如何使用此 Python 代码获取当前登录用户的名称？
How can one obtain the name of the currently logged-in user with this Python code?
当然，我讨厌利用繁忙的 StackExchange 成员的时间来解决我的问题，但我已经在我检索此代码的论坛中询问过该机制是如何工作的，但绝对没有响应。
我的问题应该很简单（不是针对我自己，因为我是所谓的网络开发业余爱好者）。我有这个代码（不是我自己的）用于后端一个基本的博客。但是有一件事我不太明白。在其中一个 HTML 文件中，有一行 {{user.name}}，它获取当前登录用户的用户名并将其张贴在页面的一角。 {{}} 只是 Jinja2 语法，它向模板打印一个 python 表达式（或者有人告诉我）。
如何获取在 Python 文件中登录的用户的用户名？我目前在自己的 Web 应用程序中尝试做的是获取登录用户的用户名并查询 Google 数据存储以获取有关用户的信息并将其放入个人资料页面，如下所示：
class Profile(BlogHandler):
def render_profile(self):
signatory = user.name
signedevents = db.GqlQuery("SELECT event FROM Signatories WHERE username IN (signatory)")
self.render("profile.html", signedevents=signedevents)
def get(self):
if self.user:
self.render_profile()
else:
self.redirect('/')
但是每当我尝试这样做时，我总是会出错。有没有其他东西可以代替 user.name？
博客代码（我确定答案在 Handler 的某处 class 但我根本无法弄清楚问题是什么）：
import os
import re
import random
import hashlib
import hmac
from string import letters
import webapp2
import jinja2
from google.appengine.ext import db
template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir),
autoescape = True)
secret = 'fart'
def render_str(template, **params):
t = jinja_env.get_template(template)
return t.render(params)
def make_secure_val(val):
return '%s|%s' % (val, hmac.new(secret, val).hexdigest())
def check_secure_val(secure_val):
val = secure_val.split('|')[0]
if secure_val == make_secure_val(val):
return val
class BlogHandler(webapp2.RequestHandler):
def write(self, *a, **kw):
self.response.out.write(*a, **kw)
def render_str(self, template, **params):
params['user'] = self.user
return render_str(template, **params)
def render(self, template, **kw):
self.write(self.render_str(template, **kw))
def set_secure_cookie(self, name, val):
cookie_val = make_secure_val(val)
self.response.headers.add_header(
'Set-Cookie',
'%s=%s; Path=/' % (name, cookie_val))
def read_secure_cookie(self, name):
cookie_val = self.request.cookies.get(name)
return cookie_val and check_secure_val(cookie_val)
def login(self, user):
self.set_secure_cookie('user_id', str(user.key().id()))
def logout(self):
self.response.headers.add_header('Set-Cookie', 'user_id=; Path=/')
def initialize(self, *a, **kw):
webapp2.RequestHandler.initialize(self, *a, **kw)
uid = self.read_secure_cookie('user_id')
self.user = uid and User.by_id(int(uid))
def render_post(response, post):
response.out.write('<b>' + post.subject + '</b><br>')
response.out.write(post.content)
class MainPage(BlogHandler):
def get(self):
self.write('Hello, Udacity!')
