API Sign: Change the S3 Provider into a signer

mod/provider/_provider.js

@@ -1,5 +1,8 @@
 /**
 @module /provider
+
+@description
+Functions for handling 3rd party service provider requests
 */
 
 const file = require('./file')
@@ -8,19 +11,39 @@ const cloudfront = require('./cloudfront')
 
 const s3 = require('./s3')
 
-module.exports = async (req, res) => {
+/**
+@function provider
+@async
+
+@description
+The provider method looks up a provider module method matching the provider request parameter and passes the req/res objects as argument to the matched method.
+
+The response from the method is returned with the HTTP response.
+
+@param {Object} req HTTP request.
+@param {Object} res HTTP response.
+@param {Object} req.params Request parameter.
+@param {string} params.signer Provider module to handle the request.
+
+@returns {Promise} The promise resolves into the response from the provider modules method.
+*/
+module.exports = async function provider(req, res){
 
   const provider = {
     cloudfront,
     file,
-    s3
+    s3: {deprecated: true, fn: s3}
+  }
+
+  if (provider[req.params.provider]?.deprecated){
+    return await provider[req.params.provider].fn(req, res)
   }
 
   if (!Object.hasOwn(provider, req.params.provider)) {
     return res.send(`Failed to validate 'provider' param.`)
   }
 
-  const response = await provider[req.params.provider](req)
+  const response = await provider[req.params.provider](req, res)
 
   req.params.content_type && res.setHeader('content-type', req.params.content_type)
 

mod/provider/s3.js

@@ -1,102 +1,44 @@
-/**
-@module /provider/s3
-*/
-
-const {
-  S3Client,
-  PutObjectCommand,
-  GetObjectCommand,
-  DeleteObjectCommand,
-  ListObjectsCommand
-} = require('@aws-sdk/client-s3');
-
-const { getSignedUrl } = require('@aws-sdk/s3-request-presigner');
-
-module.exports = async (req, res) => {
-
-  const credentials = Object.fromEntries(new URLSearchParams(process.env.AWS_S3_CLIENT))
-
-  const s3Client = new S3Client({
-    credentials,
-    region: req.params.region
-  })
-
-
-  const commands = {
-    get,
-    put,
-    trash,
-    list
-  }
-
-  if (!Object.hasOwn(commands, req.params.command)) {
-    return res.status(400).send(`S3 command validation failed.`)
-  }
-
-  return commands[req.params.command](s3Client, req)
-}
-
-async function trash(s3Client, req) {
-
-  const command = new DeleteObjectCommand({
-    Key: req.params.key,
-    Bucket: req.params.bucket
-  })
-
-  return s3Client.send(command);
-}
-
-async function get(s3Client, req) {
-
-  try {
-
-    const command = new GetObjectCommand({
-      Key: req.params.key,
-      Bucket: req.params.bucket
-    })
-
-    const signedURL = await getSignedUrl(s3Client, command, {
-      expiresIn: 3600,
-    });
-
-    return JSON.stringify(signedURL);
-
-  } catch (err) {
-    console.error(err)
-  }
-}
-
-async function put(s3Client, req) {
-
-  try {
-
-    const command = new PutObjectCommand({
-      Key: req.params.key,
-      Bucket: req.params.bucket,
-      Region: req.params.region
-    });
-
-    const signedURL = await getSignedUrl(s3Client, command, {
-      expiresIn: 3600,
-    });
-
-    return JSON.stringify(signedURL);
-
-  } catch (err) {
-    console.error(err)
-  }
-}
-
-async function list(s3Client, req) {
-
-  try {
-
-    const command = new ListObjectsCommand({ Bucket: req.params.bucket })
-    const response = await s3Client.send(command);
-
-    return response
-
-  } catch (err) {
-    console.error(err)
-  }
+/**
+@module /provider/s3
+@deprecated
+
+@description
+Provides a way to call get, put, trash and list. Directly interfaces with s3
+
+This module has been deprecated and replaced with {@link module:/sign/s3~s3}
+*/
+
+/**
+@function s3
+@async
+
+@description
+The s3 provider method will redirect requests to the signer.
+
+Provides methods for list, get, trash and put
+
+@param {Object} req HTTP request.
+@param {Object} res HTTP response.
+@param {Object} req.params Request parameter.
+
+@returns {Request} A redirect to the s3 signer.
+**/
+module.exports = async function s3(req, res) {
+
+    const commands = {
+      get,
+      put,
+      trash,
+      list
+    }
+
+    if (!Object.hasOwn(commands, req.params.command)) {
+      return res.status(400).send(`S3 command validation failed.`)
+    }
+
+    const paramString = Object.keys(req.params).filter(param => ['command','bucket','key','region'].includes(param)).map(param => `${param}=${req.params[param]}`).join('&')
+
+    res.setHeader('location', `${process.env.DIR}/api/sign/s3?${paramString}`)
+
+    return res.status(301).send()
 }

mod/sign/_sign.js

@@ -9,9 +9,11 @@ The sign module provides access to different request signer methods.
 */
 
 const cloudinary = require('./cloudinary')
+const s3 = require('./s3')
 
 const signerModules = {
-  cloudinary
+  cloudinary,
+  s3
 }
 
 /**
@@ -32,8 +34,8 @@ The response from the method is returned with the HTTP response.
 */
 module.exports = async function signer(req, res) {
 
