From 7d2cce0922f23a464a2f4460a562450b73d8a1f7 Mon Sep 17 00:00:00 2001
From: Jeff Olhoeft <jolhoeft@gmail.com>
Date: Tue, 26 Dec 2017 11:45:09 -0800
Subject: [PATCH] docs(server): Add an example of serving files

---
 examples/send_file.rs         | 142 ++++++++++++++++++++++++++++++++++
 examples/send_file_index.html |  11 +++
 2 files changed, 153 insertions(+)
 create mode 100644 examples/send_file.rs
 create mode 100644 examples/send_file_index.html

diff --git a/examples/send_file.rs b/examples/send_file.rs
new file mode 100644
index 00000000..e0ce7cee
--- /dev/null
+++ b/examples/send_file.rs
@@ -0,0 +1,142 @@
+#![deny(warnings)]
+extern crate futures;
+extern crate hyper;
+extern crate pretty_env_logger;
+
+use futures::{Future, Sink};
+use futures::sync::{mpsc, oneshot};
+
+use hyper::{Chunk, Get, StatusCode};
+use hyper::error::Error;
+use hyper::header::ContentLength;
+use hyper::server::{Http, Service, Request, Response};
+
+use std::fs::File;
+use std::io::{self, copy, Read};
+use std::thread;
+
+static NOTFOUND: &[u8] = b"Not Found";
+static INDEX: &str = "examples/send_file_index.html";
+
+fn simple_file_send(f: &str) -> Box<Future<Item = Response, Error = hyper::Error>> {
+    // Serve a file by reading it entirely into memory. As a result
+    // this is limited to serving small files, but it is somewhat
+    // simpler with a little less overhead.
+    //
+    // On channel errors, we panic with the expect method. The thread
+    // ends at that point in any case.
+    let filename = f.to_string(); // we need to copy for lifetime issues
+    let (tx, rx) = oneshot::channel();
+    thread::spawn(move || {
+        let mut file = match File::open(filename) {
+            Ok(f) => f,
+            Err(_) => {
+                tx.send(Response::new()
+                        .with_status(StatusCode::NotFound)
+                        .with_header(ContentLength(NOTFOUND.len() as u64))
+                        .with_body(NOTFOUND))
+                    .expect("Send error on open");
+                return;
+            },
+        };
+        let mut buf: Vec<u8> = Vec::new();
+        match copy(&mut file, &mut buf) {
+            Ok(_) => {
+                let res = Response::new()
+                    .with_header(ContentLength(buf.len() as u64))
+                    .with_body(buf);
+                tx.send(res).expect("Send error on successful file read");
+            },
+            Err(_) => {
+                tx.send(Response::new().with_status(StatusCode::InternalServerError)).
+                    expect("Send error on error reading file");
+            },
+        };
+    });
+
+    Box::new(rx.map_err(|e| Error::from(io::Error::new(io::ErrorKind::Other, e))))
+}
+
+struct ResponseExamples;
+
+impl Service for ResponseExamples {
+    type Request = Request;
+    type Response = Response;
+    type Error = hyper::Error;
+    type Future = Box<Future<Item = Self::Response, Error = Self::Error>>;
+
+    fn call(&self, req: Request) -> Self::Future {
+        match (req.method(), req.path()) {
+            (&Get, "/") | (&Get, "/index.html") => {
+                simple_file_send(INDEX)
+            },
+            (&Get, "/big_file.html") => {
+                // Stream a large file in chunks. This requires a
+                // little more overhead with two channels, (one for
+                // the response future, and a second for the response
+                // body), but can handle arbitrarily large files.
+                //
+                // We use an artificially small buffer, since we have
+                // a small test file.
+                let (tx, rx) = oneshot::channel();
+                thread::spawn(move || {
+                    let mut file = match File::open(INDEX) {
+                        Ok(f) => f,
+                        Err(_) => {
+                            tx.send(Response::new()
+                                    .with_status(StatusCode::NotFound)
+                                    .with_header(ContentLength(NOTFOUND.len() as u64))
+                                    .with_body(NOTFOUND))
+                                .expect("Send error on open");
+                            return;
+                        },
+                    };
+                    let (mut tx_body, rx_body) = mpsc::channel(1);
+                    let res = Response::new().with_body(rx_body);
+                    tx.send(res).expect("Send error on successful file read");
+                    let mut buf = [0u8; 16];
+                    loop {
+                        match file.read(&mut buf) {
+                            Ok(n) => {
+                                if n == 0 {
+                                    // eof
+                                    tx_body.close().expect("panic closing");
+                                    break;
+                                } else {
+                                    let chunk: Chunk = buf.to_vec().into();
+                                    match tx_body.send(Ok(chunk)).wait() {
+                                        Ok(t) => { tx_body = t; },
+                                        Err(_) => { break; }
+                                    };
+                                }
+                            },
+                            Err(_) => { break; }
+                        }
+                    }
+                });
+                
+                Box::new(rx.map_err(|e| Error::from(io::Error::new(io::ErrorKind::Other, e))))
+            },
+            (&Get, "/no_file.html") => {
+                // Test what happens when file cannot be be found
+                simple_file_send("this_file_should_not_exist.html")
+            },
+            _ => {
+                Box::new(futures::future::ok(Response::new()
+                                    .with_status(StatusCode::NotFound)))
+            }
+        }
+    }
+
+}
+
+
+fn main() {
+    pretty_env_logger::init().unwrap();
+    let addr = "127.0.0.1:1337".parse().unwrap();
+
+    let mut server = Http::new().bind(&addr, || Ok(ResponseExamples)).unwrap();
+    server.no_proto();
+    println!("Listening on http://{} with 1 thread.", server.local_addr().unwrap());
+    server.run().unwrap();
+}
diff --git a/examples/send_file_index.html b/examples/send_file_index.html
new file mode 100644
index 00000000..9153a809
--- /dev/null
+++ b/examples/send_file_index.html
@@ -0,0 +1,11 @@
+<html>
+  <head>
+    <title>Hyper responding example</title>
+  </head>
+  <body>
+    <h1>Hyper responding example</h1>
+    <a href="index.html">index.html</a> Top Level<br>
+    <a href="big_file.html">big_file.html</a> This page, streamed in chunks<br>
+    <a href="no_file.html">no_file.html</a> A 404 test, the requested file does not exist<br>
+  </body>
+</html>