Add `reqwest` http client example to fetch json

Cargo.toml

@@ -59,11 +59,12 @@ lua-src = { version = ">= 540.0.0, < 550.0.0", optional = true }
 luajit-src = { version = ">= 210.1.0, < 220.0.0", optional = true }
 
 [dev-dependencies]
-rustyline = "6.0"
+rustyline = "7.0"
 criterion = "0.3"
 trybuild = "1.0"
 futures = "0.3.5"
 hyper = "0.13"
+reqwest = { version = "0.10", features = ["json"] }
 tokio = { version = "0.2", features = ["full"] }
 futures-timer = "3.0"
 serde_json = "1.0"
@@ -76,6 +77,10 @@ harness = false
 name = "async_http_client"
 required-features = ["async"]
 
+[[example]]
+name = "async_http_reqwest"
+required-features = ["async", "serialize"]
+
 [[example]]
 name = "async_http_server"
 required-features = ["async", "send"]

examples/async_http_reqwest.rs

@@ -0,0 +1,41 @@
+use mlua::{Error, Lua, LuaSerdeExt, Result};
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let lua = Lua::new();
+    let globals = lua.globals();
+    globals.set("null", lua.null()?)?;
+
+    let fetch_json = lua.create_async_function(|lua, uri: String| async move {
+        let resp = reqwest::get(&uri)
+            .await
+            .and_then(|resp| resp.error_for_status())
+            .map_err(Error::external)?;
+        let json = resp
+            .json::<serde_json::Value>()
+            .await
+            .map_err(Error::external)?;
+        lua.to_value(&json)
+    })?;
+    globals.set("fetch_json", fetch_json)?;
+
+    let f = lua
+        .load(
+            r#"
+            function print_r(t, indent)
+                local indent = indent or ''
+                for k, v in pairs(t) do
+                    io.write(indent, tostring(k))
+                    if type(v) == "table" then io.write(':\n') print_r(v, indent..'  ')
+                    else io.write(': ', v == null and "null" or tostring(v), '\n') end
+                end
+            end
+
+            local res = fetch_json(...)
+            print_r(res)
+        "#,
+        )
+        .into_function()?;
+
+    f.call_async("https://httpbin.org/anything?arg0=val0").await
+}

examples/async_tcp_server.rs

@@ -2,8 +2,8 @@ use std::net::Shutdown;
 use std::sync::Arc;
 
 use bstr::BString;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};
-use tokio::prelude::*;
 use tokio::sync::Mutex;
 use tokio::task;