使用Python调用LinkedIn API上传图片时遇400错误：请求体不可为空

问题详情 #

完成图片上传初始化步骤后，执行图片上传时收到400错误响应：

{
"message": "Empty entity body is not allowed for create method request",
"status": 400
}

相关代码 #

image_post方法 #

def image_post(self, image_title, image_url, return_urn=False):
        url = f"{LINKEDIN_URL}images?action=initializeUpload"

        payload = {
            "initializeUploadRequest": {
                "owner": self.__linkedin_urn
            }
        }

        response_init = requests.post(url=url, headers=self.__headers, json=payload)

        LOGGER.info(response_init.json())
        LOGGER.info(response_init.status_code)

        try:
            response_json = response_init.json()
            upload_url = response_json['value']['uploadUrl']
            image = response_json['value']['image']

            mimetype, _ = mimetypes.guess_type(image_url)
            headers = {
                'Authorization': 'Bearer Redacted',
                'Content-Type': mimetype if mimetype else 'application/octet-stream'
            }

            response = requests.post(url=upload_url, headers=headers,
                                     files={"file": (image_url, self.__media_to_bytes(image_url))})

            LOGGER.info(response.json())
            LOGGER.info(response.status_code)

            if response.status_code != 201:
                LOGGER.error("Image Upload Failed")
                return Response(content=json.dumps({"message": "Failed to upload image"}),
                                status_code=status.HTTP_400_BAD_REQUEST)

            if not return_urn:
                self.__payload = {
                    "author": self.__linkedin_urn,
                    "commentary": self.request.get('commentary'),
                    "visibility": "PUBLIC",
                    "distribution": {
                        "feedDistribution": "MAIN_FEED",
                        "targetEntities": [],
                        "thirdPartyDistributionChannels": []
                    },
                    "content": {
                        "media": {
                            "title": image_title,
                            "id": image
                        }
                    },
                    "lifecycleState": "PUBLISHED",
                    "isReshareDisabledByAuthor": False
                }
            else:
                return image
        except Exception as e:
            LOGGER.error(e)
            return Response(content=json.dumps(response_init.json()), status_code=response_init.status_code)

请求头定义 #

self.__headers = {
            'Authorization': f'Bearer {self.__access_token}',
            'Content-Type': 'application/json',
            'Linkedin-Version': '202304'
        }

帖子发布方法 #

def __create_post(self, post_type):
        url = f"{LINKEDIN_URL}posts"
        post = Posts(self.request, self.__linkedin_urn, self.__get_headers(), post_type=post_type)
        self.__response = requests.post(url=url, headers=self.__get_headers(), json=post.get_payload())

修复方案 #

核心问题分析 #

报错的直接原因：

1. 使用了错误的请求方法（POST），LinkedIn图片上传接口要求用PUT提交二进制数据
2. files参数生成了multipart/form-data格式请求，不符合接口对原始二进制流的要求
3. 硬编码Authorization头的token，可能导致认证无效
4. 未校验图片二进制数据是否为空

修改后的上传代码片段 #

# 替换原上传请求部分的代码
mimetype, _ = mimetypes.guess_type(image_url)
headers = {
    'Authorization': f'Bearer {self.__access_token}',  # 使用实际有效token
    'Content-Type': mimetype if mimetype else 'application/octet-stream'
}

# 校验图片数据有效性
image_data = self.__media_to_bytes(image_url)
if not image_data:
    LOGGER.error("Image data is empty or invalid")
    return Response(content=json.dumps({"message": "Invalid image content"}), status_code=status.HTTP_400_BAD_REQUEST)

# 使用PUT请求直接发送二进制数据
response = requests.put(url=upload_url, headers=headers, data=image_data)

关键修改说明 #

• 请求方法变更：将requests.post改为requests.put，匹配LinkedIn接口要求
• 请求格式调整：去掉files参数，改用data传递二进制数据，确保请求体为原始图片字节流
• token正确性：使用初始化时的self.__access_token，避免硬编码导致的认证问题
• 数据校验：增加图片数据非空校验，提前拦截无效输入

内容的提问来源于stack exchange，提问作者Neha