Edouard Vanbelle
7705fca3af
Writing the hurl scenario surfaced a gap: a transcode that comes out
larger than the original runs a full decode + encode and increments no
counter at all. `transcodes` is bumped only on the success path, beside
`bytes_saved`, so the most expensive failure mode was invisible — a
multi-megapixel image decoded and re-encoded on every request, for
every file sharing that content, producing nothing.
That is precisely the cost the persisted negative verdict exists to
stop paying, and it could not be measured before or after. `not_beneficial`
counts it, kept separate from `transcodes` because conflating "work
done" with "work that paid off" would hide exactly what an operator
needs to see.
It is also what lets the hurl scenario assert the negative half: the
first fetch increments it, the second — a distinct file with identical
content — leaves it untouched, which is the negative row being read
rather than the verdict recomputed.
Assertions are exact equality against captured values throughout, no
`>` or `<`. A "greater than" would pass if a counter moved for the
wrong reason; equality against the prior reading catches any transcode
from any source, including one this scenario did not intend to cause.
Also fixes two URLs the first runs caught: file download is
`GET /api/files/{id}`, not `/content`, and the trash listing is
`/api/trash/resources`. And the duplicate uploads go to a second
folder — re-uploading the same filename into the same folder returns
the EXISTING file id, which would have made both halves of every
"two files, one content" pair the same row and left the scenario
asserting nothing.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
349 lines
16 KiB
Plaintext
349 lines
16 KiB
Plaintext
# =============================================================
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# OxiCloud – Transcode caching: positive and negative
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#
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# Pins that a WebP transcode is computed ONCE per distinct content and
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# then answered from the derived tier, in both directions:
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#
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# * positive — WebP is smaller, so the bytes are stored and reused
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# * negative — WebP came out larger, so the VERDICT is stored and the
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# decode + encode is not repeated
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#
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# ## Why this can assert what the thumbnail tests could not
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#
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# `derived_blob_copy.hurl` documents that thumbnail tier selection is
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# invisible over HTTP: stored blob, RAM cache and a fresh re-render all
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# return identical bytes. Transcodes are the same — but
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# `GET /api/admin/transcode/stats` now exposes the counters, so "was
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# this computed or served" becomes observable from outside the process.
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# `transcodes` is work done; `cache_hits` (RAM, keyed by file id) and
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# `disk_hits` (the durable content-keyed tier) are work avoided.
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#
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# ## Why each case uploads the same bytes twice
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#
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# The in-memory cache is keyed `{file_id}:{ext}`, so re-fetching the SAME
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# file proves only that moka works. Uploading identical content as a
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# SECOND file gives a different file id and therefore a guaranteed memory
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# miss — but the same content hash. If the second fetch still avoids a
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# transcode, only the content-keyed tier can have answered it. That is
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# precisely what the migration bought, and it is unobservable any other
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# way.
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#
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# ## Fixtures
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#
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# `red-image.png` shrinks (4780 → 186 bytes). `negative-cache-transcode.png`
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# does not — a real screenshot, which is the only thing that defeats this
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# encoder; synthetic images all come out positive. Both properties are
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# pinned by `image_transcode_service::fixture_premise`, so if an encoder
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# bump ever flips one, that unit test fails loudly instead of this
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# scenario quietly testing nothing.
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#
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# Prerequisites: setup.hurl must have run (admin user exists).
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#
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# Run:
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# hurl --variables-file tests/api/test.env --file-root tests \
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# --test tests/api/transcode_cache.hurl
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# =============================================================
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# ─────────────────────────────────────────────────────────────
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# Step 1 – Login
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/auth/login
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Content-Type: application/json
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{
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"username": "{{username}}",
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"password": "{{password}}"
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}
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HTTP 200
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[Captures]
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token: jsonpath "$.access_token"
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# ─────────────────────────────────────────────────────────────
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# Step 2 – Working folder
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/folders
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Authorization: Bearer {{token}}
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Content-Type: application/json
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{
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"name": "hurl-transcode-cache"
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}
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HTTP 201
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[Captures]
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folder_id: jsonpath "$.id"
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# ─────────────────────────────────────────────────────────────
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# Step 2b – A second folder, for the duplicate uploads.
