Examples

This section contains practical examples demonstrating common use cases for zchrome.

Quick Reference

Example	Description
Screenshots	Capture full-page and element screenshots
PDF Generation	Generate PDFs from web pages
DOM Manipulation	Query and modify the DOM
JavaScript Evaluation	Execute JavaScript and get results
Network Interception	Monitor and modify network traffic (Zig API)
Browser Interactions	Click, type, fill forms using CLI
Macro Recording	Record and replay browser interactions, video recording & streaming

Basic Pattern

Most zchrome scripts follow this pattern:

const std = @import("std");
const cdp = @import("cdp");

pub fn main(init: std.process.Init) !void {
    const allocator = init.gpa;

    // 1. Launch browser
    var browser = try cdp.Browser.launch(.{
        .headless = .new,
        .allocator = allocator,
        .io = init.io,
    });
    defer browser.close();

    // 2. Create page/session
    var session = try browser.newPage();
    defer session.detach() catch {};

    // 3. Initialize domain clients
    var page = cdp.Page.init(session);
    try page.enable();

    // 4. Navigate
    _ = try page.navigate(allocator, "https://example.com");

    // 5. Wait for content (simplified)
    var i: u32 = 0;
    while (i < 500000) : (i += 1) {
        std.atomic.spinLoopHint();
    }

    // 6. Perform operations
    // ...
}

Running Examples

To run examples in this guide:

1. Create a new Zig project:

   mkdir my-scraper
   cd my-scraper
   zig init

2. Add zchrome dependency to build.zig.zon:

   .dependencies = .{
       .cdp = .{
           .path = "../zchrome",
       },
   },

3. Configure build.zig:

   const cdp = b.dependency("cdp", .{
       .target = target,
       .optimize = optimize,
   });
   exe.root_module.addImport("cdp", cdp.module("cdp"));

4. Build and run:

   zig build run

Tips

Waiting for Page Load

The examples use a simple spin-loop for waiting. In production:

// Simple approach (examples)
var i: u32 = 0;
while (i < 500000) : (i += 1) {
    std.atomic.spinLoopHint();
}

// Better: Use lifecycle events
try page.setLifecycleEventsEnabled(true);
// Listen for "load" or "networkIdle" events

Error Handling

Always check for navigation errors:

var result = try page.navigate(allocator, url);
defer result.deinit(allocator);

if (result.error_text) |err| {
    std.debug.print("Failed: {s}\n", .{err});
    return;
}

Resource Cleanup

Use defer consistently:

var browser = try cdp.Browser.launch(.{ ... });
defer browser.close();

var session = try browser.newPage();
defer session.detach() catch {};

const data = try allocate();
defer allocator.free(data);

Multiple Pages

For parallel scraping:

var sessions: [4]*cdp.Session = undefined;
for (&sessions) |*s| {
    s.* = try browser.newPage();
}
defer for (sessions) |s| {
    s.detach() catch {};
};

// Use each session for different URLs