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Add copy buttons to the network inspector Headers and Cookies tabs - #10052

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hkarmoush:network-inspector-copy
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hkarmoush:network-inspector-copy

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@hkarmoush

@hkarmoush hkarmoush commented Oct 21, 2026 •

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Part of #8190

The Headers and Cookies tabs in the network request inspector had no way to copy their contents, and the cookie table and image metadata weren't selectable at all. This adds a copy button to the tab bar for Headers and Cookies, the same as Request and Response already have, so all the tabs work the same way.

  • Headers copies each section (General, Response Headers, Request Headers) under its title as key: value lines. Multi-value headers are joined the way they'd be sent (set-cookie gets one line per value, cookie is joined with ; ), so the text is easy to paste into a bug report. The General section is printed as plain key: value lines, the same as the tab shows it.
  • Cookies copies response cookies as their raw Set-Cookie values (parsing drops Max-Age and SameSite, so the raw header is used when it's there) and request cookies as a Cookie header value.
  • Cookie cells and image metadata are now inside a SelectionArea. Selection doesn't work in VS Code on Mac (SelectableText and SelectionArea do not work correctly when calling document.execCommand("copy") unless you right-click flutter#182756), which is why the copy buttons are the main fix here.

While in there I also fixed calculateHeadersSize, used for the HAR export. It checked value is List<String>, but headers decoded from JSON are List<dynamic>, so list values were counted with their brackets. It now shares the same formatting as the copy text, so headersSize in exported HAR files changes for requests with multi-value headers (and is now correct for them).

Per-row copy and the request list actions menu mentioned in the issue are left for a follow-up.

Before/after screenshots to come.

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The Headers and Cookies tabs now have a copy button in the tab bar, the
same as Request and Response. Headers are copied as key: value lines
under each section title. Response cookies are copied as their raw
Set-Cookie values and request cookies as a Cookie header value.

Cookie values and image metadata are now selectable too.

Also fixes calculateHeadersSize, which never joined list values because
headers decoded from JSON are List<dynamic>, not List<String>.
@hkarmoush
hkarmoush marked this pull request as ready for review October 24, 2026 10:17
@hkarmoush
hkarmoush requested review from a team, kenzieschmoll and srawlins as code owners October 24, 2026 10:17

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Code Review

This pull request adds copy buttons to the Headers and Cookies tabs of the network request inspector, and wraps cookie values and image metadata in SelectionArea to make them selectable. It also refactors the formatting logic for headers and cookies into reusable utility functions in http_utils.dart and adds comprehensive tests. The review feedback suggests improving robustness and idiomatic Dart by checking and casting to Iterable instead of List when handling multi-value headers.

Comment on lines +22 to +25
if (value is! List) {
yield '$key: $value';
continue;
}

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medium

[CONCERN] Using Iterable instead of List is more robust and idiomatic in Dart when we only need to iterate and join elements. This also prevents potential runtime TypeErrors if the header values are represented as other Iterable types (e.g., Set or Queue) or typed as List<Object?> which might not implicitly downcast to List<dynamic> in strong mode.

Suggested change
if (value is! List) {
yield '$key: $value';
continue;
}
if (value is! Iterable) {
yield '$key: $value';
continue;
}
References
  1. Key Principles: Readability, Maintainability, Consistency, and Code Reuse & DRY. (link)

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Good call, switched to checking Iterable here (and updated the doc comment to match). Added a test with a Set value too.

Comment on lines +84 to +86
.expand(
(entry) => entry.value is List ? entry.value as List : [entry.value],
)

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medium

[CONCERN] Checking and casting to Iterable instead of List is safer and more idiomatic. This avoids potential runtime TypeErrors if entry.value is a list of a more specific type (like List<Object?> or List<String>) which might fail when cast directly to List<dynamic>.

Suggested change
.expand(
(entry) => entry.value is List ? entry.value as List : [entry.value],
)
.expand(
(entry) => entry.value is Iterable
? entry.value as Iterable
: [entry.value],
)
References
  1. Key Principles: Readability, Maintainability, Consistency, and Code Reuse & DRY. (link)

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Same change here, done.

@fkarmoush

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Thanks for picking this up. Making Headers and Cookies copyable the same way as Request and Response closes a gap that's been awkward in the network inspector, and the curl-ready format (one set-cookie line per value, cookie joined with ;) means the copied text is usable as-is in a terminal or bug report. The calculateHeadersSize fix for HAR export is a nice catch too.

Looking forward to seeing this land once it's ready for review.

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2 participants