ragflow/api/db/services/file_service.py

#
#  Copyright 2024 The InfiniFlow Authors. All Rights Reserved.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
#
import asyncio
import base64
import logging
import re
import sys
import time
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path
from typing import Union

logger = logging.getLogger(__name__)

import xxhash
from peewee import fn

from api.db import KNOWLEDGEBASE_FOLDER_NAME, SKILLS_FOLDER_NAME, FileType
from api.db.db_models import DB, Document, File, File2Document, Knowledgebase, Task
from api.db.services import duplicate_name
from api.db.services.common_service import CommonService
from api.db.services.document_service import DocumentService
from api.db.services.file2document_service import File2DocumentService
from common.misc_utils import get_uuid
from common.ssrf_guard import assert_url_is_safe
from common.constants import TaskStatus, FileSource, ParserType, MAXIMUM_PAGE_NUMBER
from api.db.services.knowledgebase_service import KnowledgebaseService
from api.db.services.task_service import TaskService
from api.utils.file_utils import filename_type, read_potential_broken_pdf, thumbnail_img, sanitize_path
from rag.llm.cv_model import GptV4
from common import settings


class FileService(CommonService):
    # Service class for managing file operations and storage
    model = File

    @classmethod
    @DB.connection_context()
    def get_by_pf_id(cls, tenant_id, pf_id, page_number, items_per_page, orderby, desc, keywords):
        # Get files by parent folder ID with pagination and filtering
        # Args:
        #     tenant_id: ID of the tenant
        #     pf_id: Parent folder ID
        #     page_number: Page number for pagination
        #     items_per_page: Number of items per page
        #     orderby: Field to order by
        #     desc: Boolean indicating descending order
        #     keywords: Search keywords
        # Returns:
        #     Tuple of (file_list, total_count)
        if keywords:
            files = cls.model.select().where((cls.model.tenant_id == tenant_id), (cls.model.parent_id == pf_id), (fn.LOWER(cls.model.name).contains(keywords.lower())), ~(cls.model.id == pf_id))
        else:
            files = cls.model.select().where((cls.model.tenant_id == tenant_id), (cls.model.parent_id == pf_id), ~(cls.model.id == pf_id))
        count = files.count()
        if desc:
            files = files.order_by(cls.model.getter_by(orderby).desc())
        else:
            files = files.order_by(cls.model.getter_by(orderby).asc())

        files = files.paginate(page_number, items_per_page)

        res_files = list(files.dicts())
        for file in res_files:
            if file["type"] == FileType.FOLDER.value:
                file["size"] = cls.get_folder_size(file["id"])
                file["kbs_info"] = []
                children = list(
                    cls.model.select()
                    .where(
                        (cls.model.tenant_id == tenant_id),
                        (cls.model.parent_id == file["id"]),
                        ~(cls.model.id == file["id"]),
                    )
                    .dicts()
                )
                file["has_child_folder"] = any(value["type"] == FileType.FOLDER.value for value in children)
                continue
            kbs_info = cls.get_kb_id_by_file_id(file["id"])
            file["kbs_info"] = kbs_info

        return res_files, count

    @classmethod
    @DB.connection_context()
    def get_kb_id_by_file_id(cls, file_id):
        # Get dataset IDs associated with a file
        # Args:
        #     file_id: File ID
        # Returns:
        #     List of dictionaries containing dataset IDs and names
        kbs = (
            cls.model.select(*[Knowledgebase.id, Knowledgebase.name, File2Document.document_id])
            .join(File2Document, on=(File2Document.file_id == file_id))
            .join(Document, on=(File2Document.document_id == Document.id))
            .join(Knowledgebase, on=(Knowledgebase.id == Document.kb_id))
            .where(cls.model.id == file_id)
        )
        if not kbs:
            return []
        kbs_info_list = []
        for kb in list(kbs.dicts()):
            kbs_info_list.append({"kb_id": kb["id"], "kb_name": kb["name"], "document_id": kb["document_id"]})
        return kbs_info_list

