Firebase提取-禁止访问控制-允许起源 [英] Firebase Fetch - No Access-Control-Allow-Origin

问题描述

我正在使用 React + Redux 开发一个应用程序，并且在 Firebase 数据库中有我的 JSON 数据库.为此，我尝试从有效的URL(已通过Firebase模拟器验证)获取我的数据

I'm developing an app with React + Redux and I have my JSON database within a Firebase DB. To do this I'm tryin to fetch my data from a valid URL (validated from Firebase simulator)

let firebase = 'https://******.firebaseio.com/**/*/***/*' 
    return (dispatch) => {
        return fetch(firebase)
            .then(res => res.json())
            .then(json => dispatch({ type: 'GET_JSON', payload: json }))
    }

这向我返回错误:

Fetch API无法加载/database/data///** /"已被CORS策略阻止:所请求的资源上没有"Access-Control-Allow-Origin"标头.因此，不允许访问原始空".如果不透明的响应满足您的需求，请将请求的模式设置为"no-cors"，以在禁用CORS的情况下获取资源.

Fetch API cannot load https://console.firebase.google.com/project/****/database/data/**/*/***/*. Redirect from 'https://console.firebase.google.com/project//database/data/**///' to 'https://accounts.google.com/ServiceLogin?ltmpl=firebase&osid=1&passive=true…ole.firebase.google.com/project//database/data///**/' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.`

我尝试了许多解决方案，例如将fetch的第二个参数添加到 {模式:'no-cors'，凭据:'same-origin'} ，但是当我尝试这样做时，我得到了未捕获(承诺)SyntaxError:输入意外结束.

I've tried many solutions, like adding to fetch's second argument { mode: 'no-cors', credentials: 'same-origin'}, but when I try this i get Uncaught (in promise) SyntaxError: Unexpected end of input.

我想念什么?

推荐答案

likely error that arise to  cors blocked when using firebase is
when you initiate a put or get request with an incomplete firebase url
e.g
// wrong form
 this.http.get('https://******.firebaseio.com/data')   //this will throw an exception

// correct form                                                    
  this.http.get('https://******.firebaseio.com/data.json')

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