mirror of https://github.com/spikecodes/libreddit
308 lines
9.9 KiB
Rust
308 lines
9.9 KiB
Rust
use cached::proc_macro::cached;
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use futures_lite::{future::Boxed, FutureExt};
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use hyper::client::HttpConnector;
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use hyper::{body, body::Buf, client, header, Body, Client, Method, Request, Response, Uri};
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use hyper_rustls::HttpsConnector;
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use libflate::gzip;
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use once_cell::sync::Lazy;
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use percent_encoding::{percent_encode, CONTROLS};
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use serde_json::Value;
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use std::{io, result::Result};
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use crate::dbg_msg;
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use crate::server::RequestExt;
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const REDDIT_URL_BASE: &str = "https://www.reddit.com";
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static CLIENT: Lazy<Client<HttpsConnector<HttpConnector>>> = Lazy::new(|| {
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let https = hyper_rustls::HttpsConnectorBuilder::new().with_native_roots().https_only().enable_http1().build();
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client::Client::builder().build(https)
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});
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/// Gets the canonical path for a resource on Reddit. This is accomplished by
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/// making a `HEAD` request to Reddit at the path given in `path`.
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///
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/// This function returns `Ok(Some(path))`, where `path`'s value is identical
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/// to that of the value of the argument `path`, if Reddit responds to our
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/// `HEAD` request with a 2xx-family HTTP code. It will also return an
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/// `Ok(Some(String))` if Reddit responds to our `HEAD` request with a
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/// `Location` header in the response, and the HTTP code is in the 3xx-family;
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/// the `String` will contain the path as reported in `Location`. The return
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/// value is `Ok(None)` if Reddit responded with a 3xx, but did not provide a
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/// `Location` header. An `Err(String)` is returned if Reddit responds with a
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/// 429, or if we were unable to decode the value in the `Location` header.
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#[cached(size = 1024, time = 600, result = true)]
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pub async fn canonical_path(path: String) -> Result<Option<String>, String> {
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let res = reddit_head(path.clone(), true).await?;
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if res.status() == 429 {
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return Err("Too many requests.".to_string());
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};
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// If Reddit responds with a 2xx, then the path is already canonical.
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if res.status().to_string().starts_with('2') {
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return Ok(Some(path));
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}
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// If Reddit responds with anything other than 3xx (except for the 2xx as
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// above), return a None.
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if !res.status().to_string().starts_with('3') {
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return Ok(None);
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}
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Ok(
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res
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.headers()
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.get(header::LOCATION)
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.map(|val| percent_encode(val.as_bytes(), CONTROLS).to_string().trim_start_matches(REDDIT_URL_BASE).to_string()),
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)
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}
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pub async fn proxy(req: Request<Body>, format: &str) -> Result<Response<Body>, String> {
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let mut url = format!("{}?{}", format, req.uri().query().unwrap_or_default());
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// For each parameter in request
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for (name, value) in req.params().iter() {
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// Fill the parameter value in the url
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url = url.replace(&format!("{{{}}}", name), value);
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}
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stream(&url, &req).await
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}
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async fn stream(url: &str, req: &Request<Body>) -> Result<Response<Body>, String> {
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// First parameter is target URL (mandatory).
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let uri = url.parse::<Uri>().map_err(|_| "Couldn't parse URL".to_string())?;
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// Build the hyper client from the HTTPS connector.
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let client: client::Client<_, hyper::Body> = CLIENT.clone();
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let mut builder = Request::get(uri);
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// Copy useful headers from original request
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for &key in &["Range", "If-Modified-Since", "Cache-Control"] {
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if let Some(value) = req.headers().get(key) {
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builder = builder.header(key, value);
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}
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}
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let stream_request = builder.body(Body::empty()).map_err(|_| "Couldn't build empty body in stream".to_string())?;
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client
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.request(stream_request)
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.await
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.map(|mut res| {
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let mut rm = |key: &str| res.headers_mut().remove(key);
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rm("access-control-expose-headers");
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rm("server");
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rm("vary");
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rm("etag");
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rm("x-cdn");
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rm("x-cdn-client-region");
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rm("x-cdn-name");
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rm("x-cdn-server-region");
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rm("x-reddit-cdn");
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rm("x-reddit-video-features");
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rm("Nel");
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rm("Report-To");
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res
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})
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.map_err(|e| e.to_string())
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}
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/// Makes a GET request to Reddit at `path`. By default, this will honor HTTP
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/// 3xx codes Reddit returns and will automatically redirect.
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fn reddit_get(path: String, quarantine: bool) -> Boxed<Result<Response<Body>, String>> {
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request(&Method::GET, path, true, quarantine)
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}
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/// Makes a HEAD request to Reddit at `path`. This will not follow redirects.
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fn reddit_head(path: String, quarantine: bool) -> Boxed<Result<Response<Body>, String>> {
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request(&Method::HEAD, path, false, quarantine)
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}
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/// Makes a request to Reddit. If `redirect` is `true`, request_with_redirect
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/// will recurse on the URL that Reddit provides in the Location HTTP header
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/// in its response.
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fn request(method: &'static Method, path: String, redirect: bool, quarantine: bool) -> Boxed<Result<Response<Body>, String>> {
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// Build Reddit URL from path.
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let url = format!("{}{}", REDDIT_URL_BASE, path);
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// Construct the hyper client from the HTTPS connector.