    @classmethod
    @DB.connection_context()
    def get_by_pf_id_name(cls, id, name):
        # Get file by parent folder ID and name
        # Args:
        #     id: Parent folder ID
        #     name: File name
        # Returns:
        #     File object or None if not found
        file = cls.model.select().where((cls.model.parent_id == id) & (cls.model.name == name))
        if file.count():
            e, file = cls.get_by_id(file[0].id)
            if not e:
                raise RuntimeError("Database error (File retrieval)!")
            return file
        return None

    @classmethod
    @DB.connection_context()
    def get_id_list_by_id(cls, id, name, count, res):
        # Recursively get list of file IDs by traversing folder structure
        # Args:
        #     id: Starting folder ID
        #     name: List of folder names to traverse
        #     count: Current depth in traversal
        #     res: List to store results
        # Returns:
        #     List of file IDs
        if count < len(name):
            file = cls.get_by_pf_id_name(id, name[count])
            if file:
                res.append(file.id)
                return cls.get_id_list_by_id(file.id, name, count + 1, res)
            else:
                return res
        else:
            return res

    @classmethod
    @DB.connection_context()
    def get_all_innermost_file_ids(cls, folder_id, result_ids):
        # Get IDs of all files in the deepest level of folders
        # Args:
        #     folder_id: Starting folder ID
        #     result_ids: List to store results
        # Returns:
        #     List of file IDs
        subfolders = cls.model.select().where(cls.model.parent_id == folder_id)
        if subfolders.exists():
            for subfolder in subfolders:
                cls.get_all_innermost_file_ids(subfolder.id, result_ids)
        else:
            result_ids.append(folder_id)
        return result_ids

    @classmethod
    @DB.connection_context()
    def get_all_file_ids_by_tenant_id(cls, tenant_id):
        fields = [cls.model.id]
        files = cls.model.select(*fields).where(cls.model.tenant_id == tenant_id)
        files.order_by(cls.model.create_time.asc())
        offset, limit = 0, 100
        res = []
        while True:
            file_batch = files.offset(offset).limit(limit)
            _temp = list(file_batch.dicts())
            if not _temp:
                break
            res.extend(_temp)
            offset += limit
        return res

    @classmethod
    @DB.connection_context()
    def create_folder(cls, file, parent_id, name, count, tenant_id, created_by):
        # Recursively create folder structure
        # Args:
        #     file: Current file object
        #     parent_id: Parent folder ID
        #     name: List of folder names to create
        #     count: Current depth in creation
        #     tenant_id: Tenant ID
        #     created_by: Created by user ID
        # Returns:
        #     Created file object
        if count > len(name) - 2:
            return file
        else:
            file = cls.insert(
                {"id": get_uuid(), "parent_id": parent_id, "tenant_id": tenant_id, "created_by": created_by, "name": name[count], "location": "", "size": 0, "type": FileType.FOLDER.value}
            )
            return cls.create_folder(file, file.id, name, count + 1, tenant_id, created_by)

    @classmethod
    @DB.connection_context()
    def is_parent_folder_exist(cls, parent_id):
        # Check if parent folder exists
        # Args:
        #     parent_id: Parent folder ID
        # Returns:
        #     Boolean indicating if folder exists
        parent_files = cls.model.select().where(cls.model.id == parent_id)
        if parent_files.count():
            return True
        cls.delete_folder_by_pf_id(parent_id)
        return False

    @classmethod
    @DB.connection_context()
    def get_root_folder(cls, tenant_id):
        # Get or create root folder for tenant
        # Args:
        #     tenant_id: Tenant ID
        # Returns:
        #     Root folder dictionary
        for file in cls.model.select().where((cls.model.tenant_id == tenant_id), (cls.model.parent_id == cls.model.id)):
            return file.to_dict()

        file_id = get_uuid()
        file = {
            "id": file_id,
            "parent_id": file_id,
            "tenant_id": tenant_id,
            "created_by": tenant_id,
            "name": "/",
            "type": FileType.FOLDER.value,
            "size": 0,
            "location": "",
        }
        cls.save(**file)
        return file

