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use std::fmt;
use std::sync::{mpsc, Arc};
use std::sync::atomic::{AtomicBool, Ordering};
use std::time::{Instant, Duration};
use fetch::{self, Fetch};
use futures::Future;
use parity_reactor::Remote;
use util::Mutex;
use hyper::{server, Decoder, Encoder, Next, Method, Control};
use hyper::net::HttpStream;
use hyper::uri::RequestUri;
use hyper::status::StatusCode;
use endpoint::EndpointPath;
use handlers::{ContentHandler, StreamingHandler};
use page::{LocalPageEndpoint, PageHandlerWaiting};
const FETCH_TIMEOUT: u64 = 300;
pub enum ValidatorResponse {
Local(LocalPageEndpoint),
Streaming(StreamingHandler<fetch::Response>),
}
pub trait ContentValidator: Send + 'static {
type Error: fmt::Debug + fmt::Display;
fn validate_and_install(&self, fetch::Response) -> Result<ValidatorResponse, Self::Error>;
}
enum FetchState {
Waiting,
NotStarted(String),
Error(ContentHandler),
InProgress(mpsc::Receiver<FetchState>),
Streaming(StreamingHandler<fetch::Response>),
Done(LocalPageEndpoint, Box<PageHandlerWaiting>),
}
enum WaitResult {
Error(ContentHandler),
Done(LocalPageEndpoint),
NonAwaitable,
}
#[derive(Clone)]
pub struct FetchControl {
abort: Arc<AtomicBool>,
listeners: Arc<Mutex<Vec<(Control, mpsc::Sender<WaitResult>)>>>,
deadline: Instant,
}
impl Default for FetchControl {
fn default() -> Self {
FetchControl {
abort: Arc::new(AtomicBool::new(false)),
listeners: Arc::new(Mutex::new(Vec::new())),
deadline: Instant::now() + Duration::from_secs(FETCH_TIMEOUT),
}
}
}
impl FetchControl {
fn notify<F: Fn() -> WaitResult>(&self, status: F) {
let mut listeners = self.listeners.lock();
for (control, sender) in listeners.drain(..) {
trace!(target: "dapps", "Resuming request waiting for content...");
if let Err(e) = sender.send(status()) {
trace!(target: "dapps", "Waiting listener notification failed: {:?}", e);
} else {
let _ = control.ready(Next::read());
}
}
}
fn set_status(&self, status: &FetchState) {
match *status {
FetchState::Error(ref handler) => self.notify(|| WaitResult::Error(handler.clone())),
FetchState::Done(ref endpoint, _) => self.notify(|| WaitResult::Done(endpoint.clone())),
FetchState::Streaming(_) => self.notify(|| WaitResult::NonAwaitable),
FetchState::NotStarted(_) | FetchState::InProgress(_) | FetchState::Waiting => {},
}
}
pub fn is_deadline_reached(&self) -> bool {
self.deadline < Instant::now()
}
pub fn abort(&self) {
self.abort.store(true, Ordering::SeqCst);
}
pub fn to_async_handler(&self, path: EndpointPath, control: Control) -> Box<server::Handler<HttpStream> + Send> {
let (tx, rx) = mpsc::channel();
self.listeners.lock().push((control, tx));
Box::new(WaitingHandler {
receiver: rx,
state: FetchState::Waiting,
uri: RequestUri::default(),
path: path,
})
}
}
pub struct WaitingHandler {
receiver: mpsc::Receiver<WaitResult>,
state: FetchState,
uri: RequestUri,
path: EndpointPath,
}
impl server::Handler<HttpStream> for WaitingHandler {
fn on_request(&mut self, request: server::Request<HttpStream>) -> Next {
self.uri = request.uri().clone();
Next::wait()
}
fn on_request_readable(&mut self, decoder: &mut Decoder<HttpStream>) -> Next {
let result = self.receiver.try_recv().ok();
self.state = match result {
Some(WaitResult::Error(handler)) => FetchState::Error(handler),
Some(WaitResult::Done(endpoint)) => {
let mut page_handler = endpoint.to_page_handler(self.path.clone());
page_handler.set_uri(&self.uri);
FetchState::Done(endpoint, page_handler)
},
_ => {
warn!("A result for waiting request was not received.");
FetchState::Waiting
},
};
match self.state {
FetchState::Done(_, ref mut handler) => handler.on_request_readable(decoder),
FetchState::Streaming(ref mut handler) => handler.on_request_readable(decoder),
FetchState::Error(ref mut handler) => handler.on_request_readable(decoder),
_ => Next::write(),
}
}
fn on_response(&mut self, res: &mut server::Response) -> Next {
match self.state {
FetchState::Done(_, ref mut handler) => handler.on_response(res),
FetchState::Streaming(ref mut handler) => handler.on_response(res),
FetchState::Error(ref mut handler) => handler.on_response(res),
_ => Next::end(),
}
}
fn on_response_writable(&mut self, encoder: &mut Encoder<HttpStream>) -> Next {
match self.state {
FetchState::Done(_, ref mut handler) => handler.on_response_writable(encoder),
FetchState::Streaming(ref mut handler) => handler.on_response_writable(encoder),
FetchState::Error(ref mut handler) => handler.on_response_writable(encoder),
_ => Next::end(),
}
}
}
#[derive(Clone)]
struct Errors {
embeddable_on: Option<(String, u16)>,
}
impl Errors {
fn download_error<E: fmt::Debug>(&self, e: E) -> ContentHandler {
ContentHandler::error(
StatusCode::BadGateway,
"Download Error",
"There was an error when fetching the content.",
Some(&format!("{:?}", e)),
self.embeddable_on.clone(),
)
}
fn invalid_content<E: fmt::Debug>(&self, e: E) -> ContentHandler {
ContentHandler::error(
StatusCode::BadGateway,
"Invalid Dapp",
"Downloaded bundle does not contain a valid content.",
