How do I specify custom headers in a Pholcus scraping job?

Pholcus is a high-concurrency, distributed, web crawler software written in Go. It's designed for web data scraping purposes and allows you to specify custom headers for your web requests. Custom headers are often required when you need to simulate browser requests or when you need to pass certain information like authentication tokens, custom user-agent strings, or other metadata.

When you're setting up a Pholcus scraping job, you can specify custom headers using the SetHeader method on the request object. Here's an example of how you might do this:

package main

import (
    "github.com/henrylee2cn/pholcus/exec"
    "github.com/henrylee2cn/pholcus/spiders"
    "github.com/henrylee2cn/pholcus/web"
    . "github.com/henrylee2cn/pholcus/spider"
)

func main() {
    // Create a custom spider
    customSpider := &Spider{
        Name: "CustomSpider",
        RuleTree: &RuleTree{
            Root: func(ctx *Context) {
                // The context has a method to create a new request
                // You can set custom headers using the SetHeader method
                ctx.AddQueue(&Request{
                    Url:  "http://example.com", // Target URL
                    Rule: "processPage",
                    Header: http.Header{
                        "User-Agent": []string{"Your Custom User-Agent String"},
                        "Referer":    []string{"http://example.com"},
                    },
                })
            },
            Trunk: map[string]*Rule{
                "processPage": {
                    ParseFunc: func(ctx *Context) {
                        // Parsing logic here
                    },
                },
            },
        },
    }

    // Add our custom spider
    spiders.Register(customSpider)

    // Run Pholcus as a web server with UI
    web.Run()
}

In this example, a custom spider is registered with Pholcus that adds a request to the queue with custom headers. The SetHeader method is used to set the User-Agent and Referer headers, but you can set any headers you need in this way.

Remember to replace "Your Custom User-Agent String" with the user-agent string you want to use, and "http://example.com" with the actual URL you are targeting. You can add as many headers as needed by including them in the Header field of the Request struct.

To run your Pholcus project, you would typically build it with go build and then execute the resulting binary. The specific commands may vary depending on your setup and the build configuration of your Go project.