Flask 下载时数据流的返回

Flask 下载时数据流的返回

关于flask 的下载功能实现，网上有一大堆，大致上是这样（适用于预下载的文件就在你的服务器里）

from flask import jsonify, json, request, make_response, Response, stream_with_context, send_file
import mimetypes

@api.route("/downloadFile/<path:filename>")
def downloadFile(filename):
    import os
    baseDir = os.path.join(os.getcwd(), "static")
    pathname = os.path.join(baseDir, filename)
    print pathname
    def send_chunk():  # 流式读取
        store_path = pathname
        with open(store_path, 'rb') as target_file:
            while True:
                chunk = target_file.read(20 * 1024 * 1024)  # 每次读取20M
                if not chunk:
                    break
                yield chunk
    return Response(send_chunk(), content_type='application/octet-stream')


@api.route("/downloadFile2/<path:filename>")
def downloadFile2(filename):
    import os
    baseDir = os.path.join(os.getcwd(), "static")
    pathname = os.path.join(baseDir, filename)
    f = open(pathname, "rb")
    response = Response(f.readlines())
    # response = make_response(f.read())
    mime_type = mimetypes.guess_type(filename)[0]
    response.headers['Content-Type'] = mime_type
    response.headers['Content-Disposition'] = 'attachment; filename={}'.format(filename.encode().decode('latin-1'))
    return response

但是我遇到的情况是下载的文件不在本地服务器，所以按上面的逻辑的话，我需要自己先下载好了才能传输给用户，可以说有点蠢

所以经过研究，发现了一种解决办法（跳过自己下载好了再传输的尴尬，直接将请求到的数据返回给用户）

from werkzeug._compat import wsgi_encoding_dance

@app.route("/downloadFile/<hash_str>")
def download_file(hash_str):
    song = get_download_link(hash_str)

    # 首先定义一个生成器，每次读取512个字节
    def generate():
        if song['url']:
            r = requests.get(song['url'], cookies=request.cookies, stream=True)
            for chunk in r.iter_content(chunk_size=512):
                if chunk:
                    yield chunk
    response = Response(stream_with_context(generate()))
    name = wsgi_encoding_dance(FileName)  # .encode("utf-8").decode("latin1")
    content_disposition = "attachment; filename={}".format(name)
    response.headers['Content-Disposition'] = content_disposition

    return response