feat: Set user agent for http client (#2916)

cli/http_util.rs

@@ -1,11 +1,14 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 use crate::deno_error;
 use crate::deno_error::DenoError;
+use crate::version;
 use deno::ErrBox;
 use futures::{future, Future};
 use reqwest;
+use reqwest::header::HeaderMap;
 use reqwest::header::CONTENT_TYPE;
 use reqwest::header::LOCATION;
+use reqwest::header::USER_AGENT;
 use reqwest::r#async::Client;
 use reqwest::RedirectPolicy;
 use url::Url;
@@ -13,8 +16,14 @@ use url::Url;
 /// Create new instance of async reqwest::Client. This client supports
 /// proxies and doesn't follow redirects.
 pub fn get_client() -> Client {
+  let mut headers = HeaderMap::new();
+  headers.insert(
+    USER_AGENT,
+    format!("Deno/{}", version::DENO).parse().unwrap(),
+  );
   Client::builder()
     .redirect(RedirectPolicy::none())
+    .default_headers(headers)
     .use_sys_proxy()
     .build()
     .unwrap()

js/fetch_test.ts

@@ -220,6 +220,16 @@ testPerm({ net: true }, async function fetchInitBlobBody(): Promise<void> {
   assert(response.headers.get("content-type").startsWith("text/javascript"));
 });
 
+testPerm({ net: true }, async function fetchUserAgent(): Promise<void> {
+  const data = "Hello World";
+  const response = await fetch("http://localhost:4545/echo_server", {
+    method: "POST",
+    body: new TextEncoder().encode(data)
+  });
+  assertEquals(response.headers.get("user-agent"), `Deno/${Deno.version.deno}`);
+  await response.text();
+});
+
 // TODO(ry) The following tests work but are flaky. There's a race condition
 // somewhere. Here is what one of these flaky failures looks like:
 //

tools/http_server.py

@@ -61,6 +61,9 @@ class ContentTypeHandler(QuietSimpleHTTPRequestHandler):
             if self.headers.has_key('content-type'):
                 self.send_header('content-type',
                                  self.headers.getheader('content-type'))
+            if self.headers.has_key('user-agent'):
+                self.send_header('user-agent',
+                                 self.headers.getheader('user-agent'))
             self.end_headers()
             data_string = self.rfile.read(int(self.headers['Content-Length']))
             self.wfile.write(bytes(data_string))