Flask的圖形化管理界面搭建框架Flask-Admin的使用教程

更新時間：2016年06月13日 15:57:10 作者：digwtx

Flask-Admin是一個為Python的Flask框架服務(wù)的微型框架,可以像Django-Admin那樣為用戶生成Model層面的數(shù)據(jù)管理界面,接下來就一起來看一下Flask的圖形化管理界面搭建框架Flask-Admin的使用教程

Flask-Admin是Flask框架的一個擴展，用它能夠快速創(chuàng)建Web管理界面，它實現(xiàn)了比如用戶、文件的增刪改查等常用的管理功能；如果對它的默認界面不喜歡，可以通過修改模板文件來定制；
Flask-Admin把每一個菜單（超鏈接）看作一個view，注冊后才能顯示出來，view本身也有屬性來控制其是否可見；因此，利用這個機制可以定制自己的模塊化界面，比如讓不同權(quán)限的用戶登錄后看到不一樣的菜單；

項目地址：https://flask-admin.readthedocs.io/en/latest/

example/simple
這是最簡單的一個樣例，可以幫助我們快速、直觀的了解基本概念，學(xué)會定制Flask-Admin的界面
simple.py：

from flask import Flask

from flask.ext import admin


# Create custom admin view
class MyAdminView(admin.BaseView):
  @admin.expose('/')
  def index(self):
    return self.render('myadmin.html')


class AnotherAdminView(admin.BaseView):
  @admin.expose('/')
  def index(self):
    return self.render('anotheradmin.html')

  @admin.expose('/test/')
  def test(self):
    return self.render('test.html')


# Create flask app
app = Flask(__name__, template_folder='templates')
app.debug = True

# Flask views
@app.route('/')
def index():
  return '<a href="/admin/">Click me to get to Admin!</a>'

# Create admin interface
admin = admin.Admin()
admin.add_view(MyAdminView(category='Test'))
admin.add_view(AnotherAdminView(category='Test'))
admin.init_app(app)

if __name__ == '__main__':

  # Start app
  app.run()

在這里可以看到運行效果

BaseView

所有的view都必須繼承自BaseView：

復(fù)制代碼代碼如下:

class BaseView(name=None, category=None, endpoint=None, url=None, static_folder=None, static_url_path=None)

name: view在頁面上表現(xiàn)為一個menu（超鏈接），menu name == 'name'，缺省就用小寫的class name
category: 如果多個view有相同的category就全部放到一個dropdown里面（dropdown name=='category'）
endpoint: 假設(shè)endpoint='xxx'，則可以用url_for(xxx.index)，也能改變頁面URL（/admin/xxx）
url: 頁面URL，優(yōu)先級url > endpoint > class name
static_folder: static目錄的路徑
static_url_path: static目錄的URL
anotheradmin.html:

{% extends 'admin/master.html' %}
{% block body %}
  Hello World from AnotherMyAdmin!<br/>
  <a href="{{ url_for('.test') }}">Click me to go to test view</a>
{% endblock %}

如果AnotherAdminView增加參數(shù)endpoint='xxx'，那這里就可以寫成url_for('xxx.text')，然后頁面URL會由/admin/anotheradminview/變成/admin/xxx
如果同時指定參數(shù)url='aaa'，那頁面URL會變成/admin/aaa，url優(yōu)先級比endpoint高
Admin

復(fù)制代碼代碼如下:

class Admin(app=None, name=None, url=None, subdomain=None, index_view=None, translations_path=None, endpoint=None, static_url_path=None, base_template=None)

app: Flask Application Object；本例中可以不寫admin.init_app(app)，直接用admin = admin.Admin(app=app)是一樣的
name: Application name，缺省'Admin'；會顯示為main menu name('Home'左邊的'Admin')和page title
subdomain: ???
index_view: 'Home'那個menu對應(yīng)的就叫index view，缺省AdminIndexView
base_template: 基礎(chǔ)模板，缺省admin/base.html，該模板在Flask-Admin的源碼目錄里面
部分Admin代碼如下：

class MenuItem(object):
  """
    Simple menu tree hierarchy.
  """
  def __init__(self, name, view=None):
    self.name = name
    self._view = view
    self._children = []
    self._children_urls = set()
    self._cached_url = None
    self.url = None
    if view is not None:
      self.url = view.url

  def add_child(self, view):
    self._children.append(view)
    self._children_urls.add(view.url)

class Admin(object):

  def __init__(self, app=None, name=None,
         url=None, subdomain=None,
         index_view=None,
         translations_path=None,
         endpoint=None,
         static_url_path=None,
         base_template=None):

    self.app = app

    self.translations_path = translations_path

    self._views = []
    self._menu = []
    self._menu_categories = dict()
    self._menu_links = []

    if name is None:
      name = 'Admin'
    self.name = name

    self.index_view = index_view or AdminIndexView(endpoint=endpoint, url=url)
    self.endpoint = endpoint or self.index_view.endpoint
    self.url = url or self.index_view.url
    self.static_url_path = static_url_path
    self.subdomain = subdomain
    self.base_template = base_template or 'admin/base.html'

