__init__.py 文件源码

def send_file(self, filename, base='fs', version=-1, cache_for=31536000):
        """Return an instance of the :attr:`~flask.Flask.response_class`
        containing the named file, and implement conditional GET semantics
        (using :meth:`~werkzeug.wrappers.ETagResponseMixin.make_conditional`).

        .. code-block:: python

            @app.route('/uploads/<path:filename>')
            def get_upload(filename):
                return mongo.send_file(filename)

        :param str filename: the filename of the file to return
        :param str base: the base name of the GridFS collections to use
        :param bool version: if positive, return the Nth revision of the file
           identified by filename; if negative, return the Nth most recent
           revision. If no such version exists, return with HTTP status 404.
        :param int cache_for: number of seconds that browsers should be
           instructed to cache responses
        """
        if not isinstance(base, text_type):
            raise TypeError('"base" must be string or unicode')
        if not isinstance(version, num_type):
            raise TypeError('"version" must be an integer')
        if not isinstance(cache_for, num_type):
            raise TypeError('"cache_for" must be an integer')

        storage = GridFS(self.db, base)

        try:
            fileobj = storage.get_version(filename=filename, version=version)
        except NoFile:
            abort(404)

        # mostly copied from flask/helpers.py, with
        # modifications for GridFS
        data = wrap_file(request.environ, fileobj, buffer_size=1024 * 256)
        response = current_app.response_class(
            data,
            mimetype=fileobj.content_type,
            direct_passthrough=True)
        response.content_length = fileobj.length
        response.last_modified = fileobj.upload_date
        response.set_etag(fileobj.md5)
        response.cache_control.max_age = cache_for
        response.cache_control.s_max_age = cache_for
        response.cache_control.public = True
        response.make_conditional(request)
        return response