django企业开发实战-学习小结

写在前面

初次阅读此书是三年前，当时没经历过完整的项目觉得这书就是扯淡后来经历过项目加班与毒打今天再翻开此书觉得实乃不可多得之物花些时间啃下来吧

需求

需求文档

写文档，列举需要实现的功能，详细列举，不考虑技术实现细节

需求评审与分析

主要是将需求文档落实到技术细节，评审需求需要的技术栈，然后评审需求是否可实现，预估每个子需求的工作量等

此处可以考虑后续的衍生需求，考虑技术实现是否可行是否困难，技术需要的工作量等

功能分析

技术人员对需求评审的结果进行技术实现分析，模块划分等

模块划分可以基于数据实体制作ER图，或者建立UML图

模块划分

作用是将一个大项目分成几个小模块，让手下的人去按模块开发

框架基础和技术选型

需要选择语言框架数据库然后考虑团队开发与实现能力等

wsgi

wsgi，全称Web Server Gateway Interface，Web服务器网关接口，是用来规定web server应如何和程序交互的网关协议。可以理解为一个web应用的容器，适配了程序和操作系统之间功能，将操作系统一些功能抽象为接口提供给程序使用

可以使用wsgi，目的是使用实现统一协议的web server，不然换着乱

简单的web server

一个基本的socket监听程序

# coding:utf-8import socketEOL1 = b'\n\n'
EOL2 = b'\n\r\n'
body = 'hello, world<h1> from tjh </h1>'
resp_params = ['HTTP/1.0 200 OK','Date: Sun, 31 jul 2024 09:35:33 GMT','Content-Type: text/html; charset=utf-8','Content-Length: ()\r\n'.format(len(body.encode())),body
]resp = '\r\n'.join(resp_params)def handle_connection(conn, addr):req = b''while EOL1 not in req and EOL2 not in req:req += conn.recv(1024)print(req)conn.send(resp.encode())conn.close()def main():ss = socket.socket(socket.AF_INET, socket.SOCK_STREAM)ss.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)ss.bind(('127.0.0.1', 8000))ss.listen(5)  # conn max queue numberprint('http://127.0.0.1:8000')try:while True:conn, addr = ss.accept()handle_connection(conn, addr)finally:ss.close()if __name__ == '__main__':main()

效果

注意 Content-Type为text/plain 还是text/html

多线程版web server

还是阻塞模式，非阻塞会报错还没处理

# coding:utf-8import socket
import errno
import threading
import timeEOL1 = b'\n\n'
EOL2 = b'\n\r\n'
body = 'hello, world<h1> from tjh </h1>-from {thread_name}'
resp_params = ['HTTP/1.0 200 OK','Date: Sun, 31 jul 2024 09:35:33 GMT','Content-Type: text/html; charset=utf-8','Content-Length: {length}\r\n',body
]resp = '\r\n'.join(resp_params)def handle_connection(conn, addr):req = b''while EOL1 not in req and EOL2 not in req:req += conn.recv(1024)print(req)current_thread = threading.currentThread()content_length = len(body.format(thread_name=current_thread.name).encode())print(current_thread.name)conn.send(resp.format(thread_name=current_thread.name, length=content_length).encode())conn.close()def main():ss = socket.socket(socket.AF_INET, socket.SOCK_STREAM)# ss.setblocking(0)  # set socket mode as non block # ss.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)ss.bind(('127.0.0.1', 8000))ss.listen(10)  # conn max queue numberprint('http://127.0.0.1:8000')# ss.setblocking(0)  # set socket mode as non block try:i = 0while True:try:conn, addr = ss.accept()except socket.error as e:if e.args[0] != errno.EAGAIN:raisecontinuei += 1print(i)t = threading.Thread(target=handle_connection, args=(conn, addr), name='thread-%s' % i)t.start()finally:ss.close()if __name__ == '__main__':main()

效果

简单wsgi application

wsgi协议分为两部分，一个是web server，一个是web application。接受请求时，会通过wsgi协议将数据发给web application，application处理完后，设置对应状体和header，之后返回body给web server，web server拿到数据后，进行http协议封装，返回完整http response

