Return a download redirect even if crate version isn't in db

If we are a mirror that is just handling the index and not tracking
downloads, return the redirect URL even if we don't know about this
crate or version.

Author: carols10cents

src/krate.rs

@@ -828,7 +828,10 @@ pub fn download(req: &mut Request) -> CargoResult<Response> {
     let crate_name = &req.params()["crate_id"];
     let version = &req.params()["version"];
 
-    try!(increment_download_counts(req, crate_name, version));
+    match increment_download_counts(req, crate_name, version) {
+        _ => {} // do not try, ignore failures
+    }
+
     let redirect_url = format!("https://{}/crates/{}/{}-{}.crate",
                                req.app().bucket.host(),
                                crate_name, crate_name, version);
@@ -853,32 +856,34 @@ fn increment_download_counts(req: &Request, crate_name: &str, version: &str) ->
                                   AND versions.num = $2
                                 LIMIT 1"));
     let rows = try!(stmt.query(&[&crate_name, &version]));
-    let row = try!(rows.iter().next().chain_error(|| {
-        human("crate or version not found")
-    }));
-    let version_id: i32 = row.get("version_id");
-    let now = ::now();
-
-    // Bump download counts.
-    //
-    // Note that this is *not* an atomic update, and that's somewhat
-    // intentional. It doesn't appear that postgres supports an atomic update of
-    // a counter, so we just do the hopefully "least racy" thing. This is
-    // largely ok because these download counters are just that, counters. No
-    // need to have super high-fidelity counter.
-    //
-    // Also, we only update the counter for *today*, nothing else. We have lots
-    // of other counters, but they're all updated later on via the
-    // update-downloads script.
-    let amt = try!(tx.execute("UPDATE version_downloads
-                               SET downloads = downloads + 1
-                               WHERE version_id = $1 AND date($2) = date(date)",
-                              &[&version_id, &now]));
-    if amt == 0 {
-        try!(tx.execute("INSERT INTO version_downloads
-                         (version_id) VALUES ($1)", &[&version_id]));
+    match rows.iter().next() {
+        None => Err(human("crate or version not found")),
+        Some(row) => {
+            let version_id: i32 = row.get("version_id");
+            let now = ::now();
+
+            // Bump download counts.
+            //
+            // Note that this is *not* an atomic update, and that's somewhat
+            // intentional. It doesn't appear that postgres supports an atomic update of
+            // a counter, so we just do the hopefully "least racy" thing. This is
+            // largely ok because these download counters are just that, counters. No
+            // need to have super high-fidelity counter.
+            //
+            // Also, we only update the counter for *today*, nothing else. We have lots
+            // of other counters, but they're all updated later on via the
+            // update-downloads script.
+            let amt = try!(tx.execute("UPDATE version_downloads
+                                       SET downloads = downloads + 1
+                                       WHERE version_id = $1 AND date($2) = date(date)",
+                                      &[&version_id, &now]));
+            if amt == 0 {
+                try!(tx.execute("INSERT INTO version_downloads
+                                 (version_id) VALUES ($1)", &[&version_id]));
+            }
+            Ok(())
+        }
     }
-    Ok(())
 }
 
 /// Handles the `GET /crates/:crate_id/downloads` route.

src/tests/krate.rs

@@ -669,8 +669,8 @@ fn download_bad() {
     let mut req = ::req(app, Method::Get, "/api/v1/crates/foo/0.1.0/download");
     ::mock_user(&mut req, ::user("foo"));
     ::mock_crate(&mut req, ::krate("foo"));
-    let mut response = ok_resp!(middle.call(&mut req));
-    ::json::<::Bad>(&mut response);
+    let resp = t_resp!(middle.call(&mut req));
+    assert_eq!(resp.status.0, 302);
 }
 
 #[test]