Django 學習筆記，django學習筆記

Django 學習筆記，django學習筆記
1.Django Intor2.Django Install(1) PIP安裝

sudo apt-get isntall python-pipsudo pip install Django

(2) 源碼安裝

/usr/local/share/Django/Django-1.8.3.tar.gzDjango-1.8.3├── AUTHORS├── build├── dist├── django├── Django.egg-info├── docs├── extras├── INSTALL├── LICENSE├── MANIFEST.in├── PKG-INFO├── README.rst├── scripts├── setup.cfg├── setup.py└── tests

sudo python setup.py install 

3.Django Project(1) 建立項目

root@kallen:Django#django-admin startproject MyProjroot@kallen:Django# tree MyProj/MyProj/├── manage.py└── MyProj    ├── __init__.py    ├── settings.py    ├── urls.py    └── wsgi.py

__init__.py：Django項目是Python包，這個檔案是用來告訴Python這個檔案夾當做一個包。在Python術語中，包是一組模組的集合，主要用來把相似的檔案分組，防止出現命名衝突。

manage.py：這個腳步用來管理你的項目，你可以把它看做是你項目的的django-admin.py版本，其實，manage.py和django-admin.py是共用相同的後台代碼。

settings.py： 這是Django項目的主要設定檔，在這個檔案裡面，你可以具體說明很多選項，包括資料庫設定、網頁語言、需要turn
on的Django功能。

urls.py：這是另外一個設定檔。你可以把它看做是介於URLS和用來處理它們的Python方法之間的匹配;

(http://www.cnblogs.com/bluescorpio/archive/2009/11/28/1612805.html)

(2) 建立應用

root@kallen:Django#python manage.py startapp jobs└── MyProj    ├── jobs    │   ├── admin.py    │   ├── __init__.py    │   ├── migrations    │   │   └── __init__.py    │   ├── models.py    │   ├── tests.py    │   └── views.py    ├── manage.py    └── MyProj

(3) 建立實體類

from django.db import modelsclass Job(models.Model):    pub_date = models.DateField()    job_title = models.CharField(max_length=50)    job_description = models.TextField()    location = models.ForeignKey(Location)    def __str__(self):        return "%s (%s)" % (self.job_title, self.location)  

(4) 查看資料庫模式

root@kallen:/home/kallen/Python/Django/MyProj# python manage.py sql jobsBEGIN;CREATE TABLE `jobs_location` (    `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,    `city` varchar(50)NOT NULL,    `state` varchar(50),    `country` varchar(50)NOT NULL);CREATE TABLE `jobs_job` (    `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,    `pub_date` date NOT NULL,    `job_title` varchar(50)NOT NULL,    `job_description` longtext NOT NULL,    `location_id` integerNOT NULL);ALTER TABLE `jobs_job` ADD CONSTRAINT `location_id_refs_id_35f2feb6` FOREIGN KEY (`location_id`) REFERENCES `jobs_location` (`id`);COMMIT;

【常見錯誤】

$ python manage.py sql jobsCommandError: App 'jobs' has migrations. Only the sqlmigrate and sqlflush commandscan be used when an app has migrations.

【解決辦法】　刪除jobs下的migrations就可以了；

(5) 檢查資料庫模式

root@kallen:/home/kallen/Python/Django/MyProj#python manage.py validate/usr/local/lib/python2.7/dist-packages/Django-1.8.3-py2.7.egg/django/core/management/commands/validate.py:15: RemovedInDjango19Warning:"validate" has been deprecated in favor of"check".RemovedInDjango19Warning)System check identified no issues (0 silenced).root@kallen:/home/kallen/Python/Django/MyProj#python manage.py makemigrationsMigrations for 'jobs':0001_initial.py:- Create model Job- Create model Location- Add field location to jobroot@kallen:/home/kallen/Python/Django/MyProj#python manage.py migrateOperations to perform:  Synchronize unmigrated apps: staticfiles, messages  Apply all migrations: admin, contenttypes, jobs, auth, sessionsSynchronizing apps without migrations:  Creating tables...    Running deferred SQL...  Installing custom SQL...Running migrations:  Rendering model states... DONE  Applying jobs.0001_initial... OK

(6) 啟動測試伺服器

root@kallen:/home/kallen/Python/Django/MyProj#python manage.py runserverPerforming system checks...System check identified no issues (0 silenced).You have unapplied migrations; your app may not work properly until they are applied.Run 'python manage.py migrate' to apply them.August 14,2015-05:55:23Django version 1.8.3, using settings 'MyProj.settings'Starting development server at http://127.0.0.1:8000/Quit the server with CONTROL-C.

(7) 後台管理

root@kallen:/home/kallen/Python/Django/MyProj#python manage.py syncdb

(8) 註冊模型

from django.contrib issmport admin# Register your models here.# Register my models of job for mapping # utility class Location & Job.# Kallen Ding, Agu 17 2015from .models import Location, Job admin.site.register(Location)admin.site.register(Job) 

4.Django FAQ(1) 匯入MySQL錯誤

django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module

【解決辦法】安裝mysql-python模組

安裝步驟：

sudo apt-get install python-setuptoolssudo apt-get install libmysqld-devsudo apt-get install libmysqlclient-dev sudo apt-get install python-devsudo easy_install mysql-python

測試下： 在python互動式視窗，import MySQLdb 試試，不報錯的話，就證明安裝好了。

(2) 匯入model對象出錯

>>> from jobs.models import Jobdjango.core.exceptions.ImproperlyConfigured: Requested setting DEFAULT_INDEX_TABLESPACE, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

【解決辦法】

>>>from django.conf import settings  >>> settings.configure()

(3) CSRF Verification Failed

Forbidden (403)CSRF verification failed. Request aborted.HelpReason given for failure:    CSRF token missing or incorrect.In general, this can occur when there is a genuine Cross Site Request Forgery, or when Django's CSRF mechanism has not been used correctly. For POST forms, you need to ensure:Your browser is accepting cookies.The view function passes a request to the template's render method.In the template, there is a {% csrf_token %} template tag inside each POST form that targets an internal URL.If you are not using CsrfViewMiddleware, then you must use csrf_protect on any views that use the csrf_token template tag, as well as those that accept the POST data.You're seeing the help section of this page because you have DEBUG =Truein your Django settings file. Change that to False, and only the initial error message will be displayed.You can customize this page using the CSRF_FAILURE_VIEW setting.

【解決辦法】

第一種：在表單裡加上{% csrf_token %}就行了；

第二種：在Settings裡的MIDDLEWARE_CLASSES增加配置：

'django.middleware.csrf.CsrfViewMiddleware','django.middleware.csrf.CsrfResponseMiddleware',

方法二不可行：

ImportError: Module "django.middleware.csrf" does not define a "CsrfResponseMiddleware" attribute/class

在測試環境下只需要將這兩行注釋即可；

【參考文章】

http://queengina.com/2014/10/15/Django%E7%B3%BB%E5%88%97%EF%BC%88%E4%BA%8C%EF%BC%89/

http://stackoverflow.com/questions/6315960/djangos-querydict-bizarre-behavior-bunches-post-dictionary-into-a-single-key

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