Python實戰-編寫Web App-Day8-編寫API

API就是把Web App的功能全部封裝了，所以，通過API操作數據，可以極大地把前端和後端的代碼隔離，使得後端代碼易於測試，前端代碼編寫更簡單。一個API也是一個URL的處理函數，我們希望能直接通過一個@api來把函數變成JSON格式的REST API，這樣，獲取註冊用戶可以用一個API實現如下：

<code>@get('/api/users')
def api_get_users(*, page='1'):
    page_index = get_page_index(page)
    num = await User.findNumber('count(id)')
    p = Page(num, page_index)
    if num == 0:
        return dict(page=p, users=())
    users = await User.findAll(orderBy='created_at desc', limit=(p.offset, p.limit))
    for u in users:
        u.passwd = '******'
    return dict(page=p, users=users)/<code>

只要返回一個dict，後續的response這個middleware就可以把結果序列化為JSON並返回。

以下是所有網站所需要的後端API, 前端頁面URL的列表：

後端API包括：

獲取日誌：GET /api/blogs創建日誌：POST /api/blogs修改日誌：POST /api/blogs/:blog_id刪除日誌：POST /api/blogs/:blog_id/delete獲取評論：GET /api/comments創建評論：POST /api/blogs/:blog_id/comments刪除評論：POST /api/comments/:comment_id/delete創建新用戶：POST /api/users獲取用戶：GET /api/users管理頁面包括：

評論列表頁：GET /manage/comments日誌列表頁：GET /manage/blogs創建日誌頁：GET /manage/blogs/create修改日誌頁：GET /manage/blogs/用戶列表頁：GET /manage/users用戶瀏覽頁面包括：

註冊頁：GET /register登錄頁：GET /signin註銷頁：GET /signout首頁：GET /日誌詳情頁：GET /blog/:blog_id我們將處理這些API和URL的函數統一放在handlers.py中：

<code>#!/usr/bin/env python3
# -*- coding: utf-8 -*-
 
__author__ = 'Woodman Zhang'
 
import re, time, json, logging, hashlib, base64, asyncio
 
## markdown 是處理日誌文本的一種格式語法，具體語法使用請百度
import markdown
from aiohttp import web
from coroweb import get, post
 
## 分頁管理以及調取API時的錯誤信息
from apis import Page, APIValueError, APIResourceNotFoundError
from models import User, Comment, Blog, next_id
from config import configs
 
COOKIE_NAME = 'awesession'
_COOKIE_KEY = configs.session.secret
 
## 查看是否是管理員用戶
def check_admin(request):
    if request.__user__ is None or not request.__user__.admin:
        raise APIPermissionError()
 
## 獲取頁碼信息
def get_page_index(page_str):
    p = 1
    try:
        p = int(page_str)
    except ValueError as e:
        pass
    if p < 1:
        p = 1
    return p
 
## 計算加密cookie
def user2cookie(user, max_age):
    # build cookie string by: id-expires-sha1
    expires = str(int(time.time() + max_age))
    s = '%s-%s-%s-%s' % (user.id, user.passwd, expires, _COOKIE_KEY)
    L = [user.id, expires, hashlib.sha1(s.encode('utf-8')).hexdigest()]
    return '-'.join(L)
 
## 文本轉HTML
def text2html(text):
    lines = map(lambda s: '
%s
' % s.replace('&', '&').replace('', '>'), filter(lambda s: s.strip() != '', text.split('\n')))
    return ''.join(lines)
 
## 解密cookie
async def cookie2user(cookie_str):
    if not cookie_str:
        return None
    try:
        L = cookie_str.split('-')
        if len(L) != 3:
            return None
        uid, expires, sha1 = L
        if int(expires) < time.time():
            return None
        user = await User.find(uid)
        if user is None:
            return None
        s = '%s-%s-%s-%s' % (uid, user.passwd, expires, _COOKIE_KEY)
        if sha1 != hashlib.sha1(s.encode('utf-8')).hexdigest():
            logging.info('invalid sha1')
            return None
        user.passwd = '******'
        return user
    except Exception as e:
        logging.exception(e)
        return None
 
## 處理首頁URL
@get('/')
async def index(*, page='1'):
    page_index = get_page_index(page)
    num = await Blog.findNumber('count(id)')
    p = Page(num, page_index)
    if num == 0:
        blogs = []
    else:
        blogs = await Blog.findAll(orderBy='created_at desc', limit=(p.offset, p.limit))
    return {
        '__template__': 'blogs.html',
        'page': p,
        'blogs': blogs
    }
 
