Question

尝试从这个相对复杂的JSON对象返回字符串"image-2016-05-05+19%3A13%3A49.058890.jpg"：

{
  "Type": "Notification",
  "MessageId": "e3a008de-7053-530e-b2b4-4778704d30a0",
  "TopicArn": "arn:aws:sns:us-west-2:xxxx:xxxx",
  "Subject": "Amazon S3 Notification",
  "Message": "{\"Records\":[{\"eventVersion\":\"2.0\",\"eventSource\":\"aws:s3\",\"awsRegion\":\"us-west-2\",\"eventTime\":\"2016-05-06T02:13:50.030Z\",\"eventName\":\"ObjectCreated:Put\",\"userIdentity\":{\"principalId\":\"AWS:AIDAIZ6VOIJWE82389JSE\"},\"requestParameters\":{\"sourceIPAddress\":\"0.0.0.0\"},\"responseElements\":{\"x-amz-request-id\":\"F819FA912DBD16\",\"x-amz-id-2\":\"7oOWHPhWsgjBW6XSj8DiSj8Sj8801LKJn5NLRn8JmYsNxJXKWqlkjDFL092zHuWYZn7pIKcRwX6g=\"},\"s3\":{\"s3SchemaVersion\":\"1.0\",\"configurationId\":\"image-notification\",\"bucket\":{\"name\":\"project\",\"ownerIdentity\":{\"principalId\":\"A17D10FQZ\"},\"arn\":\"arn:aws:s3:::project\"},\"object\":{\"key\":\"image-2016-05-05+19%3A13%3A49.058890.jpg\",\"size\":54098,\"eTag\":\"fbc4bakjf8asdj8f890ece3474c55974927c\",\"sequencer\":\"00572LKJDF389238CA7B04BD\"}}}]}",
  "Timestamp": "2016-05-06T02:13:50.126Z",
  "SignatureVersion": "1",
  "Signature": "Lao5PoEchryYf1slxxxlyI0GB2Xrv03VFC+4JVlji0y1El+rQGL837PYRHdj2m/dGD9/ynJxPhIBWcoJxX4D7MBsNqaZXilqJtjp+t8Rku0avErgWQVQG+rjZcdVbSU12DI/Ku0v9LhYg2/Js+ofYGPZH9U4C+Jfup5wjgHXah4BGNmF3TO+oq08Y56edhMxV25URDcU+z5aaVW2sK2tlnynSNzLuAF5TlKuuLmYr3Buci83FkU46l6Bz/ENba1BlGGqT8P+ljdf9092z+iP42T9qUzj1HL9p9SjEDIam/03n1039JS01gbPpgdo6/2Z6kZK3LvrVRBzI0voFitLg==",
  "SigningCertURL": "https://sns.us-west-2.amazonaws.com/SimpleNotificationService-bbxxx750dd426323fafd95ee9390147a5624348ee.pem",
  "UnsubscribeURL": "https://sns.us-west-2.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-west-2:332531341234:xxxx:0e43fsSDF40e-d4a7-46c0-95ab-4fd11739267b"
}

无需执行此操作：

@key = JSON.parse(@request[:Message])["Records"][0]["s3"]["object"]["key"]

有没有办法解析和搜索这个JSON对象，通过提供像“image”这样的关键字来返回上述字符串？

Answer 1

您可以使用hashie deepLocate

request = JSON.parse(@request)
request.extend(Hashie::Extensions::DeepLocate)
request.deep_locate -> (key, value, object) { key == :key && value.include?("image") }

#=> { :key => "image-2016-05-05+19%3A13%3A49.058890.jpg" }

除了使用值进行搜索之外，如果您知道密钥，则可以执行此操作以查找该密钥的深层嵌套值。

def nested_hash_value(obj,key)
  if obj.respond_to?(:key?) && obj.key?(key)
    obj[key]
  elsif obj.respond_to?(:each)
    r = nil
    obj.find{ |*a| r=nested_hash_value(a.last,key) }
    r
  end
end


p nested_hash_value(JSON.parse(@request),:key)
#=> image-2016-05-05+19%3A13%3A49.058890.jpg

使用Ruby搜索关键字的JSON对象

1 个答案: