feat: add cache max-age of 5 seconds to ?live requests so request collapsing works

packages/sync-service/lib/electric/plug/serve_shape_plug.ex

@@ -251,10 +251,11 @@ defmodule Electric.Plug.ServeShapePlug do
 
   defp put_resp_cache_headers(%Conn{} = conn, _) do
     if conn.assigns.live do
-      conn
-      |> put_resp_header("cache-control", "no-store, no-cache, must-revalidate, max-age=0")
-      |> put_resp_header("pragma", "no-cache")
-      |> put_resp_header("expires", "0")
+      put_resp_header(
+        conn,
+        "cache-control",
+        "max-age=5, stale-while-revalidate=5"
+      )
     else
       put_resp_header(
         conn,

packages/sync-service/test/electric/plug/serve_shape_plug_test.exs

@@ -354,11 +354,9 @@ defmodule Electric.Plug.ServeShapePlugTest do
              ]
 
       assert Plug.Conn.get_resp_header(conn, "cache-control") == [
-               "no-store, no-cache, must-revalidate, max-age=0"
+               "max-age=5, stale-while-revalidate=5"
              ]
 
-      assert Plug.Conn.get_resp_header(conn, "pragma") == ["no-cache"]
-      assert Plug.Conn.get_resp_header(conn, "expires") == ["0"]
       assert Plug.Conn.get_resp_header(conn, "x-electric-chunk-last-offset") == [next_offset_str]
       assert Plug.Conn.get_resp_header(conn, "x-electric-schema") == []
     end
@@ -440,11 +438,8 @@ defmodule Electric.Plug.ServeShapePlugTest do
       assert Jason.decode!(conn.resp_body) == [%{"headers" => %{"control" => "up-to-date"}}]
 
       assert Plug.Conn.get_resp_header(conn, "cache-control") == [
-               "no-store, no-cache, must-revalidate, max-age=0"
+               "max-age=5, stale-while-revalidate=5"
              ]
-
-      assert Plug.Conn.get_resp_header(conn, "pragma") == ["no-cache"]
-      assert Plug.Conn.get_resp_header(conn, "expires") == ["0"]
     end
 
     test "send 409 when shape ID requested does not exist" do

packages/typescript-client/test/cache.test.ts

@@ -64,7 +64,7 @@ const it = testWithIssuesTable.extend<{
 })
 
 describe(`HTTP Proxy Cache`, { timeout: 30000 }, () => {
-  it(`should always get non-cached response in live mode`, async ({
+  it(`should get a short max-age cache-conrol header in live mode`, async ({
     insertIssues,
     proxyCacheBaseUrl,
     issuesTableUrl,
@@ -93,14 +93,14 @@ describe(`HTTP Proxy Cache`, { timeout: 30000 }, () => {
     expect(liveRes.status).toBe(200)
     expect(getCacheStatus(liveRes)).toBe(CacheStatus.MISS)
 
-    // Second request still gets non-cached response
+    // Second request gets a cached response
     const cachedRes = await fetch(
       `${proxyCacheBaseUrl}/v1/shape/${issuesTableUrl}?${searchParams.toString()}`,
       {}
     )
     expect(cachedRes.status).toBe(200)
 
-    expect(getCacheStatus(cachedRes)).toBe(CacheStatus.MISS)
+    expect(getCacheStatus(cachedRes)).toBe(CacheStatus.HIT)
   })
 
   it(`should get cached response on second request`, async ({

website/electric-api.yaml

@@ -134,7 +134,7 @@ paths:
               description: |-
                 Cache control header as a string of comma separated directives.
 
-                Supported directives are: `max-age`, `stale-while-revalidate`, `no-store`, `no-cache`, `must-revalidate`.
+                Supported directives are: `max-age`, `stale-while-revalidate`.
             etag:
               schema:
                 type: string
@@ -143,12 +143,6 @@ paths:
                 Etag header specifying the shape ID and offset for efficient caching.
 
                 In the format `{shape_id}:{start_offset}:{end_offset}`.
-            pragma:
-              schema:
-                type: string
-                enum:
-                  - no-cache
-              description: Pragma header for backwards compatibility with HTTP/1.0 caches (that don't have a Cache-Control HTTP/1.1 header).
             x-electric-chunk-last-offset:
               schema:
                 type: string