1

我是谷歌应用引擎的新手。

我已将图像存储在 blob 字段中。我正在尝试获取显示错误的图像。

下面我粘贴了我的代码和输出。

主文件

import cgi 
import webapp2
from google.appengine.api import users
from google.appengine.ext.webapp.template \
    import render
from os import path
from google.appengine.ext import db
from google.appengine.api import images
import urllib
import re
import datetime



class imgstore(db.Model):
    name=db.StringProperty(multiline=True, default='')
    image=db.BlobProperty()


class MainHandler(webapp2.RequestHandler):
    def get(self):
        moviequery=db.GqlQuery('SELECT * FROM imgstore')
        context={
                'list':moviequery
                }   
        tmpl = path.join(path.dirname(__file__), 'static/html/index.html')
        self.response.out.write(render(tmpl, context))

    def post(self):
       name1 =images.resize(self.request.get("file"), 32, 32) 
       formdata = db.Blob(name1)
       insert = imgstore()
       insert.name="name"
       insert.image=formdata
       insert.put()


routes=[
        (r'/', MainHandler),
        ]
app = webapp2.WSGIApplication(routes=routes,debug=True)

索引.html

> <html>
>     <head><title>test</title></head>
>     <body>hello
>        <form id="form" action="/" method="post" ENCTYPE="multipart/form-data">
>            <input type="file" name="file" >
>            <input type="submit" name="submit">
>        </form>
>        {% for lis in list%}
>        <img src="{{lis.image}}">
>        {% endfor %}
>     </body>
>         </html>

输出

Traceback (most recent call last):
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1536, in __call__
    rv = self.handle_exception(request, response, e)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1530, in __call__
    rv = self.router.dispatch(request, response)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/Users/saravase/test/main.py", line 44, in get
    self.response.out.write(render(tmpl, context))
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/webapp/template.py", line 92, in render
    return t.render(Context(template_dict))
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/webapp/template.py", line 172, in wrap_render
    return orig_render(context)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 173, in render
    return self._render(context)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 167, in _render
    return self.nodelist.render(context)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 794, in render
    bits.append(self.render_node(node, context))
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 807, in render_node
    return node.render(context)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/defaulttags.py", line 173, in render
    nodelist.append(node.render(context))
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 847, in render
    return _render_value_in_context(output, context)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/template/__init__.py", line 827, in _render_value_in_context
    value = force_unicode(value)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/_internal/django/utils/encoding.py", line 88, in force_unicode
    raise DjangoUnicodeDecodeError(s, *e.args)
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请指导我如何进一步进行。

4

1 回答 1

1

你需要做两件事。首先，您需要更改您的 HTML，以便src标记的img包含由您的应用程序提供的 URL。其次，您需要实现一个处理程序来为 URL 提供服务。

假设您的应用程序将使用如下 URL 提供存储的图像：/image/15其中 15 是id实体的imgstore。您需要添加一条路线：

routes=[
        (r'/image/(\d+)', ImageHandler),
        (r'/', MainHandler),
        ]
app = webapp2.WSGIApplication(routes=routes,debug=True)

然后你需要添加一个新的 RequestHandler 类：

class ImageHandler(webapp2.RequestHandler):
    def get(self, image_id):
        requestedImage = imgstore.get_by_id(int(image_id))
        if requestedImage is not None:
            self.response.out.write(requestedImage.image)
        else:
            # return a default image when we can't located the
            # one that was requested?

新路由包括一个数字捕获——(\d+)将作为参数传递给请求处理程序。然后我们可以使用该 id 直接从数据存储中获取图像实体；它比使用查询快得多。

那么，我们从哪里得到 id 呢？数据存储中的每个实体都会自动分配一个整数 ID，除非您在存储它时为其指定一个 ID 或名称。

您需要做的最后一件事是提供一种简单的方法，将用于为您的图像提供服务的 URL 嵌入到包含img标签的模板中。向您的 imgstore 类添加一个方法：

class imgstore(db.Model):
    name=db.StringProperty(multiline=True, default='')
    image=db.BlobProperty()

    def url_for(self):
        return "/image/%d" % self.id

现在您可以更改模板以使用新方法：

<img src="{{lis.url_for}}">
于 2012-07-25T14:31:34.713 回答