cdp-cli

A tiny Chrome DevTools Protocol helper for poking at live tabs (DOM snapshots, styles/rect metrics, screenshots, console streaming, etc.).

git clone https://github.com/veilm/cdp-cli
./cdp-cli/install.sh # will prompt for sudo. requires Go only
cdp --help

Prerequisite: run a Chromium-based browser with its CDP port exposed.

• Chromium example: chromium --remote-debugging-port=9992
• Brave example: brave --remote-debugging-port=9992
• Other Chromium-based browsers use the same flag pattern. Firefox-based browsers aren't supported
• QtWebEngine-based browsers like qutebrowser are supported; see their docs for how to enable CDP

Use cdp --help (or cdp <command> --help) for switches and examples. Highlights:

• cdp eval --session manager --file script.js --pretty (or --stdin) runs multi-line scripts without shell gymnastics.
• cdp eval --session manager --json --wait "({ready: document.readyState})" can wait for load and JSON-serialize values.
• Tip: if your JS starts with an object literal, wrap it like ({a: 1}) so it isn't parsed as a block.
• Tip: click, type, and hover also accept inline :has-text(...) at the end of the selector (e.g. .btn:has-text(Submit)), which maps to --has-text.
• cdp rect --session manager ".selector" prints a DOMRect snapshot.
• cdp tabs list --plain quickly shows the currently discoverable tabs when you're picking one to connect to.
• cdp connect --session manager --tab 3 --port 9222 binds a session by tab index or pattern.
• cdp connect --session manager --new --port 9222 opens a new tab and connects it immediately.
• cdp tabs open https://example.com spawns a fresh tab (foreground by default, pass --activate=false for background).
• cdp tabs switch 3 (or a target id/pattern) activates a tab directly from the CLI.
• cdp wait --session manager --selector ".compose" and cdp wait-visible --session manager ".compose" pause until the page is ready.
• Basic UI automation examples:
• cdp click --session manager ".btn"
• cdp hover --session manager ".card"
• cdp drag --session manager ".piece" ".slot"
• cdp gesture --session manager "canvas" "0.1,0.5 0.9,0.5" (draw, swipe, slide, trace)
• cdp key --session manager "Ctrl+s"
• cdp type --session manager ".input" "hello"
• cdp scroll --session manager 800 --element ".scroll-pane"
• cdp upload --session manager "input[type=file]" ./file.txt
• cdp upload supports multiple files and can --wait for the selector to exist (with --poll and --timeout).
• cdp network-log --session manager --dir /tmp/network --url '.*\\.json' mirrors every Fetch response into timestamped folders so you can tail -F or jq through the saved request/response artifacts without extra tooling.
• cdp keep-alive --session manager toggles focus/lifecycle emulation and foregrounds the tab so throttled UI pieces start rendering again.
• Set CDP_PRETTY=1 in your shell to make pretty JSON the default for eval output.
• Set CDP_PORT=9310 (or whatever you need) to change the default DevTools port used by commands that talk to the browser.
• Set CDP_SESSION_NAME=manager to make --session optional for commands that operate on a saved session.

WebNav Helpers (Injected JS API)

Most UI automation commands (click, hover, drag, gesture, key, type, scroll) now call a small helper API injected into the page. This lets you reuse the same logic from your own cdp eval scripts without copy-pasting long snippets.

• Auto-injection: the first time you run one of those commands, the helpers are injected automatically.
• Manual injection: cdp inject --session <name> (use --force to re-inject).

Helper Surface

The injection defines a global object and convenience aliases:

• window.WebNav (namespace)
• window.WebNavClick, window.WebNavHover, window.WebNavDrag, window.WebNavGesture, window.WebNavKey, window.WebNavTypePrepare, window.WebNavTypeFallback, window.WebNavScroll, window.WebNavFocus

Each helper accepts either an HTMLElement or a CSS selector string (or string array for click/hover/type).

Examples

cdp eval --session manager "window.WebNavClick('#save-button')"
cdp eval --session manager "window.WebNavClick(window.myElement)"
cdp eval --session manager "window.WebNavTypePrepare('#title', '', '', 'Hello', false)"
cdp eval --session manager "window.WebNavScroll(200, 0, '#scroll-pane', true)"

Notes:

• WebNavClick(target, hasTextSpec, attValueSpec, count) returns {submitForm, selector}.
• WebNavClick accepts NodeList/HTMLCollection/iterables. By default it clicks the first element; pass opts={all:true} to click all (e.g. WebNavClick(document.querySelectorAll('button'), '', '', 1, {all:true})).
• WebNavHover(target, hasTextSpec, attValueSpec) returns {x, y, selector}.
• WebNavDrag(fromTarget, toTarget, fromIndex, toIndex, delayMs) performs a drag/drop.
• WebNavGesture(target, points, delayMs) performs pointer down/move/up along [[x,y], ...] relative to the element.
• WebNavKey({key, code, ctrlKey, shiftKey, altKey, metaKey}) dispatches keydown/keyup.
• WebNavTypePrepare(target, hasTextSpec, attValueSpec, inputText, append) prepares selection/value and returns a state object. If handled is false, you can follow with Input.insertText (what cdp type does).
• WebNavTypeFallback(target, hasTextSpec, attValueSpec, inputText, append) is a last-resort textContent setter.
• WebNavScroll(yPx, xPx, elementTarget, emit) scrolls window or element and returns {scrollTop, scrollLeft}.
• WebNavElements.hasText(text, opts) filters an element collection by text content. It is available on NodeList as hasText when WebNav is injected.

Example:

cdp eval --session manager "WebNavClick(document.querySelectorAll('button').hasText('Press me'))"

License

MIT