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#
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# Re-uploading the same filename into the SAME folder overwrites the
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# existing file and returns its id, so both halves of a "two distinct
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# files, one content" pair would be the same row and the test would
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# assert nothing. A second folder keeps the name free.
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/folders
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Authorization: Bearer {{token}}
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Content-Type: application/json
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{
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"name": "hurl-transcode-cache-dup"
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}
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HTTP 201
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[Captures]
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folder_dup_id: jsonpath "$.id"
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# ─────────────────────────────────────────────────────────────
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# Step 3 – Baseline counters.
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#
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# Absolute values are meaningless here — earlier scenarios in the same
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# run transcode images too. Everything below is asserted as a DELTA
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# from this point, which is also why this file must not assume it runs
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# first.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/admin/transcode/stats
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Authorization: Bearer {{token}}
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HTTP 200
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[Captures]
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base_transcodes: jsonpath "$.transcodes"
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base_not_beneficial: jsonpath "$.not_beneficial"
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# ═════════════════════════════════════════════════════════════
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# POSITIVE CASE — WebP is smaller
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# ═════════════════════════════════════════════════════════════
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# ─────────────────────────────────────────────────────────────
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# Step 4 – Upload a shrinkable image
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/files/upload
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Authorization: Bearer {{token}}
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[MultipartFormData]
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folder_id: {{folder_id}}
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file: file,fixtures/red-image.png; image/png
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HTTP 201
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[Captures]
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pos_a_id: jsonpath "$.id"
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pos_hash: jsonpath "$.content_hash"
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# ─────────────────────────────────────────────────────────────
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# Step 5 – Fetch it as a WebP-capable client.
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#
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# `Accept: image/webp` is what selects the transcode path;
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# `BrowserCapabilities::from_accept_header` looks for exactly this.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/files/{{pos_a_id}}
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Authorization: Bearer {{token}}
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Accept: image/webp,image/png,*/*
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HTTP 200
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[Asserts]
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header "Content-Type" contains "image/webp"
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# ─────────────────────────────────────────────────────────────
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# Step 6 – That was work actually done, not a cache hit.
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#
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# Captured rather than computed: hurl has no arithmetic in predicates,
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# and pinning the exact value here is stronger anyway — the later steps
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# assert equality against it, so any transcode from any source shows up.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/admin/transcode/stats
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Authorization: Bearer {{token}}
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HTTP 200
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[Captures]
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after_positive: jsonpath "$.transcodes"
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after_positive_disk: jsonpath "$.disk_hits"
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[Asserts]
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jsonpath "$.not_beneficial" == {{base_not_beneficial}}
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# ─────────────────────────────────────────────────────────────
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# Step 7 – The SAME bytes uploaded as a second, distinct file.
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#
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# Same content hash, different file id. Asserting the hash matches is
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# what makes the next step meaningful: if these two files did not share
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# content, a second transcode would be correct rather than a regression.
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/files/upload
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Authorization: Bearer {{token}}
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[MultipartFormData]
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folder_id: {{folder_dup_id}}
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file: file,fixtures/red-image.png; image/png
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HTTP 201
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[Captures]
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pos_b_id: jsonpath "$.id"
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[Asserts]
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jsonpath "$.content_hash" == "{{pos_hash}}"
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jsonpath "$.id" != "{{pos_a_id}}"
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# ─────────────────────────────────────────────────────────────
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# Step 8 – Fetching the second file still yields WebP.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/files/{{pos_b_id}}
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Authorization: Bearer {{token}}
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Accept: image/webp,image/png,*/*
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HTTP 200
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[Asserts]
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header "Content-Type" contains "image/webp"
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# ─────────────────────────────────────────────────────────────
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# Step 9 – …WITHOUT a second transcode.