##### user stuff
def make_salt(length = 5):
return ''.join(random.choice(letters) for x in xrange(length))
def make_pw_hash(name, pw, salt = None):
if not salt:
salt = make_salt()
h = hashlib.sha256(name + pw + salt).hexdigest()
return '%s,%s' % (salt, h)
def valid_pw(name, password, h):
salt = h.split(',')[0]
return h == make_pw_hash(name, password, salt)
def users_key(group = 'default'):
return db.Key.from_path('users', group)
class User(db.Model):
name = db.StringProperty(required = True)
pw_hash = db.StringProperty(required = True)
email = db.StringProperty()
@classmethod
def by_id(cls, uid):
return User.get_by_id(uid, parent = users_key())
@classmethod
def by_name(cls, name):
u = User.all().filter('name =', name).get()
return u
@classmethod
def register(cls, name, pw, email = None):
pw_hash = make_pw_hash(name, pw)
return User(parent = users_key(),
name = name,
pw_hash = pw_hash,
email = email)
@classmethod
def login(cls, name, pw):
u = cls.by_name(name)
if u and valid_pw(name, pw, u.pw_hash):
return u
这里的一切可能都不重要，但如果仅使用上面的代码无法找到答案，请继续。
##### blog stuff
def blog_key(name = 'default'):
return db.Key.from_path('blogs', name)
class Post(db.Model):
subject = db.StringProperty(required = True)
content = db.TextProperty(required = True)
created = db.DateTimeProperty(auto_now_add = True)
last_modified = db.DateTimeProperty(auto_now = True)
def render(self):
self._render_text = self.content.replace('\n', '<br>')
return render_str("post.html", p = self)
class BlogFront(BlogHandler):
def get(self):
posts = greetings = Post.all().order('-created')
self.render('front.html', posts = posts)
class PostPage(BlogHandler):
def get(self, post_id):
key = db.Key.from_path('Post', int(post_id), parent=blog_key())
post = db.get(key)
if not post:
self.error(404)
return
self.render("permalink.html", post = post)
class NewPost(BlogHandler):
def get(self):
if self.user:
self.render("newpost.html")
else:
self.redirect("/login")
def post(self):
if not self.user:
self.redirect('/blog')
subject = self.request.get('subject')
content = self.request.get('content')
if subject and content:
p = Post(parent = blog_key(), subject = subject, content = content)
p.put()
self.redirect('/blog/%s' % str(p.key().id()))
else:
error = "subject and content, please!"
self.render("newpost.html", subject=subject, content=content, error=error)
###### Unit 2 HW's
class Rot13(BlogHandler):
def get(self):
self.render('rot13-form.html')
def post(self):
rot13 = ''
text = self.request.get('text')
if text:
rot13 = text.encode('rot13')
self.render('rot13-form.html', text = rot13)
USER_RE = re.compile(r"^[a-zA-Z0-9_-]{3,20}$")
def valid_username(username):
return username and USER_RE.match(username)
PASS_RE = re.compile(r"^.{3,20}$")
def valid_password(password):
return password and PASS_RE.match(password)
EMAIL_RE = re.compile(r'^[\S]+@[\S]+\.[\S]+$')
def valid_email(email):
return not email or EMAIL_RE.match(email)
class Signup(BlogHandler):
def get(self):
self.render("signup-form.html")
def post(self):
have_error = False
self.username = self.request.get('username')
self.password = self.request.get('password')
self.verify = self.request.get('verify')
self.email = self.request.get('email')
params = dict(username = self.username,
email = self.email)
if not valid_username(self.username):
params['error_username'] = "That's not a valid username."
have_error = True
if not valid_password(self.password):
params['error_password'] = "That wasn't a valid password."
have_error = True
elif self.password != self.verify:
params['error_verify'] = "Your passwords didn't match."
have_error = True
if not valid_email(self.email):
params['error_email'] = "That's not a valid email."
have_error = True
if have_error:
self.render('signup-form.html', **params)
else:
self.done()
def done(self, *a, **kw):
raise NotImplementedError
class Unit2Signup(Signup):
def done(self):
self.redirect('/unit2/welcome?username=' + self.username)
class Register(Signup):
def done(self):
#make sure the user doesn't already exist
u = User.by_name(self.username)
if u:
msg = 'That user already exists.'
self.render('signup-form.html', error_username = msg)
else:
u = User.register(self.username, self.password, self.email)
u.put()
self.login(u)
self.redirect('/blog')
class Login(BlogHandler):
def get(self):
self.render('login-form.html')
def post(self):
username = self.request.get('username')
password = self.request.get('password')
u = User.login(username, password)
if u:
self.login(u)
self.redirect('/blog')
else:
msg = 'Invalid login'
self.render('login-form.html', error = msg)
class Logout(BlogHandler):
def get(self):
self.logout()
self.redirect('/blog')
class Unit3Welcome(BlogHandler):
def get(self):
if self.user:
self.render('welcome.html', username = self.user.name)
else:
self.redirect('/signup')
class Welcome(BlogHandler):
def get(self):
username = self.request.get('username')
if valid_username(username):
self.render('welcome.html', username = username)
else:
self.redirect('/unit2/signup')
app = webapp2.WSGIApplication([('/', MainPage),
('/unit2/rot13', Rot13),
('/unit2/signup', Unit2Signup),
('/unit2/welcome', Welcome),
('/blog/?', BlogFront),
('/blog/([0-9]+)', PostPage),
('/blog/newpost', NewPost),
('/signup', Register),
('/login', Login),
('/logout', Logout),
('/unit3/welcome', Unit3Welcome),
],
debug=True)
如果有什么需要我澄清的，请告诉我。预先感谢您的帮助。
好的，您将继承 BlogHandler。
要获取用户名信息，按照 Unit3Welcome() 示例，我认为您需要将 signatory = user.name 更改为 signatory = self.user.name
要填充 jinja2 模板中的 {{user.name}} 字段，它需要获取模板值 dict 它接收一个 user 变量（也是 dict 类型）包含一个 name 键（大概有相应的用户名）。例如：{'user': {'name': 'johndoe'}}.
