Google App Engine：通过 Blobstore 上传和转换用户个人资料照片

Question

我试图让每个用户上传一张个人资料照片，并将它们转换为 100x100 像素。

我创建了一个 ProfilePhoto 模型：

class ProfilePhoto(ndb.Model):
    user_key = ndb.KeyProperty()
    blob_key = ndb.BlobKeyProperty()
    serving_url = ndb.StringProperty()
    created = ndb.DateTimeProperty(auto_now_add = True)

上传处理程序：

class ProfilePhotoForm(BaseHandler):

    def get(self, user_id):
        user_id = int(user_id)
        if is_author:
            author_key = ndb.Key('Account', user_id)
            profile_photo = ProfilePhoto.query(ProfilePhoto.user_key == author_key).fetch()
            if profile_photo:
                photo_blob_key = profile_photo[0].blob_key
            else:
                photo_blob_key = None

            upload_url = blobstore.create_upload_url('/%s/upload' % user_id)

            user = User.get_by_id(int(user_id))
            self.render(
                'profile-photo-form.html', 
                user = user,
                upload_url = upload_url,
                photo_blob_key = photo_blob_key,
                profile_photo = profile_photo)
        else:
            self.write('You are not author.')

    def post(self, user_id):
        user_id = int(user_id)
        user = User.get_by_id(user_id)
        user.profile_photo = self.request.POST.get('profile_photo').file.read()
        user.put()
        self.redirect('/u/%s' % user_id)

那么UploadHandler和ServeHandler看起来是这样的：

class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):

    def post(self, user_id):
        user_key = ndb.Key('User', user_id)
        photo = self.get_uploads('profile_photo')
        if photo:
            existing_photos = ProfilePhoto.query(ProfilePhoto.user_key == user_key).fetch()
            if existing_photos:
                # Deleting previous user photos if they exist
                for e in existing_photos:
                    blobstore.delete(e.blob_key)
                    e.key.delete()

            photo_info = photo[0]

            serving_url = images.get_serving_url(photo_info.key())

            profile_photo = ProfilePhoto(
                user_key = ndb.Key('User', user_id), 
                blob_key = photo_info.key(),
                serving_url = serving_url)

            profile_photo.put()

            #self.redirect('/profile-photo/%s' % photo_info.key())
            self.redirect('/u/%s' % user_id)
        else:
            self.redirect('/u/%s' % user_id)


class ServeHandler(blobstore_handlers.BlobstoreDownloadHandler):

    def get(self, blob_key):
        blob_key = str(urllib.unquote(blob_key))
        blob_info = blobstore.BlobInfo.get(blob_key)
        self.send_blob(blob_info)

最后，表格如下所示：

<form action="{{upload_url}}" method="post" enctype="multipart/form-data">


            <label>Profile Photo<br> <input type="file" name="profile_photo"></label>

            {% if profile_photo %}
                <h4 class="sub-title">Current Photo</h4>
                <img src="/profile-photo/{{photo_blob_key}}" />
            {% endif %}

    <input type="Submit" value="Save">
</form>

图像当前在我的模板中输出如下：

<img src="/profile-photo/{{photo_blob_key}}" />

所以现在我已经收集到转换图像并将它们输出到我的模板的最佳方法是使用get_serving_url() 方法，但此时我对如何使用它感到很困惑。

Answer 1

在你的模板里放

<img src="{{ profile_photo.serving_url }}=s100">