Load a profile from URL doesn't work for perf script profiles

Profiles generated using perf script can be opened from the file selection dialog, but loading the same file by URL fails with:

The profile could not be downloaded and decoded. This does not look like a supported file type. 
JSON parsing error: SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

[mstange]

You can also give this a try: https://github.com/mstange/fxprof-perf-convert It’s not finished yet but it should work for most use cases.

[copy]

For reference, this minimal patch fixes the issue (but will break other formats):

diff --git a/src/actions/receive-profile.js b/src/actions/receive-profile.js
index 744ccfb0..da8259b9 100644
--- a/src/actions/receive-profile.js
+++ b/src/actions/receive-profile.js
@@ -1224,11 +1224,7 @@ async function _extractProfileOrZipFromResponse(
       // and try to process it as a profile.
       return {
         responseType: 'PROFILE',
-        profile: await _extractJsonFromResponse(
-          response,
-          reportError,
-          contentType
-        ),
+        profile: await response.text()
       };
     default:
       throw assertExhaustiveCheck(contentType);

So now I can write a shell script that runs perf and automatically opens the profile in a local instance of this UI:

#!/bin/bash
set -euo pipefail
perf record -o /tmp/perf.data "$@"
perf script -i /tmp/perf.data -F +pid > ~/www/profiler/dist/test.perf
cd ~/www/profiler/dist
pidof nginx || nginx
xdg-open http://localhost:9000/from-url/%2Ftest.perf

With nginx configured as follows:

    server {
        listen 127.0.0.1:9000;
        server_name  localhost;
        location / {
            root   /home/fabian/www/profiler/dist;
            index  index.html;
            add_header Cache-Control no-cache;
            if_modified_since off;
            expires off;
            etag off;
        }
        error_page  404  =200 /index.html;
    }

Pretty cool!