我既不熟悉您使用的渲染器的工作原理，也不熟悉 SQL 以及 signedevents 的填充方式，因此您可能需要适应。
为了轻松检查（以调试打印样式）实际上是什么进入了模板，您可以在 html 的某处临时插入这样的段落：<p>user: ({{ user }})</p> 并且您应该得到转储user 变量就在你的浏览器中:)
您好，我记得这件事与 App Engine 有关，也许它与旧的 'db' 数据存储区有关。 Google 现在建议使用 'ndb'。
由于您还设置了 cookie，因此您实际上可以使用它在欢迎页面中呈现您的用户名。
我就是这样解决的，希望对您有所帮助。
class Register(SignUp):
def done(self):
#make sure the user doesn't already exist
u = User.by_name(self.request.get("username"))
if u:
msg = 'That user already exists.'
self.render('signup-form.html', username_exists = msg)
else:
username = self.request.get("username")
password = self.request.get("password")
email = self.request.get("email")
u = User.register(username, password , email)
u.put()
self.login(u)
self.redirect('/blog/welcome')
class Welcome(BlogHandler):
def get(self):
cookie = self.request.cookies.get("user_id")
val = check_secure_val(cookie)
u = User.by_id(int(val))
if u:
print u
self.render('welcome.html', username = u.name)
else:
self.redirect('/blog/signup')
当然，我讨厌利用繁忙的 StackExchange 成员的时间来解决我的问题，但我已经在我检索此代码的论坛中询问过该机制是如何工作的，但绝对没有响应。
我的问题应该很简单（不是针对我自己，因为我是所谓的网络开发业余爱好者）。我有这个代码（不是我自己的）用于后端一个基本的博客。但是有一件事我不太明白。在其中一个 HTML 文件中，有一行 {{user.name}}，它获取当前登录用户的用户名并将其张贴在页面的一角。 {{}} 只是 Jinja2 语法，它向模板打印一个 python 表达式（或者有人告诉我）。
如何获取在 Python 文件中登录的用户的用户名？我目前在自己的 Web 应用程序中尝试做的是获取登录用户的用户名并查询 Google 数据存储以获取有关用户的信息并将其放入个人资料页面，如下所示：
class Profile(BlogHandler):
def render_profile(self):
signatory = user.name
signedevents = db.GqlQuery("SELECT event FROM Signatories WHERE username IN (signatory)")
self.render("profile.html", signedevents=signedevents)
def get(self):
if self.user:
self.render_profile()
else:
self.redirect('/')
但是每当我尝试这样做时，我总是会出错。有没有其他东西可以代替 user.name？
博客代码（我确定答案在 Handler 的某处 class 但我根本无法弄清楚问题是什么）：
import os
import re
import random
import hashlib
import hmac
from string import letters
import webapp2
import jinja2
from google.appengine.ext import db
template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir),
autoescape = True)
secret = 'fart'
def render_str(template, **params):
t = jinja_env.get_template(template)
return t.render(params)
def make_secure_val(val):
return '%s|%s' % (val, hmac.new(secret, val).hexdigest())
def check_secure_val(secure_val):
val = secure_val.split('|')[0]
if secure_val == make_secure_val(val):
return val
class BlogHandler(webapp2.RequestHandler):
def write(self, *a, **kw):
self.response.out.write(*a, **kw)
def render_str(self, template, **params):
params['user'] = self.user
return render_str(template, **params)
def render(self, template, **kw):
self.write(self.render_str(template, **kw))
def set_secure_cookie(self, name, val):
cookie_val = make_secure_val(val)
self.response.headers.add_header(
'Set-Cookie',
'%s=%s; Path=/' % (name, cookie_val))
def read_secure_cookie(self, name):
cookie_val = self.request.cookies.get(name)
return cookie_val and check_secure_val(cookie_val)
def login(self, user):
self.set_secure_cookie('user_id', str(user.key().id()))
def logout(self):
self.response.headers.add_header('Set-Cookie', 'user_id=; Path=/')
def initialize(self, *a, **kw):
webapp2.RequestHandler.initialize(self, *a, **kw)
uid = self.read_secure_cookie('user_id')
self.user = uid and User.by_id(int(uid))
def render_post(response, post):
response.out.write('<b>' + post.subject + '</b><br>')
response.out.write(post.content)
class MainPage(BlogHandler):
def get(self):
self.write('Hello, Udacity!')