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#
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# The memory cache could not have served this: it is keyed by file id
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# and this is a different file. Only the content-keyed derived tier
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# answers here, which is the whole point of keying derivations by
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# content rather than by file.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/admin/transcode/stats
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Authorization: Bearer {{token}}
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HTTP 200
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[Asserts]
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jsonpath "$.transcodes" == {{after_positive}}
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jsonpath "$.not_beneficial" == {{base_not_beneficial}}
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jsonpath "$.disk_hits" != {{after_positive_disk}}
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# ═════════════════════════════════════════════════════════════
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# NEGATIVE CASE — WebP comes out larger
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# ═════════════════════════════════════════════════════════════
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# ─────────────────────────────────────────────────────────────
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# Step 10 – Upload an image the encoder cannot shrink
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/files/upload
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Authorization: Bearer {{token}}
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[MultipartFormData]
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folder_id: {{folder_id}}
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file: file,fixtures/negative-cache-transcode.png; image/png
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HTTP 201
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[Captures]
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neg_a_id: jsonpath "$.id"
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neg_hash: jsonpath "$.content_hash"
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# ─────────────────────────────────────────────────────────────
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# Step 11 – A WebP-capable client gets the ORIGINAL back.
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#
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# Not a failure: transcoding to something larger would cost the client
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# bandwidth, so the service serves the PNG and remembers why.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/files/{{neg_a_id}}
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Authorization: Bearer {{token}}
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Accept: image/webp,image/png,*/*
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HTTP 200
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[Asserts]
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header "Content-Type" contains "image/png"
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# ─────────────────────────────────────────────────────────────
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# Step 12 – The attempt still cost one decode + encode.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/admin/transcode/stats
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Authorization: Bearer {{token}}
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HTTP 200
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[Captures]
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after_negative: jsonpath "$.not_beneficial"
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[Asserts]
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# The decode + encode ran and produced nothing usable, which is counted
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# separately from `transcodes` — that only counts work that paid off.
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jsonpath "$.transcodes" == {{after_positive}}
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# ─────────────────────────────────────────────────────────────
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# Step 13 – Same bytes again, as a distinct file.
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# ─────────────────────────────────────────────────────────────
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POST {{base_url}}/api/files/upload
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Authorization: Bearer {{token}}
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[MultipartFormData]
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folder_id: {{folder_dup_id}}
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file: file,fixtures/negative-cache-transcode.png; image/png
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HTTP 201
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[Captures]
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neg_b_id: jsonpath "$.id"
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[Asserts]
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jsonpath "$.content_hash" == "{{neg_hash}}"
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jsonpath "$.id" != "{{neg_a_id}}"
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# ─────────────────────────────────────────────────────────────
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# Step 14 – Original again, as expected.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/files/{{neg_b_id}}
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Authorization: Bearer {{token}}
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Accept: image/webp,image/png,*/*
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HTTP 200
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[Asserts]
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header "Content-Type" contains "image/png"
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# ─────────────────────────────────────────────────────────────
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# Step 15 – …and the verdict was NOT recomputed.
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#
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# This is the assertion the negative row exists for. Without it the
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# server re-runs a full decode + encode of a half-megabyte screenshot on
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# every request for every file sharing that content, only to throw the
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# result away each time. A counter that moved here would mean the
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# negative row was not written, not read, or not keyed by content.
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# ─────────────────────────────────────────────────────────────
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GET {{base_url}}/api/admin/transcode/stats
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Authorization: Bearer {{token}}
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HTTP 200
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[Asserts]
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jsonpath "$.not_beneficial" == {{after_negative}}
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jsonpath "$.transcodes" == {{after_positive}}
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# ─────────────────────────────────────────────────────────────
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# Step 16 – Teardown. Hurl files share one database, so a folder left
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# behind changes what later scenarios see.
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# ─────────────────────────────────────────────────────────────
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DELETE {{base_url}}/api/folders/{{folder_id}}
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Authorization: Bearer {{token}}
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HTTP 204
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DELETE {{base_url}}/api/folders/{{folder_dup_id}}
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Authorization: Bearer {{token}}
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HTTP 204
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GET {{base_url}}/api/trash/resources
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Authorization: Bearer {{token}}
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HTTP 200
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[Captures]
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trash_id: jsonpath "$.items[?(@.resource.id == '{{folder_id}}')].resource.id"
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trash_dup_id: jsonpath "$.items[?(@.resource.id == '{{folder_dup_id}}')].resource.id"
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DELETE {{base_url}}/api/trash/{{trash_id}}
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Authorization: Bearer {{token}}
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HTTP 200
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DELETE {{base_url}}/api/trash/{{trash_dup_id}}
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Authorization: Bearer {{token}}
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HTTP 200
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