Django ORM性能优化和图片验证码

发布时间：2020-12-17 00:03:03 所属栏目：Python 来源：网络整理

导读：= models.User.objects.all().values( , , 2 = 3. select_related(外键/一对一) --> = models.User.objects.all().select_related( 4. prefetch_related( ) --> = models.User.objects.all().prefetch_related( 5. only( ) --> = models.User.objects.all().

= models.User.objects.all().values(,,2=3. select_related(外键/一对一) -->= models.User.objects.all().select_related(4. prefetch_related() -->= models.User.objects.all().prefetch_related(5. only() -->= models.User.objects.all().only(= models.User.objects.all().defer()

def get_vcode():
tmp = []
for i in range(5):
l = chr(random.randint(97,122)) # 生成随机的小写字母
u = chr(random.randint(65,90)) # 生成随机的大写字母
n = str(random.randint(0,9)) # 生成一个随机的数字
# 从上面三个随机选一个
r = random.choice([l,u,n])
tmp.append(r)
return "".join(tmp)

if name == 'main':
ret = get_vcode()
print(ret)

PIL def random_color():
return random.randint(0,255),random.randint(0,255)

def vcode():
# 创建一个随机颜色的图片对象
image_obj = Image.new(
"RGB",(250,35),random_color()
)

with open(</span><span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;static/imgs/vcode.png</span><span style="color: #800000;"&gt;"</span>,<span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;wb</span><span style="color: #800000;"&gt;"</span><span style="color: #000000;"&gt;) as f1:
    image_obj.save(f1,format</span>=<span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;PNG</span><span style="color: #800000;"&gt;"</span><span style="color: #000000;"&gt;)

</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 在该图片对象上生成一个画笔对象</span>
draw_obj =<span style="color: #000000;"&gt; ImageDraw.Draw(image_obj)
</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 加载一个字体对象</span>
font_obj = ImageFont.truetype(<span style="color: #800000;"&gt;'</span><span style="color: #800000;"&gt;static/font/kumo.ttf</span><span style="color: #800000;"&gt;'</span>,28<span style="color: #000000;"&gt;)
tmp </span>=<span style="color: #000000;"&gt; []
</span><span style="color: #0000ff;"&gt;for</span> i <span style="color: #0000ff;"&gt;in</span> range(5<span style="color: #000000;"&gt;):
    l </span>= chr(random.randint(97,n])
    draw_obj.text((i </span>* 45 + 30,0),r,fill=random_color(),font=<span style="color: #000000;"&gt;font_obj,)

with open(</span><span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;static/imgs/vcode.png</span><span style="color: #800000;"&gt;"</span>,format</span>=<span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;PNG</span><span style="color: #800000;"&gt;"</span><span style="color: #000000;"&gt;)

# 专门返回验证码图片的视图函数
def vcode(request):
from PIL import Image,ImageFont

</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 定义一个生成随机颜色代码的函数</span>
<span style="color: #0000ff;"&gt;def</span><span style="color: #000000;"&gt; random_color():
    </span><span style="color: #0000ff;"&gt;return</span> random.randint(0,255<span style="color: #000000;"&gt;)

</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 创建一个随机颜色的图片对象</span>
image_obj =<span style="color: #000000;"&gt; Image.new(
    </span><span style="color: #800000;"&gt;"</span><span style="color: #800000;"&gt;RGB</span><span style="color: #800000;"&gt;"</span><span style="color: #000000;"&gt;,random_color()
)
</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 在该图片对象上生成一个画笔对象</span>
draw_obj =<span style="color: #000000;"&gt; ImageDraw.Draw(image_obj)
</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 加载一个字体对象</span>
font_obj = ImageFont.truetype(<span style="color: #800000;"&gt;'</span><span style="color: #800000;"&gt;static/font/kumo.ttf</span><span style="color: #800000;"&gt;'</span>,n])
    </span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; 将选中过的那个字符写到图片上</span>
    draw_obj.text((40 * i + 30,font=<span style="color: #000000;"&gt;font_obj)
    tmp.append(r)

</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; # 加干扰线</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; width = 250  # 图片宽度（防止越界）</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; height = 35</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; for i in range(5):</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     x1 = random.randint(0,width)</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     x2 = random.randint(0,width)</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     y1 = random.randint(0,height)</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     y2 = random.randint(0,height)</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     draw_obj.line((x1,y1,x2,y2),fill=random_color())</span>
<span style="color: #008000;"&gt;#

# # 加干扰点
# for i in range(40):
# draw_obj.point([random.randint(0,width),height)],fill=random_color())
# x = random.randint(0,width)
# y = random.randint(0,height)
# draw_obj.arc((x,y,x+4,y+4),90,fill=random_color())

v_code = "".join(tmp).upper()
# 将生成的验证码保存
request.session["v_code"] = v_code

</span><span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt; with open("static/images/vcode.png","wb") as f1:</span>
<span style="color: #008000;"&gt;#</span><span style="color: #008000;"&gt;     image_obj.save(f1,format="PNG")</span>
<span style="color: #008000;"&gt;#

# with open("static/images/vcode.png","rb") as f:
# img_data = f.read()
# 直接在内存中保存图片替代io操作
from io import BytesIO
f1 = BytesIO()
image_obj.save(f1,format="PNG")
img_data = f1.getvalue()
return HttpResponse(img_data,content_type="image/png")

vcode()

（编辑：李大同）

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Django ORM性能优化 和 图片验证码

Django ORM性能优化和图片验证码