4 files changed, 29 insertions, 20 deletions

diff --git a/src/libexpr/common-eval-args.cc b/src/libexpr/common-eval-args.cc
index 8e94d358e..7c0d268bd 100644
--- a/src/libexpr/common-eval-args.cc
+++ b/src/libexpr/common-eval-args.cc
@@ -61,9 +61,11 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
 
 Path lookupFileArg(EvalState & state, string s)
 {
-    if (isUri(s))
-        return getDownloader()->downloadCached(state.store, s, true).path;
-    else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
+    if (isUri(s)) {
+        CachedDownloadRequest request(s);
+        request.unpack = true;
+        return getDownloader()->downloadCached(state.store, request).path;
+    } else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
         Path p = s.substr(1, s.size() - 2);
         return state.findFile(p);
     } else
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 75f04df3e..0cfe29c96 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -657,7 +657,9 @@ std::pair<bool, std::string> EvalState::resolveSearchPathElem(const SearchPathEl
 
     if (isUri(elem.second)) {
         try {
-            res = { true, getDownloader()->downloadCached(store, elem.second, true).path };
+            CachedDownloadRequest request(elem.second);
+            request.unpack = true;
+            res = { true, getDownloader()->downloadCached(store, request).path };
         } catch (DownloadError & e) {
             printError(format("warning: Nix search path entry '%1%' cannot be downloaded, ignoring") % elem.second);
             res = { false, "" };
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 55a1bde11..070e72f3a 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -2050,9 +2050,9 @@ static void prim_splitVersion(EvalState & state, const Pos & pos, Value * * args
 void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
     const string & who, bool unpack, const std::string & defaultName)
 {
-    string url;
-    Hash expectedHash;
-    string name = defaultName;
+    CachedDownloadRequest request("");
+    request.unpack = unpack;
+    request.name = defaultName;
 
     state.forceValue(*args[0]);
 
@@ -2063,27 +2063,27 @@ void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
         for (auto & attr : *args[0]->attrs) {
             string n(attr.name);
             if (n == "url")
-                url = state.forceStringNoCtx(*attr.value, *attr.pos);
+                request.uri = state.forceStringNoCtx(*attr.value, *attr.pos);
             else if (n == "sha256")
-                expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
+                request.expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
             else if (n == "name")
-                name = state.forceStringNoCtx(*attr.value, *attr.pos);
+                request.name = state.forceStringNoCtx(*attr.value, *attr.pos);
             else
                 throw EvalError(format("unsupported argument '%1%' to '%2%', at %3%") % attr.name % who % attr.pos);
         }
 
-        if (url.empty())
+        if (request.uri.empty())
             throw EvalError(format("'url' argument required, at %1%") % pos);
 
     } else
-        url = state.forceStringNoCtx(*args[0], pos);
+        request.uri = state.forceStringNoCtx(*args[0], pos);
 
-    state.checkURI(url);
+    state.checkURI(request.uri);
 
-    if (evalSettings.pureEval && !expectedHash)
+    if (evalSettings.pureEval && !request.expectedHash)
         throw Error("in pure evaluation mode, '%s' requires a 'sha256' argument", who);
 
-    Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash).path;
+    Path res = getDownloader()->downloadCached(state.store, request).path;
 
     if (state.allowedPaths)
         state.allowedPaths->insert(res);
diff --git a/src/libexpr/primops/flake.cc b/src/libexpr/primops/flake.cc
index c6c380118..e2fdf08ca 100644
--- a/src/libexpr/primops/flake.cc
+++ b/src/libexpr/primops/flake.cc
@@ -136,9 +136,11 @@ std::shared_ptr<FlakeRegistry> EvalState::getGlobalFlakeRegistry()
     std::call_once(_globalFlakeRegistryInit, [&]() {
         auto path = evalSettings.flakeRegistry;
 
-        if (!hasPrefix(path, "/"))
-            path = getDownloader()->downloadCached(store,
-                evalSettings.flakeRegistry, false, "registry").path;
+        if (!hasPrefix(path, "/")) {
+            CachedDownloadRequest request(evalSettings.flakeRegistry);
+            request.name = "flake-registry.json";
+            path = getDownloader()->downloadCached(store, request).path;
+        }
 
         _globalFlakeRegistry = readRegistry(path);
     });
@@ -244,8 +246,11 @@ static SourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool
         if (accessToken != "")
             url += "?access_token=" + accessToken;
 
-        auto result = getDownloader()->downloadCached(state.store, url, true, "source",
-            Hash(), nullptr, resolvedRef.rev ? 1000000000 : settings.tarballTtl);
+        CachedDownloadRequest request(url);
+        request.unpack = true;
+        request.name = "source";
+        request.ttl = resolvedRef.rev ? 1000000000 : settings.tarballTtl;
+        auto result = getDownloader()->downloadCached(state.store, request);
 
         if (!result.etag)
             throw Error("did not receive an ETag header from '%s'", url);