使用Next.js调用LinkedIn API自动发帖遇422错误求排查

问题背景 #

我用Next.js搭建了Web应用，想实现发布新内容时自动同步到自己的LinkedIn主页。已经创建了LinkedIn App，拿到了Client ID和Client Secret，但找到的资料都是针对代其他用户发帖的OAuth场景，不符合我给自己主页发帖的需求。按照方案写了调用代码后，接口返回422 Unprocessable Entity。

调用代码 #

const linkedinPost = await fetch(`https://api.linkedin.com/v2/ugcPosts`, {
        method: "post",
        headers: {
          "Authorization": `Bearer ${process.env.NEXT_PUBLIC_LINKEDIN_ACCESS_TOKEN_DRJ_2}`,
          "Content-Type": "application/json"
        }, 
        body: JSON.stringify({
          "author": "urn:li:person:8675309",
          "lifecycleState": "PUBLISHED",
          "specificContent": {
              "com.linkedin.ugc.ShareContent": {
                  "shareCommentary": {
                      "text": "This text is to be posted",
                  },
                  "shareMediaCategory": "NONE"
              }
          },
          "visibility": {
              "com.linkedin.ugc.MemberNetworkVisibility": "PUBLIC"
          }
        })
      });

响应日志 #

Response {
  [Symbol(realm)]: null,
  [Symbol(state)]: {
    aborted: false,
    rangeRequested: false,
    timingAllowPassed: true,
    requestIncludesCredentials: true,
    type: 'default',
    status: 422,
    timingInfo: {
      startTime: 492846.5113720894,
      redirectStartTime: 0,
      redirectEndTime: 0,
      postRedirectStartTime: 492846.5113720894,
      finalServiceWorkerStartTime: 0,
      finalNetworkResponseStartTime: 0,
      finalNetworkRequestStartTime: 0,
      endTime: 0,
      encodedBodySize: 0,
      decodedBodySize: 0,
      finalConnectionTimingInfo: null
    },
    cacheState: '',
    statusText: 'Unprocessable Entity',
    headersList: HeadersList {
      cookies: [Array],
      [Symbol(headers map)]: [Map],
      [Symbol(headers map sorted)]: null
    },
    urlList: [ URL {} ],
    body: { stream: undefined }
  },
  [Symbol(headers)]: HeadersList {
    cookies: [
      'bcookie="v=2&07f3a4fc-656e-4486-8277-7f8de8a53e92"; domain=.linkedin.com; Path=/; Secure; Expires=Thu, 05-Dec-2024 10:13:09 GMT; SameSite=None',
      'lidc="b=OB72:s=O:r=O:a=O:p=O:g=3281:u=14:x=1:i=1701857588:t=1701859352:v=2:sig=AQFr_d1F9snHikizALVmxzSowEosPeV0"'
    ],
    [Symbol(headers map)]: Map(14) {
      'x-li-responseorigin' => [Object],
      'content-type' => [Object],
      'x-linkedin-error-response' => [Object],
      'x-restli-gateway-error' => [Object],
      'x-restli-protocol-version' => [Object],
      'content-length' => [Object],
      'date' => [Object],
      'connection' => [Object],
      'x-li-fabric' => [Object],
      'x-li-pop' => [Object],
      'x-li-proto' => [Object],
      'x-li-uuid' => [Object],
      'set-cookie' => [Object],
      'x-li-route-key' => [Object]
    },
    [Symbol(headers map sorted)]: null
  }
}

可能的原因及解决方法 #

1. 请求体存在语法错误 #

代码中shareCommentary.text字段末尾多了一个逗号："text": "This text is to be posted",，严格的JSON解析会识别为语法错误，导致接口无法处理请求。去掉该逗号即可。

2. 缺少必要的请求头 #

LinkedIn UGC Posts API要求必须携带X-Restli-Protocol-Version头，值为2.0.0，否则会返回格式错误。在headers中添加该字段。

3. Access Token权限不足 #

发布内容到自己主页需要w_member_social权限，若获取token时未申请该权限，接口会拒绝请求。需重新生成包含该权限的access token。

4. Author URN错误 #

author字段的urn:li:person:8675309是示例ID，需替换为你自己的LinkedIn用户ID。可以通过LinkedIn的用户信息接口获取自己的正确ID。

5. Access Token暴露风险（额外提示） #

不要用NEXT_PUBLIC_开头的环境变量存储access token，这类变量会暴露在客户端代码中，导致token泄露。应将接口调用放在Next.js的API路由中，使用普通环境变量存储敏感信息。

修改后的示例代码 #

const linkedinPost = await fetch(`https://api.linkedin.com/v2/ugcPosts`, {
  method: "post",
  headers: {
    "Authorization": `Bearer ${process.env.LINKEDIN_ACCESS_TOKEN}`,
    "Content-Type": "application/json",
    "X-Restli-Protocol-Version": "2.0.0"
  }, 
  body: JSON.stringify({
    "author": "urn:li:person:你的真实用户ID",
    "lifecycleState": "PUBLISHED",
    "specificContent": {
        "com.linkedin.ugc.ShareContent": {
            "shareCommentary": {
                "text": "This text is to be posted"
            },
            "shareMediaCategory": "NONE"
        }
    },
    "visibility": {
        "com.linkedin.ugc.MemberNetworkVisibility": "PUBLIC"
    }
  })
});

// 建议添加响应解析，查看具体错误信息
const responseData = await linkedinPost.json();
console.log(responseData);

内容的提问来源于stack exchange，提问作者26ph19