Flask 下載時數據流的返回

Flask 下載時數據流的返回

 

關於flask 的下載功能實現，網上有一大堆，大致上是這樣（適用於預下載的文件就在你的服務器里）

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():  # 流式讀取
        store_path = pathname
        with open(store_path, 'rb') as target_file:
            while True:
                chunk = target_file.read(20 * 1024 * 1024)  # 每次讀取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

但是我遇到的情況是下載的文件不在本地服務器，所以按上面的邏輯的話，我需要自己先下載好了才能傳輸給用戶，可以說有點蠢

所以經過研究，發現了一種解決辦法（跳過自己下載好了再傳輸的尷尬，直接將請求到的數據返回給用戶）

from werkzeug._compat import wsgi_encoding_dance

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

    # 首先定義一個生成器，每次讀取512個字節
    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