    # Add predefined index view
    self.add_view(self.index_view)

    # Register with application
    if app is not None:
      self._init_extension()

  def add_view(self, view):

    # Add to views
    self._views.append(view)

    # If app was provided in constructor, register view with Flask app
    if self.app is not None:
      self.app.register_blueprint(view.create_blueprint(self))
      self._add_view_to_menu(view)

  def _add_view_to_menu(self, view):

    if view.category:
      category = self._menu_categories.get(view.category)

      if category is None:
        category = MenuItem(view.category)
        self._menu_categories[view.category] = category
        self._menu.append(category)

      category.add_child(MenuItem(view.name, view))
    else:
      self._menu.append(MenuItem(view.name, view))

  def init_app(self, app):

    self.app = app

    self._init_extension()

    # Register views
    for view in self._views:
      app.register_blueprint(view.create_blueprint(self))
      self._add_view_to_menu(view)

從上面的代碼可以看出init_app(app)和Admin(app=app)是一樣的：
將每個view注冊為blueprint（Flask里的概念，可以簡單理解為模塊）
記錄所有view，以及所屬的category和url
AdminIndexView

復(fù)制代碼代碼如下:

class AdminIndexView(name=None, category=None, endpoint=None, url=None, template='admin/index.html')

name: 缺省'Home'
endpoint: 缺省'admin'
url: 缺省'/admin'
如果要封裝出自己的view，可以參照AdminIndexView的寫法：

class AdminIndexView(BaseView):

  def __init__(self, name=None, category=None,
         endpoint=None, url=None,
         template='admin/index.html'):
    super(AdminIndexView, self).__init__(name or babel.lazy_gettext('Home'),
                       category,
                       endpoint or 'admin',
                       url or '/admin',
                       'static')
    self._template = template

  @expose()
  def index(self):
    return self.render(self._template)
base_template

base_template缺省是/admin/base.html，是頁面的主要代碼（基于bootstrap），它里面又import admin/layout.html；
layout是一些宏，主要用于展開、顯示menu；
在模板中使用一些變量來取出之前注冊view時保存的信息（如menu name和url等）：
# admin/layout.html (部分)

{% macro menu() %}
 {% for item in admin_view.admin.menu() %}
  {% if item.is_category() %}
   {% set children = item.get_children() %}
   {% if children %}
    {% if item.is_active(admin_view) %}<li class="active dropdown">{% else %}<li class="dropdown">{% endif %}
     <a class="dropdown-toggle" data-toggle="dropdown" href="javascript:void(0)">{{ item.name }}<b class="caret"></b></a>
     <ul class="dropdown-menu">
      {% for child in children %}
       {% if child.is_active(admin_view) %}<li class="active">{% else %}<li>{% endif %}
        <a href="{{ child.get_url() }}">{{ child.name }}</a>
       </li>
      {% endfor %}
     </ul>
    </li>
   {% endif %}
  {% else %}
   {% if item.is_accessible() and item.is_visible() %}
    {% if item.is_active(admin_view) %}<li class="active">{% else %}<li>{% endif %}
     <a href="{{ item.get_url() }}">{{ item.name }}</a>
    </li>
   {% endif %}
  {% endif %}
 {% endfor %}
{% endmacro %}

example/file
這個樣例能幫助我們快速搭建起文件管理界面，但我們的重點是學(xué)習(xí)使用ActionsMixin模塊
file.py：

import os
import os.path as op

from flask import Flask

from flask.ext import admin
from flask.ext.admin.contrib import fileadmin

# Create flask app
app = Flask(__name__, template_folder='templates', static_folder='files')

# Create dummy secrey key so we can use flash
app.config['SECRET_KEY'] = '123456790'


# Flask views
@app.route('/')
def index():
  return '<a href="/admin/">Click me to get to Admin!</a>'


if __name__ == '__main__':
  # Create directory
  path = op.join(op.dirname(__file__), 'files')
  try:
    os.mkdir(path)
  except OSError:
    pass