##### user stuff
def make_salt(length = 5):
return ''.join(random.choice(letters) for x in xrange(length))
def make_pw_hash(name, pw, salt = None):
if not salt:
salt = make_salt()
h = hashlib.sha256(name + pw + salt).hexdigest()
return '%s,%s' % (salt, h)
def valid_pw(name, password, h):
salt = h.split(',')[0]
return h == make_pw_hash(name, password, salt)
def users_key(group = 'default'):
return db.Key.from_path('users', group)
class User(db.Model):
name = db.StringProperty(required = True)
pw_hash = db.StringProperty(required = True)
email = db.StringProperty()
@classmethod
def by_id(cls, uid):
return User.get_by_id(uid, parent = users_key())
@classmethod
def by_name(cls, name):
u = User.all().filter('name =', name).get()
return u
@classmethod
def register(cls, name, pw, email = None):
pw_hash = make_pw_hash(name, pw)
return User(parent = users_key(),
name = name,
pw_hash = pw_hash,
email = email)
@classmethod
def login(cls, name, pw):
u = cls.by_name(name)
if u and valid_pw(name, pw, u.pw_hash):
return u
这里的一切可能都不重要，但如果仅使用上面的代码无法找到答案，请继续。
##### blog stuff
def blog_key(name = 'default'):
return db.Key.from_path('blogs', name)
class Post(db.Model):
subject = db.StringProperty(required = True)
content = db.TextProperty(required = True)
created = db.DateTimeProperty(auto_now_add = True)
last_modified = db.DateTimeProperty(auto_now = True)
def render(self):
self._render_text = self.content.replace('\n', '<br>')
return render_str("post.html", p = self)
class BlogFront(BlogHandler):
def get(self):
posts = greetings = Post.all().order('-created')
self.render('front.html', posts = posts)
class PostPage(BlogHandler):
def get(self, post_id):
key = db.Key.from_path('Post', int(post_id), parent=blog_key())
post = db.get(key)
if not post:
self.error(404)
return
self.render("permalink.html", post = post)
class NewPost(BlogHandler):
def get(self):
if self.user:
self.render("newpost.html")
else:
self.redirect("/login")
def post(self):
if not self.user:
self.redirect('/blog')
subject = self.request.get('subject')
content = self.request.get('content')
if subject and content:
p = Post(parent = blog_key(), subject = subject, content = content)
p.put()
self.redirect('/blog/%s' % str(p.key().id()))
else:
error = "subject and content, please!"
self.render("newpost.html", subject=subject, content=content, error=error)
###### Unit 2 HW's
class Rot13(BlogHandler):
def get(self):
self.render('rot13-form.html')
def post(self):
rot13 = ''
text = self.request.get('text')
if text:
rot13 = text.encode('rot13')
self.render('rot13-form.html', text = rot13)
USER_RE = re.compile(r"^[a-zA-Z0-9_-]{3,20}$")
def valid_username(username):
return username and USER_RE.match(username)
PASS_RE = re.compile(r"^.{3,20}$")
def valid_password(password):
return password and PASS_RE.match(password)
EMAIL_RE = re.compile(r'^[\S]+@[\S]+\.[\S]+$')
def valid_email(email):
return not email or EMAIL_RE.match(email)
class Signup(BlogHandler):
def get(self):
self.render("signup-form.html")
def post(self):
have_error = False
self.username = self.request.get('username')
self.password = self.request.get('password')
self.verify = self.request.get('verify')
self.email = self.request.get('email')
params = dict(username = self.username,
email = self.email)
if not valid_username(self.username):
params['error_username'] = "That's not a valid username."
