Remove database_file_handler; give precendence to router error messages

The database handler was unused; the router already serves the favicon and it
doesn't do anything else. Note that 'database handler' is different
from 'files served from storage', the router already handles those.

This also fixes the long standing bug that all 404 errors are either
'crate not found' or 'resource not found'.

Author: jyn514

src/web/error.rs

@@ -163,9 +163,6 @@ mod tests {
 
     #[test]
     fn check_404_page_content_resource() {
-        // Resources with a `.js` and `.ico` extension are special cased in the
-        // routes_handler which is currently run last. This means that `get("resource.exe")` will
-        // fail with a `no so such crate` instead of 'no such resource'
         wrapper(|env| {
             let page = kuchiki::parse_html().one(
                 env.frontend()
@@ -180,7 +177,7 @@ mod tests {
                     .next()
                     .unwrap()
                     .text_contents(),
-                "The requested crate does not exist",
+                "The requested resource does not exist",
             );
 
             Ok(())
@@ -200,7 +197,7 @@ mod tests {
                     .next()
                     .unwrap()
                     .text_contents(),
-                "The requested crate does not exist",
+                "The requested version does not exist",
             );
 
             Ok(())
@@ -219,7 +216,7 @@ mod tests {
                     .next()
                     .unwrap()
                     .text_contents(),
-                "The requested crate does not exist",
+                "The requested version does not exist",
             );
 
             Ok(())
@@ -242,7 +239,7 @@ mod tests {
                     .next()
                     .unwrap()
                     .text_contents(),
-                "The requested crate does not exist",
+                "The requested version does not exist",
             );
 
             Ok(())

src/web/mod.rs

@@ -105,7 +105,6 @@ use iron::{
     status::Status,
     Chain, Handler, Iron, IronError, IronResult, Listening, Request, Response, Url,
 };
-use metrics::RequestRecorder;
 use page::TemplateData;
 use postgres::Client;
 use router::NoRoute;
@@ -121,7 +120,6 @@ const DEFAULT_BIND: &str = "0.0.0.0:3000";
 struct CratesfyiHandler {
     shared_resource_handler: Box<dyn Handler>,
     router_handler: Box<dyn Handler>,
-    database_file_handler: Box<dyn Handler>,
     inject_extensions: InjectExtensions,
 }
 
@@ -140,19 +138,13 @@ impl CratesfyiHandler {
         let inject_extensions = InjectExtensions::new(context, template_data)?;
 
         let routes = routes::build_routes();
-        let blacklisted_prefixes = routes.page_prefixes();
-
         let shared_resources =
             Self::chain(inject_extensions.clone(), rustdoc::SharedResourceHandler);
         let router_chain = Self::chain(inject_extensions.clone(), routes.iron_router());
 
         Ok(CratesfyiHandler {
             shared_resource_handler: Box::new(shared_resources),
             router_handler: Box::new(router_chain),
-            database_file_handler: Box::new(routes::BlockBlacklistedPrefixes::new(
-                blacklisted_prefixes,
-                Box::new(RequestRecorder::new(file::DatabaseFileHandler, "database")),
-            )),
             inject_extensions,
         })
     }
@@ -165,7 +157,9 @@ impl Handler for CratesfyiHandler {
             handle: impl FnOnce() -> IronResult<Response>,
         ) -> IronResult<Response> {
             if e.response.status == Some(status::NotFound) {
-                handle()
+                // the routes are ordered from most specific to least; give precedence to the
+                // original error message.
+                handle().or(Err(e))
             } else {
                 Err(e)
             }
@@ -174,8 +168,7 @@ impl Handler for CratesfyiHandler {
         // This is kind of a mess.
         //
         // Almost all files should be served through the `router_handler`; eventually
-        // `shared_resource_handler` should go through the router too, and `database_file_handler`
-        // could be removed altogether.
+        // `shared_resource_handler` should go through the router too.
         //
         // Unfortunately, combining `shared_resource_handler` with the `router_handler` breaks
         // things, because right now `shared_resource_handler` allows requesting files from *any*
@@ -188,7 +181,6 @@ impl Handler for CratesfyiHandler {
         self.router_handler
             .handle(req)
             .or_else(|e| if_404(e, || self.shared_resource_handler.handle(req)))
-            .or_else(|e| if_404(e, || self.database_file_handler.handle(req)))
             .or_else(|e| {
                 let err = if let Some(err) = e.error.downcast_ref::<error::Nope>() {
                     *err

src/web/rustdoc.rs

@@ -516,7 +516,7 @@ pub fn target_redirect_handler(req: &mut Request) -> IronResult<Response> {
 
     let crate_details = match CrateDetails::new(&mut conn, &name, &version) {
         Some(krate) => krate,
-        None => return Err(Nope::ResourceNotFound.into()),
+        None => return Err(Nope::VersionNotFound.into()),
     };
 
     //   [crate, :name, :version, target-redirect, :target, *path]