    @classmethod
    @DB.connection_context()
    def get_kb_folder(cls, tenant_id):
        # Get dataset folder for tenant
        # Args:
        #     tenant_id: Tenant ID
        # Returns:
        #     Knowledge base folder dictionary
        root_folder = cls.get_root_folder(tenant_id)
        root_id = root_folder["id"]
        kb_folder = cls.model.select().where((cls.model.tenant_id == tenant_id), (cls.model.parent_id == root_id), (cls.model.name == KNOWLEDGEBASE_FOLDER_NAME)).first()
        if not kb_folder:
            kb_folder = cls.new_a_file_from_kb(tenant_id, KNOWLEDGEBASE_FOLDER_NAME, root_id)
            return kb_folder
        return kb_folder.to_dict()

    @classmethod
    @DB.connection_context()
    def new_a_file_from_kb(cls, tenant_id, name, parent_id, ty=FileType.FOLDER.value, size=0, location=""):
        # Create a new file from dataset
        # Args:
        #     tenant_id: Tenant ID
        #     name: File name
        #     parent_id: Parent folder ID
        #     ty: File type
        #     size: File size
        #     location: File location
        # Returns:
        #     Created file dictionary
        for file in cls.query(tenant_id=tenant_id, parent_id=parent_id, name=name):
            return file.to_dict()
        file = {
            "id": get_uuid(),
            "parent_id": parent_id,
            "tenant_id": tenant_id,
            "created_by": tenant_id,
            "name": name,
            "type": ty,
            "size": size,
            "location": location,
            "source_type": FileSource.KNOWLEDGEBASE,
        }
        cls.save(**file)
        return file

    @classmethod
    @DB.connection_context()
    def init_skills_folder(cls, root_id, tenant_id):
        # Initialize skills folder if not exists
        # Args:
        #     root_id: Root folder ID
        #     tenant_id: Tenant ID
        for _ in cls.model.select().where((cls.model.name == SKILLS_FOLDER_NAME) & (cls.model.parent_id == root_id)):
            return
        file_id = get_uuid()
        file = {
            "id": file_id,
            "parent_id": root_id,
            "tenant_id": tenant_id,
            "created_by": tenant_id,
            "name": SKILLS_FOLDER_NAME,
            "type": FileType.FOLDER.value,
            "size": 0,
            "location": "",
        }
        cls.save(**file)

    @classmethod
    @DB.connection_context()
    def init_knowledgebase_docs(cls, root_id, tenant_id):
        # Initialize dataset documents
        # Args:
        #     root_id: Root folder ID
        #     tenant_id: Tenant ID
        for _ in cls.model.select().where((cls.model.name == KNOWLEDGEBASE_FOLDER_NAME) & (cls.model.parent_id == root_id)):
            return
        folder = cls.new_a_file_from_kb(tenant_id, KNOWLEDGEBASE_FOLDER_NAME, root_id)

        for kb in Knowledgebase.select(*[Knowledgebase.id, Knowledgebase.name]).where(Knowledgebase.tenant_id == tenant_id):
            kb_folder = cls.new_a_file_from_kb(tenant_id, kb.name, folder["id"])
            for doc in DocumentService.query(kb_id=kb.id):
                FileService.add_file_from_kb(doc.to_dict(), kb_folder["id"], tenant_id)

    @classmethod
    @DB.connection_context()
    def get_parent_folder(cls, file_id):
        # Get parent folder of a file
        # Args:
        #     file_id: File ID
        # Returns:
        #     Parent folder object
        file = cls.model.select().where(cls.model.id == file_id)
        if file.count():
            e, file = cls.get_by_id(file[0].parent_id)
            if not e:
                raise RuntimeError("Database error (File retrieval)!")
        else:
            raise RuntimeError("Database error (File doesn't exist)!")
        return file

    @classmethod
    @DB.connection_context()
    def get_all_parent_folders(cls, start_id):
        # Get all parent folders in path
        # Args:
        #     start_id: Starting file ID
        # Returns:
        #     List of parent folder objects
        parent_folders = []
        current_id = start_id
        while current_id:
            e, file = cls.get_by_id(current_id)
            if e and file.parent_id != file.id:
                parent_folders.append(file)
                current_id = file.parent_id
            else:
                parent_folders.append(file)
                break
        return parent_folders

    @classmethod
    @DB.connection_context()
    def insert(cls, file):
        # Insert a new file record
        # Args:
        #     file: File data dictionary
        # Returns:
        #     Created file object
        if not cls.save(**file):
            raise RuntimeError("Database error (File)!")
        return File(**file)