## 處理日誌詳情頁面URL
@get('/blog/{id}')
async def get_blog(id):
    blog = await Blog.find(id)
    comments = await Comment.findAll('blog_id=?', [id], orderBy='created_at desc')
    for c in comments:
        c.html_content = markdown.markdown(c.content)
    blog.html_content = markdown.markdown(blog.content)
    return {
        '__template__': 'blog.html',
        'blog': blog,
        'comments': comments
    }
 
## 處理註冊頁面URL
@get('/register')
def register():
    return {
       '__template__': 'register.html'
    }
 
## 處理登錄頁面URL
@get('/signin')
def signin():
    return {
        '__template__': 'signin.html'
    }
 
## 用戶登錄驗證API
@post('/api/authenticate')
async def authenticate(*, email, passwd):
    if not email:
        raise APIValueError('email', 'Invalid email.')
    if not passwd:
        raise APIValueError('passwd', 'Invalid password.')
    users = await User.findAll('email=?', [email])
    if len(users) == 0:
        raise APIValueError('email', 'Email not exist.')
    user = users[0]
    # check passwd:
    sha1 = hashlib.sha1()
    sha1.update(user.id.encode('utf-8'))
    sha1.update(b':')
    sha1.update(passwd.encode('utf-8'))
    if user.passwd != sha1.hexdigest():
        raise APIValueError('passwd', 'Invalid password.')
    # authenticate ok, set cookie:
    r = web.Response()
    r.set_cookie(COOKIE_NAME, user2cookie(user, 86400), max_age=86400, httponly=True)
    user.passwd = '******'
    r.content_type = 'application/json'
    r.body = json.dumps(user, ensure_ascii=False).encode('utf-8')
    return r
 
## 用戶註銷
@get('/signout')
def signout(request):
    referer = request.headers.get('Referer')
    r = web.HTTPFound(referer or '/')
    r.set_cookie(COOKIE_NAME, '-deleted-', max_age=0, httponly=True)
    logging.info('user signed out.')
    return r
 
## 獲取管理頁面
@get('/manage/')
def manage():
    return 'redirect:/manage/comments'
 
## 評論管理頁面
@get('/manage/comments')
def manage_comments(*, page='1'):
    return {
        '__template__': 'manage_comments.html',
        'page_index': get_page_index(page)
    }
 
## 日誌管理頁面
@get('/manage/blogs')
def manage_blogs(*, page='1'):
    return {
        '__template__': 'manage_blogs.html',
        'page_index': get_page_index(page)
    }
 
## 創建日誌頁面
@get('/manage/blogs/create')
def manage_create_blog():
    return {
        '__template__': 'manage_blog_edit.html',
        'id': '',
        'action': '/api/blogs'
    }
 
## 編輯日誌頁面
@get('/manage/blogs/edit')
def manage_edit_blog(*, id):
    return {
        '__template__': 'manage_blog_edit.html',
        'id': id,
        'action': '/api/blogs/%s' % id
    }
 
## 用戶管理頁面
@get('/manage/users')
def manage_users(*, page='1'):
    return {
        '__template__': 'manage_users.html',
        'page_index': get_page_index(page)
    }
 
## 獲取評論信息API
@get('/api/comments')
async def api_comments(*, page='1'):
    page_index = get_page_index(page)
    num = await Comment.findNumber('count(id)')
    p = Page(num, page_index)
    if num == 0:
        return dict(page=p, comments=())
    comments = await Comment.findAll(orderBy='created_at desc', limit=(p.offset, p.limit))
    return dict(page=p, comments=comments)
 
## 用戶發表評論API
@post('/api/blogs/{id}/comments')
async def api_create_comment(id, request, *, content):
    user = request.__user__
    if user is None:
        raise APIPermissionError('Please signin first.')
    if not content or not content.strip():
        raise APIValueError('content')
    blog = await Blog.find(id)
    if blog is None:
        raise APIResourceNotFoundError('Blog')
    comment = Comment(blog_id=blog.id, user_id=user.id, user_name=user.name, user_image=user.image, content=content.strip())
    await comment.save()
    return comment
 
## 管理員刪除評論API
@post('/api/comments/{id}/delete')
async def api_delete_comments(id, request):
    check_admin(request)
    c = await Comment.find(id)
    if c is None:
        raise APIResourceNotFoundError('Comment')
    await c.remove()
    return dict(id=id)
 