  # Create admin interface
  admin = admin.Admin(app)
  admin.add_view(fileadmin.FileAdmin(path, '/files/', name='Files'))

  # Start app
  app.run(debug=True)

FileAdmin是已經(jīng)寫好的的一個view，直接用即可：

復(fù)制代碼代碼如下:

class FileAdmin(base_path, base_url, name=None, category=None, endpoint=None, url=None, verify_path=True)

base_path: 文件存放的相對路徑
base_url: 文件目錄的URL
FileAdmin中和ActionsMixin相關(guān)代碼如下：
class FileAdmin(BaseView, ActionsMixin):

  def __init__(self, base_path, base_url,
         name=None, category=None, endpoint=None, url=None,
         verify_path=True):

    self.init_actions()

@expose('/action/', methods=('POST',))
def action_view(self):
  return self.handle_action()

# Actions
@action('delete',
    lazy_gettext('Delete'),
    lazy_gettext('Are you sure you want to delete these files?'))
def action_delete(self, items):
  if not self.can_delete:
    flash(gettext('File deletion is disabled.'), 'error')
    return

  for path in items:
    base_path, full_path, path = self._normalize_path(path)

    if self.is_accessible_path(path):
      try:
        os.remove(full_path)
        flash(gettext('File "%(name)s" was successfully deleted.', name=path))
      except Exception as ex:
        flash(gettext('Failed to delete file: %(name)s', name=ex), 'error')

@action('edit', lazy_gettext('Edit'))
def action_edit(self, items):
  return redirect(url_for('.edit', path=items))
@action()用于wrap跟在后面的函數(shù)，這里的作用就是把參數(shù)保存起來：
def action(name, text, confirmation=None)
  def wrap(f):
    f._action = (name, text, confirmation)
    return f

  return wrap

name: action name
text: 可用于按鈕名稱
confirmation: 彈框確認信息
init_actions()把所有action的信息保存到ActionsMixin里面：

# 調(diào)試信息
_actions = [('delete', lu'Delete'), ('edit', lu'Edit')]
_actions_data = {'edit': (<bound method FileAdmin.action_edit of <flask_admin.contrib.fileadmin.FileAdmin object at 0x1aafc50>>, lu'Edit', None), 'delete': (<bound method FileAdmin.action_delete of <flask_admin.contrib.fileadmin.FileAdmin object at 0x1aafc50>>, lu'Delete', lu'Are you sure you want to delete these files?')}

action_view()用于處理POST給/action/的請求，然后調(diào)用handle_action()，它再調(diào)用不同的action處理，最后返回當(dāng)前頁面：

# 省略無關(guān)代碼
def handle_action(self, return_view=None):

  action = request.form.get('action')
  ids = request.form.getlist('rowid')

  handler = self._actions_data.get(action)

  if handler and self.is_action_allowed(action):
    response = handler[0](ids)

    if response is not None:
      return response

  if not return_view:
    url = url_for('.' + self._default_view)
  else:
    url = url_for('.' + return_view)

  return redirect(url)

ids是一個文件清單，作為參數(shù)傳給action處理函數(shù)（參數(shù)items）：

# 調(diào)試信息
ids: [u'1.png', u'2.png']

再分析頁面代碼，F(xiàn)iles頁面對應(yīng)文件為admin/file/list.html，重點看With selected下拉菜單相關(guān)代碼：
{% import 'admin/actions.html' as actionslib with context %}

{% if actions %}
  <div class="btn-group">
    {{ actionslib.dropdown(actions, 'dropdown-toggle btn btn-large') }}
  </div>
{% endif %}

{% block actions %}
  {{ actionslib.form(actions, url_for('.action_view')) }}
{% endblock %}

{% block tail %}
  {{ actionslib.script(_gettext('Please select at least one file.'),
           actions,
           actions_confirmation) }}
{% endblock %}

上面用到的三個宏在actions.html：

{% macro dropdown(actions, btn_class='dropdown-toggle') -%}
  <a class="{{ btn_class }}" data-toggle="dropdown" href="javascript:void(0)">{{ _gettext('With selected') }}<b class="caret"></b></a>
  <ul class="dropdown-menu">
    {% for p in actions %}
    <li>
      <a href="javascript:void(0)" onclick="return modelActions.execute('{{ p[0] }}');">{{ _gettext(p[1]) }}</a>
    </li>
    {% endfor %}
  </ul>
{% endmacro %}

