1. Sections of a URL

URLs have quite a few sections. Some are required, some are not.

Assignment

Let's use the url.URL struct again. This time, we'll parse a URL string and add all the different parts to a custom ParsedURL struct. We'll learn more about each part later.

Complete the newParsedURL function. It should return a ParsedURL with all the parts of a URL. For example, given this URL:

http://testuser:[e-mail]:8080/testpath?testsearch=testvalue#testhash

newParsedURL should return a struct with these fields:

return ParsedURL{
	protocol: "http",
	username: "testuser",
	password: "testpass",
	hostname: "testdomain.com",
	port:     "8080",
	pathname: "/testpath",
	search:   "testsearch=testvalue",
	hash:     "testhash",
}

Use these fields and methods of the URL struct:

• Scheme

• User.Username()

• User.Password() - this method returns two values: the password if set and whether it was set

• Hostname()

• Port()

• Path

• RawQuery

• Fragment

package main

import (
	"net/url"
)

func newParsedURL(urlString string) ParsedURL {
	parsedUrl, err := url.Parse(urlString)
	if err != nil {
		return ParsedURL{}
	}

	return ParsedURL{
		protocol: "",
		username: "",
		password: "",
		hostname: "",
		port:     "",
		pathname: "",
		search:   "",
		hash:     "",
	}
}

Here's what each field maps to:

Protocol (Scheme)

parsedUrl.Scheme  // "http"

Username

parsedUrl.User.Username()  // "testuser"

Password (Two Return Values!)

pass, wasSet := parsedUrl.User.Password()
// pass = "testpass"
// wasSet = true (if password exists)

// We ignore wasSet with _
pass, _ := parsedUrl.User.Password()

Hostname

parsedUrl.Hostname()  // "testdomain.com"

Port

parsedUrl.Port()  // "8080"

Pathname (Path)

parsedUrl.Path  // "/testpath"

Search (RawQuery)

parsedUrl.RawQuery  // "testsearch=testvalue"

Hash (Fragment)

parsedUrl.Fragment  // "testhash"

Visual Breakdown of URL

http://testuser:[e-mail]:8080/testpath?testsearch=testvalue#testhash
^^^^   ^^^^^^^^ ^^^^^^^^ ^^^^^^^^^^^^^^ ^^^^ ^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^
 |        |        |           |         |       |              |               |
Scheme Username Password   Hostname   Port    Path        RawQuery        Fragment

Why Password Returns Two Values

pass, wasSet := parsedUrl.User.Password()

The boolean tells you if a password was actually set:

// URL: http://[e-mail]
pass, wasSet := parsedUrl.User.Password()
// pass = ""
// wasSet = false (no password in URL)

// URL: http://user:[e-mail]
pass, wasSet := parsedUrl.User.Password()
// pass = "pass"
// wasSet = true (password exists)

Since you're just getting the password, you ignore the boolean with _:

pass, _ := parsedUrl.User.Password()

Completed implementation

func newParsedURL(urlString string) ParsedURL {
	// Parse the URL string
	parsedUrl, err := url.Parse(urlString)
	if err != nil {
		return ParsedURL{}  // Return empty on error
	}
	
	// Get password (returns string and bool, we only need string)
	pass, _ := parsedUrl.User.Password()
	
	return ParsedURL{
		protocol: parsedUrl.Scheme,          // "http"
		username: parsedUrl.User.Username(), // "testuser"
		password: pass,                      // "testpass"
		hostname: parsedUrl.Hostname(),      // "testdomain.com"
		port:     parsedUrl.Port(),          // "8080"
		pathname: parsedUrl.Path,            // "/testpath"
		search:   parsedUrl.RawQuery,        // "testsearch=testvalue"
		hash:     parsedUrl.Fragment,        // "testhash"
	}
}

Key Points to Remember

• Password returns two values — use pass, _ := parsedUrl.User.Password()

• Path vs RawQuery — Path is pathname, RawQuery is search

• Fragment — this is the hash (part after #)

• Scheme — this is the protocol