Scrapy uses the Twisted asynchronous network library to handle network traffic.The overall structure is broadly as follows (note: Images from the Internet):1. Scrapy engine (Scrapy engines)The Scrapy engine is used to control the data processing flow of the entire system and to trigger transactions. More detailed information can be found in the following data processing process.2, Scheduler (Dispatch)The scheduler accepts requests from the Scrapy engine and sorts them into queues and returns the
1, overview
Scrapy is an application framework written with pure Python for crawling Web site data and extracting structural data, which is very versatile.
The power of the framework, users only need to customize the development of a few modules can be easily implemented a crawler, used to crawl Web content and a variety of pictures, very convenient.
Scrapy uses the twisted[' tw?st?d] (its main opponent is Tornado), the asynchronous network framework to handle network traffic, c
a lot of learning python programming language friends will learn python web crawler technology, but also specialized in web crawler technology, then how to learn python crawler technology, Let's talk today about the very popular python crawl framework scrapyusing python to crawl data, Next, learn the architecture of scrapy to make it easier to use this tool. I. OverviewShows the general architecture of Scrapy , which contains its main components and the data processing flow of the system (shown
I. OverviewShows the general architecture of Scrapy, which contains its main components and the data processing flow of the system (shown by the green arrows). The following will explain the role of each component and the process of data processing.Second, the component1. Scrapy engine (Scrapy engines)The Scrapy engine is used to control the data processing flow of the entire system and to trigger transactions. More detailed information can be found in the following data processing process.2, Sc
inevitably encounter some needs, we need to modify the image of the cache path.
Analysis:
We notice that the Picasso bottom is actually using okhttp to download the picture, and there is a. Downloader (Downloader Downloader) method when setting up the Picasso. We can pass in a okhttpdownloader (...).
Realize:
1. Method One
Okhttp dependence
Compile ' com.squareu
platforms found out you were doing so.
Moral aspects of the non-evaluation, single technically feasible, but there are some limitations.
The possible reasons are:
At present, most of the technology of the live platform is using the RTMP (real-time Messaging Protocol) protocol to transmit (host) and receive the live stream (viewer side).
These live platforms also use the HLS (HTTP live Streaming) protocol for live viewing in a mobile WEB e
adept at processing simple work but a large amount of data gpu.
GPU decoding is called hard decoding.
CPU decoding is soft decoding.
iOS provided by the player class is hard decoding, so video playback on the CPU will not be a lot of pressure, but the supported playback format is relatively single, generally is MP4, MOV, M4V these several.
HTTP Live Streamingabout HLSHTTP Live Streaming (abbreviated as HLS) is an HTTP-based stre
1 Install Nginx to increase nginx-rtmp-module support download good nginx-rtmp-module after decompression, and then add this module Nginx installation (--add-module)./configure--prefix=/usr/local/nginx--add-module= (nginx-rtmp-module path)2 after the installation is complete, open nginx configuration file nginx.conf to configureFirst add the rtmp configuration to the insidertmp {server {Listen 1935;Application Video {Live on;}Application HLS {Live on;
This article from the NetEase cloud community
Preface
This article is for mobile video live development Novice, in order to quickly get started, using the powerful Google search engine with their own understanding of the "video broadcast background Knowledge".
Background Knowledge
noun explanation
Push-Stream Protocol
RTMP
Real Time Messaging Protocol (live messaging protocol)
With Flash Player as the player client, Flash Player is now installed on nearly 99% of the world's PCs, so it is genera
Tags: URL 5.0 ges Tutorial nload get the keyword folder to useNginx third-party module ngx_http_accesskey_module to implement the download file anti-theft chain 1, the specific installation tutorial: HTTP://WWW.CNBLOGS.COM/TINYWAN/P/5983694.HTML/2, Nginx configuration fileLocation/hls {
Alias/tmp/hls;
}location/download {
accesskey on ;
Accesskey_has
install
8. Install pyOpenSSL
This step is optional and the corresponding installation package is:
Https://launchpad.net/pyopenssl
If necessary, you can select the desired version. Skip this step.9. Install Scrapy
As follows:
Http://scrapy.org/download/Http://pypi.python.org/pypi/ScrapyHttp://pypi.python.org/packages/source/S/Scrapy/Scrapy-0.14.0.2841.tar.gz#md5=fe63c5606ca4c0772d937b51869be200
The installation process is as follows:
[Root @ localhost scrapy] # tar-xvzf Scrapy-0.14.0.2841.tar
downloading pictures (such as a gray avatar) or when the picture is downloaded to show a circular progress bar, then the above code is no way;③ again, for example, we want to download a variety of images, for different site sources have different ways to download ....These special needs tell us that the above code is completely out of the way. So for the completeness and scalability of the control, we need a configurator, a monitor, a downloader. And
, triggering transactions (framework core)
Scheduler (Scheduler)Used to accept requests sent by the engine, pressed into the queue, and returned when the engine was requested again. It can be imagined as a priority queue for a URL (crawling the URL of a Web page or a link), which determines what the next URL to crawl is, and removes duplicate URLs
Downloader (Downloader)Used to download Web content
, triggering transactions (framework core)
Scheduler (Scheduler)Used to accept requests sent by the engine, pressed into the queue, and returned when the engine was requested again. It can be imagined as a priority queue for a URL (crawling the URL of a Web page or a link), which determines what the next URL to crawl is, and removes duplicate URLs
Downloader (Downloader)Used to download Web content
APK downloader is a chrome extension that helps you download the Android Application APK file from Google Play (formerly Android Market) on your computer. @ Appinn
IvanStudentsThe Group Discussion Group recommends a method for downloading Android programs from Google Play on a computer, which can be directly downloaded to the APK file.
Google Play has a well-known alternative system. For example, paid software policies for different regions have cause
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