url_manager.py

'''
@Description: 
@Author: Steven
@Date: 2018-09-18 10:15:44
@LastEditors  : Steven
@LastEditTime : 2020-01-09 09:38:18
'''
# -*- coding: utf-8 -*-
# Created on 2018年3月9日
# @author: Administrator
from urllib.parse import quote_plus
from typing import Iterable


class UrlManager:
    def __init__(self):
        self.new_urls = set()
        self.old_urls = set()
        self.site = 'https://www.dhgate.com/w/{0}/{1}.html'

    def build_url(self, key_word: str, page_num: int):
        key_word = quote_plus(key_word)
        urls = [self.site.format(key_word, page) for page in range(page_num)]
        self.add_new_urls(urls)

    def add_new_urls(self, urls: Iterable):
        for url in urls:
            self.add_new_url(url)

    def add_new_url(self, url: str):
        if url is None:
            return
        if url not in self.new_urls and url not in self.old_urls:
            self.new_urls.add(url)

    def has_new_url(self) -> bool:
        return len(self.new_urls) != 0

    def get_new_url(self) -> str:
        new_url = self.new_urls.pop()
        self.old_urls.add(new_url)
        return new_url

    def show_urls(self):
        for url in self.new_urls:
            print(url)