    @classmethod
    @DB.connection_context()
    def delete(cls, file):
        #
        return cls.delete_by_id(file.id)

    @classmethod
    @DB.connection_context()
    def delete_by_pf_id(cls, folder_id):
        return cls.model.delete().where(cls.model.parent_id == folder_id).execute()

    @classmethod
    @DB.connection_context()
    def delete_folder_by_pf_id(cls, user_id, folder_id):
        try:
            files = cls.model.select().where((cls.model.tenant_id == user_id) & (cls.model.parent_id == folder_id))
            for file in files:
                cls.delete_folder_by_pf_id(user_id, file.id)
            return (cls.model.delete().where((cls.model.tenant_id == user_id) & (cls.model.id == folder_id)).execute(),)
        except Exception:
            logging.exception("delete_folder_by_pf_id")
            raise RuntimeError("Database error (File retrieval)!")

    @classmethod
    @DB.connection_context()
    def get_file_count(cls, tenant_id):
        files = cls.model.select(cls.model.id).where(cls.model.tenant_id == tenant_id)
        return len(files)

    @classmethod
    @DB.connection_context()
    def get_folder_size(cls, folder_id):
        size = 0

        def dfs(parent_id):
            nonlocal size
            for f in cls.model.select(*[cls.model.id, cls.model.size, cls.model.type]).where(cls.model.parent_id == parent_id, cls.model.id != parent_id):
                size += f.size
                if f.type == FileType.FOLDER.value:
                    dfs(f.id)

        dfs(folder_id)
        return size

    @classmethod
    @DB.connection_context()
    def add_file_from_kb(cls, doc, kb_folder_id, tenant_id):
        for _ in File2DocumentService.get_by_document_id(doc["id"]):
            return
        file = {
            "id": get_uuid(),
            "parent_id": kb_folder_id,
            "tenant_id": tenant_id,
            "created_by": tenant_id,
            "name": doc["name"],
            "type": doc["type"],
            "size": doc["size"],
            "location": doc["location"],
            "source_type": FileSource.KNOWLEDGEBASE,
        }
        cls.save(**file)
        File2DocumentService.save(**{"id": get_uuid(), "file_id": file["id"], "document_id": doc["id"]})

    @classmethod
    @DB.connection_context()
    def move_file(cls, file_ids, folder_id):
        try:
            cls.filter_update((cls.model.id << file_ids,), {"parent_id": folder_id})
        except Exception:
            logging.exception("move_file")
            raise RuntimeError("Database error (File move)!")

    @classmethod
    @DB.connection_context()
    def upload_document(self, kb, file_objs, user_id, src="local", parent_path: str | None = None):
        root_folder = self.get_root_folder(user_id)
        pf_id = root_folder["id"]
        self.init_knowledgebase_docs(pf_id, user_id)
        kb_root_folder = self.get_kb_folder(user_id)
        kb_folder = self.new_a_file_from_kb(kb.tenant_id, kb.name, kb_root_folder["id"])

        safe_parent_path = sanitize_path(parent_path)

        err, files = [], []
        for file in file_objs:
            doc_id = file.id if hasattr(file, "id") else get_uuid()
            e, doc = DocumentService.get_by_id(doc_id)
            if e:
                try:
                    if str(doc.kb_id) != str(kb.id):
                        logging.warning(
                            "Existing document id collision detected for %s: belongs to kb_id=%s, incoming kb_id=%s. "
                            "Skipping update to avoid cross-KB overwrite.",
                            doc_id,
                            doc.kb_id,
                            kb.id,
                        )
                        user_msg = "Existing document id collision with another knowledge base; skipping update."
                        err.append(file.filename + ": " + user_msg)
                        continue
                    blob = file.read()
                    # Connector-supplied fingerprint (e.g. xxhash128(S3 ETag))
                    # takes precedence: for connector-sourced docs the bypass
                    # path uses the fingerprint as content_hash, so reverting
                    # to xxhash128(blob) here would defeat it.
                    incoming_fp = getattr(file, "fingerprint", None)
                    new_hash = incoming_fp or xxhash.xxh128(blob).hexdigest()
                    old_hash = doc.content_hash or ""
                    settings.STORAGE_IMPL.put(kb.id, doc.location, blob, kb.tenant_id)
                    doc.size = len(blob)
                    doc.content_hash = new_hash
                    doc = doc.to_dict()
                    DocumentService.update_by_id(doc["id"], doc)
                    if new_hash != old_hash:
                        files.append((doc, blob))
                except Exception as exc:
                    logging.exception(f"Failed to update document {doc_id}: {exc}")
                    err.append(file.filename + ": " + str(exc))
                continue
            try:
                DocumentService.check_doc_health(kb.tenant_id, file.filename)
                filename = duplicate_name(DocumentService.query, name=file.filename, kb_id=kb.id)
                filetype = filename_type(filename)
                if filetype == FileType.OTHER.value:
                    raise RuntimeError("This type of file has not been supported yet!")

                location = filename if not safe_parent_path else f"{safe_parent_path}/{filename}"
                while settings.STORAGE_IMPL.obj_exist(kb.id, location):
                    location += "_"

                blob = file.read()
                if filetype == FileType.PDF.value:
                    blob = read_potential_broken_pdf(blob)
                settings.STORAGE_IMPL.put(kb.id, location, blob)


                img = thumbnail_img(filename, blob)
                thumbnail_location = ""
                if img is not None:
                    thumbnail_location = f"thumbnail_{doc_id}.png"
                    settings.STORAGE_IMPL.put(kb.id, thumbnail_location, img)

                incoming_fp = getattr(file, "fingerprint", None)
                doc = {
                    "id": doc_id,
                    "kb_id": kb.id,
                    "parser_id": self.get_parser(filetype, filename, kb.parser_id),
                    "pipeline_id": kb.pipeline_id,
                    "parser_config": kb.parser_config,
                    "created_by": user_id,
                    "type": filetype,
                    "name": filename,
                    "source_type": src,
                    "suffix": Path(filename).suffix.lstrip("."),
                    "location": location,
                    "size": len(blob),
                    "thumbnail": thumbnail_location,
                    "content_hash": incoming_fp or xxhash.xxh128(blob).hexdigest(),
                }
                DocumentService.insert(doc)

                FileService.add_file_from_kb(doc, kb_folder["id"], kb.tenant_id)
                files.append((doc, blob))
            except Exception as e:
                err.append(file.filename + ": " + str(e))

        return err, files

    @classmethod
    @DB.connection_context()
    def list_all_files_by_parent_id(cls, parent_id):
        try:
            files = cls.model.select().where((cls.model.parent_id == parent_id) & (cls.model.id != parent_id))
            return list(files)
        except Exception:
            logging.exception("list_by_parent_id failed")
            raise RuntimeError("Database error (list_by_parent_id)!")

    @staticmethod
    def parse_docs(file_objs, user_id):
        with ThreadPoolExecutor(max_workers=12) as exe:
            threads = []
            for file in file_objs:
                threads.append(exe.submit(FileService.parse, file.filename, file.read(), False))

            res = []
            for th in threads:
                res.append(th.result())

        return "\n\n".join(res)

    @staticmethod
    def parse(filename, blob, img_base64=True, tenant_id=None, layout_recognize=None):
        from rag.app import audio, email, naive, picture, presentation
        from api.apps import current_user

        def dummy(prog=None, msg=""):
            pass

        FACTORY = {ParserType.PRESENTATION.value: presentation, ParserType.PICTURE.value: picture, ParserType.AUDIO.value: audio, ParserType.EMAIL.value: email}
        parser_config = {"chunk_token_num": 16096, "delimiter": "\n!?;。；！？", "layout_recognize": layout_recognize or "Plain Text"}
        kwargs = {"lang": "English", "callback": dummy, "parser_config": parser_config, "from_page": 0, "to_page": MAXIMUM_PAGE_NUMBER, "tenant_id": current_user.id if current_user else tenant_id}
        file_type = filename_type(filename)
        if img_base64 and file_type == FileType.VISUAL.value:
            return GptV4.image2base64(blob)
        cks = FACTORY.get(FileService.get_parser(filename_type(filename), filename, ""), naive).chunk(filename, blob, **kwargs)
        return f"\n -----------------\nFile: {filename}\nContent as following: \n" + "\n".join([ck["content_with_weight"] for ck in cks])