# coding: utf-8import os
import sysfrom app import simple_appdef wsgi_to_bytes(s):return s.encode()def run_with_cgi(app):environ = dict(os.environ.items())environ['wsgi.input'] = sys.stdin.bufferenviron['wsgi.errors'] = sys.stderrenviron['wsgi.version'] = (1, 0)environ['wsgi.multithread'] = Falseenviron['wsgi.multiprocess'] = Trueenviron['wsgi.run_once'] = Trueif environ.get('HTTPS', 'off') in ('on', '1'):environ['wsgi.url_scheme'] = 'https'else:environ['wsgi.url_scheme'] = 'http'headers_set = []headers_sent = []def write(data):out = sys.stdout.bufferif not headers_set:raise AssertionError('write() before start_response()')elif not headers_sent:status, resp_headers = headers_sent[:] = headers_setout.write(wsgi_to_bytes('Status: %s\r\n' % status))for header in resp_headers:out.write(wsgi_to_bytes('%s: %s\r\n' % header))out.write(wsgi_to_bytes('\r\n'))out.write(data)out.flush()def start_response(status, resp_headers, exc_info=None):if exc_info:try:if headers_sent:raise (exc_info[0], exc_info[1], exc_info[2])finally:exc_info = Noneelif headers_set:raise AssertionError('headers already set')headers_set[:] = [status, resp_headers]return writeresult = app(environ, start_response)try:for data in result:if data:write(data)if not headers_sent:write('')finally:if hasattr(result, 'close'):result.close()if __name__ == '__main__':run_with_cgi(simple_app)

理解wsgi

wsgi规定，application必须是一个可调用对象，则这个可调用对象可以是函数或实现了__call__方法的实例

wsgi中间件和werkzeug

flask

截至目前有了两种方法提供web服务：直接通过socket处理请求，或者通过实现wsgi application部分协议

入门推荐

py微型框架有比如web.py, bottle，flask等 flask是一个不错的微型框架

tornado

高性能。tornado不是基于wsgi协议的框架，但提供了wsgi的支持，特性是异步和非阻塞。可以使用自带的http server进行部署而不是wsgi，因为wsgi是一个同步接口

和flask相比，tornado更侧重性能，整体并不比flask丰富，flask更多的支持对业务的满足

django

和微型框架不同，django框架不是仅需要两三个py文件就能跑起来的web框架，django功能更全也更大

django起步

管理系统后台开发

先安装django，再django-admin startproject project_name创建初始项目

cd到project下，创建一个app

models.py

from django.db import models# Create your models here.
class Student(models.Model):SEX_ITEMS = [(1, '男'), (2, '女'), (0, '未知')]STATUS_ITEMS = [(0, '申请'), (1, '通过'), (2, '拒绝')]name = models.CharField(max_length=128, verbose_name='姓名')sex = models.IntegerField(choices=SEX_ITEMS, verbose_name='性别')profession = models.CharField(max_length=128, verbose_name='职业')email = models.EmailField(verbose_name='Email')qq = models.CharField(max_length=128, verbose_name='QQ')phone = models.CharField(max_length=128, verbose_name='电话')status = models.IntegerField(choices=STATUS_ITEMS, default=0, verbose_name='审核状态')created_time = models.DateTimeField(auto_now_add=True, editable=False, verbose_name='创建时间')def __str__(self):return '<Student: {}>'.format(self.name)class Meta:verbose_name = verbose_name_plural = '学员信息'

admin.py

from django.contrib import admin# Register your models here.
from .models import Studentclass StudentAdmin(admin.ModelAdmin):list_display = ('id', 'name', 'sex', 'profession', 'email', 'qq', 'phone', 'status', 'created_time')list_filter = ('sex', 'status', 'created_time')search_fields = ('name', 'profession')fieldsets = ((None, {'fields': ('name',('sex', 'profession'),('email', 'qq', 'phone'),'status')}))admin.register(Student, StudentAdmin)

将创建的app在setting中加到installed_apps下