所以我已经创建了一个pdf文档，它应该保存在媒体/帖子中。路径已经在函数中，但是pdf没有保存在那里，而是保存在主项目文件夹中。我在这里忽略了什么？
关于def的一点解释：帖子被创建并上传到提要，而帖子中的图像被重命名并放入另一个文件夹。另外，一个pdf文件也被创建，其中包含了发布的材料。我如何确定这个pdf文件在服务器上的位置？我以为它是用path_name和path_file解决的，但它不起作用。提前感谢。

def post_create(request):
    if request.method == 'POST':
        form = PostCreateForm(request.POST, request.FILES)

        if form.is_valid():
            form.cleaned_data['num_post'] = Post.objects.count() + 1
            Post.objects.create(**form.cleaned_data)
    else:
        form = PostCreateForm()

    return render(request, 'index.html', {'form': form})


def upload(request):
    if request.method == 'POST':
        image = request.FILES.get('image_upload')
        caption = request.POST['caption']
        num_post = Post.objects.count()+1
        new_post = Post.objects.create(image=image, caption=caption, num_post=num_post)
        new_post.save()


        #create pdf
        buffer = io.BytesIO()

        x_start = 100
        y_start = 10

        folder_path = f"media/postings/post{num_post}.pdf"
        folder_name = os.path.basename(folder_path)
        print(folder_path)
        p = canvas.Canvas(folder_name, pagesize=A4,)
        #p == request.FILES.get('postings')

        p.drawImage(ImageReader(image.file), x_start, y_start, width=420, preserveAspectRatio=True, mask='auto')
        p.drawString(150, 650, new_post.caption)
        p.drawString(100, 650, "caption:")
        p.drawString(100, 170, str(new_post.created_at))
        p.drawString(200, 700, str(num_post))
        p.drawString(100, 700, "post no.:")
        p.drawString(250, 700, "//")
        p.drawString(100, 690, "===========================================================")
        p.drawString(300, 700, str(new_post.id))
        #p.showPage()
        p.save()

        buffer.seek(0)
        #return render(request, '/', {'folder_name': folder_name, })
        return redirect('/'), folder_path

    else:
        return redirect('/')

class Post(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4)
    num_post = models.IntegerField(default=0)
    image = models.ImageField(upload_to=post_images)
    caption = models.TextField(max_length=300)
    created_at = models.DateTimeField(auto_now_add=True)
    number_of_likes = models.IntegerField(default=0)
    like_list = models.TextField(max_length=300)
    #likes_row = models.TextField(max_length=1000, default="hi")
    number_of_dislikes = models.IntegerField(default=0)
    interaction_count = models.IntegerField(default=0)
    #downloads = models.FileField(upload_to='postings', blank=True, null=True)

    @property
    def filename(self):
        return os.path.basename(self.image.name).split('.')[0]

    def __str__(self):
        return self.caption