摘要：而其他的引擎，例如能夠幫我們進行驗證登錄自此，官網的我們已經大致有了了解后續我們可以選擇運用該框架實現一些簡單的應用，或者可以深入研究其源碼，提升自身的編程水平

在初識Bottle（一）中，我們了解了Bottle的基本用法
在Bottle源碼閱讀（一）和Bottle源碼閱讀（二）可以查看個人對bottle源碼的相關閱讀筆記

下面繼續閱讀Bottle的官方文檔https://bottlepy.org/docs/dev...

在bottle中例如css等的文件是不會被自動加載的，因此需要自己定義callback函數，通過調用使用

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

通過error裝飾器可以對相應的錯誤碼自定義對應的應用函數

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

Bottl框架允許應用函數返回如下類型的結果

Dictionaries字典：
python的字典通過框架被轉換為json字符串，而header中的Content-Type則會被設置為application/json

Empty Strings, False, None or other non-true values：
header中的Content-Length被設置為0

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

通過在應用函數中改變response的屬性可以自定義

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."

通過static_file接口，我們可以實現調用和下載

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)

通過abort可以快速定義錯誤碼相應的錯誤頁內容
redirect實現重定向

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對象包括了響應的metadata例如狀態碼，headers，cookie等

response的狀態碼控制瀏覽器的行為，默認200ok
response的header可以通過set_header()來設置，對同一個header項，還可以通過add_header添加額外內容
cookie是保留在用戶瀏覽器的一些數據，可以通過get_cookie和set_cookie來操作

@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是容易被偽造的，所以Bottle框架提供了cookie的簽名機制，只需要提供一個secret的參數作為密鑰
Bottle會自動持久化和去持久化保存在cookie中的數據，cookie不超過4k。
此時cookie仍然能從瀏覽器中查看到，而且是可以被復制的，所以最好不要將密鑰的信息放在用戶客戶端

@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 對象包括了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: 
  

文件上傳到服務端后

@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"

通過BaseRequest.body我們可以直接獲取原始的請求體，也可以獲取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內建了前端模板引擎，在官網給出的這個例子中，會加載./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

模板在編譯后會被緩存到內存中，修改后需要執行bottle.TEMPLATES.clear()清除緩存模板

Bottle提供了一系列的第三方引擎，這些能夠有效地減少重復性工作
官網使用SQLitePlugin作為例子，在每一次調用需要與數據庫進行交互的callback函數時，該引擎會自動創建連接和關閉連接。而其他的引擎，例如’auth‘能夠幫我們進行驗證登錄

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官網的tutorial我們已經大致有了了解
后續我們可以選擇運用該框架實現一些簡單的應用，或者可以深入研究其源碼，提升自身的編程水平