解析URL

提取URL中的各部分信息，如schema, host等。

package common

import (
    "errors"
    "net/url"
    "strings"
)

//urlencode
func UrlEncode(url1 string) string {
    return url.QueryEscape(url1)
}

func UrlDecode(url1 string) (string, error) {
    return url.QueryUnescape(url1)
}

//FormatUrl is a function for spiders to format urls when the url comes like "/path/to/html" to "http://www.xxx.com/path/to/html"
func FormatUrl(url1, site string) (string, error) {

    if strings.HasPrefix(strings.TrimSpace(url1), "javascript:") {
        return "", errors.New("starts with 'javascript:'")
    }

    u, err := url.Parse(url1)
    if err != nil {
        return "", err
    }
    if u.Scheme == "" {
        u.Scheme = "http"

    }
    if u.Host == "" {
        u.Host = site
    }
    return u.String(), nil
}

//IsCurrentSite is a function to test the current url belongs to the current site.
func IsCurrentSite(url1 string, site string, protocol string) bool {
    u, err := url.Parse(url1)
    if err != nil {
        return false
    }
    if u.Scheme != protocol {
        return false
    }
    if u.Host == site || u.Host == "" {
        return true
    }
    return false
}