Make the async Client default (#626)

The previously default Client is moved to `reqwest::blocking`, while the
async client becomes the main API.

Closes #622

examples/async.rs

@@ -1,16 +0,0 @@
-#![deny(warnings)]
-
-use reqwest::r#async::Client;
-
-#[tokio::main]
-async fn main() -> Result<(), reqwest::Error> {
-    let mut res = Client::new().get("https://hyper.rs").send().await?;
-
-    println!("Status: {}", res.status());
-
-    let body = res.text().await?;
-
-    println!("Body:\n\n{}", body);
-
-    Ok(())
-}

examples/async_multiple_requests.rs

@@ -1,41 +0,0 @@
-#![deny(warnings)]
-
-use reqwest::r#async::{Client, Response};
-use serde::Deserialize;
-use std::future::Future;
-
-#[derive(Deserialize, Debug)]
-struct Slideshow {
-    title: String,
-    author: String,
-}
-
-#[derive(Deserialize, Debug)]
-struct SlideshowContainer {
-    slideshow: Slideshow,
-}
-
-async fn into_json<F>(f: F) -> Result<SlideshowContainer, reqwest::Error>
-where
-    F: Future<Output = Result<Response, reqwest::Error>>,
-{
-    let mut resp = f.await?;
-    resp.json::<SlideshowContainer>().await
-}
-
-#[tokio::main]
-async fn main() -> Result<(), reqwest::Error> {
-    let client = Client::new();
-
-    let request1 = client.get("https://httpbin.org/json").send();
-
-    let request2 = client.get("https://httpbin.org/json").send();
-
-    let (try_json1, try_json2) =
-        futures::future::join(into_json(request1), into_json(request2)).await;
-
-    println!("{:?}", try_json1?);
-    println!("{:?}", try_json2?);
-
-    Ok(())
-}

examples/blocking.rs

@@ -0,0 +1,19 @@
+//! `cargo run --example blocking`
+#![deny(warnings)]
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    env_logger::init();
+
+    println!("GET https://www.rust-lang.org");
+
+    let mut res = reqwest::blocking::get("https://www.rust-lang.org/")?;
+
+    println!("Status: {}", res.status());
+    println!("Headers:\n{:?}", res.headers());
+
+    // copy the response body directly to stdout
+    res.copy_to(&mut std::io::stdout())?;
+
+    println!("\n\nDone.");
+    Ok(())
+}

examples/form.rs

@@ -1,7 +1,9 @@
-fn main() {
+#[tokio::main]
+async fn main() {
     reqwest::Client::new()
         .post("http://www.baidu.com")
         .form(&[("one", "1")])
         .send()
+        .await
         .unwrap();
 }

examples/json_dynamic.rs

@@ -4,7 +4,8 @@
 //! really care about the structure of the JSON and just need to display it or
 //! process it at runtime.
 
-fn main() -> Result<(), reqwest::Error> {
+#[tokio::main]
+async fn main() -> Result<(), reqwest::Error> {
     let echo_json: serde_json::Value = reqwest::Client::new()
         .post("https://jsonplaceholder.typicode.com/posts")
         .json(&serde_json::json!({
@@ -12,8 +13,10 @@ fn main() -> Result<(), reqwest::Error> {
             "body": "https://docs.rs/reqwest",
             "userId": 1
         }))
-        .send()?
-        .json()?;
+        .send()
+        .await?
+        .json()
+        .await?;
 
     println!("{:#?}", echo_json);
     // Object(

examples/json_typed.rs

@@ -15,7 +15,8 @@ struct Post {
     user_id: i32,
 }
 
-fn main() -> Result<(), reqwest::Error> {
+#[tokio::main]
+async fn main() -> Result<(), reqwest::Error> {
     let new_post = Post {
         id: None,
         title: "Reqwest.rs".into(),
@@ -25,8 +26,10 @@ fn main() -> Result<(), reqwest::Error> {
     let new_post: Post = reqwest::Client::new()
         .post("https://jsonplaceholder.typicode.com/posts")
         .json(&new_post)
-        .send()?
-        .json()?;
+        .send()
+        .await?
+        .json()
+        .await?;
 
     println!("{:#?}", new_post);
     // Post {

examples/simple.rs

@@ -1,19 +1,17 @@
-//! `cargo run --example simple`
 #![deny(warnings)]
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    env_logger::init();
-
-    println!("GET https://www.rust-lang.org");
-
-    let mut res = reqwest::get("https://www.rust-lang.org/")?;
+#[tokio::main]
+async fn main() -> Result<(), reqwest::Error> {
+    let mut res = reqwest::Client::new()
+        .get("https://hyper.rs")
+        .send()
+        .await?;
 
     println!("Status: {}", res.status());
-    println!("Headers:\n{:?}", res.headers());
 
-    // copy the response body directly to stdout
-    res.copy_to(&mut std::io::stdout())?;
+    let body = res.text().await?;
+
+    println!("Body:\n\n{}", body);
 
-    println!("\n\nDone.");
     Ok(())
 }