Spotify PKCE code_verifier 不正确 [英] Spotify PKCE code_verifier was incorrect

问题描述

听到我现在可以使用 Spotify Web API 而无需通过 PKCE 的后端应用程序，我感到很兴奋.不幸的是，我似乎有某种误解，无法让它发挥作用.

I was excited to hear that I can now use the Spotify web API without having a backend application via PKCE. Unfortunately, I seem to have some sort of misunderstanding and have been unable to get it to work.

一路上我很可能犯了一些小错误，但我犯了一次没有用，我把石板擦干净，再试一次，但仍然没有运气.由此我认为我一定是误解了 文档.

I am likely making some minor mistake along the way, but I did it once to no avail and I wiped the slate clean and tried again but still without luck. From this I gather that I must be misunderstanding the documentation.

我会解释我在做什么，希望这里有人能指出我遗漏了什么或做错了什么.我假设我有一个基本的概念误解.

I will explain what I am doing and hopefully someone here can point out what I'm missing or doing wrong. I'm assuming I have a fundamental conceptual misunderstanding.

我首先使用名为 crypto-random-string 的 npm 包生成一个加密随机字符串.我将它存储在浏览器的本地存储中，然后使用 js-sha256 对其进行哈希处理，然后使用另一个名为 base64url 的 npm 包对其进行编码.

I first generate a cryptographically random string using an npm package called crypto-random-string. I store that in the browser's local storage before using js-sha256 to hash it and then using another npm package called base64url to encode it.

    let verifier = cryptoRandomString({length: 50})
    window.localStorage.setItem('verifier', verifier)

    let params = {
      client_id: '[MY CLIENT ID]',
      response_type: 'code',
      redirect_uri: 'http://localhost:3000/callback',
      code_challenge_method: 'S256',
      code_challenge: base64url(sha256(verifier))
    }

    let endpoint = new URL('https://accounts.spotify.com/authorize');
    endpoint.search = new URLSearchParams(params);

    window.location = endpoint.toString();

从这里，我使用正确的 url 参数重定向到/authorize 端点.我已经成功地做到了这一点，然后被相应地重定向到我提供的 redirect_uri，在那里我从 url 参数中获取给定的代码.

From here, I redirect to the /authorize endpoint with the proper url parameters. I have gotten this far successfully and then been redirected accordingly to my provided redirect_uri, where I grab the given code from the url parameters.

此时，我尝试使用 client_id、grant_type、从 url 参数中获取的代码、我的 redirect_uri 和本地存储的 code_verifier 获取/api/token 端点.

At this point, I try the fetch to the /api/token endpoint with the client_id, grant_type, the code I got from the url params, my redirect_uri, and the locally stored code_verifier.

    let params = new URLSearchParams(window.location.search);
    console.log(params.get('code'));

    let newParams = {
      client_id: '[MY CLIENT ID]',
      grant_type: 'authorization_code',
      code: params.get('code'),
      redirect_uri: 'http://localhost:3000/callback',
      code_verifier: window.localStorage.getItem('verifier')
    }

    let endpoint = new URL('https://accounts.spotify.com/api/token');

    endpoint.search = new URLSearchParams(newParams);

    fetch(endpoint.toString(), {
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded'
      }
    }).then(data => data.json()).then(console.log)

此时，在我两次尝试后，我收到了错误:

At this point, after both of my attempts I received the error:

{ error: "invalid_grant", error_description: "code_verifier was incorrect" }

有什么我明显做错的地方吗?该错误使我相信就 code_verifier 的实际生成而言，我做错了什么，但我不知道该问题可能是什么.

Is there anything that I am obviously doing wrong? The error leads me to believe I'm doing something wrong as far as the actual generation of the code_verifier, but I am at a loss to what that issue may be.

推荐答案

Spotify 论坛上有人向我指出 这个 答案.不知道为什么，但按以下方式进行编码确实有效:

Someone on the Spotify forum pointed me to this answer. Not sure why exactly, but doing the encoding the following way does work:

    async function sha256(plain) {
      const encoder = new TextEncoder()
      const data = encoder.encode(plain)
    
      return window.crypto.subtle.digest('SHA-256', data)
    }
    
    function base64urlencode(a){
      return btoa(String.fromCharCode.apply(null, new Uint8Array(a))
        .replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '')
    }
    
    const hashed = await sha256(verifyCode)
    const codeChallenge = base64urlencode(hashed)

这篇关于Spotify PKCE code_verifier 不正确的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！