dev vouch dev on at. thats about it
atvouch.dev
simplify routes on common denominators
authored by
Luna
and committed by
tangled.org
a88f8408
36747aa6
+65
-1
+30
-1
appview/lib/atvouch/graph.ex
+30
-1
appview/lib/atvouch/graph.ex
···
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end)
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end)
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-
{:routes, target_did, paths}
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{:routes, target_did, deduplicate_paths(paths)}
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end
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end
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# Remove paths that are "subsumed" by shorter paths.
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# A path P2 is subsumed by P1 if P1's intermediates are a subsequence of P2's intermediates.
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defp deduplicate_paths(paths) do
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sorted = Enum.sort_by(paths, &length/1)
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Enum.reduce(sorted, [], fn path, kept ->
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if Enum.any?(kept, fn shorter -> subsumes?(shorter, path) end) do
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kept
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else
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kept ++ [path]
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end
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end)
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end
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defp subsumes?(shorter, longer) when length(shorter) >= length(longer), do: false
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defp subsumes?(shorter, longer) do
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# Extract intermediate nodes (drop source and target)
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short_mids = shorter |> Enum.drop(1) |> Enum.drop(-1)
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long_mids = longer |> Enum.drop(1) |> Enum.drop(-1)
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subsequence?(short_mids, long_mids)
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end
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defp subsequence?([], _), do: true
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defp subsequence?(_, []), do: false
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defp subsequence?([h | st], [h | lt]), do: subsequence?(st, lt)
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defp subsequence?(short, [_ | lt]), do: subsequence?(short, lt)
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# Returns DIDs that `source_did` has vouched for (outgoing edges)
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defp vouched_by(source_did) do
+35
appview/test/atvouch/xrpc_get_routes_test.exs
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appview/test/atvouch/xrpc_get_routes_test.exs
···
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assert route_paths(body) == [["did:plc:alice", "did:plc:bob", "did:plc:carol"]]
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end
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test "shorter path subsumes longer path through same intermediary" do
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# A->B, B->C gives path A->B->C
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# A->D, D->B, B->C gives path A->D->B->C
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# The 2-hop path through B should subsume the 3-hop path through D->B
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create_vouch("did:plc:alice", "did:plc:bob")
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create_vouch("did:plc:alice", "did:plc:dave")
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create_vouch("did:plc:bob", "did:plc:carol")
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create_vouch("did:plc:dave", "did:plc:bob")
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conn = get_routes("did:plc:carol", "did:plc:alice")
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assert conn.status == 200
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body = Jason.decode!(conn.resp_body)
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paths = route_paths(body)
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assert paths == [["did:plc:alice", "did:plc:bob", "did:plc:carol"]]
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end
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test "keeps paths with different intermediaries" do
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# A->B->C and A->D->C have different intermediaries, both kept
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create_vouch("did:plc:alice", "did:plc:bob")
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create_vouch("did:plc:alice", "did:plc:dave")
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create_vouch("did:plc:bob", "did:plc:carol")
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create_vouch("did:plc:dave", "did:plc:carol")
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conn = get_routes("did:plc:carol", "did:plc:alice")
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assert conn.status == 200
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body = Jason.decode!(conn.resp_body)
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paths = route_paths(body)
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assert length(paths) == 2
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middles = Enum.map(paths, fn [_, mid, _] -> mid end) |> MapSet.new()
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assert middles == MapSet.new(["did:plc:bob", "did:plc:dave"])
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end
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test "direct vouch takes priority even when indirect paths exist" do
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create_vouch("did:plc:alice", "did:plc:carol")
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create_vouch("did:plc:alice", "did:plc:bob")