Flask 应用程序构建器如何使用文件项制作 REST API

问题描述

我正在制作一个 REST api，可以像这样在flask-appbuilder中基于MODEL-VIEW上传文件。 但我不知道如何调用 REST API (POST /File)。 我尝试了几种不同的方法。但我不能。 让我知道正确的或替代的方法。

[客户端代码]

file = {'file':open('test.txt','rb'),'description':'test'}
requests.post(url,headers=headers,files=file)

==> 失败

模型.py

class Files(Model):
    __tablename__ = "project_files"
    id = Column(Integer,primary_key=True)
    file = Column(FileColumn,nullable=False)
    description = Column(String(150))

    def download(self):
        return Markup(
            '<a href="'
            + url_for("ProjectFilesModelView.download",filename=str(self.file))
            + '">Download</a>'
        )

    def file_name(self):
        return get_file_original_name(str(self.file))

view.py

class FileApi(ModelRestApi):
    resource_name = "File"
    datamodel = sqlAInterface(Files)
    allow_browser_login = True


appbuilder.add_api(FileApi)

解决方法

你可以使用这个。

from app.models import Project,ProjectFiles

class DataFilesModelView(ModelView):
datamodel = SQLAInterface(ProjectFiles)

label_columns = {"file_name": "File Name","download": "Download"}
add_columns = ["file","description","project"]
edit_columns = ["file","project"]
list_columns = ["file_name","download"]
show_columns = ["file_name","download"]

最后将视图添加到菜单中。

appbuilder.add_view(DataFilesModelView,"File View")

,

FileColumn 只是一个字符串字段，用于在数据库中保存文件名。实际文件保存到 config['UPLOAD_FOLDER']。 这由 flask_appbuilder.filemanager.FileManager 处理。

此外，ModelRestApi 假定您正在发布 JSON 数据。为了上传文件，我遵循了 Flask's documentation，它建议发送一个 multipart/form-data 请求。因此，需要覆盖 ModelRestApi.post_headless()。

这是我的解决方案，我还确保当 Files 数据库行 被删除，文件系统中的相关文件也被删除。

from flask_appbuilder.models.sqla.interface import SQLAInterface
from flask_appbuilder.api import ModelRestApi
from flask_appbuilder.const import API_RESULT_RES_KEY
from flask_appbuilder.filemanager import FileManager

from flask import current_app,request

from marshmallow import ValidationError
from sqlalchemy.exc import IntegrityError

from app.models import Files


class FileApi(ModelRestApi):
    resource_name = "file"
    datamodel = SQLAInterface(Files)

    def post_headless(self):
        if not request.form or not request.files:
            msg = "No data"
            current_app.logger.error(msg)
            return self.response_400(message=msg)

        file_obj = request.files.getlist('file')
        if len(file_obj) != 1:
            msg = ("More than one file provided.\n"
                   "Please upload exactly one file at a time")
            current_app.logger.error(msg)
            return self.response_422(message=msg)
        else:
            file_obj = file_obj[0]

        fm = FileManager()
        uuid_filename = fm.generate_name(file_obj.filename,file_obj)
        form = request.form.to_dict(flat=True)

        # Add the unique filename provided by FileManager,which will
        # be saved to the database. The original filename can be 
        # retrieved using 
        # flask_appbuilder.filemanager.get_file_original_name()
        form['file'] = uuid_filename

        try:
            item = self.add_model_schema.load(
                    form,session=self.datamodel.session)
        except ValidationError as err:
            current_app.logger.error(err)
            return self.response_422(message=err.messages)

        # Save file to filesystem
        fm.save_file(file_obj,item.file)

        try:
            self.datamodel.add(item,raise_exception=True)
            return self.response(
                201,**{API_RESULT_RES_KEY: self.add_model_schema.dump(
                    item,many=False),"id": self.datamodel.get_pk_value(item),},)
        except IntegrityError as e:
            # Delete file from filesystem if the db record cannot be
            # created
            fm.delete_file(item.file)
            current_app.logger.error(e)
            return self.response_422(message=str(e.orig))

    def pre_delete(self,item):
        """
        Delete file from filesystem before removing the record from the 
        database
        """
        fm = FileManager()
        current_app.logger.info(f"Deleting {item.file} from filesystem")
        fm.delete_file(item.file)