'static str = "successful operation"; } impl<T: JsonSchema + Serialize + Send + Sync + 'static> From<HttpResponseOk<T>> for HttpHandlerResult { fn from(response: HttpResponseOk<T>) -> HttpHandlerResult { HttpResponseOk::for_object(&response.0) } } /** * `HttpResponseDeleted` represents an HTTP 204 "No Content" response, intended * for use when an API operation has successfully deleted an object. */ pub struct HttpResponseDeleted(); impl HttpTypedResponse for HttpResponseDeleted { type Body = (); const STATUS_CODE: StatusCode = StatusCode::NO_CONTENT; const DESCRIPTION: &'static str = "successful deletion"; } impl From<HttpResponseDeleted> for HttpHandlerResult { fn from(_: HttpResponseDeleted) -> HttpHandlerResult { Ok(Response::builder() .status(HttpResponseDeleted::STATUS_CODE) .body(Body::empty())?) } } /** * `HttpResponseUpdatedNoContent` represents an HTTP 204 "No Content" response, * intended for use when an API operation has successfully updated an object and * has nothing to return. */ pub struct HttpResponseUpdatedNoContent(); impl HttpTypedResponse for HttpResponseUpdatedNoContent { type Body = (); const STATUS_CODE: StatusCode = StatusCode::NO_CONTENT; const DESCRIPTION: &'static str = "resource updated"; } impl From<HttpResponseUpdatedNoContent> for HttpHandlerResult { fn from(_: HttpResponseUpdatedNoContent) -> HttpHandlerResult { Ok(Response::builder() .status(HttpResponseUpdatedNoContent::STATUS_CODE) .body(Body::empty())?) } } #[cfg(test)] mod test { use super::GetMetadata; use crate::{ api_description::ApiEndpointParameterName, ApiEndpointParameter, ApiEndpointParameterLocation, PaginationParams, }; use schemars::JsonSchema; use serde::{Deserialize, Serialize}; #[derive(Deserialize, Serialize, JsonSchema)] #[allow(dead_code)] struct A { foo: String, bar: u32, baz: Option<String>, } #[derive(JsonSchema)] #[allow(dead_code)] struct B<T> { #[serde(flatten)] page: T, limit: Option<u64>, } #[derive(JsonSchema)] #[allow(dead_code)] #[schemars(untagged)] enum C<T> { First(T), Next { page_token: String }, } fn compare(actual: Vec<ApiEndpointParameter>, expected: Vec<(&str, bool)>) { /* * This is order-dependent. We might not really care if the order * changes, but it will be interesting to understand why if it does. */ actual.iter().zip(expected.iter()).for_each( |(param, (name, required))| { if let ApiEndpointParameter { name: ApiEndpointParameterName::Path(aname), required: arequired, .. } = param { assert_eq!(aname, name); assert_eq!(arequired, required); } else { panic!(); } }, ); } #[test] fn test_metadata_simple() { let params = A::metadata(&ApiEndpointParameterLocation::Path); let expected = vec![("bar", true), ("baz", false), ("foo", true)]; compare(params, expected); } #[test] fn test_metadata_flattened() { let params = B::<A>::metadata(&ApiEndpointParameterLocation::Path); let expected = vec![ ("bar", true), ("baz", false), ("foo", true), ("limit", false), ]; compare(params, expected); } #[test] fn test_metadata_flattened_enum() { let params = B::<C<A>>::metadata(&ApiEndpointParameterLocation::Path); let expected = vec![ ("limit", false), ("bar", false), ("baz", false), ("foo", false), ("page_token", false), ]; compare(params, expected); } #[test] fn test_metadata_pagination() { let params = PaginationParams::<A, A>::metadata( &ApiEndpointParameterLocation::Path, ); let expected = vec![ ("limit", false), ("page_token", false), ("bar", false), ("baz", false), ("foo", false), ]; compare(params, expected); } }