使用 Amazon S3 觸發器建立縮圖

AGopher發表於2021-12-18

S3觸發器

使用 Amazon S3 觸發器建立縮圖

環境

centos （注意，必須是Linux環境)

node12.x

安裝教程

curl -sL https://rpm.nodesource.com/setup_12.x | sudo bash -

yum install -y nodejs yum install -y nodejs

參考文件：https://blog.csdn.net/Z_Z_W_/article/details/104988833

教程

\1. 建立一個名為lambda-s3資料夾

\2. 建立index.js檔案，儲存該內容如下，由程式碼可以看出，桶都是我們手動建立的，並不是程式碼幫我們建的

// dependencies const AWS = require('aws-sdk'); const util = require('util'); const sharp = require('sharp'); // get reference to S3 client const s3 = new AWS.S3(); exports.handler = async (event, context, callback) => {   // Read options from the event parameter.  console.log("Reading options from event:\n", util.inspect(event, {depth: 5}));  const srcBucket = event.Records[0].s3.bucket.name;  // Object key may have spaces or unicode non-ASCII characters.  const srcKey    = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, " "));  const dstBucket = srcBucket + "-resized";  const dstKey    = "resized-" + srcKey;   // Infer the image type from the file suffix.  const typeMatch = srcKey.match(/\.([^.]*)$/);  if (!typeMatch) {      console.log("Could not determine the image type.");      return;  }   // Check that the image type is supported    const imageType = typeMatch[1].toLowerCase();  if (imageType != "jpg" && imageType != "png") {      console.log(`Unsupported image type: ${imageType}`);      return;  }   // Download the image from the S3 source bucket.    try {      const params = {          Bucket: srcBucket,          Key: srcKey      };      var origimage = await s3.getObject(params).promise();   } catch (error) {      console.log(error);      return;  }     // set thumbnail width. Resize will set the height automatically to maintain aspect ratio.  const width  = 200;   // Use the sharp module to resize the image and save in a buffer.  try {       var buffer = await sharp(origimage.Body).resize(width).toBuffer();            } catch (error) {      console.log(error);      return;  }    // Upload the thumbnail image to the destination bucket  try {      const destparams = {          Bucket: dstBucket,          Key: dstKey,          Body: buffer,          ContentType: "image"      };       const putResult = await s3.putObject(destparams).promise();         } catch (error) {      console.log(error);      return;  }         console.log('Successfully resized ' + srcBucket + '/' + srcKey +      ' and uploaded to ' + dstBucket + '/' + dstKey);  };

\3. 使用非root使用者在lambda-s3目錄下安裝sharp包，npm run sharp。注意：安裝sharp包對版本嚴格限制

參考文件：https://sharp.pixelplumbing.com/install

安裝好之後如下結構

\4. 在lambda下面打包成zip，將該zip檔案download下來，命令sz,然後把這個zip檔案上傳至aws lambda服務的 lambda函式

zip -r function.zip . ,該壓縮檔案我會放在最下面，負責人只需要知道原理就行，如果遇到這個需求，將該壓縮檔案下載下來就行，免去以上所有步驟

\5. 首先我們需要在s3建立一個源公開桶名為 meross-userfiles-mobilehub-1868304105，然後建立一個縮圖桶 meross-userfiles-mobilehub-1868304105-resized。key的路徑：如果你的key,都以public開頭，那麼對應縮圖桶的key路徑是以resized-public開頭，詳細請看以上js程式碼