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// Copyright 2020 Tetrate // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. //! `Envoy` `HTTP Client API`. use std::time::Duration; use crate::host::{self, ByteString, HeaderMap}; pub use crate::abi::proxy_wasm::types::HttpRequestHandle as HttpClientRequestHandle; /// An interface of the `Envoy` `HTTP Client`. /// /// # Examples /// /// #### Basic usage of [`HttpClient`]: /// /// ``` /// # use envoy_sdk as envoy; /// # use envoy::host::Result; /// # fn action() -> Result<()> { /// use std::time::Duration; /// use envoy::host::HttpClient; /// /// let client = HttpClient::default(); /// /// let request_id = client.send_request( /// "cluster_name", /// &[("header", "value")], /// Some(b"request body"), /// Some(&[("trailer", "value")]), /// Duration::from_secs(5), /// )?; /// # Ok(()) /// # } /// ``` /// /// #### Injecting [`HttpClient`] into a HTTP Filter as a dependency: /// /// ``` /// # use envoy_sdk as envoy; /// use envoy::host::HttpClient; /// /// struct MyHttpFilter<'a> { /// http_client: &'a dyn HttpClient, /// } /// /// impl<'a> MyHttpFilter<'a> { /// /// Creates a new instance parameterized with a given [`HttpClient`] implementation. /// pub fn new(http_client: &'a dyn HttpClient) -> Self { /// MyHttpFilter { http_client } /// } /// /// /// Creates a new instance parameterized with the default [`HttpClient`] implementation. /// pub fn default() -> Self { /// Self::new(HttpClient::default()) /// } /// } /// ``` /// /// #### Sending a request and receiving a response inside a `HTTP Filter`: /// /// ``` /// # use envoy_sdk as envoy; /// use std::time::Duration; /// use envoy::error::format_err; /// use envoy::extension::{HttpFilter, Result}; /// use envoy::extension::filter::http::{FilterHeadersStatus, RequestHeadersOps, Ops}; /// use envoy::host::HttpClient; /// use envoy::host::http::client::{HttpClientRequestHandle, HttpClientResponseOps}; /// /// struct MyHttpFilter<'a> { /// http_client: &'a dyn HttpClient, /// /// active_request: Option<HttpClientRequestHandle>, /// } /// /// impl<'a> HttpFilter for MyHttpFilter<'a> { /// fn on_request_headers(&mut self, _num_headers: usize, _end_of_stream: bool, ops: &dyn RequestHeadersOps) -> Result<FilterHeadersStatus> { /// self.http_client.send_request( /// "cluster_name", /// &[("header", "value")], /// Some(b"request body"), /// Some(&[("trailer", "value")]), /// Duration::from_secs(5), /// )?; /// Ok(FilterHeadersStatus::StopIteration) // stop further request processing /// } /// /// fn on_http_call_response( /// &mut self, /// request: HttpClientRequestHandle, /// _num_headers: usize, /// body_size: usize, /// _num_trailers: usize, /// filter_ops: &dyn Ops, /// http_client_ops: &dyn HttpClientResponseOps, /// ) -> Result<()> { /// if self.active_request != Some(request) { /// // don't use `assert!()` to avoid panicing in production code /// return Err(format_err!("received unexpected response from HttpClient")); /// } /// let response_headers = http_client_ops.http_call_response_headers()?; /// let response_body = http_client_ops.http_call_response_body(0, body_size)?; /// # stringify! { /// ... look into response headers and response body ... /// # }; /// filter_ops.resume_request() // resume further request processing /// } /// } /// ``` /// /// [`HttpClient`]: trait.HttpClient.html pub trait HttpClient { /// Sends an HTTP request asynchronously. /// /// # Arguments /// /// * `upstream` - name of `Envoy` `Cluster` to send request to. /// * `headers` - request headers /// * `body` - request body /// * `trailers` - request trailers /// * `timeout` - request timeout /// /// # Return value /// /// opaque [`identifier`][`HttpClientRequestHandle`] of the request sent. Can be used to correlate requests and responses. /// /// [`HttpClientRequestHandle`]: struct.HttpClientRequestHandle.html fn send_request( &self, upstream: &str, headers: &[(&str, &str)], body: Option<&[u8]>, trailers: Option<&[(&str, &str)]>, timeout: Duration, ) -> host::Result<HttpClientRequestHandle>; } impl dyn HttpClient { /// Returns the default implementation that interacts with `Envoy` /// through its [`ABI`]. /// /// [`ABI`]: https://github.com/proxy-wasm/spec pub fn default() -> &'static dyn HttpClient { &impls::Host } } /// An interface for accessing data of the HTTP response received by [`HttpClient`]. /// /// [`HttpClient`]: trait.HttpClient.html pub trait HttpClientResponseOps { fn http_call_response_headers(&self) -> host::Result<HeaderMap>; fn http_call_response_header(&self, name: &str) -> host::Result<Option<ByteString>>; fn http_call_response_body(&self, start: usize, max_size: usize) -> host::Result<ByteString>; fn http_call_response_trailers(&self) -> host::Result<HeaderMap>; fn http_call_response_trailer(&self, name: &str) -> host::Result<Option<ByteString>>; } impl dyn HttpClientResponseOps { /// Returns the default implementation that interacts with `Envoy` /// through its [`ABI`]. /// /// [`ABI`]: https://github.com/proxy-wasm/spec pub fn default() -> &'static dyn HttpClientResponseOps { &impls::Host } } mod impls { use std::time::Duration; use crate::abi::proxy_wasm::hostcalls; use crate::abi::proxy_wasm::types::{BufferType, MapType}; use super::{HttpClient, HttpClientRequestHandle, HttpClientResponseOps}; use crate::host::{self, ByteString, HeaderMap}; pub(super) struct Host; impl HttpClient for Host { fn send_request( &self, upstream: &str, headers: &[(&str, &str)], body: Option<&[u8]>, trailers: Option<&[(&str, &str)]>, timeout: Duration, ) -> host::Result<HttpClientRequestHandle> { hostcalls::dispatch_http_call( upstream, headers, body, trailers.unwrap_or_default(), timeout, ) } } impl HttpClientResponseOps for Host { fn http_call_response_headers(&self) -> host::Result<HeaderMap> { hostcalls::get_map(MapType::HttpCallResponseHeaders) } fn http_call_response_header(&self, name: &str) -> host::Result<Option<ByteString>> { hostcalls::get_map_value(MapType::HttpCallResponseHeaders, name) } fn http_call_response_body( &self, start: usize, max_size: usize, ) -> host::Result<ByteString> { hostcalls::get_buffer(BufferType::HttpCallResponseBody, start, max_size) } fn http_call_response_trailers(&self) -> host::Result<HeaderMap> { hostcalls::get_map(MapType::HttpCallResponseTrailers) } fn http_call_response_trailer(&self, name: &str) -> host::Result<Option<ByteString>> { hostcalls::get_map_value(MapType::HttpCallResponseTrailers, name) } } }