摘要：而其他的引擎，例如能够帮我们进行验证登录自此，官网的我们已经大致有了了解后续我们可以选择运用该框架实现一些简单的应用，或者可以深入研究其源码，提升自身的编程水平

在初识Bottle（一）中，我们了解了Bottle的基本用法
在Bottle源码阅读（一）和Bottle源码阅读（二）可以查看个人对bottle源码的相关阅读笔记

下面继续阅读Bottle的官方文档https://bottlepy.org/docs/dev...

在bottle中例如css等的文件是不会被自动加载的，因此需要自己定义callback函数，通过调用使用

from bottle import static_file
@route("/static/")
def server_static(filename):
    return static_file(filename, root="/path/to/your/static/files")

通过error装饰器可以对相应的错误码自定义对应的应用函数

from bottle import error
@error(404)
def error404(error):
    return "Nothing here, sorry"

Bottl框架允许应用函数返回如下类型的结果

Dictionaries字典：
python的字典通过框架被转换为json字符串，而header中的Content-Type则会被设置为application/json

Empty Strings, False, None or other non-true values：
header中的Content-Length被设置为0

Unicode strings
Byte strings
Instances of HTTPError or HTTPResponse
File objects
Iterables and generators

通过在应用函数中改变response的属性可以自定义

from bottle import response
@route("/iso")
def get_iso():
    response.charset = "ISO-8859-15"
    return u"This will be sent with ISO-8859-15 encoding."

@route("/latin9")
def get_latin():
    response.content_type = "text/html; charset=latin9"
    return u"ISO-8859-15 is also known as latin9."

通过static_file接口，我们可以实现调用和下载

from bottle import static_file
@route("/images/")
def send_image(filename):
    return static_file(filename, root="/path/to/image/files", mimetype="image/png")

@route("/static/")
def send_static(filename):
    return static_file(filename, root="/path/to/static/files")
    
@route("/download/")
def download(filename):
    return static_file(filename, root="/path/to/static/files", download=filename)

通过abort可以快速定义错误码相应的错误页内容
redirect实现重定向

from bottle import route, abort
@route("/restricted")
def restricted():
    abort(401, "Sorry, access denied.")
    
from bottle import redirect
@route("/wrong/url")
def wrong():
    redirect("/right/url")

response对象包括了响应的metadata例如状态码，headers，cookie等

response的状态码控制浏览器的行为，默认200ok
response的header可以通过set_header()来设置，对同一个header项，还可以通过add_header添加额外内容
cookie是保留在用户浏览器的一些数据，可以通过get_cookie和set_cookie来操作

@route("/hello")
def hello_again():
    if request.get_cookie("visited"):
        return "Welcome back! Nice to see you again"
    else:
        response.set_cookie("visited", "yes")
        return "Hello there! Nice to meet you"

cookie是容易被伪造的，所以Bottle框架提供了cookie的签名机制，只需要提供一个secret的参数作为密钥
Bottle会自动持久化和去持久化保存在cookie中的数据，cookie不超过4k。
此时cookie仍然能从浏览器中查看到，而且是可以被复制的，所以最好不要将密钥的信息放在用户客户端

@route("/login")
def do_login():
    username = request.forms.get("username")
    password = request.forms.get("password")
    if check_login(username, password):
        response.set_cookie("account", username, secret="some-secret-key")
        return template("
Welcome {{name}}! You are now logged in.
", name=username)
    else:
        return "
Login failed.
"

@route("/restricted")
def restricted_area():
    username = request.get_cookie("account", secret="some-secret-key")
    if username:
        return template("Hello {{name}}. Welcome back.", name=username)
    else:
        return "You are not logged in. Access denied."

request 对象包括了Cookies, HTTP header, HTML

from bottle import request, route, template

@route("/hello")
def hello():
    name = request.cookies.username or "Guest"
    return template("Hello {{name}}", name=name)

name = request.cookies.name

# is a shortcut for:

name = request.cookies.getunicode("name") # encoding="utf-8" (default)

# which basically does this:

try:
    name = request.cookies.get("name", "").decode("utf-8")
except UnicodeError:
    name = u""

for choice in request.forms.getall("multiple_choice"):
    do_something(choice)

from bottle import route, request, response, template
@route("/forum")
def display_forum():
    forum_id = request.query.id
    page = request.query.page or "1"
    return template("Forum ID: {{id}} (page {{page}})", id=forum_id, page=page)

  Category:      
  Select a file: 
  

文件上传到服务端后

@route("/upload", method="POST")
def do_upload():
    category   = request.forms.get("category")
    upload     = request.files.get("upload")
    name, ext = os.path.splitext(upload.filename)
    if ext not in (".png",".jpg",".jpeg"):
        return "File extension not allowed."

    save_path = get_save_path_for_category(category)
    upload.save(save_path) # appends upload.filename automatically
    return "OK"

通过BaseRequest.body我们可以直接获取原始的请求体，也可以获取environ

@route("/my_ip")
def show_ip():
    ip = request.environ.get("REMOTE_ADDR")
    # or ip = request.get("REMOTE_ADDR")
    # or ip = request["REMOTE_ADDR"]
    return template("Your IP is: {{ip}}", ip=ip)

Bottle内建了前端模板引擎，在官网给出的这个例子中，会加载./views/中的hello_template.tpl

@route("/hello")
@route("/hello/")
def hello(name="World"):
    return template("hello_template", name=name)
或者
@route("/hello")
@route("/hello/")
@view("hello_template")
def hello(name="World"):
    return dict(name=name)

%if name == "World":
    
Hello {{name}}!
    
This is a test.
%else:
    
Hello {{name.title()}}!
    
How are you?
%end

模板在编译后会被缓存到内存中，修改后需要执行bottle.TEMPLATES.clear()清除缓存模板

Bottle提供了一系列的第三方引擎，这些能够有效地减少重复性工作
官网使用SQLitePlugin作为例子，在每一次调用需要与数据库进行交互的callback函数时，该引擎会自动创建连接和关闭连接。而其他的引擎，例如’auth‘能够帮我们进行验证登录

from bottle import route, install, template
from bottle_sqlite import SQLitePlugin

install(SQLitePlugin(dbfile="/tmp/test.db"))

@route("/show/")
def show(db, post_id):
    c = db.execute("SELECT title, content FROM posts WHERE id = ?", (post_id,))
    row = c.fetchone()
    return template("show_post", title=row["title"], text=row["content"])

@route("/contact")
def contact_page():
    """ This callback does not need a db connection. Because the "db"
        keyword argument is missing, the sqlite plugin ignores this callback
        completely. """
    return template("contact")

sqlite_plugin = SQLitePlugin(dbfile="/tmp/test.db")
install(sqlite_plugin)

uninstall(sqlite_plugin) # uninstall a specific plugin
uninstall(SQLitePlugin)  # uninstall all plugins of that type
uninstall("sqlite")      # uninstall all plugins with that name
uninstall(True)          # uninstall all plugins at once

自此，Bottle官网的tutorial我们已经大致有了了解
后续我们可以选择运用该框架实现一些简单的应用，或者可以深入研究其源码，提升自身的编程水平