chrome-devtools-cli v1.3.0

1. High-Level Summary (TL;DR)

• Impact: High - Introduces new memory profiling capabilities and enhances the screenshot functionality.
• Key Changes:
  • ✨ Added take-heapsnapshot command to capture V8 heap snapshots via CDP streaming without holding the entire snapshot in memory.
  • ✨ Added inspect-heapsnapshot-node command to parse and inspect specific nodes in a local .heapsnapshot file entirely offline.
  • 🖼️ Enhanced the screenshot command with --quality, --max-width, and --max-height options, and improved page layout metrics gathering.
  • 🛠️ Implemented absolute path resolution for CLI arguments (--output, --file-path) to prevent path mismatch issues between the CLI process and the background daemon.

2. Visual Overview (Code & Logic Map)

graph TD
    subgraph "CLI Entry & Routing (src/lib.rs)"
        D("run()")
        C("build_request()")
        C_Abs("absolutize_path()")
    end

    subgraph "Memory Commands (src/commands/memory.rs)"
        E("take_heapsnapshot()")
        F("inspect_heapsnapshot_node_offline()")
        G("parse_node_from_snapshot()")
    end
    
    subgraph "Screenshot Commands (src/commands/screenshot.rs)"
        H("take_screenshot()")
    end

    %% Flow for take-heapsnapshot and screenshot
    C -- "Resolves relative paths" --> C_Abs
    C_Abs -- "Sends absolute paths" --> E
    C_Abs -- "Sends absolute paths" --> H
    
    %% Flow for inspect-heapsnapshot-node
    D -- "Intercepts offline command" --> F
    F -- "Parses JSON schema" --> G

    style D fill:#f3e5f5,color:#7b1fa2
    style C fill:#f3e5f5,color:#7b1fa2
    style C_Abs fill:#f3e5f5,color:#7b1fa2
    style E fill:#c8e6c9,color:#1a5e20
    style F fill:#bbdefb,color:#0d47a1
    style G fill:#bbdefb,color:#0d47a1
    style H fill:#fff3e0,color:#e65100

3. Detailed Change Analysis

Memory Profiling (src/commands/memory.rs & src/lib.rs)

• What Changed:
  • Introduced take_heapsnapshot which enables the HeapProfiler and streams chunks directly to a temporary file via non-blocking CDP events. It atomically renames the temp file upon completion to prevent corrupted files.
  • Introduced inspect_heapsnapshot_node_offline which parses a .heapsnapshot JSON file to find a specific node by ID. This command is intercepted in run() (Source: src/lib.rs) to execute entirely offline, bypassing the need for a Chrome daemon connection.

Screenshot Enhancements (src/commands/screenshot.rs)

• What Changed:
  • Refactored take_screenshot to accept a ScreenshotOptions struct instead of multiple loose parameters.
  • Added support for quality, max_width, and max_height.
  • Switched from Runtime.evaluate to Page.getLayoutMetrics to retrieve page dimensions. This avoids a JavaScript execution round-trip and works natively on non-HTML pages (e.g., PDF viewers, chrome:// pages).

Path Resolution (src/lib.rs)

• What Changed:
  • Added absolutize_path to resolve relative paths (like --output ./file.png) using the CLI's current working directory before sending the request to the daemon. This fixes a bug where the daemon would resolve relative paths against its own startup directory instead of the user's current directory.

New API Commands & Parameters

Command	Parameter	Type	Required	Description
take-heapsnapshot	--output	String	Yes	Path to save the heap snapshot file
inspect-heapsnapshot-node	--file-path	String	Yes	Path to the local .heapsnapshot file
inspect-heapsnapshot-node	--node-id	u64	Yes	ID of the node to inspect
screenshot	--quality	u64	No	Compression quality (0-100), ignores PNG
screenshot	--max-width	f64	No	Downscale screenshot to max width
screenshot	--max-height	f64	No	Downscale screenshot to max height

4. Impact & Risk Assessment

• Breaking Changes: None. The CLI interface is purely additive. Internal Rust method signatures (like take_screenshot) have changed, but external usage remains compatible.