scrapy crawl

A: Crawlspider introductionCrawlspider is actually a subclass of the spider, which, in addition to the features and functions inherited from the spider, derives its own unique and more powerful features and functions. One of the most notable features is the "Linkextractors link Extractor". The spider is the base class for all reptiles and is designed only to crawl the pages in the Start_url list, and to continue the

This article mainly introduces how to run scrapy from a script in Python. The example analyzes the usage skills of running Python scripts, which has some reference value, for more information about how to run scrapy in a script, see the example in this article. Share it with you for your reference. The details are as follows: The code is as follows: #! /Usr/bin/pythonImport OSOS. environ. setdefault ('

. Python installation of third-party components an error generally occurs because:so many installation errors, one is not according to the requirements of the Guide, check and make up the pre-requisite, the second is the use of Easy_ Install and source setup.py, have encountered the C compiler incompatibility problem, and PIP can be installed smoothly, later with Pip, and do not have to spend time looking for resources everywhere,Use python2.7 pip to install scripy again, error;Remove python2.7

Using scrapy for data mining recently, using scrapy to fetch data and store it in MongoDB, this paper records the environment construction process to make memoOs:ubuntu 14.04 python:2.7.6 scrapy:1.0.5 db:mongodb 3　　ubuntu14.04 built-in python2.7 , so python and Pip installation no longer repeat. A . installation scrapyPip install

Start Crawl page: (2) write crawl of source fileTo make the code easy to modify and to crawl pages more clearly and efficiently, we write the code to the source file for crawling.The following steps are mainly divided into:I. Create a crawler frame using scrapy:Two. Modify and write the source code to determine the pages and content we want to crawlThree. Start c

Sometimes you need to log in when crawling a Web site, in Scrapy you can save cookies by simulating a login and then crawl to the appropriate page. Here I demonstrate the whole principle by logging in to GitHub and then crawling my own issue list. To implement a login requires form submission, first access the GitHub login page Https://github.com/login through the browser, and then use the browser debugging

; Windows NT 6.1; WOW64; trident/5.0; SLCC2;. NET CLR 2.0.50727;. NET CLR 3.5.30729;. NET CLR 3.0.30729; Media Center PC 6.0;. net4.0c;. NET4.0E)", "mozilla/5.0 (Windows NT 5.1) applewebkit/537.1 (khtml, like Gecko) chrome/21.0.1180.89 safari/537.1", "mozilla/5.0 (Windows NT 6.1; WOW64) applewebkit/537.1 (khtml, like Gecko) chrome/21.0.1180.89 safari/537.1", "mozilla/5.0 (IPad; U CPU os 4_2_1 like Mac os X; ZH-CN) applewebkit/533.17.9 (khtml, like Gecko) version/5.0.2 mobile/8c148 safar

Perform some necessary parameter initialization. Open_spider (spider): The Spider object is called when it is turned on. Close_spider (spider): Called when the Spider object is closed Spider Directory corresponding to the file under the folder spider _ init _: Initialize the crawler name, start _urls list Start_requests: Generate requests object to scrapy download and re

Scrapy mainly has the following components:1, Engine (scrapy)Used to process the entire system's data flow, triggering transactions (framework core)2, Scheduler (Scheduler)Used to receive a request from the engine, pressed into the queue, and returned when the engine requests again, can be imagined as a URL (crawl web site URL or link) Priority queue, it determin

Modify the allister/items.py file:#-*-Coding:utf-8-*-# Define Here the models for your scraped items## see documentation in:# https://doc.scrapy.org/en/ Latest/topics/items.htmlimport scrapyclass Allisteritem (scrapy. Item): name = Scrapy. Field () Level = Scrapy. Field () info = scrapy. Field ()　　5.3 Writing