have_error = True
if not valid_password(self.password):
params['error_password'] = "That wasn't a valid password."
have_error = True
elif self.password != self.verify:
params['error_verify'] = "Your passwords didn't match."
have_error = True
if not valid_email(self.email):
params['error_email'] = "That's not a valid email."
have_error = True
if have_error:
self.render('signup-form.html', **params)
else:
self.done()
def done(self, *a, **kw):
raise NotImplementedError
class Unit2Signup(Signup):
def done(self):
self.redirect('/unit2/welcome?username=' + self.username)
class Register(Signup):
def done(self):
#make sure the user doesn't already exist
u = User.by_name(self.username)
if u:
msg = 'That user already exists.'
self.render('signup-form.html', error_username = msg)
else:
u = User.register(self.username, self.password, self.email)
u.put()
self.login(u)
self.redirect('/blog')
class Login(BlogHandler):
def get(self):
self.render('login-form.html')
def post(self):
username = self.request.get('username')
password = self.request.get('password')
u = User.login(username, password)
if u:
self.login(u)
self.redirect('/blog')
else:
msg = 'Invalid login'
self.render('login-form.html', error = msg)
class Logout(BlogHandler):
def get(self):
self.logout()
self.redirect('/blog')
class Unit3Welcome(BlogHandler):
def get(self):
if self.user:
self.render('welcome.html', username = self.user.name)
else:
self.redirect('/signup')
class Welcome(BlogHandler):
def get(self):
username = self.request.get('username')
if valid_username(username):
self.render('welcome.html', username = username)
else:
self.redirect('/unit2/signup')
app = webapp2.WSGIApplication([('/', MainPage),
('/unit2/rot13', Rot13),
('/unit2/signup', Unit2Signup),
('/unit2/welcome', Welcome),
('/blog/?', BlogFront),
('/blog/([0-9]+)', PostPage),
('/blog/newpost', NewPost),
('/signup', Register),
('/login', Login),
('/logout', Logout),
('/unit3/welcome', Unit3Welcome),
],
debug=True)
如果有什么需要我澄清的，请告诉我。预先感谢您的帮助。
好的，您将继承 BlogHandler。
要获取用户名信息，按照 Unit3Welcome() 示例，我认为您需要将 signatory = user.name 更改为 signatory = self.user.name
要填充 jinja2 模板中的 {{user.name}} 字段，它需要获取模板值 dict 它接收一个 user 变量（也是 dict 类型）包含一个 name 键（大概有相应的用户名）。例如：{'user': {'name': 'johndoe'}}.
我既不熟悉您使用的渲染器的工作原理，也不熟悉 SQL 以及 signedevents 的填充方式，因此您可能需要适应。
为了轻松检查（以调试打印样式）实际上是什么进入了模板，您可以在 html 的某处临时插入这样的段落：<p>user: ({{ user }})</p> 并且您应该得到转储user 变量就在你的浏览器中:)
您好，我记得这件事与 App Engine 有关，也许它与旧的 'db' 数据存储区有关。 Google 现在建议使用 'ndb'。 由于您还设置了 cookie，因此您实际上可以使用它在欢迎页面中呈现您的用户名。
我就是这样解决的，希望对您有所帮助。
class Register(SignUp):
def done(self):
#make sure the user doesn't already exist
u = User.by_name(self.request.get("username"))
if u:
msg = 'That user already exists.'
self.render('signup-form.html', username_exists = msg)
else:
username = self.request.get("username")
password = self.request.get("password")
email = self.request.get("email")
u = User.register(username, password , email)
u.put()
self.login(u)
self.redirect('/blog/welcome')
class Welcome(BlogHandler):
def get(self):
cookie = self.request.cookies.get("user_id")
val = check_secure_val(cookie)
u = User.by_id(int(val))
if u:
print u
self.render('welcome.html', username = u.name)
else:
self.redirect('/blog/signup')