docs(server): Add a forms server example

Add an example program illustrating parsing a request body through generating a response body.
2017-12-12 18:32:19 -08:00
parent 16aa92cf03
commit 61877f6f6e
2 changed files with 107 additions and 0 deletions
--- a/examples/params.rs
+++ b/examples/params.rs
@@ -0,0 +1,106 @@
+#![deny(warnings)]
+extern crate futures;
+extern crate hyper;
+extern crate pretty_env_logger;
+extern crate url;
+
+use futures::{Future, Stream};
+
+use hyper::{Get, Post, StatusCode};
+use hyper::header::ContentLength;
+use hyper::server::{Http, Service, Request, Response};
+
+use std::collections::HashMap;
+use url::form_urlencoded;
+
+static INDEX: &[u8] = b"<html><body><form action=\"post\" method=\"post\">Name: <input type=\"text\" name=\"name\"><br>Number: <input type=\"text\" name=\"number\"><br><input type=\"submit\"></body></html>";
+static MISSING: &[u8] = b"Missing field";
+static NOTNUMERIC: &[u8] = b"Number field is not numeric";
+
+struct ParamExample;
+
+impl Service for ParamExample {
+    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, "/post") => {
+                Box::new(futures::future::ok(Response::new()
+                                             .with_header(ContentLength(INDEX.len() as u64))
+                                             .with_body(INDEX)))
+            },
+            (&Post, "/post") => {
+                Box::new(req.body().concat2().map(|b| {
+                    // Parse the request body. form_urlencoded::parse
+                    // always succeeds, but in general parsing may
+                    // fail (for example, an invalid post of json), so
+                    // returning early with BadRequest may be
+                    // necessary.
+                    //
+                    // Warning: this is a simplified use case. In
+                    // principle names can appear multiple times in a
+                    // form, and the values should be rolled up into a
+                    // HashMap<String, Vec<String>>. However in this
+                    // example the simpler approach is sufficient.
+                    let params = form_urlencoded::parse(b.as_ref()).into_owned().collect::<HashMap<String, String>>();
+
+                    // Validate the request parameters, returning
+                    // early if an invalid input is detected.
+                    let name = if let Some(n) = params.get("name") {
+                        n
+                    } else {
+                        return Response::new()
+                            .with_status(StatusCode::UnprocessableEntity)
+                            .with_header(ContentLength(MISSING.len() as u64))
+                            .with_body(MISSING);
+                    };
+                    let number = if let Some(n) = params.get("number") {
+                        if let Ok(v) = n.parse::<f64>() {
+                            v
+                        } else {
+                            return Response::new()
+                                .with_status(StatusCode::UnprocessableEntity)
+                                .with_header(ContentLength(NOTNUMERIC.len() as u64))
+                                .with_body(NOTNUMERIC);
+                        }
+                    } else {
+                        return Response::new()
+                            .with_status(StatusCode::UnprocessableEntity)
+                            .with_header(ContentLength(MISSING.len() as u64))
+                            .with_body(MISSING);
+                    };
+
+                    // Render the response. This will often involve
+                    // calls to a database or web service, which will
+                    // require creating a new stream for the response
+                    // body. Since those may fail, other error
+                    // responses such as InternalServiceError may be
+                    // needed here, too.
+                    let body = format!("Hello {}, your number is {}", name, number);
+                    Response::new()
+                        .with_header(ContentLength(body.len() as u64))
+                        .with_body(body)
+                }))
+            },
+            _ => {
+                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(ParamExample)).unwrap();
+    server.no_proto();
+    println!("Listening on http://{} with 1 thread.", server.local_addr().unwrap());
+    server.run().unwrap();
+}