Django环境搭建及开发
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# 如果同时安装了Python 2和Pyhton 3要指定版本
mkvirtualenv -p python3 env
或
mkvirtualenv --python=python3路径 env
pip install django mysqlclient
pip install django-crispy-forms django-formtools httplib2
虽然很多领域如机器学习的开发者当前更青睐于Python 2，但Python 3已经被越来越多的开发者们所使用，本文旨在整理Python 3环境下安装最新Django版本所出现的问题，其中有很多内容和Python 2下相似或相同。
1.用户表重写
在继承AbstractUser表重写该类时会提示Reverse accessor for ‘User.*’ clashes with reverse accessor for ‘*.*’
auth . User . groups : ( fields . E304 ) Reverse accessor for 'User.groups' clashes with reverse accessor for 'UserProfile.groups' .
HINT : Add or change a related_name argument to the definition for 'User.groups' or 'UserProfile.groups' .
auth . User . user_permissions : ( fields . E304 ) Reverse accessor for 'User.user_permissions' clashes with reverse accessor for 'UserProfile.user_permissions' .
HINT : Add or change a related_name argument to the definition for 'User.user_permissions' or 'UserProfile.user_permissions' .
解决这一问题只需要按照你定义的app名称和类名在settings.py中添加如下内容：
AUTH_USER_MODEL = 'appName.ClassName'
此外添加图片时要按照所提示的安装Pillow
users . UserProfile . avatar : ( fields . E210 ) Cannot use ImageField because Pillow is not installed .
HINT : Get Pillow at https : //pypi.python.org/pypi/Pillow or run command "pip install Pillow".
MySQL Strict Mode && InconsistentMigrationHistory
# 报错
WARNINGS :
? : ( mysql . W002 ) MySQL Strict Mode is not set for database connection 'default'
HINT : MySQL 's Strict Mode fixes many data integrity problems in MySQL, such as data truncation upon insertion, by escalating warnings into errors.
# setttings.py的DATABASES下配置
' OPTIONS ': {
' init_command ': "SET sql_mode=' STRICT_TRANS_TABLES '",
}
# 报错
django.db.migrations.exceptions.InconsistentMigrationHistory: Migration admin.0001_initial is applied before its dependency users.0001_initial on database ' default '.
# 针对以上报错请备份数据库，删除所有数据表以及migration文件重新执行makemigrations, migrate指令
2.settings.py常见配置
# 将所有新建app合并到apps目录下
sys . path . insert ( 0 , os . path . join ( BASE_DIR , 'apps' ) )
# 语言
LANGUAGE_CODE = 'zh-hans'
# 时区
TIME_ZONE = 'Asia/Shanghai'
USE_TZ = False
3. Warning: (1366, “Incorrect string value…)
# Python 2
# coding:utf-8
a = '\xE7\x94\xA8\xE6\x88\xB7'
print a
# Python 3
a = '\xE7\x94\xA8\xE6\x88\xB7'
a = a . encode ( 'raw_unicode_escape' ) . decode ( )
print ( a )
4. CSRF verification failed. Request aborted.
5.error: command ‘clang’ failed with exit status 1(pymssql)
brew unlink freetds ;
brew install freetds @ 0.91 ;
brew link --force freetds @ 0.91
6.安装Pillow缺少zlib的问题
ValueError : zlib is required unless explicitly disabled using --disable -zlib , aborting
# 执行
xcode -select --install
7.django.db.utils.OperationalError: (1050, “Table ‘xxx’ already exists”)
这通常是由于删除 migrations 目录下迁移记录以及django_migrations表中对应内容，但数据表中仍存在该字段所致，在 migrate 时添加–fake 参数可解决这一问题
python manage . py migrate appName --fake
8.RuntimeError: Model class apps.xxx.models.xxx doesn’t declare an explicit app_label and isn’t in an application in INSTALLED_APPS.
# 将对应的 apps.py 下的
name = 'xxxx'
# 修改为
name = 'apps.xxxx'
这是由于我将的有 app 提取到 apps 目录下产生的名称冲突所致
9.Google分析等线上才使用的代码如何在线下进行屏蔽？
一种比较简单的方式是通过 debug的配置来进行区分
# settings.py
DEBUG = True
INTERNAL_IPS = (
'127.0.0.1' ,
'localhost' ,
)
# 然后在 template 中使用
{ % if not debug % }
# 生产环境才需要加载的内容
{ % endif % }
10.django.db.utils.OperationalError: (1071, ‘Specified key was too long; max key length is 767 bytes’)
ALTER DATABASE ` databasename ` CHARACTER SET utf8 ;
