python - 在浏览器中将 PUT 上传到 S3 时忽略内容类型？

Question

在我的 django 项目上(几乎)成功地从浏览器设置了 s3 上传后，我遇到了最后一个我似乎无法弄清楚的障碍。在创建签名以将某些内容上传到 s3 时，似乎没有任何方法可以忽略设置内容类型。

删除内容类型会有所帮助的原因是，在 safari 和 chrome 中，一些具有流行扩展名的文件(甚至 .zip 也不起作用)会给我一个“我们计算的请求签名与您提供的签名。请检查您的 key 和签名方法”，因为浏览器无法识别我认为的 mime 类型(至少每当我打印出来并且出现错误时，它都是空白的)。

这是我遵循的指南:https://devcenter.heroku.com/articles/s3-upload-python ，除非它无法确定 mime 类型，否则效果很好。这也是我稍微修改过的代码的副本:

    import base64
    from hashlib import sha1
    import hmac
    AWS_ACCESS_KEY = 'X'
    AWS_SECRET_KEY = 'XX'
    S3_BUCKET = 'XX/X/X'

    object_name =  urllib.quote_plus(request.GET['s3_object_name'])
    print "object_name: ", object_name.lower()
    mime_type = request.GET['s3_object_type']
    #on some files this is blank and thats the ones that give me 403 errors from s3
    print "mime Type: ", mime_type


    expires = int(time.time()+15)
    amz_headers = "x-amz-acl:public-read"
    # Generate the PUT request that JavaScript will use:
    put_request = "PUT\n\n%s\n%d\n%s\n/%s/%s" % (mime_type, expires, amz_headers, S3_BUCKET, object_name)
    # Generate the signature with which the request can be signed:
    signature = base64.encodestring(hmac.new(AWS_SECRET_KEY, put_request, sha1).digest())
    # Remove surrounding whitespace and quote special characters:
    signature = urllib.quote_plus(signature.strip())

    # Build the URL of the file in anticipation of its imminent upload:
    url = 'https://%s.s3.amazonaws.com/media/attachments/%s' % ('S3_BUCKET', object_name)

    content = json.dumps({
        'signed_request': '%s?AWSAccessKeyId=%s&Expires=%d&Signature=%s' % (url, AWS_ACCESS_KEY, expires, signature),
        'url': url
    })
    print content

    # Return the signed request and the anticipated URL back to the browser in JSON format:
    return HttpResponse(content, mimetype='text/plain; charset=x-user-defined')

Answer 1

基本上这个问题可以归因于以下事实:在指南提供的 s3_upload.js 中，读取 file.type 不正确，因此我修改了这部分代码

    object_name =  urllib.quote_plus(request.GET['s3_object_name'])
    print "object_name: ", object_name.lower()
    mime_type = request.GET['s3_object_type']
    #on some files this is blank and thats the ones that give me 403 errors from s3
    print "mime Type: ", mime_type

到

    mime_type = request.GET['s3_object_type']
    print "mime Type: ", mime_type
    mtype,encoding = mimetypes.guess_type(object_name)
    print "guessed mime type", mtype
    mime_type = mtype

然后将内容更改为

content = json.dumps({
        'signed_request': '%s?AWSAccessKeyId=%s&Expires=%d&Signature=%s' % (url, AWS_ACCESS_KEY, expires, signature),
        'url': url,
        'mime_type' : mime_type
    })

将其传递回 JavaScript 脚本。从那里我只是修改了脚本以在执行 put 时使用我的 mime_type 作为内容类型 header ，而不是它一直在执行的操作(使用 file.type)