Global Fetch Service (#3915)
* Dapps web Conflicts: dapps/src/apps/fetcher.rs dapps/src/handlers/fetch.rs * Rewriting fetch * Parity-wide fetch service * Obey the limits and support cancellation. * Removing temporary files. * Actually use Fetch for dapps * Re-implementing file fetching to avoid temporary files. * Serde to 0.8.19 * Fixing content & dapps fetch
This commit is contained in:
Tomasz Drwięga
Gav Wood
265
dapps/src/apps/fetcher/mod.rs
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265
dapps/src/apps/fetcher/mod.rs
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// Copyright 2015, 2016 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Fetchable Dapps support.
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//! Manages downloaded (cached) Dapps and downloads them when necessary.
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//! Uses `URLHint` to resolve addresses into Dapps bundle file location.
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mod installers;
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use std::{fs, env};
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use std::path::PathBuf;
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use std::sync::Arc;
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use rustc_serialize::hex::FromHex;
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use fetch::{Client as FetchClient, Fetch};
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use hash_fetch::urlhint::{URLHintContract, URLHint, URLHintResult};
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use parity_reactor::Remote;
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use hyper;
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use hyper::status::StatusCode;
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use {SyncStatus, random_filename};
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use util::Mutex;
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use page::LocalPageEndpoint;
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use handlers::{ContentHandler, ContentFetcherHandler};
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use endpoint::{Endpoint, EndpointPath, Handler};
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use apps::cache::{ContentCache, ContentStatus};
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/// Limit of cached dapps/content
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const MAX_CACHED_DAPPS: usize = 20;
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pub trait Fetcher: Send + Sync + 'static {
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fn contains(&self, content_id: &str) -> bool;
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fn to_async_handler(&self, path: EndpointPath, control: hyper::Control) -> Box<Handler>;
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}
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pub struct ContentFetcher<F: Fetch = FetchClient, R: URLHint + Send + Sync + 'static = URLHintContract> {
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dapps_path: PathBuf,
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resolver: R,
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cache: Arc<Mutex<ContentCache>>,
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sync: Arc<SyncStatus>,
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embeddable_on: Option<(String, u16)>,
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remote: Remote,
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fetch: F,
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}
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impl<R: URLHint + Send + Sync + 'static, F: Fetch> Drop for ContentFetcher<F, R> {
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fn drop(&mut self) {
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// Clear cache path
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let _ = fs::remove_dir_all(&self.dapps_path);
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}
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}
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impl<R: URLHint + Send + Sync + 'static, F: Fetch> ContentFetcher<F, R> {
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pub fn new(resolver: R, sync_status: Arc<SyncStatus>, embeddable_on: Option<(String, u16)>, remote: Remote, fetch: F) -> Self {
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let mut dapps_path = env::temp_dir();
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dapps_path.push(random_filename());
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ContentFetcher {
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dapps_path: dapps_path,
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resolver: resolver,
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sync: sync_status,
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cache: Arc::new(Mutex::new(ContentCache::default())),
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embeddable_on: embeddable_on,
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remote: remote,
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fetch: fetch,
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}
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}
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fn still_syncing(address: Option<(String, u16)>) -> Box<Handler> {
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Box::new(ContentHandler::error(
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StatusCode::ServiceUnavailable,
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"Sync In Progress",
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"Your node is still syncing. We cannot resolve any content before it's fully synced.",
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Some("<a href=\"javascript:window.location.reload()\">Refresh</a>"),
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address,
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))
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}
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#[cfg(test)]
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fn set_status(&self, content_id: &str, status: ContentStatus) {
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self.cache.lock().insert(content_id.to_owned(), status);
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}
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}
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impl<R: URLHint + Send + Sync + 'static, F: Fetch> Fetcher for ContentFetcher<F, R> {
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fn contains(&self, content_id: &str) -> bool {
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{
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let mut cache = self.cache.lock();
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// Check if we already have the app
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if cache.get(content_id).is_some() {
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return true;
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}
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}
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// fallback to resolver
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if let Ok(content_id) = content_id.from_hex() {
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// else try to resolve the app_id
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let has_content = self.resolver.resolve(content_id).is_some();
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// if there is content or we are syncing return true
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has_content || self.sync.is_major_importing()
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} else {
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false
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}
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}
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fn to_async_handler(&self, path: EndpointPath, control: hyper::Control) -> Box<Handler> {
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let mut cache = self.cache.lock();
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let content_id = path.app_id.clone();
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let (new_status, handler) = {
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let status = cache.get(&content_id);
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match status {
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// Just serve the content
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Some(&mut ContentStatus::Ready(ref endpoint)) => {
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(None, endpoint.to_async_handler(path, control))
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},
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// Content is already being fetched
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Some(&mut ContentStatus::Fetching(ref fetch_control)) => {
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trace!(target: "dapps", "Content fetching in progress. Waiting...");
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(None, fetch_control.to_async_handler(path, control))
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},