## 獲取用戶信息API
@get('/api/users')
async def api_get_users(*, page='1'):
    page_index = get_page_index(page)
    num = await User.findNumber('count(id)')
    p = Page(num, page_index)
    if num == 0:
        return dict(page=p, users=())
    users = await User.findAll(orderBy='created_at desc', limit=(p.offset, p.limit))
    for u in users:
        u.passwd = '******'
    return dict(page=p, users=users)
 
## 定義EMAIL和HASH的格式規範
_RE_EMAIL = re.compile(r'^[a-z0-9\.\-\_]+\@[a-z0-9\-\_]+(\.[a-z0-9\-\_]+){1,4}#39;)
_RE_SHA1 = re.compile(r'^[0-9a-f]{40}#39;)
 
## 用戶註冊API
@post('/api/users')
async def api_register_user(*, email, name, passwd):
    if not name or not name.strip():
        raise APIValueError('name')
    if not email or not _RE_EMAIL.match(email):
        raise APIValueError('email')
    if not passwd or not _RE_SHA1.match(passwd):
        raise APIValueError('passwd')
    users = await User.findAll('email=?', [email])
    if len(users) > 0:
        raise APIError('register:failed', 'email', 'Email is already in use.')
    uid = next_id()
    sha1_passwd = '%s:%s' % (uid, passwd)
    user = User(id=uid, name=name.strip(), email=email, passwd=hashlib.sha1(sha1_passwd.encode('utf-8')).hexdigest(), image='http://www.gravatar.com/avatar/%s?d=mm&s=120' % hashlib.md5(email.encode('utf-8')).hexdigest())
    await user.save()
    # make session cookie:
    r = web.Response()
    r.set_cookie(COOKIE_NAME, user2cookie(user, 86400), max_age=86400, httponly=True)
    user.passwd = '******'
    r.content_type = 'application/json'
    r.body = json.dumps(user, ensure_ascii=False).encode('utf-8')
    return r
 
## 獲取日誌列表API
@get('/api/blogs')
async def api_blogs(*, page='1'):
    page_index = get_page_index(page)
    num = await Blog.findNumber('count(id)')
    p = Page(num, page_index)
    if num == 0:
        return dict(page=p, blogs=())
    blogs = await Blog.findAll(orderBy='created_at desc', limit=(p.offset, p.limit))
    return dict(page=p, blogs=blogs)
 
## 獲取日誌詳情API
@get('/api/blogs/{id}')
async def api_get_blog(*, id):
    blog = await Blog.find(id)
    return blog
 
## 發表日誌API
@post('/api/blogs')
async def api_create_blog(request, *, name, summary, content):
    check_admin(request)
    if not name or not name.strip():
        raise APIValueError('name', 'name cannot be empty.')
    if not summary or not summary.strip():
        raise APIValueError('summary', 'summary cannot be empty.')
    if not content or not content.strip():
        raise APIValueError('content', 'content cannot be empty.')
    blog = Blog(user_id=request.__user__.id, user_name=request.__user__.name, user_image=request.__user__.image, name=name.strip(), summary=summary.strip(), content=content.strip())
    await blog.save()
    return blog
 
## 編輯日誌API
@post('/api/blogs/{id}')
async def api_update_blog(id, request, *, name, summary, content):
    check_admin(request)
    blog = await Blog.find(id)
    if not name or not name.strip():
        raise APIValueError('name', 'name cannot be empty.')
    if not summary or not summary.strip():
        raise APIValueError('summary', 'summary cannot be empty.')
    if not content or not content.strip():
        raise APIValueError('content', 'content cannot be empty.')
    blog.name = name.strip()
    blog.summary = summary.strip()
    blog.content = content.strip()
    await blog.update()
    return blog
 
## 刪除日誌API
@post('/api/blogs/{id}/delete')
async def api_delete_blog(request, *, id):
    check_admin(request)
    blog = await Blog.find(id)
    await blog.remove()
    return dict(id=id)
 
## 刪除用戶API
@post('/api/users/{id}/delete')
async def api_delete_users(id, request):
    check_admin(request)
    id_buff = id
    user = await User.find(id)
    if user is None:
        raise APIResourceNotFoundError('Comment')
    await user.remove()
    # 給被刪除的用戶在評論中標記
    comments = await Comment.findAll('user_id=?',[id])
    if comments:
        for comment in comments:
            id = comment.id
            c = await Comment.find(id)
            c.user_name = c.user_name + ' (該用戶已被刪除)'
            await c.update()
    id = id_buff
    return dict(id=id)/<code> 

關鍵字: api 編寫 return