flask中，读取本地/远程图片返回给前端

读取本地图片返回给前端有如下几种方式：

1. 通过send_from_directory函数

# -*- coding: utf-8 -*-
from flask import Flask, render_template, send_file, send_from_directory,json, jsonify，make_response
 
@app.route('/get_file/', methods=['GET'])
def get_file(file_name):
    basedir = os.path.abspath(os.path.dirname(__file__))
    # basedir一般是在配置文件中
    try:
        response = make_response(
            send_from_directory(basedir, file_name, as_attachment=True))
        return response
    except Exception as e:
        return f"文件读取异常{e}"

2. send_file函数

# -*- coding: utf-8 -*-
from flask import Flask, render_template, send_file
 

@app.route('/get_file/', methods=['GET'])
def get_local_resource(file_name):
    basedir = os.path.abspath(os.path.dirname(__file__))
    # basedir一般是在配置文件中
    file_path = os.path.join(basedir, file_name)
　　# 向api返回（图片）文件
    return send_file(file_path)

3. 从本地读取文件流，构建respone对象

from app import app
from urllib.parse import quote
from flask import jsonify, request, make_response
from werkzeug.utils import secure_filename

@app.route('/api/down/', methods=['GET'])
def down_file(filename):    
    basedir = os.path.abspath(os.path.dirname(__file__))
    # basedir一般是在配置文件中
    if filename is None:
        return "未找到该文件！"
    file = open(os.path.join(basedir, '%s' % filename), "rb").read()
    response = make_response(file)
    utf_filename = quote(filename.encode("utf-8"))
    response.headers["Content-Disposition"] = "attachment;filename*=utf-8''{}".format(utf_filename)
    response.headers["Content-Type"] = "application/octet-stream; charset=UTF-8"
    return response