当前位置：首页 > news >正文

RAG实战之dify源码文件解析-pdf文件解析流程

news 2025/7/10 11:22:44

通过对dify源码的解析，用户上传的文档首先经过api处理后传递给文件处理服务层，对于知识管理，上传的 PDF 通过 IndexingRunnerindexing_runner.py进入索引管道。这个过程通常通过 Celery tasksdocument_indexing_task.py 异步执行。ExtractProcessor作为文档处理的中央处理器根据文档的格式选择具体的Extractor，PdfExtractor 类专门用于 PDF 文件，利用使用 pypdfium2 这个高效的 PDF 解析库，按页读取 PDF 内容。
在这里插入图片描述

PDF格式文档解析工作流程

Dify的文件解析功能是一个分层的系统架构，主要通过以下几个核心组件来实现：

核心架构

1. 基础抽象类

Dify定义了一个抽象基类BaseExtractor，为所有文件提取器提供统一的接口

"""Abstract interface for document loader implementations."""from abc import ABC, abstractmethodclass BaseExtractor(ABC):"""Interface for extract files."""@abstractmethoddef extract(self):raise NotImplementedError

2. 中央处理器

ExtractProcessor类作为核心协调器，负责根据文件类型选择合适的提取器来处理不同格式的文件。
主要方法说明

load_from_upload_file
输入：UploadFile 对象
功能：从上传的文件中抽取内容。可以返回 Document 列表，也可以只返回文本内容。
load_from_url
输入：文件/网页的 URL
功能：通过 ssrf_proxy 获取远程文件内容，自动推断文件类型，保存到本地临时文件后进行抽取。
extract
输入：ExtractSetting（抽取设置），可选 file_path
功能：根据数据源类型（本地文件、Notion、网站）和文件类型，选择合适的抽取器并执行抽取，返回 Document 列表。

