如何在Django中自定义小部件的html输出？

Question

我在文档中找不到这个,但认为它一定是可能的.我正在谈论ClearableFileInput小部件.从django 1.2.6中的项目我有这样的形式:

# the profile picture upload form
class ProfileImageUploadForm(forms.ModelForm):
    """
    simple form for uploading an image. only a filefield is provided
    """
    delete = forms.BooleanField(required=False,widget=forms.CheckboxInput())

    def save(self):
        # some stuff here to check if "delete" is checked
        # and then delete the file
        # 8 lines

    def is_valid(self):
        # some more stuff here to make the form valid
        # allthough the file input field is empty
        # another 8 lines

    class Meta:
        model = SocialUserProfile
        fields = ('image',)

然后我使用此模板代码呈现:

<form action="/profile/edit/" method="post" enctype="multipart/form-data">
    Delete your image:
<label> {{ upload_form.delete }} Ok, delete </label>
<button name="delete_image" type="submit" value="Save">Delete Image</button>
    Or upload a new image:
    {{ upload_form.image }}
    <button name="upload_image" type="submit" value="Save">Start Upload</button>
{% csrf_token %}
</form>

由于Django 1.3.1现在使用ClearableFileInput作为默认小部件,我很确定我可以跳过我的form.save的16行,只是缩短表单代码,如下所示:

# the profile picture upload form
class ProfileImageUploadForm(forms.ModelForm):
    """
    simple form for uploading an image. only a filefield is provided
    """

    class Meta:
        model = SocialUserProfile
        fields = ('image',)

这会给我一种良好的感觉,我有较少的自定义表单代码,并可以依赖Django内置.

当然,我想保持html输出和以前一样.当只使用现有的模板代码时,会弹出我不想要的地方,例如"Currently:somefilename.png".

进一步分割形式,{{ upload_form.image.file }}似乎似乎没有工作.我想到的下一件事就是编写一个自定义小部件.这将完全违背我努力删除尽可能多的自定义代码.

任何想法在这种情况下最简单的事情是什么？

Answer 1

首先,widgets.py在应用程序中创建一个文件.对于我的例子,我会让你成为一个AdminImageWidget延伸的课程AdminFileWidget.基本上,我想要一个图像上传字段,在<img src="" />标签中显示当前上传的图像,而不是仅输出文件的路径.

将以下类放在您的widgets.py文件中:

from django.contrib.admin.widgets import AdminFileWidget
from django.utils.translation import ugettext as _
from django.utils.safestring import mark_safe
import os
import Image

class AdminImageWidget(AdminFileWidget):
    def render(self, name, value, attrs=None):
        output = []
        if value and getattr(value, "url", None):

            image_url = value.url
            file_name=str(value)

            # defining the size
            size='100x100'
            x, y = [int(x) for x in size.split('x')]
            try :
                # defining the filename and the miniature filename
                filehead, filetail  = os.path.split(value.path)
                basename, format        = os.path.splitext(filetail)
                miniature                   = basename + '_' + size + format
                filename                        = value.path
                miniature_filename  = os.path.join(filehead, miniature)
                filehead, filetail  = os.path.split(value.url)
                miniature_url           = filehead + '/' + miniature

                # make sure that the thumbnail is a version of the current original sized image
                if os.path.exists(miniature_filename) and os.path.getmtime(filename) > os.path.getmtime(miniature_filename):
                    os.unlink(miniature_filename)

                # if the image wasn't already resized, resize it
                if not os.path.exists(miniature_filename):
                    image = Image.open(filename)
                    image.thumbnail([x, y], Image.ANTIALIAS)
                    try:
                        image.save(miniature_filename, image.format, quality=100, optimize=1)
                    except:
                        image.save(miniature_filename, image.format, quality=100)

                output.append(u' <div><a href="%s" target="_blank"><img src="%s" alt="%s" /></a></div> %s ' % \
                (miniature_url, miniature_url, miniature_filename, _('Change:')))
            except:
                pass
        output.append(super(AdminFileWidget, self).render(name, value, attrs))
        return mark_safe(u''.join(output))

好的,那么这里发生了什么？

1. 我导入一个现有的小部件(你可能从头开始,但是如果你正在开始那么应该能够扩展ClearableFileInput)
2. 我只想改变小部件的输出/表示,而不是底层逻辑.所以,我重写了widget的render功能.
3. 在渲染函数中,我构建了我想要的输出作为一个数组,output = []你不必这样做,但它节省了一些连接.3个关键线:
   • output.append(u' <div><a href="%s" target="_blank"><img src="%s" alt="%s" /></a></div> %s ' % (miniature_url, miniature_url, miniature_filename, _('Change:'))) 向输出添加img标记
   • output.append(super(AdminFileWidget, self).render(name, value, attrs)) 将父级的输出添加到我的小部件
   • return mark_safe(u''.join(output)) 用空字符串连接我的输出数组并在显示之前免除它的转义

我该如何使用它？

class SomeModelForm(forms.ModelForm):
    """Author Form"""
    photo = forms.ImageField(
        widget = AdminImageWidget()
    )

    class Meta:
        model = SomeModel

要么

class SomeModelForm(forms.ModelForm):
    """Author Form"""
    class Meta:
        model = SomeModel
        widgets = {'photo' : AdminImageWidget(),}

这给了我们: