how-to-resize-image-with-aws-lambda

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如何用AWS lambda改变图片尺寸

Resize Images on the Fly with Amazon S3, AWS Lambda, and Amazon API Gateway

创建并配置桶

  • 创建一个桶 ${your_bucket_name}

  • 配置 权限/存储桶策略

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    {
        "Version": "2012-10-17",
        "Id": "${your_policy_Id}",
        "Statement": [
            {
                "Sid": "${your_policy_statement_sid}",
                "Effect": "Allow",
                "Principal": "*",//${your_statement_principal},if you don't konw that,use '*' as default, delete this comments when you use it
                "Action": [
                    "s3:DeleteObject",
                    "s3:GetObject",
                    "s3:PutObject"
                ],
                "Resource": "arn:aws:s3:::${your_bucket_name}/*"
            }
        ]
    }

  • 启用 属性/静态网站托管, 索引文档填入index.html,将会用到静态网址 ${your_s3_static_hostname}

创建lamdba函数

  • 如果你想用lambda,应该先开通这个应用
  • 创建lamdba function,选择空白函数，下一步
  • 配置触发器，选择 API Gateway,安全性，选择打开，下一步
  • 名称 resize,运行语言 Node.js 6.10.0,代码输入种类 上传.zip
  • 环境变量 BUCKET is ${your_bucket_name},URL is ${your_s3_static_hostname}

  • 创建一个普通角色，下面是创建信息

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    {
      "Version": "2012-10-17",
      "Statement": [
        {
          "Effect": "Allow",
          "Action": [
            "logs:CreateLogGroup",
            "logs:CreateLogStream",
            "logs:PutLogEvents"
          ],
          "Resource": "arn:aws:logs:*:*:*"
        },
        {
          "Effect": "Allow",
          "Action": "s3:PutObject",
          "Resource": "arn:aws:s3:::${your_bucket_name}/*"    
        }
      ]
    }
    • 内存选择 1536，超时选择 10s,下一步，创建

    设置s3重定向

    • lambda.resize/触发器，复制这个触发器的主网址${your_trigger_hostname}
      //such as your_trigger_host = ‘xxxxxxxxx.execute-api.us-west-2.amazonaws.com’;
    • s3/${your_bucket_name}/属性/静态网站托管/重定向规则
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        <RoutingRules>
          <RoutingRule>
              <Condition>
                  <KeyPrefixEquals/>
                  <HttpErrorCodeReturnedEquals>404</HttpErrorCodeReturnedEquals>
              </Condition>
              <Redirect>
                  <Protocol>https</Protocol>
                  <HostName>${your_trigger_hostname}</HostName>
                  <ReplaceKeyPrefixWith>prod/${your_lambda_resize_name}?key=</ReplaceKeyPrefixWith>
                  <HttpRedirectCode>307</HttpRedirectCode>
              </Redirect>
          </RoutingRule>
      </RoutingRules>

测试

上传一张图片 test.jpg

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http://${your_s3_static_hostname}/300×300/test.jpg
http://${your_s3_static_hostname}/25×25/test.jpg
http://${your_s3_static_hostname}/500×500/test.jpg

完