141 lines
3.6 KiB
Go
141 lines
3.6 KiB
Go
/*
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* Scope - A simple and minimal metasearch engine
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* Copyright (C) 2021 Arsen Musayelyan
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package web
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import (
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"net/http"
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"strconv"
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"strings"
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"github.com/PuerkitoBio/goquery"
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)
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var ddgURL = urlMustParse("https://html.duckduckgo.com/html")
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const uddgPrefix = "//duckduckgo.com/l/?uddg="
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// DDG represents the DuckDuckGo search engine
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type DDG struct {
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keyword string
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userAgent string
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page int
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doc *goquery.Document
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initDone bool
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baseSel *goquery.Selection
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}
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// SetKeyword sets the keyword for searching
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func (d *DDG) SetKeyword(keyword string) {
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d.keyword = keyword
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}
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// SetPage sets the page number for searching
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func (d *DDG) SetPage(page int) {
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d.page = page * 30
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}
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// SetUserAgent sets the user agent for the request
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func (d *DDG) SetUserAgent(ua string) {
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d.userAgent = ua
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}
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// Init runs requests for the DuckDuckGo search engine
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func (d *DDG) Init() error {
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// Copy URL so that it can be changed
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initURL := copyURL(ddgURL)
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// Get query parameters
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query := initURL.Query()
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// Set query
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query.Set("q", d.keyword)
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if d.page > 0 {
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query.Set("s", strconv.Itoa(d.page))
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query.Set("dc", strconv.Itoa(d.page+1))
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}
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// Update URL query
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initURL.RawQuery = query.Encode()
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// Create new request for modified URL
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req, err := http.NewRequest(
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http.MethodGet,
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initURL.String(),
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nil,
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)
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if err != nil {
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return err
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}
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// If user agent empty, use default
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if d.userAgent == "" {
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d.userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36"
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}
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// Set user agent of request
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req.Header.Set("User-Agent", d.userAgent)
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// Perform request
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res, err := http.DefaultClient.Do(req)
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if err != nil {
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return err
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}
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defer res.Body.Close()
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// Create goquery document from reader
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doc, err := goquery.NewDocumentFromReader(res.Body)
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if err != nil {
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return err
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}
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d.doc = doc
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d.baseSel = doc.Find(`#links > .result`)
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d.initDone = true
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return nil
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}
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// Each runs eachCb with the index of each search result
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func (d *DDG) Each(eachCb func(int) error) error {
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for i := 0; i < d.baseSel.Length(); i++ {
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err := eachCb(i)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Title returns the title of the search result corresponding to i
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func (d *DDG) Title(i int) (string, error) {
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return strings.TrimSpace(get(d.baseSel, i).Children().First().ChildrenFiltered("h2").Text()), nil
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}
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// Link returns the link to the search result corresponding to i
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func (d *DDG) Link(i int) (string, error) {
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link := get(d.baseSel, i).Children().First().ChildrenFiltered("a").AttrOr("href", "")
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if strings.HasPrefix(link, uddgPrefix) {
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link = urlMustParse(link).Query().Get("uddg")
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}
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return link, nil
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}
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// Desc returns the description of the search result corresponding to i
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func (d *DDG) Desc(i int) (string, error) {
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return get(d.baseSel, i).Children().First().ChildrenFiltered("a").Text(), nil
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}
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// Name returns "ddg"
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func (d *DDG) Name() string {
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return "ddg"
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}
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