    @staticmethod
    def get_parser(doc_type, filename, default):
        if doc_type == FileType.VISUAL:
            return ParserType.PICTURE.value
        if doc_type == FileType.AURAL:
            return ParserType.AUDIO.value
        if re.search(r"\.(ppt|pptx|pages)$", filename):
            return ParserType.PRESENTATION.value
        if re.search(r"\.(msg|eml)$", filename):
            return ParserType.EMAIL.value
        return default

    @staticmethod
    def get_blob(user_id, location):
        bname = f"{user_id}-downloads"
        return settings.STORAGE_IMPL.get(bname, location)

    @staticmethod
    def put_blob(user_id, location, blob):
        bname = f"{user_id}-downloads"
        return settings.STORAGE_IMPL.put(bname, location, blob)

    @classmethod
    @DB.connection_context()
    def delete_docs(cls, doc_ids, tenant_id):
        root_folder = FileService.get_root_folder(tenant_id)
        pf_id = root_folder["id"]
        FileService.init_knowledgebase_docs(pf_id, tenant_id)
        errors = ""
        kb_table_num_map = {}
        for doc_id in doc_ids:
            try:
                e, doc = DocumentService.get_by_id(doc_id)
                if not e:
                    raise Exception("Document not found!")
                tenant_id = DocumentService.get_tenant_id(doc_id)
                if not tenant_id:
                    raise Exception("Tenant not found!")

                b, n = File2DocumentService.get_storage_address(doc_id=doc_id)

                TaskService.filter_delete([Task.doc_id == doc_id])
                if not DocumentService.remove_document(doc, tenant_id):
                    raise Exception("Database error (Document removal)!")

                f2d = File2DocumentService.get_by_document_id(doc_id)
                deleted_file_count = 0
                if f2d:
                    deleted_file_count = FileService.filter_delete([File.source_type == FileSource.KNOWLEDGEBASE, File.id == f2d[0].file_id])
                File2DocumentService.delete_by_document_id(doc_id)
                if deleted_file_count > 0:
                    settings.STORAGE_IMPL.rm(b, n)

                doc_parser = doc.parser_id
                if doc_parser == ParserType.TABLE:
                    kb_id = doc.kb_id
                    if kb_id not in kb_table_num_map:
                        counts = DocumentService.count_by_kb_id(kb_id=kb_id, keywords="", run_status=[TaskStatus.DONE], types=[])
                        kb_table_num_map[kb_id] = counts
                    kb_table_num_map[kb_id] -= 1
                    if kb_table_num_map[kb_id] <= 0:
                        KnowledgebaseService.delete_field_map(kb_id)
            except Exception as e:
                errors += str(e)

        return errors

    _ALLOWED_SCHEMES = {"http", "https"}

    @staticmethod
    def _validate_url_for_crawl(url: str) -> tuple[str, str]:
        """Raise ValueError if the URL is not safe to crawl (SSRF guard).

        Delegates to :func:`common.ssrf_guard.assert_url_is_safe`, which
        validates the scheme, hostname, and every DNS-resolved address, and
        returns ``(hostname, resolved_ip)`` for DNS pinning.

        Only the scheme and host (and port when present) are forwarded to the
        guard so that credentials or query parameters in *url* are never
        written to the log.
        """
        from urllib.parse import urlparse
        parsed = urlparse(url)
        port_suffix = f":{parsed.port}" if parsed.port else ""
        redacted = f"{parsed.scheme}://{parsed.hostname}{port_suffix}"
        return assert_url_is_safe(redacted, allowed_schemes=FileService._ALLOWED_SCHEMES)

    @staticmethod
    def upload_info(user_id, file, url: str|None=None):
        def structured(filename, filetype, blob, content_type):
            nonlocal user_id
            if filetype == FileType.PDF.value:
                blob = read_potential_broken_pdf(blob)

            location = get_uuid()
            FileService.put_blob(user_id, location, blob)

            return {
                "id": location,
                "name": filename,
                "size": sys.getsizeof(blob),
                "extension": filename.split(".")[-1].lower(),
                "mime_type": content_type,
                "created_by": user_id,
                "created_at": time.time(),
                "preview_url": None
            }

        if url:
            import requests as _requests
            from urllib.parse import urljoin as _urljoin

