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The Way to Go

Polling Websites and Reading Web Page

This lesson gives insight into how to check the status of a website with Go and how to read a page on the web.

We'll cover the following...

Introduction

Sending a website a very simple request and seeing how the website responds is known as polling a website.

Explanation

Consider the following example where a request includes only an HTTP header.

Go (1.6.2)
package main
import (
"fmt"
"net/http"
)
var urls = []string{
  "http://www.google.com/",
  "http://golang.org/",
  "http://blog.golang.org/",
}
func main() {
  // Executes an HTTP HEAD request for all URL's
  // and returns the HTTP status string or an error string.
  for _, url := range urls {
    resp, err := http.Head(url)
    if err != nil {
    fmt.Println("Error:", url, err)
  }
  fmt.Println(url, ": ", resp.Status)
  }
}

In the program above, we import the package net/http (see line 4). All URLs in an array of strings urls (defined at line 7) are polled. At line 16, we start an iteration over urls with a for-range loop. At line 17, a simple http.Head() request is sent to each url to see how they react. The function’s signature is: func Head(url string) (r *Response, err error). When there is ...