flask 博客中的图像问题

class User(UserMixin, db.Model):__tablename__ = 'users'id = db.Column(db.Integer, primary_key=True)email = db.Column(db.String(64), unique=True, index=True)username = db.Column(db.String(64), unique=True, index=True)role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))password_hash = db.Column(db.String(128))confirmed = db.Column(db.Boolean, default=False)name = db.Column(db.String(64))location = db.Column(db.String(64))about_me = db.Column(db.Text())member_since = db.Column(db.DateTime(), default=datetime.utcnow)last_seen = db.Column(db.DateTime(), default=datetime.utcnow)avatar_hash = db.Column(db.String(32))

以上的avatar_hash  是数据库中的表示。  这个是 用户头像。  但是下面的例子是文章图片

2. 上传图像    

首先  表格Form

class PostForm(Form):avatar = FileField('Change the picture')name = StringField('What is your posts name?', validators=[Required()])body = PageDownField("What's on your mind?", validators=[Required()])submit = SubmitField('Submit')

3.视图函数 views

def index():form = PostForm()if current_user.can(Permission.WRITE_ARTICLES) and \form.validate_on_submit():post = Post(body=form.body.data, name=form.name.data,author=current_user._get_current_object())db.session.add(post)f = request.files['avatar']fname = secure_filename(f.filename)if fname != '':UPLOAD_FOLDER = '\\app\\static\\avatar\\'f.save(os.getcwd() + UPLOAD_FOLDER + post.name + "_" + fname)post.avatar_hash = post.name + "_" + fnamereturn redirect(url_for('.index'))

<div class="post-thumbnail"><a href="{
   { url_for('.user', username=post.author.username) }}">{% if post.avatar_hash != 'None' %}<img style="width:45px; height:45px"src={
   {url_for('static',filename='avatar/' + post.avatar_hash)}}>            </a>{%else%}<img style="width:45px; height:45px"src={
   {url_for('static',filename='avatar/123.jpg')}}>{% endif%}</div>