Python 2.7 python pip错误'；无法获取索引基URL'；在虚拟环境中

可以直接使用

pip install-r requirements.txt

，但是，当我尝试在virtualenv中使用它时，失败了，出现以下错误：

test@te:~$ cd flaskbb/
test@te:~/flaskbb$ 
test@te:~/flaskbb$ source .venv/bin/activate
(.venv)test@te:~/flaskbb$ pip install -r requirements.txt 
Obtaining file:///home/test/flaskbb (from -r requirements.txt (line 50))
  Running setup.py egg_info for package from file:///home/test/flaskbb

    no previously-included directories found matching 'flaskbb/themes/*/node_modules'
    no previously-included directories found matching 'flaskbb/themes/*/.sass-cache'
    warning: no previously-included files matching '__pycache__' found anywhere in distribution
    warning: no previously-included files matching '*.py[co]' found anywhere in distribution
Downloading/unpacking alembic==0.9.1 (from -r requirements.txt (line 1))
  Cannot fetch index base URL http://pypi.python.org/simple/
  Could not find any downloads that satisfy the requirement alembic==0.9.1 (from -r requirements.txt (line 1))
No distributions at all found for alembic==0.9.1 (from -r requirements.txt (line 1))
Storing complete log in /home/test/.pip/pip.log
(.venv)test@te:~/flaskbb$

这是我的系统：

test@te:~$ uname -ar
Linux te 3.2.0-101-generic #141-Ubuntu SMP Thu Mar 10 21:43:24 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
test@te:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.5 LTS
Release:    12.04
Codename:   precise
test@te:~$ uname -r
3.2.0-101-generic

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谢谢你的帮助

您可以指定https URL：

---

sudo pip install-r requirements.txt-i

您可以指定https URL：

---

sudo pip install-r requirements.txt-i

此处可能重复的

-i

选项指向符合PEP 503（简单存储库API）的存储库，该存储库也可以是以相同格式列出的本地目录。此处

-i

选项指向符合PEP 503的存储库（简单存储库API），也可以是以相同格式布局的本地目录。