Some(&format!("{:?}", e)),
self.embeddable_on.clone(),
)
}
fn timeout_error(&self) -> ContentHandler {
ContentHandler::error(
StatusCode::GatewayTimeout,
"Download Timeout",
&format!("Could not fetch content within {} seconds.", FETCH_TIMEOUT),
None,
self.embeddable_on.clone(),
)
}
fn method_not_allowed(&self) -> ContentHandler {
ContentHandler::error(
StatusCode::MethodNotAllowed,
"Method Not Allowed",
"Only <code>GET</code> requests are allowed.",
None,
self.embeddable_on.clone(),
)
}
}
pub struct ContentFetcherHandler<H: ContentValidator, F: Fetch> {
fetch_control: FetchControl,
control: Control,
remote: Remote,
status: FetchState,
fetch: F,
installer: Option<H>,
path: EndpointPath,
errors: Errors,
}
impl<H: ContentValidator, F: Fetch> ContentFetcherHandler<H, F> {
pub fn new(
url: String,
path: EndpointPath,
control: Control,
installer: H,
embeddable_on: Option<(String, u16)>,
remote: Remote,
fetch: F,
) -> Self {
ContentFetcherHandler {
fetch_control: FetchControl::default(),
control: control,
remote: remote,
fetch: fetch,
status: FetchState::NotStarted(url),
installer: Some(installer),
path: path,
errors: Errors {
embeddable_on: embeddable_on,
},
}
}
pub fn fetch_control(&self) -> FetchControl {
self.fetch_control.clone()
}
fn fetch_content(&self, uri: RequestUri, url: &str, installer: H) -> mpsc::Receiver<FetchState> {
let (tx, rx) = mpsc::channel();
let abort = self.fetch_control.abort.clone();
let path = self.path.clone();
let tx2 = tx.clone();
let control = self.control.clone();
let errors = self.errors.clone();
let future = self.fetch.fetch_with_abort(url, abort.into()).then(move |result| {
trace!(target: "dapps", "Fetching content finished. Starting validation: {:?}", result);
let new_state = match result {
Ok(response) => match installer.validate_and_install(response) {
Ok(ValidatorResponse::Local(endpoint)) => {
trace!(target: "dapps", "Validation OK. Returning response.");
let mut handler = endpoint.to_page_handler(path);
handler.set_uri(&uri);
FetchState::Done(endpoint, handler)
},
Ok(ValidatorResponse::Streaming(handler)) => {
trace!(target: "dapps", "Validation OK. Streaming response.");
FetchState::Streaming(handler)
},
Err(e) => {
trace!(target: "dapps", "Error while validating content: {:?}", e);
FetchState::Error(errors.invalid_content(e))
},
},
Err(e) => {
warn!(target: "dapps", "Unable to fetch content: {:?}", e);
FetchState::Error(errors.download_error(e))
},
};
let _ = tx2.send(new_state);
let _ = control.ready(Next::read());
Ok(()) as Result<(), ()>
});
let future = self.fetch.process(future);
let control = self.control.clone();
let errors = self.errors.clone();
self.remote.spawn_with_timeout(|| future, Duration::from_secs(FETCH_TIMEOUT), move || {
let _ = tx.send(FetchState::Error(errors.timeout_error()));
let _ = control.ready(Next::read());
});
rx
}
}
impl<H: ContentValidator, F: Fetch> server::Handler<HttpStream> for ContentFetcherHandler<H, F> {
fn on_request(&mut self, request: server::Request<HttpStream>) -> Next {
let status = if let FetchState::NotStarted(ref url) = self.status {
let uri = request.uri().clone();
let installer = self.installer.take().expect("Installer always set initialy; installer used only in on_request; on_request invoked only once; qed");
Some(match *request.method() {
Method::Get => {
trace!(target: "dapps", "Fetching content from: {:?}", url);
let receiver = self.fetch_content(uri, url, installer);
FetchState::InProgress(receiver)
},
_ => FetchState::Error(self.errors.method_not_allowed()),
})
} else { None };
if let Some(status) = status {
self.fetch_control.set_status(&status);
self.status = status;
}
Next::read()
}
fn on_request_readable(&mut self, decoder: &mut Decoder<HttpStream>) -> Next {
let (status, next) = match self.status {
FetchState::InProgress(_) if self.fetch_control.is_deadline_reached() => {
trace!(target: "dapps", "Fetching dapp failed because of timeout.");
(Some(FetchState::Error(self.errors.timeout_error())), Next::write())
},
FetchState::InProgress(ref receiver) => {
let rec = receiver.try_recv();
match rec {
Ok(state) => (Some(state), Next::write()),
_ => (None, Next::wait())
}
},
FetchState::Error(ref mut handler) => (None, handler.on_request_readable(decoder)),
_ => (None, Next::write()),
};
if let Some(status) = status {
self.fetch_control.set_status(&status);
self.status = status;
}
next
}
fn on_response(&mut self, res: &mut server::Response) -> Next {
match self.status {
FetchState::Done(_, ref mut handler) => handler.on_response(res),
FetchState::Streaming(ref mut handler) => handler.on_response(res),
FetchState::Error(ref mut handler) => handler.on_response(res),
_ => Next::end(),
}
}
fn on_response_writable(&mut self, encoder: &mut Encoder<HttpStream>) -> Next {
match self.status {
FetchState::Done(_, ref mut handler) => handler.on_response_writable(encoder),
FetchState::Streaming(ref mut handler) => handler.on_response_writable(encoder),
FetchState::Error(ref mut handler) => handler.on_response_writable(encoder),
_ => Next::end(),
}
}
}