POST /v2/knowledgeBase?Action=UploadDocuments HTTP/1.1
HOST: qianfan.baidubce.com
Authorization: Bearer <API Key>
Content-Type: multipart/form-data

form-data参数：
file：待上传的文件
payload：json字符串，结构如下：
{   
    "id":"knowledgeBaseID",
    "source": { # 数据来源
        "type": "file" # file
    },
    "contentFormat": "rawText", # rawText (允许配置后续分割策略)
    "processOption": {
        "template": "custom", # 可选项为 ppt、paper、qaPair、resume、custom、default
        "parser": {
            "choices": ["layoutAnalysis", "ocr"]
        },
        "chunker": {
            "choices": ["separator"], # separator, pattern, onePage
            "separator": { #当choices中包含 separator时需要填写这个参数
                "separators": ["!", "?"], # separator，可以新增分页符
                "targetLength": 333,
                "overlapRate": 0.09
            },
           // "pattern": {   #当choices中包含 pattern时需要填写这个参数
             //   "markPosition": "head",
             //   "regex": "正则表达式",
             //   "targetLength": 333,
             //   "overlapRate": 0.09
            //},
            "prependInfo": ["title", "filename"]
        },
        "knowledgeAugmentation": {
            "choices": ["faq"] # faq，spokenQuery、spo、shortSummary按需增加
        }
    }
}