Google App Engine JSON属性错误

我只是一个初学者在python/json。我有一个html文档，基本上允许人们输入（1）类名和（1）prereq。在我的post方法中，我试图创建一个新的字典，添加（键）类名和（值）prereq。但是我得到这个追溯错误：Google App Engine JSON属性错误

Traceback (most recent call last): 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2- .5.2\webapp2.py", line 1535, in __call__ 
rv = self.handle_exception(request, response, e) 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2- 2.5.2\webapp2.py", line 1529, in __call__ 
rv = self.router.dispatch(request, response) 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1278, in default_dispatcher 
return route.handler_adapter(request, response) 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1102, in __call__ 
return handler.dispatch() 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 572, in dispatch 
return self.handle_exception(e, self.app.debug) 
File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 570, in dispatch 
return method(*args, **kwargs) 
File "C:\Users\Desktop\classes\main.py", line 27, in post 
self.response.write(template.render(extracted_output)) 
File "C:\Program Files (x86)\Google\google_appengine\lib\jinja2-2.6\jinja2\environment.py", line 889, in render 
vars = dict(*args, **kwargs) 
ValueError: dictionary update sequence element #0 has length 1; 2 is required

另一个问题是，当我创建一个新的Class_Name对象，是class_title自动将JsonProperty？

class Class_Name(ndb.Model): 
    class_title = ndb.JsonProperty() 

def post(self): 
    classname = self.request.get('classname') 
    prereq = self.request.get('prereq') 
    new_dictionary = {} 
    new_dictionary [classname] = prereq 
    new_class = Class_Name(class_title = new_dictionary) 
    new_class.put() 
    dictionary_extracted = new_class.class_title 
    extracted_output = json.dumps(dictionary_extracted) 
    template = jinja2_environment.get_template('template/post.html') 
    self.response.write(template.render(extracted_output))

来源

2015-08-28 amay20

'template.render'需要一个字典或kwargs来定义模板变量，但是你已经传递了一个'json'字符串。模板期望什么变量名称？ –

为我的'模板/ post.html'，我所做的就是打印字典这样{{extracted_output}} – amay20

在您的代码段：

extracted_output = json.dumps(dictionary_extracted) 
template = jinja2_environment.get_template('template/post.html') 
self.response.write(template.render(extracted_output))

json.dumps返回一个字符串 - 然后你传递只是串到template.render ...永远无法工作！

如果，你在评论说，（你应该修改你的问题，以使其更清晰！），你的模板包含为{{extracted_output}}，那么这个变量名必须传递给render，即最后一条语句必须变成

self.response.write(template.render(extracted_output=extracted_output))

来源

2015-08-28 22:25:51

谢谢我让我的程序工作！ – amay20

Google App Engine JSON属性错误

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