[Yunnglin]

What

Removes the legacy Gradio-era image convention from messages_to_markdown and makes the Web dashboard resolve server-side media paths in both rendering chains.

Why

messages_to_markdown emitted ![image](gradio_api/file=<abs path>), introduced by #1019 when the dashboard was Gradio-based. That convention is dead:

• gradio appears in no requirements/*.txt and not in pyproject.toml
• evalscope app is only a [DEPRECATED] Use "evalscope service" instead alias
• nothing in Python code, evalscope/web/src or tests/ interprets gradio_api
• the React dashboard serves server-side files via /api/v1/reports/media/file?path=

Consequence: every benchmark that puts a local path in ContentImage (miniwob, browsergym, general_vqa custom data, …) had broken images in the compare view, and Sample.pretty_print printed the unusable prefix as noise.

Dropping the prefix alone is not enough — MarkdownRenderer passed the markdown src straight to ImageLightbox, which renders <img src> verbatim. Only the structured Messages chain proxied media, via the module-private resolveMediaSrc in MediaBlocks.tsx.

Changes

1. evalscope/api/messages/chat_message.py — emit ![image]({abs_path}) instead of the gradio_api/file= form.
2. evalscope/web/src/utils/media.ts (new) — resolveMediaSrc extracted here and shared. It is not exported from MediaBlocks.tsx because MediaBlocks already imports MarkdownRenderer, so re-importing would create a cycle.
3. MarkdownRenderer.tsx — the img renderer now resolves src through resolveMediaSrc, so the markdown chain proxies local paths exactly like the structured chain.
4. evalscope/utils/data_utils.py — absolutise local media paths when serialising prediction messages (see below).

Extra fix: relative paths in the structured chain

While verifying, the single-report detail view turned out to be broken too — not by this change, but pre-existing on main. ContentImage values may be relative paths (the custom VQA data behind general_vqa uses custom_eval/multimodal/images/dog.jpg). A client cannot tell a relative path from a base64 payload, so resolveMediaSrc fell into the base64 branch and produced data:image/jpeg;base64,custom_eval/... → net::ERR_INVALID_URL.

Same prediction, before this PR:

Input    (markdown chain)   : ![image](gradio_api/file=/abs/.../dog.jpg)   → 404
Messages (structured chain) : 'custom_eval/multimodal/images/dog.jpg'      → ERR_INVALID_URL

Local media paths are now absolutised in _serialize_messages, mirroring what messages_to_markdown already did, so both chains expose media identically. Note this resolution is relative to the service process CWD — that constraint already applied to the markdown chain (messages_markdown is computed at read time), so it is not newly introduced.

Verification

Real run: general_vqa on the custom VQA sample data, DashScope qwen-vl-plus + qwen-vl-max, then a live dashboard.

API payload after the fix — both fields now carry an absolute path:

markdown Input img : /abs/.../custom_eval/multimodal/images/dog.jpg
structured image   : /abs/.../custom_eval/multimodal/images/dog.jpg

In the browser:

• Compare view (markdown chain, the case this issue is about): image renders, src = /api/v1/reports/media/file?path=%2F...%2Fdog.jpg, 200 OK
• Single-report chat view (structured chain, regression guard + relative-path fix): image renders, same proxy URL, no console errors

Test gate:

• tests/api/test_messages_to_markdown.py (new, 4 cases) — no gradio_api, absolute path emitted, relative path absolutised, data URI passthrough, base64 max_length truncation
• tests/report/test_prediction_media_paths.py (new, 3 cases) — relative path absolutised, absolute path preserved, data URI / base64 untouched
• MarkdownRenderer.test.tsx (+2 cases) — local absolute path proxied; http and data: sources untouched
• ChatView.test.tsx unchanged and still green (structured-chain guard)
• make lint clean; pytest tests/cli/test_all.py::TestRun::test_ci_lite passes; npm run test 243/243; npm run lint and npm run build (tsc -b + vite) clean

Note for reviewers

evalscope/web/dist is not tracked, so the frontend part needs make web-build to take effect in a running dashboard.

[Copilot]

Pull request overview

This PR removes the legacy gradio_api/file= Markdown convention and makes the Web dashboard consistently proxy server-side media paths for both rendering chains (structured Messages blocks and Markdown-rendered content), including fixing relative-path handling by absolutizing media paths during message serialization.

Changes:

• Update messages_to_markdown to emit local images as plain absolute paths (no gradio_api prefix).
• Share a single resolveMediaSrc helper across structured and Markdown rendering so local paths are proxied uniformly.
• Absolutize relative media paths when serializing prediction messages, with regression tests across Python and React.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
evalscope/api/messages/chat_message.py	Drops gradio_api/file= and emits absolute local image paths in Markdown.
evalscope/utils/data_utils.py	Absolutizes local media paths inside serialized structured ContentBlocks for frontend compatibility.
evalscope/web/src/utils/media.ts	New shared resolveMediaSrc utility to proxy absolute paths and preserve http(s)/data URIs.
evalscope/web/src/components/single/chat/MediaBlocks.tsx	Uses shared resolveMediaSrc for structured media blocks.
evalscope/web/src/components/common/MarkdownRenderer.tsx	Proxies Markdown <img src> through resolveMediaSrc to match structured chain behavior.
evalscope/web/src/components/common/MarkdownRenderer.test.tsx	Adds coverage for Markdown image source proxying and passthrough behavior.
tests/api/test_messages_to_markdown.py	Adds regression tests for Markdown emission (no gradio_api, absolutization, passthrough, truncation).
tests/report/test_prediction_media_paths.py	Adds tests ensuring structured-message media paths are absolutized/preserved appropriately.

Suppressed comments (1)

tests/api/test_messages_to_markdown.py:28

• Test expectation should match the safer local-path Markdown emission (wrapping the destination in <...>), otherwise it will fail once local paths are escaped for Markdown parsing.

    assert f'![image]({image_path.resolve()})' in markdown

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