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// We need to start fetching the content
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None => {
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trace!(target: "dapps", "Content unavailable. Fetching... {:?}", content_id);
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let content_hex = content_id.from_hex().expect("to_handler is called only when `contains` returns true.");
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let content = self.resolver.resolve(content_hex);
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let cache = self.cache.clone();
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let id = content_id.clone();
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let on_done = move |result: Option<LocalPageEndpoint>| {
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let mut cache = cache.lock();
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match result {
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Some(endpoint) => cache.insert(id.clone(), ContentStatus::Ready(endpoint)),
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// In case of error
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None => cache.remove(&id),
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};
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};
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match content {
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// Don't serve dapps if we are still syncing (but serve content)
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Some(URLHintResult::Dapp(_)) if self.sync.is_major_importing() => {
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(None, Self::still_syncing(self.embeddable_on.clone()))
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},
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Some(URLHintResult::Dapp(dapp)) => {
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let (handler, fetch_control) = ContentFetcherHandler::new(
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dapp.url(),
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path,
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control,
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installers::Dapp::new(
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content_id.clone(),
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self.dapps_path.clone(),
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Box::new(on_done),
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self.embeddable_on.clone(),
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),
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self.embeddable_on.clone(),
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self.remote.clone(),
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self.fetch.clone(),
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);
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(Some(ContentStatus::Fetching(fetch_control)), Box::new(handler) as Box<Handler>)
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},
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Some(URLHintResult::Content(content)) => {
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let (handler, fetch_control) = ContentFetcherHandler::new(
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content.url,
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path,
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control,
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installers::Content::new(
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content_id.clone(),
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content.mime,
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self.dapps_path.clone(),
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Box::new(on_done),
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),
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self.embeddable_on.clone(),
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self.remote.clone(),
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self.fetch.clone(),
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);
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(Some(ContentStatus::Fetching(fetch_control)), Box::new(handler) as Box<Handler>)
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},
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None if self.sync.is_major_importing() => {
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(None, Self::still_syncing(self.embeddable_on.clone()))
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},
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None => {
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// This may happen when sync status changes in between
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// `contains` and `to_handler`
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(None, Box::new(ContentHandler::error(
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StatusCode::NotFound,
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"Resource Not Found",
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"Requested resource was not found.",
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None,
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self.embeddable_on.clone(),
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)) as Box<Handler>)
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},
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}
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},
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}
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};
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if let Some(status) = new_status {
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cache.clear_garbage(MAX_CACHED_DAPPS);
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cache.insert(content_id, status);
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}
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handler
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}
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}
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#[cfg(test)]
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mod tests {
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use std::env;
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use std::sync::Arc;
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use util::Bytes;
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use fetch::Client;
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use hash_fetch::urlhint::{URLHint, URLHintResult};
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use parity_reactor::Remote;
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use apps::cache::ContentStatus;
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use endpoint::EndpointInfo;
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use page::LocalPageEndpoint;
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use super::{ContentFetcher, Fetcher};
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struct FakeResolver;
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impl URLHint for FakeResolver {
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fn resolve(&self, _id: Bytes) -> Option<URLHintResult> {
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None
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}
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}
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#[test]
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fn should_true_if_contains_the_app() {
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// given
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let path = env::temp_dir();
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let fetcher = ContentFetcher::new(FakeResolver, Arc::new(|| false), None, Remote::new_sync(), Client::new().unwrap());
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let handler = LocalPageEndpoint::new(path, EndpointInfo {
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name: "fake".into(),
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description: "".into(),
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version: "".into(),
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author: "".into(),
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icon_url: "".into(),
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}, Default::default(), None);
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// when
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fetcher.set_status("test", ContentStatus::Ready(handler));
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fetcher.set_status("test2", ContentStatus::Fetching(Default::default()));
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// then
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assert_eq!(fetcher.contains("test"), true);
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assert_eq!(fetcher.contains("test2"), true);
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assert_eq!(fetcher.contains("test3"), false);
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}
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}
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