django上传图片

这两天一直在琢磨django上传图片的做法，网上找到一堆资料都不行。

不过功夫不负有心人，我找啊找，终于发现了新大陆，找到一张老外的帖子，解决问题。

下面我们以一个例子来讲解一下这个过程。

1.首先要创建Photo的模型，比如：

class Photo(models.Model):
    item = models.ForeignKey(Item)
    title = models.CharField(max_length=100)
    image = ThumbnailImageField(upload_to='photos')
    caption = models.CharField(max_length=250, blank=True)
    slug = models.SlugField(max_length=40)
        
    class Meta:
        ordering = ['title']
        
    def __unicode__(self):
        return self.title

    @permalink
    def get_absolute_url(self):
        return ('photo_detail', None, {'slug': self.slug})

这里还用到一个Item类和一个ThumbnailImageField类。Item类类似于专辑，收着好多图片；而ThumbnailImageField主要是用来展示缩略图的，在上传图片时不仅保存原文件，还保存一个缩略图副本。

class Item(models.Model):
    name = models.CharField(max_length=250)
    description = models.TextField()
    slug = models.SlugField(max_length=40)

    class Meta:
        ordering = ['name']
        
    def __unicode__(self):
        return self.name
        
    @permalink
    def get_absolute_url(self):
        return ('item_detail', None, {'slug': self.slug})

class ThumbnailImageFieldFile(ImageFieldFile):
    def _get_thumb_path(self):
        return _add_thumb(self.path)
    thumb_path = property(_get_thumb_path)
    
    def _get_thumb_url(self):
        return _add_thumb(self.url)
    thumb_url = property(_get_thumb_url)

    def save(self, name, content, save=True):
        super(ThumbnailImageFieldFile, self).save(name, content, save)
        img = Image.open(self.path)
        img.thumbnail(
            (self.field.thumb_width, self.field.thumb_height),
            Image.ANTIALIAS
        )
        print self.thumb_path
        print self.thumb_url
        img.save(self.thumb_path, 'JPEG')

    def delete(self, save=True):
        if os.path.exists(self.thumb_path):
            os.remove(self.thumb_path)
        super(ThumbnailImageFieldFile, self).delete(save)

可以看到，在Photo里面Item是作为外码出现的，所以在上传图片时首先要有一个item。但是如果你想体验简单的上传图片的功能的话，把外码去掉或者把item属性去掉，然后适当改改下面的处理函数就OK了。

2.创建与模型相对应的PhotoForm

class PhotoForm(forms.Form):
    item = models.ForeignKey(Item)
    title = models.CharField(max_length=100)
    image = ThumbnailImageField(upload_to='photos')
    caption = models.CharField(max_length=250, blank=True)
    slug = models.SlugField(max_length=40)

3.在add_photo.html中创建一个表单form，加入要Photo模型对应的属性域：

<form action="/add_photo/" method="POST" enctype="multipart/form-data">
			<div class="inline-group" id="photo_set-group">
				<h2>Photos</h2>
				<div class="inline-related dynamic-photo_set" id="photo_set-0">
					<h3> <b>Photo:</b>
						 
						<span class="inline_label">#1</span>
					</h3>
					<fieldset class="module aligned ">
						<div class="form-row field-item">
							<div>
								<label class="required" for="id_item">Item:</label>
								<select id="id_item" name="item">
									<!-- 动态加载所有的item -->
									<option value="" selected="selected">---------</option>
									<option value="3">default</option>
								</select>
							</div>
						</div>
						<div class="form-row field-title">
							<div>
								<label class="required" for="id_title">Title:</label>
								<input class="vTextField" id="id_title" maxlength="100" name="title" type="text"></div>
						</div>
						<div class="form-row field-image">
							<div>
								<label class="required" for="id_image">Image:</label>
								<input id="id_image" name="image" type="file"></div>
						</div>
						<div class="form-row field-caption">
							<div>
								<label for="id_caption">Caption:</label>
								<input class="vTextField" id="id_caption" maxlength="250" name="caption" type="text"></div>
						</div>
						<div class="form-row field-slug">
							<div>
								<label class="required" for="id_slug">Slug:</label>
								<input class="vTextField" id="id_slug" maxlength="40" name="slug" type="text"></div>
						</div>
					</fieldset>
					<div class="submit-row">
						<input type="submit" value="保存" class="default" name="_save"></div>
				</div>
			</div>
		</div>
	</form>

4.在views.py中添加处理函数，比如用户提交后就让add_photo()来处理

def add_photo(request):
	if request.method == 'POST':
		# 往数据表中添加一行记录，并保存文件
		form = PhotoForm(request.POST,request.FILES)
		if form.is_valid():
			#往数据表中添加一行记录
			item_id = request.POST['item'] #获取item的id值
			title = request.POST['title']
			caption = request.POST['caption']
			slug = request.POST['slug']
			image = 'photos/%s' % request.FILES['image']
			photo = Photo(item_id=item_id, title=title, image=image, caption=caption, slug=slug)
			photo.save()
			# 保存文件到本地计算机
			obj = Photo.objects.get(id=item_id)
			file_content = ContentFile(request.FILES['image'].read())
			obj.image.save(request.FILES['image'].name, file_content)
		return HttpResponseRedirect('/gallery/items/')
	else:
		return render_to_response('add_photo.html')

这样就算大功告成了。