-  if (!Object.hasOwn(signerModules, req.params.signer)) {
-    return res.send(`Failed to validate 'provider' param.`)
+  if (!Object.hasOwn(signerModules, req.params.signer) || !signerModules[req.params.signer]) {
+    return res.send(`Failed to validate 'sign' param.`)
   }
 
   const response = await signerModules[req.params.signer](req, res)

mod/sign/s3.js

@@ -0,0 +1,149 @@
+/**
+@module /sign/s3
+@requires aws-sdk/client-s3
+@requires aws-sdk/s3-request-presigner
+Signs requests to S3. Provides functions for get, list, delete and put to S3. 
+*/
+
+//The S3 packages are optional. 
+//Need a temporary assignment to determine if they are available.
+let
+  S3Client,
+  PutObjectCommand,
+  GetObjectCommand,
+  DeleteObjectCommand,
+  ListObjectsCommand,
+  getSignedUrl;
+
+//Check for credentials 
+if (!process.env?.AWS_S3_CLIENT) {
+  console.log('S3 Sign: Missing credentials from env: AWS_S3_CLIENT')
+  module.exports = null
+}
+else {
+
+  //Attempt import if credentials are found
+  try {
+
+    //Assign constructors and functions from the sdks.
+    const clientSDK = require('@aws-sdk/client-s3');
+    getSignedUrl = require('@aws-sdk/s3-request-presigner').getSignedUrl;
+
+    S3Client = clientSDK.S3Client
+    PutObjectCommand = clientSDK.PutObjectCommand
+    GetObjectCommand = clientSDK.GetObjectCommand
+    DeleteObjectCommand = clientSDK.DeleteObjectCommand
+    ListObjectsCommand = clientSDK.ListObjectsCommand
+
+    //Export the function .
+    module.exports = s3
+  }
+  catch (err) {
+
+    //The module has not been installed.
+    if (err.code === 'MODULE_NOT_FOUND') {
+      console.log('AWS-SDK is not available')
+      module.exports = null
+    }
+    else throw err
+  }
+}
+
+
+/**
+@function s3
+@async
+
+@description
+The s3 signer method signs requests for the s3 service.
+
+Provides methods for list, get, trash and put
+
+@param {Object} req HTTP request.
+@param {Object} res HTTP response.
+@param {Object} req.params Request parameter.
+@param {string} params.region
+@param {string} params.bucket
+@param {string} params.key
+@param {string} params.command
+
+@returns {Promise<String>} The signed url associated to the request params.
+**/
+async function s3(req, res) {
+
+  //Read credentials from an env key
+  const credentials = Object.fromEntries(new URLSearchParams(process.env.AWS_S3_CLIENT))
+
+  const s3Client = new S3Client({
+    credentials,
+    region: req.params.region
+  })
+
+  req.params.s3Client = s3Client
+
+  //Assign the corresponding function to the requested command
+  const commands = {
+    get: () => objectAction(req.params, GetObjectCommand),
+    trash: () => objectAction(req.params, DeleteObjectCommand),
+    put: () => objectAction(req.params, PutObjectCommand),
+    list: () => objectAction(req.params, ListObjectsCommand)
+  }
+
+  if (!Object.hasOwn(commands, req.params.command)) {
+    return res.status(400).send(`S3 command validation failed.`)
+  }
+
+  return commands[req.params.command]()
+}
+
+/**
+@function objectAction
+@async
+
+@description
+Generates the signed url for the command and parameters specified from the request
+
+@param {Function} objectCommand The S3 function to be carried out.
+@param {Object} reqParams Request parameters.
+@property {string} reqParams.region
+@property {string} reqParams.bucket
+@property {string} reqParams.key
+@property {string} reqParams.command
+
+@returns {String} The signed url associated to the request params.
+**/
+async function objectAction(reqParams, objectCommand) {
+
+  //The parameters required per action for S3
+  //S3 Parameters are capitalised
+  const actionParams = {
+    get: { 'key': 'Key', 'bucket': 'Bucket' },
+    list: { 'bucket': 'Bucket' },
+    put: { 'key': 'Key', 'bucket': 'Bucket', 'region': 'Region' },
+    trash: { 'key': 'Key', 'bucket': 'Bucket' }
+  }
+
+  try {
+
+    //Transfrom our keys into aws key names
+    const commandParams = Object.keys(reqParams)
+      .filter(key => Object.keys(actionParams[reqParams.command]).includes(key))
+      .reduce((acc, key) => ({
+        ...acc,
+        ...{ [actionParams[reqParams.command][key]]: reqParams[key] }
+      }),
+        {}
+      )
+
+    const command = new objectCommand(commandParams)
+
+    const signedURL = await getSignedUrl(reqParams.s3Client, command, {
+      expiresIn: 3600,
+    });
+
+    return JSON.stringify(signedURL);
+
+  } catch (err) {
+    console.error(err)
+  }
+}

package.json

@@ -20,10 +20,12 @@
     "test-docs": "jsdoc --configure jsdoc_test.json --verbose"
   },
   "license": "MIT",
-  "dependencies": {
+  "optionalDependencies": {
     "@aws-sdk/client-s3": "^3.621.0",
+    "@aws-sdk/s3-request-presigner": "^3.621.0"
+  },
+  "dependencies": {
     "@aws-sdk/cloudfront-signer": "^3.621.0",
-    "@aws-sdk/s3-request-presigner": "^3.621.0",
     "jsonwebtoken": "^9.0.2",
     "nodemailer": "^6.9.7",
     "pg": "^8.7.3",