{% macro form(actions, url) %}
  {% if actions %}
  <form id="action_form" action="{{ url }}" method="POST" style="display: none">
    {% if csrf_token %}
    <input type="hidden" name="csrf_token" value="{{ csrf_token() }}"/>
    {% endif %}
    <input type="hidden" id="action" name="action" />
  </form>
  {% endif %}
{% endmacro %}

{% macro script(message, actions, actions_confirmation) %}
  {% if actions %}
  <script src="{{ admin_static.url(filename='admin/js/actions.js') }}"></script>
  <script language="javascript">
    var modelActions = new AdminModelActions({{ message|tojson|safe }}, {{ actions_confirmation|tojson|safe }});
  </script>
  {% endif %}
{% endmacro %}

最終生成的頁面（部分）：

<div class="btn-group">
  <a class="dropdown-toggle btn btn-large" href="javascript:void(0)" data-toggle="dropdown">
    With selected
    <b class="caret"></b>
  </a>

  <ul class="dropdown-menu">
    <li>
      <a onclick="return modelActions.execute('delete');" href="javascript:void(0)">Delete</a>
    </li>
    <li>
      <a onclick="return modelActions.execute('edit');" href="javascript:void(0)">Edit</a>
    </li>
  </ul>
</div>

<form id="action_form" action="/admin/fileadmin/action/" method="POST" style="display: none">
  <input type="hidden" id="action" name="action" />
</form>

<script src="/admin/static/admin/js/actions.js"></script>
<script language="javascript">
  var modelActions = new AdminModelActions("Please select at least one file.", {"delete": "Are you sure you want to delete these files?"});
</script>

選擇菜單后的處理方法在actions.js:

var AdminModelActions = function(actionErrorMessage, actionConfirmations) {
  // Actions helpers. TODO: Move to separate file
  this.execute = function(name) {
    var selected = $('input.action-checkbox:checked').size();

    if (selected === 0) {
      alert(actionErrorMessage);
      return false;
    }

    var msg = actionConfirmations[name];

    if (!!msg)
      if (!confirm(msg))
        return false;

    // Update hidden form and submit it
    var form = $('#action_form');
    $('#action', form).val(name);

    $('input.action-checkbox', form).remove();
    $('input.action-checkbox:checked').each(function() {
      form.append($(this).clone());
    });

    form.submit();

    return false;
  };

  $(function() {
    $('.action-rowtoggle').change(function() {
      $('input.action-checkbox').attr('checked', this.checked);
    });
  });
};

對比一下修改前后的表單：

# 初始化
<form id="action_form" style="display: none" method="POST" action="/admin/fileadmin/action/">
  <input id="action" type="hidden" name="action">
</form>

# 'Delete'選中的三個文件
<form id="action_form" style="display: none" method="POST" action="/admin/fileadmin/action/">
  <input id="action" type="hidden" name="action" value="delete">
  <input class="action-checkbox" type="checkbox" value="1.png" name="rowid">
  <input class="action-checkbox" type="checkbox" value="2.png" name="rowid">
  <input class="action-checkbox" type="checkbox" value="3.png" name="rowid">
</form>

# 'Edit'選中的一個文件
<form id="action_form" style="display: none" method="POST" action="/admin/fileadmin/action/">
  <input id="action" type="hidden" name="action" value="edit">
  <input class="action-checkbox" type="checkbox" value="1.png" name="rowid">
</form>

總結(jié)一下，當(dāng)我們點擊下拉菜單中的菜單項（Delete,Edit），本地JavaScript代碼會彈出確認框（假設(shè)有確認信息），然后提交一個表單給/admin/fileadmin/action/，請求處理函數(shù)action_view()根據(jù)表單類型再調(diào)用不同的action處理函數(shù)，最后返回一個頁面。

Flask-Admin字段（列）格式化
在某些情況下，我們需要對模型的某個屬性進行格式化。比如，默認情況下，日期時間顯示出來會比較長，這時可能需要只顯示月和日，這時候，列格式化就派上用場了。

比如，如果你要顯示雙倍的價格，你可以這樣做：

class MyModelView(BaseModelView):
  column_formatters = dict(price=lambda v, c, m, p: m.price*2)

或者在Jinja2模板中使用宏：

from flask.ext.admin.model.template import macro

class MyModelView(BaseModelView):
  column_formatters = dict(price=macro('render_price'))

# in template
{% macro render_price(model, column) %}
  {{ model.price * 2 }}
{% endmacro %}

回調(diào)函數(shù)模型：

def formatter(view, context, model, name):
  # `view` is current administrative view
  # `context` is instance of jinja2.runtime.Context
  # `model` is model instance
  # `name` is property name
  pass

正好和上面的v, c, m, p相對應(yīng)。

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