博客经常需要给文章配图。我加入图片附件模型，并把图片写入阿里云 OSS。五个配置全部来自环境变量，密钥不写进代码。
上传链路是 Django 收文件，ImageField 校验图片，自定义 Storage 调用 OSS SDK，数据库只保存对象键。
自定义 Storage
新建 blog/storage.py，继承 django.core.files.storage.Storage。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
| import os
import oss2
from django.core.exceptions import ImproperlyConfigured
from django.core.files.storage import Storage
from django.utils.deconstruct import deconstructible
@deconstructible
class AliyunOSSStorage(Storage):
def _config(self):
keys = ["OSS_ACCESS_KEY_ID", "OSS_ACCESS_KEY_SECRET", "OSS_BUCKET_NAME", "OSS_ENDPOINT", "OSS_REGION"]
values = {key: os.environ.get(key) for key in keys}
missing = [key for key, value in values.items() if not value]
if missing:
raise ImproperlyConfigured("缺少 OSS 环境变量：" + ", ".join(missing))
return values
def _bucket(self):
config = self._config()
auth = oss2.ProviderAuthV4(oss2.credentials.EnvironmentVariableCredentialsProvider())
endpoint = config["OSS_ENDPOINT"]
if not endpoint.startswith(("http://", "https://")):
endpoint = "https://" + endpoint
return oss2.Bucket(auth, endpoint, config["OSS_BUCKET_NAME"], region=config["OSS_REGION"])
|
@deconstructible 不能少。没有它，Django 生成迁移时无法序列化 storage=AliyunOSSStorage()。
保存文件时生成新对象键。
1
2
3
4
5
6
7
8
| from datetime import datetime
from uuid import uuid4
def _save(self, name, content):
ext = os.path.splitext(name)[1].lower()
key = f"blog/attachments/{datetime.now():%Y%m%d}/{uuid4().hex}{ext}"
self._bucket().put_object(key, content.read())
return key
|
用 UUID 命名可以避免覆盖。原文件名不再出现在对象键里，数据库里的 title 负责给人看。
附件模型和后台
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| from django.db import models
from .storage import AliyunOSSStorage
class Attachment(models.Model):
post = models.ForeignKey(
Post, verbose_name="文章", on_delete=models.CASCADE,
related_name="attachments",
)
image = models.ImageField(
"图片", upload_to="blog/attachments/", storage=AliyunOSSStorage()
)
title = models.CharField("标题", max_length=80, blank=True)
uploaded_by = models.ForeignKey(
"auth.User", verbose_name="上传人", on_delete=models.CASCADE
)
created_at = models.DateTimeField("创建时间", auto_now_add=True)
|
ImageField 会检查上传内容能不能作为图片打开。post 用 PROTECT 也可以，这里选择 CASCADE，表示附件是文章的一部分。
Admin 注册很直接。
1
2
3
4
| @admin.register(Attachment)
class AttachmentAdmin(admin.ModelAdmin):
list_display = ["title", "post", "uploaded_by", "created_at"]
raw_id_fields = ["post"]
|
详情页展示附件。
1
2
3
4
5
6
7
8
9
10
| {% if post.attachments.all %}
<div class="attachments">
{% for attachment in post.attachments.all %}
<figure>
<img src="{{ attachment.image.url }}" alt="{{ attachment.title|default:attachment.image.name }}">
{% if attachment.title %}<figcaption>{{ attachment.title }}</figcaption>{% endif %}
</figure>
{% endfor %}
</div>
{% endif %}
|
测试时不请求阿里云
测试用本地 FileSystemStorage 替换字段上的存储，验证 Django 模型和上传流程。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
| from django.core.files.storage import FileSystemStorage
from django.core.files.uploadedfile import SimpleUploadedFile
png = bytes.fromhex("89504e470d0a1a0a0000000d49484452000000010000000108060000001f15c4890000000a49444154789c6300010000050001")
original = Attachment._meta.get_field("image").storage
with tempfile.TemporaryDirectory() as root:
Attachment._meta.get_field("image").storage = FileSystemStorage(location=root)
try:
attachment = Attachment.objects.create(
post=post,
uploaded_by=user,
title="结构图",
image=SimpleUploadedFile("diagram.png", png, content_type="image/png"),
)
self.assertTrue(Path(attachment.image.path).exists())
finally:
Attachment._meta.get_field("image").storage = original
|
真实上传由 OSS SDK 完成，单元测试不重复测试 SDK。它要证明的是模型、字段和存储接口接得正确。
运行迁移和测试。
1
2
3
4
| uv add Pillow oss2
uv run manage.py makemigrations blog
uv run manage.py migrate
uv run manage.py test
|
迁移输出如下。
1
2
3
| Migrations for 'blog':
blog\migrations\0005_attachment.py
+ Create model Attachment
|
测试结果如下。
1
2
3
| Ran 26 tests in 5.135s
OK
|
运行前导出五个环境变量。.env 不进入 Git。
1
2
3
4
5
| export OSS_ACCESS_KEY_ID=...
export OSS_ACCESS_KEY_SECRET=...
export OSS_BUCKET_NAME=...
export OSS_ENDPOINT=...
export OSS_REGION=...
|
图片上传到 OSS 后，详情页只引用远端 URL。Django 进程不长期保存文件，也不把桶地址和密钥混进数据库。
源码
GitHub 地址：https://github.com/yidao620c/simpleblog