SUPPORT_URL_CONTENT_TYPES = ["application/pdf", "text/plain", "application/json"]
USER_AGENT = ("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124"" Safari/537.36"
)class ExtractProcessor:@classmethoddef load_from_upload_file(cls, upload_file: UploadFile, return_text: bool = False, is_automatic: bool = False) -> Union[list[Document], str]:extract_setting = ExtractSetting(datasource_type="upload_file", upload_file=upload_file, document_model="text_model")if return_text:delimiter = "\n"return delimiter.join([document.page_content for document in cls.extract(extract_setting, is_automatic)])else:return cls.extract(extract_setting, is_automatic)@classmethoddef load_from_url(cls, url: str, return_text: bool = False) -> Union[list[Document], str]:response = ssrf_proxy.get(url, headers={"User-Agent": USER_AGENT})with tempfile.TemporaryDirectory() as temp_dir:suffix = Path(url).suffixif not suffix and suffix != ".":# get content-typeif response.headers.get("Content-Type"):suffix = "." + response.headers.get("Content-Type").split("/")[-1]else:content_disposition = response.headers.get("Content-Disposition")filename_match = re.search(r'filename="([^"]+)"', content_disposition)if filename_match:filename = unquote(filename_match.group(1))match = re.search(r"\.(\w+)$", filename)if match:suffix = "." + match.group(1)else:suffix = ""# FIXME mypy: Cannot determine type of 'tempfile._get_candidate_names' better not use it herefile_path = f"{temp_dir}/{next(tempfile._get_candidate_names())}{suffix}"  # type: ignorePath(file_path).write_bytes(response.content)extract_setting = ExtractSetting(datasource_type="upload_file", document_model="text_model")if return_text:delimiter = "\n"return delimiter.join([document.page_contentfor document in cls.extract(extract_setting=extract_setting, file_path=file_path)])else:return cls.extract(extract_setting=extract_setting, file_path=file_path)@classmethoddef extract(cls, extract_setting: ExtractSetting, is_automatic: bool = False, file_path: Optional[str] = None) -> list[Document]:if extract_setting.datasource_type == DatasourceType.FILE.value:with tempfile.TemporaryDirectory() as temp_dir:if not file_path:assert extract_setting.upload_file is not None, "upload_file is required"upload_file: UploadFile = extract_setting.upload_filesuffix = Path(upload_file.key).suffix# FIXME mypy: Cannot determine type of 'tempfile._get_candidate_names' better not use it herefile_path = f"{temp_dir}/{next(tempfile._get_candidate_names())}{suffix}"  # type: ignorestorage.download(upload_file.key, file_path)input_file = Path(file_path)file_extension = input_file.suffix.lower()etl_type = dify_config.ETL_TYPEextractor: Optional[BaseExtractor] = Noneif etl_type == "Unstructured":unstructured_api_url = dify_config.UNSTRUCTURED_API_URL or ""unstructured_api_key = dify_config.UNSTRUCTURED_API_KEY or ""if file_extension in {".xlsx", ".xls"}:extractor = ExcelExtractor(file_path)elif file_extension == ".pdf":extractor = PdfExtractor(file_path)elif file_extension in {".md", ".markdown", ".mdx"}:extractor = (UnstructuredMarkdownExtractor(file_path, unstructured_api_url, unstructured_api_key)if is_automaticelse MarkdownExtractor(file_path, autodetect_encoding=True))/**选择具体文档提取类**/elif file_extension == ".epub":extractor = UnstructuredEpubExtractor(file_path, unstructured_api_url, unstructured_api_key)else:# txtextractor = TextExtractor(file_path, autodetect_encoding=True)else:if file_extension in {".xlsx", ".xls"}:extractor = ExcelExtractor(file_path)elif file_extension == ".pdf":extractor = PdfExtractor(file_path)elif file_extension in {".md", ".markdown", ".mdx"}:extractor = MarkdownExtractor(file_path, autodetect_encoding=True)elif file_extension in {".htm", ".html"}:extractor = HtmlExtractor(file_path)elif file_extension == ".docx":extractor = WordExtractor(file_path, upload_file.tenant_id, upload_file.created_by)elif file_extension == ".csv":extractor = CSVExtractor(file_path, autodetect_encoding=True)elif file_extension == ".epub":extractor = UnstructuredEpubExtractor(file_path)else:# txtextractor = TextExtractor(file_path, autodetect_encoding=True)return extractor.extract()elif extract_setting.datasource_type == DatasourceType.NOTION.value:assert extract_setting.notion_info is not None, "notion_info is required"extractor = NotionExtractor(notion_workspace_id=extract_setting.notion_info.notion_workspace_id,notion_obj_id=extract_setting.notion_info.notion_obj_id,notion_page_type=extract_setting.notion_info.notion_page_type,document_model=extract_setting.notion_info.document,tenant_id=extract_setting.notion_info.tenant_id,)return extractor.extract()elif extract_setting.datasource_type == DatasourceType.WEBSITE.value:assert extract_setting.website_info is not None, "website_info is required"if extract_setting.website_info.provider == "firecrawl":extractor = FirecrawlWebExtractor(url=extract_setting.website_info.url,job_id=extract_setting.website_info.job_id,tenant_id=extract_setting.website_info.tenant_id,mode=extract_setting.website_info.mode,only_main_content=extract_setting.website_info.only_main_content,)return extractor.extract()elif extract_setting.website_info.provider == "watercrawl":extractor = WaterCrawlWebExtractor(url=extract_setting.website_info.url,job_id=extract_setting.website_info.job_id,tenant_id=extract_setting.website_info.tenant_id,mode=extract_setting.website_info.mode,only_main_content=extract_setting.website_info.only_main_content,)return extractor.extract()elif extract_setting.website_info.provider == "jinareader":extractor = JinaReaderWebExtractor(url=extract_setting.website_info.url,job_id=extract_setting.website_info.job_id,tenant_id=extract_setting.website_info.tenant_id,mode=extract_setting.website_info.mode,only_main_content=extract_setting.website_info.only_main_content,)return extractor.extract()else:raise ValueError(f"Unsupported website provider: {extract_setting.website_info.provider}")else:raise ValueError(f"Unsupported datasource type: {extract_setting.datasource_type}")