            _MAX_CRAWL_REDIRECTS = 10

            # Pre-resolve the full redirect chain so that AsyncWebCrawler never
            # follows a server-sent redirect to an unvalidated (potentially
            # internal) host. Each hop is SSRF-checked before being followed;
            # the validated (hostname, ip) pairs are pinned via Chromium's
            # --host-resolver-rules so the browser cannot re-resolve any of them
            # through a fresh DNS query.
            current_url = url
            current_hostname, current_ip = FileService._validate_url_for_crawl(current_url)
            # Accumulate MAP rules for every hostname we encounter in the chain.
            host_pins: dict[str, str] = {current_hostname: current_ip}

            for _ in range(_MAX_CRAWL_REDIRECTS):
                try:
                    _resp = _requests.get(
                        current_url,
                        timeout=10,
                        allow_redirects=False,
                    )
                except _requests.RequestException as _exc:
                    raise ValueError(f"Failed to fetch {current_url!r}: {_exc}") from _exc

                if _resp.status_code not in (301, 302, 303, 307, 308):
                    break

                _location = _resp.headers.get("Location")
                if not _location:
                    break

                _next_url = _urljoin(current_url, _location)
                _next_hostname, _next_ip = FileService._validate_url_for_crawl(_next_url)
                host_pins[_next_hostname] = _next_ip
                current_url = _next_url
            else:
                raise ValueError(
                    f"Exceeded {_MAX_CRAWL_REDIRECTS} redirects fetching {url!r}"
                )

            # Build a single MAP rule string covering every validated hostname
            # in the redirect chain. Chromium uses the pinned IP for each,
            # skipping DNS entirely and eliminating the rebinding window.
            _map_rules = ",".join(f"MAP {h} {ip}" for h, ip in host_pins.items())

            from crawl4ai import (
                AsyncWebCrawler,
                BrowserConfig,
                CrawlerRunConfig,
                DefaultMarkdownGenerator,
                PruningContentFilter,
                CrawlResult
            )
            filename = re.sub(r"\?.*", "", url.split("/")[-1])
            async def adownload():
                browser_config = BrowserConfig(
                    headless=True,
                    verbose=False,
                    extra_args=[f"--host-resolver-rules={_map_rules}"],
                )
                async with AsyncWebCrawler(config=browser_config) as crawler:
                    crawler_config = CrawlerRunConfig(
                        markdown_generator=DefaultMarkdownGenerator(
                            content_filter=PruningContentFilter()
                        ),
                        pdf=True,
                        screenshot=False
                    )
                    # Use the final resolved URL so the browser starts at the
                    # redirect destination rather than re-following the chain.
                    result: CrawlResult = await crawler.arun(
                        url=current_url,
                        config=crawler_config
                    )
                    return result
            page = asyncio.run(adownload())
            if page.pdf:
                if filename.split(".")[-1].lower() != "pdf":
                    filename += ".pdf"
                return structured(filename, "pdf", page.pdf, page.response_headers["content-type"])

            return structured(filename, "html", str(page.markdown).encode("utf-8"), page.response_headers["content-type"])

        DocumentService.check_doc_health(user_id, file.filename)
        return structured(file.filename, filename_type(file.filename), file.read(), file.content_type)

    @staticmethod
    def get_files(files: Union[None, list[dict]], raw: bool = False, layout_recognize: str = None) -> Union[list[str], tuple[list[str], list[dict]]]:
        if not files:
            return  []
        def image_to_base64(file):
            return "data:{};base64,{}".format(file["mime_type"],
                                        base64.b64encode(FileService.get_blob(file["created_by"], file["id"])).decode("utf-8"))
        with ThreadPoolExecutor(max_workers=5) as exe:
            threads = []
            imgs = []
            for file in files:
                if file["mime_type"].find("image") >=0:
                    if raw:
                        imgs.append(FileService.get_blob(file["created_by"], file["id"]))
                    else:
                        threads.append(exe.submit(image_to_base64, file))
                    continue
                threads.append(exe.submit(FileService.parse, file["name"], FileService.get_blob(file["created_by"], file["id"]), True, file["created_by"], layout_recognize))

            if raw:
                return [th.result() for th in threads], imgs
            else:
                return [th.result() for th in threads]