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let client: client::Client<_, hyper::Body> = CLIENT.clone();
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// Build request to Reddit. When making a GET, request gzip compression.
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// (Reddit doesn't do brotli yet.)
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let builder = Request::builder()
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.method(method)
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.uri(&url)
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.header("User-Agent", format!("web:libreddit:{}", env!("CARGO_PKG_VERSION")))
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.header("Host", "www.reddit.com")
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.header("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8")
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.header("Accept-Encoding", if method == Method::GET { "gzip" } else { "identity" })
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.header("Accept-Language", "en-US,en;q=0.5")
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.header("Connection", "keep-alive")
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.header(
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"Cookie",
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if quarantine {
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"_options=%7B%22pref_quarantine_optin%22%3A%20true%2C%20%22pref_gated_sr_optin%22%3A%20true%7D"
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} else {
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""
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},
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)
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.body(Body::empty());
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async move {
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match builder {
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Ok(req) => match client.request(req).await {
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Ok(mut response) => {
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// Reddit may respond with a 3xx. Decide whether or not to
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// redirect based on caller params.
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if response.status().to_string().starts_with('3') {
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if !redirect {
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return Ok(response);
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};
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return request(
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method,
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response
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.headers()
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.get(header::LOCATION)
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.map(|val| {
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// We need to make adjustments to the URI
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// we get back from Reddit. Namely, we
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// must:
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//
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// 1. Remove the authority (e.g.
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// https://www.reddit.com) that may be
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// present, so that we recurse on the
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// path (and query parameters) as
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// required.
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//
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// 2. Percent-encode the path.
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let new_path = percent_encode(val.as_bytes(), CONTROLS).to_string().trim_start_matches(REDDIT_URL_BASE).to_string();
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format!("{}{}raw_json=1", new_path, if new_path.contains('?') { "&" } else { "?" })
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})
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.unwrap_or_default()
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.to_string(),
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true,
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quarantine,
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)
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.await;
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};
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match response.headers().get(header::CONTENT_ENCODING) {
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// Content not compressed.
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None => Ok(response),
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// Content encoded (hopefully with gzip).
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Some(hdr) => {
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match hdr.to_str() {
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Ok(val) => match val {
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"gzip" => {}
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"identity" => return Ok(response),
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_ => return Err("Reddit response was encoded with an unsupported compressor".to_string()),
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},
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Err(_) => return Err("Reddit response was invalid".to_string()),
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}
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// We get here if the body is gzip-compressed.
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// The body must be something that implements
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// std::io::Read, hence the conversion to
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// bytes::buf::Buf and then transformation into a
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// Reader.
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let mut decompressed: Vec<u8>;
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{
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let mut aggregated_body = match body::aggregate(response.body_mut()).await {
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Ok(b) => b.reader(),
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Err(e) => return Err(e.to_string()),
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};
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let mut decoder = match gzip::Decoder::new(&mut aggregated_body) {
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Ok(decoder) => decoder,
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Err(e) => return Err(e.to_string()),
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};
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decompressed = Vec::<u8>::new();
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if let Err(e) = io::copy(&mut decoder, &mut decompressed) {
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return Err(e.to_string());
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};
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}
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response.headers_mut().remove(header::CONTENT_ENCODING);
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response.headers_mut().insert(header::CONTENT_LENGTH, decompressed.len().into());
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*(response.body_mut()) = Body::from(decompressed);
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Ok(response)
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}
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}
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}
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Err(e) => {
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dbg_msg!("{} {}: {}", method, path, e);
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Err(e.to_string())
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}
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},
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Err(_) => Err("Post url contains non-ASCII characters".to_string()),
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}
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}
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.boxed()
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}
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// Make a request to a Reddit API and parse the JSON response
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#[cached(size = 100, time = 30, result = true)]
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pub async fn json(path: String, quarantine: bool) -> Result<Value, String> {
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// Closure to quickly build errors
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let err = |msg: &str, e: String| -> Result<Value, String> {
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// eprintln!("{} - {}: {}", url, msg, e);
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Err(format!("{}: {}", msg, e))
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};
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// Fetch the url...
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match reddit_get(path.clone(), quarantine).await {
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Ok(response) => {
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let status = response.status();
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// asynchronously aggregate the chunks of the body
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match hyper::body::aggregate(response).await {
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Ok(body) => {
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// Parse the response from Reddit as JSON
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match serde_json::from_reader(body.reader()) {
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Ok(value) => {
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let json: Value = value;
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// If Reddit returned an error
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if json["error"].is_i64() {
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Err(
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json["reason"]
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.as_str()
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.unwrap_or_else(|| {
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json["message"].as_str().unwrap_or_else(|| {
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eprintln!("{}{} - Error parsing reddit error", REDDIT_URL_BASE, path);
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"Error parsing reddit error"
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})
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})
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.to_string(),
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)
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} else {
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Ok(json)
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}
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}
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Err(e) => {
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if status.is_server_error() {
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Err("Reddit is having issues, check if there's an outage".to_string())
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} else {
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err("Failed to parse page JSON data", e.to_string())
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}
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}
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}
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}
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Err(e) => err("Failed receiving body from Reddit", e.to_string()),
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}
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}
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Err(e) => err("Couldn't send request to Reddit", e),
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}
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}
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