django-jinjia 集成

现成包可以参考这里：  http://niwibe.github.io/django-jinja/ 

Requirements

• Python 2.7, 3.3 or 3.4

• Django 1.4, 1.5, 1.6 and 1.7

• jinja2 >= 2.7.0 

不过下面的实现没有用到上面的django-jinja 扩展。

不知道随着django版本的演变，又没有吸取jinjia2设计的精华，如果有，那么再手工集成就是多此一举。决定来个性能测试，环境：

win7 家庭版 64bit / python 2.7.3 / django 1.6.5

由于需要页面每次请求都返回不同的内容，因此简单做了个随机数，视图如下：

from django.shortcuts import render
from django.http import HttpResponse
import random
# Create your views here.
def getRandom(req):
	return render(req,'testjj.txt',{'r_int':random.randint(1,10000)})

　　

在虚拟机上用ab进行测试：

 ab -c 5 -n 1000  http://192.168.1.8:8000/

结果如下：

Concurrency Level:      5
Time taken for tests:   5.021 seconds
Complete requests:      1000
Failed requests:        95
   (Connect: 0, Receive: 0, Length: 95, Exceptions: 0)
Write errors:           0
Total transferred:      165895 bytes
HTML transferred:       3895 bytes
Requests per second:    199.18 [#/sec] (mean)
Time per request:       25.103 [ms] (mean)
Time per request:       5.021 [ms] (mean, across all concurrent requests)
Transfer rate:          32.27 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.2      0       2
Processing:    17   24   3.9     24      65
Waiting:       15   22   3.7     22      62
Total:         18   25   4.0     24      67

Percentage of the requests served within a certain time (ms)
  50%     24
  66%     25
  75%     26
  80%     26
  90%     28
  95%     29
  98%     31
  99%     41
 100%     67 (longest request)

　　

总时间5.021s。上面没有采用jinjia2， 下面采用jinjia2，代码修改如下,

主要是增加template_loader，ok，先看看django的默认的template loader的逻辑，默认的loader有两个，如下，可以参考这里。

django.template.loaders.filesystem.Loader

django.template.loaders.app_directories.Loader

算法的核心是根据某种规则，计算出模板文件的路径，并read然后decode返回。

loader修改如下（源码参考这里，文档参考这里）

from django.template.loader import BaseLoader
from django.template.loaders.app_directories import app_template_dirs
from django.template import TemplateDoesNotExist
from django.core import urlresolvers
from django.conf import settings
import jinja2

class Template(jinja2.Template):
    def render(self, context):
        # flatten the Django Context into a single dictionary.
        context_dict = {}
        for d in context.dicts:
            context_dict.update(d)
        return super(Template, self).render(context_dict)

class Loader(BaseLoader):
    is_usable = True

    env = jinja2.Environment(loader=jinja2.FileSystemLoader(app_template_dirs))
    env.template_class = Template

    # These are available to all templates.
    env.globals['url_for'] = urlresolvers.reverse
    env.globals['MEDIA_URL'] = settings.MEDIA_URL
    #env.globals['STATIC_URL'] = settings.STATIC_URL

    def load_template(self, template_name, template_dirs=None):
        try:
            template = self.env.get_template(template_name)
        except jinja2.TemplateNotFound:
            raise TemplateDoesNotExist(template_name)
        return template, template.filename

然后在template_loaders中添加该loader。并重新测试，结果如下：

Time taken for tests:   4.223 seconds
Complete requests:      1000
Failed requests:        100
   (Connect: 0, Receive: 0, Length: 100, Exceptions: 0)
Write errors:           0
Total transferred:      165887 bytes
HTML transferred:       3887 bytes
Requests per second:    236.78 [#/sec] (mean)
Time per request:       21.117 [ms] (mean)
Time per request:       4.223 [ms] (mean, across all concurrent requests)
Transfer rate:          38.36 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.2      0       2
Processing:    12   20   3.3     20      49
Waiting:       11   18   3.0     17      47
Total:         12   21   3.3     20      50

Percentage of the requests served within a certain time (ms)
  50%     20
  66%     21
  75%     22
  80%     23
  90%     24
  95%     26
  98%     29
  99%     34
 100%     50 (longest request)

　可见，总时间少了接近1秒！

对比图如下：

因此，django团队，在这块貌似还是没有采取与jinja2一样的技术或者机制咯。看来大有比较自己集成。